widget.cpp

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/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */
 
#include "stdafx.h"
#include "company_func.h"
#include "window_gui.h"
#include "viewport_func.h"
#include "zoom_func.h"
#include "strings_func.h"
#include "transparency.h"
#include "core/geometry_func.hpp"
#include "settings_type.h"
#include "querystring_gui.h"
 
#include "table/sprites.h"
#include "table/strings.h"
#include "table/string_colours.h"
 
#include "safeguards.h"
 
static Point HandleScrollbarHittest(const Scrollbar *sb, int top, int bottom, bool horizontal)
{
  /* Base for reversion */
  int rev_base = top + bottom;
  int button_size;
  if (horizontal) {
    button_size = NWidgetScrollbar::GetHorizontalDimension().width;
  } else {
    button_size = NWidgetScrollbar::GetVerticalDimension().height;
  }
  top += button_size;    // top    points to just below the up-button
  bottom -= button_size; // bottom points to top of the down-button
 
  int height = (bottom - top);
  int pos = sb->GetPosition();
  int count = sb->GetCount();
  int cap = sb->GetCapacity();
 
  if (count != 0) top += height * pos / count;
 
  if (cap > count) cap = count;
  if (count != 0) bottom -= (count - pos - cap) * height / count;
 
  Point pt;
  if (horizontal && _current_text_dir == TD_RTL) {
    pt.x = rev_base - bottom;
    pt.y = rev_base - top;
  } else {
    pt.x = top;
    pt.y = bottom;
  }
  return pt;
}
 
static void ScrollbarClickPositioning(Window *w, NWidgetScrollbar *sb, int x, int y, int mi, int ma)
{
  int pos;
  int button_size;
  bool rtl = false;
 
  if (sb->type == NWID_HSCROLLBAR) {
    pos = x;
    rtl = _current_text_dir == TD_RTL;
    button_size = NWidgetScrollbar::GetHorizontalDimension().width;
  } else {
    pos = y;
    button_size = NWidgetScrollbar::GetVerticalDimension().height;
  }
  if (pos < mi + button_size) {
    /* Pressing the upper button? */
    SetBit(sb->disp_flags, NDB_SCROLLBAR_UP);
    if (_scroller_click_timeout <= 1) {
      _scroller_click_timeout = 3;
      sb->UpdatePosition(rtl ? 1 : -1);
    }
    w->mouse_capture_widget = sb->index;
  } else if (pos >= ma - button_size) {
    /* Pressing the lower button? */
    SetBit(sb->disp_flags, NDB_SCROLLBAR_DOWN);
 
    if (_scroller_click_timeout <= 1) {
      _scroller_click_timeout = 3;
      sb->UpdatePosition(rtl ? -1 : 1);
    }
    w->mouse_capture_widget = sb->index;
  } else {
    Point pt = HandleScrollbarHittest(sb, mi, ma, sb->type == NWID_HSCROLLBAR);
 
    if (pos < pt.x) {
      sb->UpdatePosition(rtl ? 1 : -1, Scrollbar::SS_BIG);
    } else if (pos > pt.y) {
      sb->UpdatePosition(rtl ? -1 : 1, Scrollbar::SS_BIG);
    } else {
      _scrollbar_start_pos = pt.x - mi - button_size;
      _scrollbar_size = ma - mi - button_size * 2;
      w->mouse_capture_widget = sb->index;
      _cursorpos_drag_start = _cursor.pos;
    }
  }
 
  w->SetDirty();
}
 
void ScrollbarClickHandler(Window *w, NWidgetCore *nw, int x, int y)
{
  int mi, ma;
 
  if (nw->type == NWID_HSCROLLBAR) {
    mi = nw->pos_x;
    ma = nw->pos_x + nw->current_x;
  } else {
    mi = nw->pos_y;
    ma = nw->pos_y + nw->current_y;
  }
  NWidgetScrollbar *scrollbar = dynamic_cast<NWidgetScrollbar*>(nw);
  assert(scrollbar != nullptr);
  ScrollbarClickPositioning(w, scrollbar, x, y, mi, ma);
}
 
int GetWidgetFromPos(const Window *w, int x, int y)
{
  NWidgetCore *nw = w->nested_root->GetWidgetFromPos(x, y);
  return (nw != nullptr) ? nw->index : -1;
}
 
void DrawFrameRect(int left, int top, int right, int bottom, Colours colour, FrameFlags flags)
{
  assert(colour < COLOUR_END);
 
  uint dark         = _colour_gradient[colour][3];
  uint medium_dark  = _colour_gradient[colour][5];
  uint medium_light = _colour_gradient[colour][6];
  uint light        = _colour_gradient[colour][7];
 
  if (flags & FR_TRANSPARENT) {
    GfxFillRect(left, top, right, bottom, PALETTE_TO_TRANSPARENT, FILLRECT_RECOLOUR);
  } else {
    uint interior;
 
    if (flags & FR_LOWERED) {
      GfxFillRect(left,                 top,                left,                   bottom,                   dark);
      GfxFillRect(left + WD_BEVEL_LEFT, top,                right,                  top,                      dark);
      GfxFillRect(right,                top + WD_BEVEL_TOP, right,                  bottom - WD_BEVEL_BOTTOM, light);
      GfxFillRect(left + WD_BEVEL_LEFT, bottom,             right,                  bottom,                   light);
      interior = (flags & FR_DARKENED ? medium_dark : medium_light);
    } else {
      GfxFillRect(left,                 top,                left,                   bottom - WD_BEVEL_BOTTOM, light);
      GfxFillRect(left + WD_BEVEL_LEFT, top,                right - WD_BEVEL_RIGHT, top,                      light);
      GfxFillRect(right,                top,                right,                  bottom - WD_BEVEL_BOTTOM, dark);
      GfxFillRect(left,                 bottom,             right,                  bottom,                   dark);
      interior = medium_dark;
    }
    if (!(flags & FR_BORDERONLY)) {
      GfxFillRect(left + WD_BEVEL_LEFT, top + WD_BEVEL_TOP, right - WD_BEVEL_RIGHT, bottom - WD_BEVEL_BOTTOM, interior);
    }
  }
}
 
static inline void DrawImageButtons(const Rect &r, WidgetType type, Colours colour, bool clicked, SpriteID img)
{
  assert(img != 0);
  DrawFrameRect(r.left, r.top, r.right, r.bottom, colour, (clicked) ? FR_LOWERED : FR_NONE);
 
  if ((type & WWT_MASK) == WWT_IMGBTN_2 && clicked) img++; // Show different image when clicked for #WWT_IMGBTN_2.
  Dimension d = GetSpriteSize(img);
  DrawSprite(img, PAL_NONE, CenterBounds(r.left, r.right, d.width) + clicked, CenterBounds(r.top, r.bottom, d.height) + clicked);
}
 
static inline void DrawLabel(const Rect &r, WidgetType type, bool clicked, StringID str)
{
  if (str == STR_NULL) return;
  if ((type & WWT_MASK) == WWT_TEXTBTN_2 && clicked) str++;
  Dimension d = GetStringBoundingBox(str);
  int offset = std::max(0, ((int)(r.bottom - r.top + 1) - (int)d.height) / 2); // Offset for rendering the text vertically centered
  DrawString(r.left + clicked, r.right + clicked, r.top + offset + clicked, str, TC_FROMSTRING, SA_HOR_CENTER);
}
 
static inline void DrawText(const Rect &r, TextColour colour, StringID str)
{
  Dimension d = GetStringBoundingBox(str);
  int offset = std::max(0, ((int)(r.bottom - r.top + 1) - (int)d.height) / 2); // Offset for rendering the text vertically centered
  if (str != STR_NULL) DrawString(r.left, r.right, r.top + offset, str, colour);
}
 
static inline void DrawInset(const Rect &r, Colours colour, StringID str)
{
  DrawFrameRect(r.left, r.top, r.right, r.bottom, colour, FR_LOWERED | FR_DARKENED);
  if (str != STR_NULL) DrawString(r.left + WD_INSET_LEFT, r.right - WD_INSET_RIGHT, r.top + WD_INSET_TOP, str);
}
 
static inline void DrawMatrix(const Rect &r, Colours colour, bool clicked, uint16 data, uint resize_x, uint resize_y)
{
  DrawFrameRect(r.left, r.top, r.right, r.bottom, colour, (clicked) ? FR_LOWERED : FR_NONE);
 
  int num_columns = GB(data, MAT_COL_START, MAT_COL_BITS);  // Lower 8 bits of the widget data: Number of columns in the matrix.
  int column_width; // Width of a single column in the matrix.
  if (num_columns == 0) {
    column_width = resize_x;
    num_columns = (r.right - r.left + 1) / column_width;
  } else {
    column_width = (r.right - r.left + 1) / num_columns;
  }
 
  int num_rows = GB(data, MAT_ROW_START, MAT_ROW_BITS); // Upper 8 bits of the widget data: Number of rows in the matrix.
  int row_height; // Height of a single row in the matrix.
  if (num_rows == 0) {
    row_height = resize_y;
    num_rows = (r.bottom - r.top + 1) / row_height;
  } else {
    row_height = (r.bottom - r.top + 1) / num_rows;
  }
 
  int col = _colour_gradient[colour & 0xF][6];
 
  int x = r.left;
  for (int ctr = num_columns; ctr > 1; ctr--) {
    x += column_width;
    GfxFillRect(x, r.top + 1, x, r.bottom - 1, col);
  }
 
  x = r.top;
  for (int ctr = num_rows; ctr > 1; ctr--) {
    x += row_height;
    GfxFillRect(r.left + 1, x, r.right - 1, x, col);
  }
 
  col = _colour_gradient[colour & 0xF][4];
 
  x = r.left - 1;
  for (int ctr = num_columns; ctr > 1; ctr--) {
    x += column_width;
    GfxFillRect(x, r.top + 1, x, r.bottom - 1, col);
  }
 
  x = r.top - 1;
  for (int ctr = num_rows; ctr > 1; ctr--) {
    x += row_height;
    GfxFillRect(r.left + 1, x, r.right - 1, x, col);
  }
}
 
static inline void DrawVerticalScrollbar(const Rect &r, Colours colour, bool up_clicked, bool bar_dragged, bool down_clicked, const Scrollbar *scrollbar)
{
  int centre = (r.right - r.left) / 2;
  int height = NWidgetScrollbar::GetVerticalDimension().height;
 
  /* draw up/down buttons */
  DrawFrameRect(r.left, r.top, r.right, r.top + height - 1, colour, (up_clicked) ? FR_LOWERED : FR_NONE);
  DrawSprite(SPR_ARROW_UP, PAL_NONE, r.left + 1 + up_clicked, r.top + 1 + up_clicked);
 
  DrawFrameRect(r.left, r.bottom - (height - 1), r.right, r.bottom, colour, (down_clicked) ? FR_LOWERED : FR_NONE);
  DrawSprite(SPR_ARROW_DOWN, PAL_NONE, r.left + 1 + down_clicked, r.bottom - (height - 2) + down_clicked);
 
  int c1 = _colour_gradient[colour & 0xF][3];
  int c2 = _colour_gradient[colour & 0xF][7];
 
  /* draw "shaded" background */
  GfxFillRect(r.left, r.top + height, r.right, r.bottom - height, c2);
  GfxFillRect(r.left, r.top + height, r.right, r.bottom - height, c1, FILLRECT_CHECKER);
 
  /* draw shaded lines */
  GfxFillRect(r.left + centre - 3, r.top + height, r.left + centre - 3, r.bottom - height, c1);
  GfxFillRect(r.left + centre - 2, r.top + height, r.left + centre - 2, r.bottom - height, c2);
  GfxFillRect(r.left + centre + 2, r.top + height, r.left + centre + 2, r.bottom - height, c1);
  GfxFillRect(r.left + centre + 3, r.top + height, r.left + centre + 3, r.bottom - height, c2);
 
  Point pt = HandleScrollbarHittest(scrollbar, r.top, r.bottom, false);
  DrawFrameRect(r.left, pt.x, r.right, pt.y, colour, bar_dragged ? FR_LOWERED : FR_NONE);
}
 
static inline void DrawHorizontalScrollbar(const Rect &r, Colours colour, bool left_clicked, bool bar_dragged, bool right_clicked, const Scrollbar *scrollbar)
{
  int centre = (r.bottom - r.top) / 2;
  int width = NWidgetScrollbar::GetHorizontalDimension().width;
 
  DrawFrameRect(r.left, r.top, r.left + width - 1, r.bottom, colour, left_clicked ? FR_LOWERED : FR_NONE);
  DrawSprite(SPR_ARROW_LEFT, PAL_NONE, r.left + 1 + left_clicked, r.top + 1 + left_clicked);
 
  DrawFrameRect(r.right - (width - 1), r.top, r.right, r.bottom, colour, right_clicked ? FR_LOWERED : FR_NONE);
  DrawSprite(SPR_ARROW_RIGHT, PAL_NONE, r.right - (width - 2) + right_clicked, r.top + 1 + right_clicked);
 
  int c1 = _colour_gradient[colour & 0xF][3];
  int c2 = _colour_gradient[colour & 0xF][7];
 
  /* draw "shaded" background */
  GfxFillRect(r.left + width, r.top, r.right - width, r.bottom, c2);
  GfxFillRect(r.left + width, r.top, r.right - width, r.bottom, c1, FILLRECT_CHECKER);
 
  /* draw shaded lines */
  GfxFillRect(r.left + width, r.top + centre - 3, r.right - width, r.top + centre - 3, c1);
  GfxFillRect(r.left + width, r.top + centre - 2, r.right - width, r.top + centre - 2, c2);
  GfxFillRect(r.left + width, r.top + centre + 2, r.right - width, r.top + centre + 2, c1);
  GfxFillRect(r.left + width, r.top + centre + 3, r.right - width, r.top + centre + 3, c2);
 
  /* draw actual scrollbar */
  Point pt = HandleScrollbarHittest(scrollbar, r.left, r.right, true);
  DrawFrameRect(pt.x, r.top, pt.y, r.bottom, colour, bar_dragged ? FR_LOWERED : FR_NONE);
}
 
static inline void DrawFrame(const Rect &r, Colours colour, StringID str)
{
  int x2 = r.left; // by default the left side is the left side of the widget
 
  if (str != STR_NULL) x2 = DrawString(r.left + WD_FRAMETEXT_LEFT, r.right - WD_FRAMETEXT_RIGHT, r.top, str);
 
  int c1 = _colour_gradient[colour][3];
  int c2 = _colour_gradient[colour][7];
 
  /* If the frame has text, adjust the top bar to fit half-way through */
  int dy1 = 4;
  if (str != STR_NULL) dy1 = FONT_HEIGHT_NORMAL / 2 - 1;
  int dy2 = dy1 + 1;
 
  if (_current_text_dir == TD_LTR) {
    /* Line from upper left corner to start of text */
    GfxFillRect(r.left, r.top + dy1, r.left + 4, r.top + dy1, c1);
    GfxFillRect(r.left + 1, r.top + dy2, r.left + 4, r.top + dy2, c2);
 
    /* Line from end of text to upper right corner */
    GfxFillRect(x2, r.top + dy1, r.right - 1, r.top + dy1, c1);
    GfxFillRect(x2, r.top + dy2, r.right - 2, r.top + dy2, c2);
  } else {
    /* Line from upper left corner to start of text */
    GfxFillRect(r.left, r.top + dy1, x2 - 2, r.top + dy1, c1);
    GfxFillRect(r.left + 1, r.top + dy2, x2 - 2, r.top + dy2, c2);
 
    /* Line from end of text to upper right corner */
    GfxFillRect(r.right - 5, r.top + dy1, r.right - 1, r.top + dy1, c1);
    GfxFillRect(r.right - 5, r.top + dy2, r.right - 2, r.top + dy2, c2);
  }
 
  /* Line from upper left corner to bottom left corner */
  GfxFillRect(r.left, r.top + dy2, r.left, r.bottom - 1, c1);
  GfxFillRect(r.left + 1, r.top + dy2 + 1, r.left + 1, r.bottom - 2, c2);
 
  /* Line from upper right corner to bottom right corner */
  GfxFillRect(r.right - 1, r.top + dy2, r.right - 1, r.bottom - 2, c1);
  GfxFillRect(r.right, r.top + dy1, r.right, r.bottom - 1, c2);
 
  GfxFillRect(r.left + 1, r.bottom - 1, r.right - 1, r.bottom - 1, c1);
  GfxFillRect(r.left, r.bottom, r.right, r.bottom, c2);
}
 
static inline void DrawShadeBox(const Rect &r, Colours colour, bool clicked)
{
  DrawImageButtons(r, WWT_SHADEBOX, colour, clicked, clicked ? SPR_WINDOW_SHADE: SPR_WINDOW_UNSHADE);
}
 
static inline void DrawStickyBox(const Rect &r, Colours colour, bool clicked)
{
  DrawImageButtons(r, WWT_STICKYBOX, colour, clicked, clicked ? SPR_PIN_UP : SPR_PIN_DOWN);
}
 
static inline void DrawDefSizeBox(const Rect &r, Colours colour, bool clicked)
{
  DrawImageButtons(r, WWT_DEFSIZEBOX, colour, clicked, SPR_WINDOW_DEFSIZE);
}
 
static inline void DrawDebugBox(const Rect &r, Colours colour, bool clicked)
{
  DrawImageButtons(r, WWT_DEBUGBOX, colour, clicked, SPR_WINDOW_DEBUG);
}
 
static inline void DrawResizeBox(const Rect &r, Colours colour, bool at_left, bool clicked)
{
  DrawFrameRect(r.left, r.top, r.right, r.bottom, colour, (clicked) ? FR_LOWERED : FR_NONE);
  if (at_left) {
    Dimension d = GetSpriteSize(SPR_WINDOW_RESIZE_LEFT);
    DrawSprite(SPR_WINDOW_RESIZE_LEFT, PAL_NONE, r.left + WD_RESIZEBOX_RIGHT + clicked,
         r.bottom + 1 - WD_RESIZEBOX_BOTTOM - d.height + clicked);
  } else {
    Dimension d = GetSpriteSize(SPR_WINDOW_RESIZE_RIGHT);
    DrawSprite(SPR_WINDOW_RESIZE_RIGHT, PAL_NONE, r.right + 1 - WD_RESIZEBOX_RIGHT - d.width + clicked,
         r.bottom + 1 - WD_RESIZEBOX_BOTTOM - d.height + clicked);
  }
}
 
static inline void DrawCloseBox(const Rect &r, Colours colour)
{
  if (colour != COLOUR_WHITE) DrawFrameRect(r.left, r.top, r.right, r.bottom, colour, FR_NONE);
  Dimension d = GetSpriteSize(SPR_CLOSEBOX);
  int s = UnScaleGUI(1); /* Offset to account for shadow of SPR_CLOSEBOX */
  DrawSprite(SPR_CLOSEBOX, (colour != COLOUR_WHITE ? TC_BLACK : TC_SILVER) | (1 << PALETTE_TEXT_RECOLOUR), CenterBounds(r.left, r.right, d.width - s), CenterBounds(r.top, r.bottom, d.height - s));
}
 
void DrawCaption(const Rect &r, Colours colour, Owner owner, StringID str)
{
  bool company_owned = owner < MAX_COMPANIES;
 
  DrawFrameRect(r.left, r.top, r.right, r.bottom, colour, FR_BORDERONLY);
  DrawFrameRect(r.left + 1, r.top + 1, r.right - 1, r.bottom - 1, colour, company_owned ? FR_LOWERED | FR_DARKENED | FR_BORDERONLY : FR_LOWERED | FR_DARKENED);
 
  if (company_owned) {
    GfxFillRect(r.left + 2, r.top + 2, r.right - 2, r.bottom - 2, _colour_gradient[_company_colours[owner]][4]);
  }
 
  if (str != STR_NULL) {
    Dimension d = GetStringBoundingBox(str);
    int offset = std::max(0, ((int)(r.bottom - r.top + 1) - (int)d.height) / 2); // Offset for rendering the text vertically centered
    DrawString(r.left + WD_CAPTIONTEXT_LEFT, r.right - WD_CAPTIONTEXT_RIGHT, r.top + offset, str, TC_FROMSTRING, SA_HOR_CENTER);
  }
}
 
static inline void DrawButtonDropdown(const Rect &r, Colours colour, bool clicked_button, bool clicked_dropdown, StringID str)
{
  int text_offset = std::max(0, ((int)(r.bottom - r.top + 1) - FONT_HEIGHT_NORMAL) / 2); // Offset for rendering the text vertically centered
 
  int dd_width  = NWidgetLeaf::dropdown_dimension.width;
  int dd_height = NWidgetLeaf::dropdown_dimension.height;
  int image_offset = std::max(0, ((int)(r.bottom - r.top + 1) - dd_height) / 2);
 
  if (_current_text_dir == TD_LTR) {
    DrawFrameRect(r.left, r.top, r.right - dd_width, r.bottom, colour, clicked_button ? FR_LOWERED : FR_NONE);
    DrawFrameRect(r.right + 1 - dd_width, r.top, r.right, r.bottom, colour, clicked_dropdown ? FR_LOWERED : FR_NONE);
    DrawSprite(SPR_ARROW_DOWN, PAL_NONE, r.right - (dd_width - 2) + clicked_dropdown, r.top + image_offset + clicked_dropdown);
    if (str != STR_NULL) DrawString(r.left + WD_DROPDOWNTEXT_LEFT + clicked_button, r.right - dd_width - WD_DROPDOWNTEXT_RIGHT + clicked_button, r.top + text_offset + clicked_button, str, TC_BLACK);
  } else {
    DrawFrameRect(r.left + dd_width, r.top, r.right, r.bottom, colour, clicked_button ? FR_LOWERED : FR_NONE);
    DrawFrameRect(r.left, r.top, r.left + dd_width - 1, r.bottom, colour, clicked_dropdown ? FR_LOWERED : FR_NONE);
    DrawSprite(SPR_ARROW_DOWN, PAL_NONE, r.left + 1 + clicked_dropdown, r.top + image_offset + clicked_dropdown);
    if (str != STR_NULL) DrawString(r.left + dd_width + WD_DROPDOWNTEXT_LEFT + clicked_button, r.right - WD_DROPDOWNTEXT_RIGHT + clicked_button, r.top + text_offset + clicked_button, str, TC_BLACK);
  }
}
 
static inline void DrawDropdown(const Rect &r, Colours colour, bool clicked, StringID str)
{
  DrawButtonDropdown(r, colour, false, clicked, str);
}
 
void Window::DrawWidgets() const
{
  this->nested_root->Draw(this);
 
  if (this->flags & WF_WHITE_BORDER) {
    DrawFrameRect(0, 0, this->width - 1, this->height - 1, COLOUR_WHITE, FR_BORDERONLY);
  }
 
  if (this->flags & WF_HIGHLIGHTED) {
    extern bool _window_highlight_colour;
    for (uint i = 0; i < this->nested_array_size; i++) {
      const NWidgetBase *widget = this->GetWidget<NWidgetBase>(i);
      if (widget == nullptr || !widget->IsHighlighted()) continue;
 
      int left = widget->pos_x;
      int top  = widget->pos_y;
      int right  = left + widget->current_x - 1;
      int bottom = top  + widget->current_y - 1;
 
      int colour = _string_colourmap[_window_highlight_colour ? widget->GetHighlightColour() : TC_WHITE];
 
      GfxFillRect(left,                 top,    left,                   bottom - WD_BEVEL_BOTTOM, colour);
      GfxFillRect(left + WD_BEVEL_LEFT, top,    right - WD_BEVEL_RIGHT, top,                      colour);
      GfxFillRect(right,                top,    right,                  bottom - WD_BEVEL_BOTTOM, colour);
      GfxFillRect(left,                 bottom, right,                  bottom,                   colour);
    }
  }
}
 
void Window::DrawSortButtonState(int widget, SortButtonState state) const
{
  if (state == SBS_OFF) return;
 
  assert(this->nested_array != nullptr);
  const NWidgetBase *nwid = this->GetWidget<NWidgetBase>(widget);
 
  /* Sort button uses the same sprites as vertical scrollbar */
  Dimension dim = NWidgetScrollbar::GetVerticalDimension();
  int offset = this->IsWidgetLowered(widget) ? 1 : 0;
  int x = offset + nwid->pos_x + (_current_text_dir == TD_LTR ? nwid->current_x - dim.width : 0);
  int y = offset + nwid->pos_y + (nwid->current_y - dim.height) / 2;
 
  DrawSprite(state == SBS_DOWN ? SPR_ARROW_DOWN : SPR_ARROW_UP, PAL_NONE, x, y);
}
 
int Window::SortButtonWidth()
{
  return NWidgetScrollbar::GetVerticalDimension().width + 1;
}
 
 
NWidgetBase::NWidgetBase(WidgetType tp) : ZeroedMemoryAllocator()
{
  this->type = tp;
}
 
/* ~NWidgetContainer() takes care of #next and #prev data members. */
 
void NWidgetBase::SetDirty(const Window *w) const
{
  int abs_left = w->left + this->pos_x;
  int abs_top = w->top + this->pos_y;
  AddDirtyBlock(abs_left, abs_top, abs_left + this->current_x, abs_top + this->current_y);
}
 
NWidgetBase *NWidgetBase::GetWidgetOfType(WidgetType tp)
{
  return (this->type == tp) ? this : nullptr;
}
 
NWidgetResizeBase::NWidgetResizeBase(WidgetType tp, uint fill_x, uint fill_y) : NWidgetBase(tp)
{
  this->fill_x = fill_x;
  this->fill_y = fill_y;
}
 
void NWidgetResizeBase::SetMinimalSize(uint min_x, uint min_y)
{
  this->min_x = std::max(this->min_x, min_x);
  this->min_y = std::max(this->min_y, min_y);
}
 
void NWidgetResizeBase::SetMinimalTextLines(uint8 min_lines, uint8 spacing, FontSize size)
{
  this->min_y = min_lines * GetCharacterHeight(size) + spacing;
}
 
void NWidgetResizeBase::SetFill(uint fill_x, uint fill_y)
{
  this->fill_x = fill_x;
  this->fill_y = fill_y;
}
 
void NWidgetResizeBase::SetResize(uint resize_x, uint resize_y)
{
  this->resize_x = resize_x;
  this->resize_y = resize_y;
}
 
void NWidgetResizeBase::AssignSizePosition(SizingType sizing, uint x, uint y, uint given_width, uint given_height, bool rtl)
{
  this->StoreSizePosition(sizing, x, y, given_width, given_height);
}
 
NWidgetCore::NWidgetCore(WidgetType tp, Colours colour, uint fill_x, uint fill_y, uint32 widget_data, StringID tool_tip) : NWidgetResizeBase(tp, fill_x, fill_y)
{
  this->colour = colour;
  this->index = -1;
  this->widget_data = widget_data;
  this->tool_tip = tool_tip;
  this->scrollbar_index = -1;
}
 
void NWidgetCore::SetIndex(int index)
{
  assert(index >= 0);
  this->index = index;
}
 
void NWidgetCore::SetDataTip(uint32 widget_data, StringID tool_tip)
{
  this->widget_data = widget_data;
  this->tool_tip = tool_tip;
}
 
void NWidgetCore::SetToolTip(StringID tool_tip)
{
  this->tool_tip = tool_tip;
}
 
void NWidgetCore::FillNestedArray(NWidgetBase **array, uint length)
{
  if (this->index >= 0 && (uint)(this->index) < length) array[this->index] = this;
}
 
NWidgetCore *NWidgetCore::GetWidgetFromPos(int x, int y)
{
  return (IsInsideBS(x, this->pos_x, this->current_x) && IsInsideBS(y, this->pos_y, this->current_y)) ? this : nullptr;
}
 
NWidgetContainer::NWidgetContainer(WidgetType tp) : NWidgetBase(tp)
{
  this->head = nullptr;
  this->tail = nullptr;
}
 
NWidgetContainer::~NWidgetContainer()
{
  while (this->head != nullptr) {
    NWidgetBase *wid = this->head->next;
    delete this->head;
    this->head = wid;
  }
  this->tail = nullptr;
}
 
NWidgetBase *NWidgetContainer::GetWidgetOfType(WidgetType tp)
{
  if (this->type == tp) return this;
  for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
    NWidgetBase *nwid = child_wid->GetWidgetOfType(tp);
    if (nwid != nullptr) return nwid;
  }
  return nullptr;
}
 
void NWidgetContainer::Add(NWidgetBase *wid)
{
  assert(wid->next == nullptr && wid->prev == nullptr);
 
  if (this->head == nullptr) {
    this->head = wid;
    this->tail = wid;
  } else {
    assert(this->tail != nullptr);
    assert(this->tail->next == nullptr);
 
    this->tail->next = wid;
    wid->prev = this->tail;
    this->tail = wid;
  }
}
 
void NWidgetContainer::FillNestedArray(NWidgetBase **array, uint length)
{
  for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
    child_wid->FillNestedArray(array, length);
  }
}
 
NWidgetStacked::NWidgetStacked() : NWidgetContainer(NWID_SELECTION)
{
  this->index = -1;
}
 
void NWidgetStacked::SetIndex(int index)
{
  this->index = index;
}
 
void NWidgetStacked::SetupSmallestSize(Window *w, bool init_array)
{
  if (this->index >= 0 && init_array) { // Fill w->nested_array[]
    assert(w->nested_array_size > (uint)this->index);
    w->nested_array[this->index] = this;
  }
 
  /* Zero size plane selected */
  if (this->shown_plane >= SZSP_BEGIN) {
    Dimension size    = {0, 0};
    Dimension padding = {0, 0};
    Dimension fill    = {(this->shown_plane == SZSP_HORIZONTAL), (this->shown_plane == SZSP_VERTICAL)};
    Dimension resize  = {(this->shown_plane == SZSP_HORIZONTAL), (this->shown_plane == SZSP_VERTICAL)};
    /* Here we're primarily interested in the value of resize */
    if (this->index >= 0) w->UpdateWidgetSize(this->index, &size, padding, &fill, &resize);
 
    this->smallest_x = size.width;
    this->smallest_y = size.height;
    this->fill_x = fill.width;
    this->fill_y = fill.height;
    this->resize_x = resize.width;
    this->resize_y = resize.height;
    return;
  }
 
  /* First sweep, recurse down and compute minimal size and filling. */
  this->smallest_x = 0;
  this->smallest_y = 0;
  this->fill_x = (this->head != nullptr) ? 1 : 0;
  this->fill_y = (this->head != nullptr) ? 1 : 0;
  this->resize_x = (this->head != nullptr) ? 1 : 0;
  this->resize_y = (this->head != nullptr) ? 1 : 0;
  for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
    child_wid->SetupSmallestSize(w, init_array);
 
    this->smallest_x = std::max(this->smallest_x, child_wid->smallest_x + child_wid->padding_left + child_wid->padding_right);
    this->smallest_y = std::max(this->smallest_y, child_wid->smallest_y + child_wid->padding_top + child_wid->padding_bottom);
    this->fill_x = LeastCommonMultiple(this->fill_x, child_wid->fill_x);
    this->fill_y = LeastCommonMultiple(this->fill_y, child_wid->fill_y);
    this->resize_x = LeastCommonMultiple(this->resize_x, child_wid->resize_x);
    this->resize_y = LeastCommonMultiple(this->resize_y, child_wid->resize_y);
  }
}
 
void NWidgetStacked::AssignSizePosition(SizingType sizing, uint x, uint y, uint given_width, uint given_height, bool rtl)
{
  assert(given_width >= this->smallest_x && given_height >= this->smallest_y);
  this->StoreSizePosition(sizing, x, y, given_width, given_height);
 
  if (this->shown_plane >= SZSP_BEGIN) return;
 
  for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
    uint hor_step = (sizing == ST_SMALLEST) ? 1 : child_wid->GetHorizontalStepSize(sizing);
    uint child_width = ComputeMaxSize(child_wid->smallest_x, given_width - child_wid->padding_left - child_wid->padding_right, hor_step);
    uint child_pos_x = (rtl ? child_wid->padding_right : child_wid->padding_left);
 
    uint vert_step = (sizing == ST_SMALLEST) ? 1 : child_wid->GetVerticalStepSize(sizing);
    uint child_height = ComputeMaxSize(child_wid->smallest_y, given_height - child_wid->padding_top - child_wid->padding_bottom, vert_step);
    uint child_pos_y = child_wid->padding_top;
 
    child_wid->AssignSizePosition(sizing, x + child_pos_x, y + child_pos_y, child_width, child_height, rtl);
  }
}
 
void NWidgetStacked::FillNestedArray(NWidgetBase **array, uint length)
{
  if (this->index >= 0 && (uint)(this->index) < length) array[this->index] = this;
  NWidgetContainer::FillNestedArray(array, length);
}
 
void NWidgetStacked::Draw(const Window *w)
{
  if (this->shown_plane >= SZSP_BEGIN) return;
 
  int plane = 0;
  for (NWidgetBase *child_wid = this->head; child_wid != nullptr; plane++, child_wid = child_wid->next) {
    if (plane == this->shown_plane) {
      child_wid->Draw(w);
      return;
    }
  }
 
  NOT_REACHED();
}
 
NWidgetCore *NWidgetStacked::GetWidgetFromPos(int x, int y)
{
  if (this->shown_plane >= SZSP_BEGIN) return nullptr;
 
  if (!IsInsideBS(x, this->pos_x, this->current_x) || !IsInsideBS(y, this->pos_y, this->current_y)) return nullptr;
  int plane = 0;
  for (NWidgetBase *child_wid = this->head; child_wid != nullptr; plane++, child_wid = child_wid->next) {
    if (plane == this->shown_plane) {
      return child_wid->GetWidgetFromPos(x, y);
    }
  }
  return nullptr;
}
 
void NWidgetStacked::SetDisplayedPlane(int plane)
{
  this->shown_plane = plane;
}
 
NWidgetPIPContainer::NWidgetPIPContainer(WidgetType tp, NWidContainerFlags flags) : NWidgetContainer(tp)
{
  this->flags = flags;
}
 
void NWidgetPIPContainer::SetPIP(uint8 pip_pre, uint8 pip_inter, uint8 pip_post)
{
  this->pip_pre = pip_pre;
  this->pip_inter = pip_inter;
  this->pip_post = pip_post;
}
 
void NWidgetPIPContainer::Draw(const Window *w)
{
  for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
    child_wid->Draw(w);
  }
}
 
NWidgetCore *NWidgetPIPContainer::GetWidgetFromPos(int x, int y)
{
  if (!IsInsideBS(x, this->pos_x, this->current_x) || !IsInsideBS(y, this->pos_y, this->current_y)) return nullptr;
 
  for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
    NWidgetCore *nwid = child_wid->GetWidgetFromPos(x, y);
    if (nwid != nullptr) return nwid;
  }
  return nullptr;
}
 
NWidgetHorizontal::NWidgetHorizontal(NWidContainerFlags flags) : NWidgetPIPContainer(NWID_HORIZONTAL, flags)
{
}
 
void NWidgetHorizontal::SetupSmallestSize(Window *w, bool init_array)
{
  this->smallest_x = 0; // Sum of minimal size of all children.
  this->smallest_y = 0; // Biggest child.
  this->fill_x = 0;     // smallest non-zero child widget fill step.
  this->fill_y = 1;     // smallest common child fill step.
  this->resize_x = 0;   // smallest non-zero child widget resize step.
  this->resize_y = 1;   // smallest common child resize step.
 
  /* 1a. Forward call, collect biggest nested array index, and longest/widest child length. */
  uint longest = 0; // Longest child found.
  uint max_vert_fill = 0; // Biggest vertical fill step.
  for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
    child_wid->SetupSmallestSize(w, init_array);
    longest = std::max(longest, child_wid->smallest_x);
    max_vert_fill = std::max(max_vert_fill, child_wid->GetVerticalStepSize(ST_SMALLEST));
    this->smallest_y = std::max(this->smallest_y, child_wid->smallest_y + child_wid->padding_top + child_wid->padding_bottom);
  }
  /* 1b. Make the container higher if needed to accommodate all children nicely. */
  uint max_smallest = this->smallest_y + 3 * max_vert_fill; // Upper limit to computing smallest height.
  uint cur_height = this->smallest_y;
  for (;;) {
    for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
      uint step_size = child_wid->GetVerticalStepSize(ST_SMALLEST);
      uint child_height = child_wid->smallest_y + child_wid->padding_top + child_wid->padding_bottom;
      if (step_size > 1 && child_height < cur_height) { // Small step sizes or already fitting children are not interesting.
        uint remainder = (cur_height - child_height) % step_size;
        if (remainder > 0) { // Child did not fit entirely, widen the container.
          cur_height += step_size - remainder;
          assert(cur_height < max_smallest); // Safeguard against infinite height expansion.
          /* Remaining children will adapt to the new cur_height, thus speeding up the computation. */
        }
      }
    }
    if (this->smallest_y == cur_height) break;
    this->smallest_y = cur_height; // Smallest height got changed, try again.
  }
  /* 2. For containers that must maintain equal width, extend child minimal size. */
  if (this->flags & NC_EQUALSIZE) {
    for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
      if (child_wid->fill_x == 1) child_wid->smallest_x = longest;
    }
  }
  /* 3. Move PIP space to the children, compute smallest, fill, and resize values of the container. */
  if (this->head != nullptr) this->head->padding_left += this->pip_pre;
  for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
    if (child_wid->next != nullptr) {
      child_wid->padding_right += this->pip_inter;
    } else {
      child_wid->padding_right += this->pip_post;
    }
 
    this->smallest_x += child_wid->smallest_x + child_wid->padding_left + child_wid->padding_right;
    if (child_wid->fill_x > 0) {
      if (this->fill_x == 0 || this->fill_x > child_wid->fill_x) this->fill_x = child_wid->fill_x;
    }
    this->fill_y = LeastCommonMultiple(this->fill_y, child_wid->fill_y);
 
    if (child_wid->resize_x > 0) {
      if (this->resize_x == 0 || this->resize_x > child_wid->resize_x) this->resize_x = child_wid->resize_x;
    }
    this->resize_y = LeastCommonMultiple(this->resize_y, child_wid->resize_y);
  }
  /* We need to zero the PIP settings so we can re-initialize the tree. */
  this->pip_pre = this->pip_inter = this->pip_post = 0;
}
 
void NWidgetHorizontal::AssignSizePosition(SizingType sizing, uint x, uint y, uint given_width, uint given_height, bool rtl)
{
  assert(given_width >= this->smallest_x && given_height >= this->smallest_y);
 
  /* Compute additional width given to us. */
  uint additional_length = given_width;
  if (sizing == ST_SMALLEST && (this->flags & NC_EQUALSIZE)) {
    /* For EQUALSIZE containers this does not sum to smallest_x during initialisation */
    for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
      additional_length -= child_wid->smallest_x + child_wid->padding_right + child_wid->padding_left;
    }
  } else {
    additional_length -= this->smallest_x;
  }
 
  this->StoreSizePosition(sizing, x, y, given_width, given_height);
 
  /* In principle, the additional horizontal space is distributed evenly over the available resizable children. Due to step sizes, this may not always be feasible.
   * To make resizing work as good as possible, first children with biggest step sizes are done. These may get less due to rounding down.
   * This additional space is then given to children with smaller step sizes. This will give a good result when resize steps of each child is a multiple
   * of the child with the smallest non-zero stepsize.
   *
   * Since child sizes are computed out of order, positions cannot be calculated until all sizes are known. That means it is not possible to compute the child
   * size and position, and directly call child->AssignSizePosition() with the computed values.
   * Instead, computed child widths and heights are stored in child->current_x and child->current_y values. That is allowed, since this method overwrites those values
   * then we call the child.
   */
 
  /* First loop: Find biggest stepsize, find number of children that want a piece of the pie, handle vertical size for all children,
   * handle horizontal size for non-resizing children.
   */
  int num_changing_childs = 0; // Number of children that can change size.
  uint biggest_stepsize = 0;
  for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
    uint hor_step = child_wid->GetHorizontalStepSize(sizing);
    if (hor_step > 0) {
      num_changing_childs++;
      biggest_stepsize = std::max(biggest_stepsize, hor_step);
    } else {
      child_wid->current_x = child_wid->smallest_x;
    }
 
    uint vert_step = (sizing == ST_SMALLEST) ? 1 : child_wid->GetVerticalStepSize(sizing);
    child_wid->current_y = ComputeMaxSize(child_wid->smallest_y, given_height - child_wid->padding_top - child_wid->padding_bottom, vert_step);
  }
 
  /* Second loop: Allocate the additional horizontal space over the resizing children, starting with the biggest resize steps. */
  while (biggest_stepsize > 0) {
    uint next_biggest_stepsize = 0;
    for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
      uint hor_step = child_wid->GetHorizontalStepSize(sizing);
      if (hor_step > biggest_stepsize) continue; // Already done
      if (hor_step == biggest_stepsize) {
        uint increment = additional_length / num_changing_childs;
        num_changing_childs--;
        if (hor_step > 1) increment -= increment % hor_step;
        child_wid->current_x = child_wid->smallest_x + increment;
        additional_length -= increment;
        continue;
      }
      next_biggest_stepsize = std::max(next_biggest_stepsize, hor_step);
    }
    biggest_stepsize = next_biggest_stepsize;
  }
  assert(num_changing_childs == 0);
 
  /* Third loop: Compute position and call the child. */
  uint position = rtl ? this->current_x : 0; // Place to put next child relative to origin of the container.
  NWidgetBase *child_wid = this->head;
  while (child_wid != nullptr) {
    uint child_width = child_wid->current_x;
    uint child_x = x + (rtl ? position - child_width - child_wid->padding_left : position + child_wid->padding_left);
    uint child_y = y + child_wid->padding_top;
 
    child_wid->AssignSizePosition(sizing, child_x, child_y, child_width, child_wid->current_y, rtl);
    uint padded_child_width = child_width + child_wid->padding_right + child_wid->padding_left;
    position = rtl ? position - padded_child_width : position + padded_child_width;
 
    child_wid = child_wid->next;
  }
}
 
NWidgetHorizontalLTR::NWidgetHorizontalLTR(NWidContainerFlags flags) : NWidgetHorizontal(flags)
{
  this->type = NWID_HORIZONTAL_LTR;
}
 
void NWidgetHorizontalLTR::AssignSizePosition(SizingType sizing, uint x, uint y, uint given_width, uint given_height, bool rtl)
{
  NWidgetHorizontal::AssignSizePosition(sizing, x, y, given_width, given_height, false);
}
 
NWidgetVertical::NWidgetVertical(NWidContainerFlags flags) : NWidgetPIPContainer(NWID_VERTICAL, flags)
{
}
 
void NWidgetVertical::SetupSmallestSize(Window *w, bool init_array)
{
  this->smallest_x = 0; // Biggest child.
  this->smallest_y = 0; // Sum of minimal size of all children.
  this->fill_x = 1;     // smallest common child fill step.
  this->fill_y = 0;     // smallest non-zero child widget fill step.
  this->resize_x = 1;   // smallest common child resize step.
  this->resize_y = 0;   // smallest non-zero child widget resize step.
 
  /* 1a. Forward call, collect biggest nested array index, and longest/widest child length. */
  uint highest = 0; // Highest child found.
  uint max_hor_fill = 0; // Biggest horizontal fill step.
  for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
    child_wid->SetupSmallestSize(w, init_array);
    highest = std::max(highest, child_wid->smallest_y);
    max_hor_fill = std::max(max_hor_fill, child_wid->GetHorizontalStepSize(ST_SMALLEST));
    this->smallest_x = std::max(this->smallest_x, child_wid->smallest_x + child_wid->padding_left + child_wid->padding_right);
  }
  /* 1b. Make the container wider if needed to accommodate all children nicely. */
  uint max_smallest = this->smallest_x + 3 * max_hor_fill; // Upper limit to computing smallest height.
  uint cur_width = this->smallest_x;
  for (;;) {
    for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
      uint step_size = child_wid->GetHorizontalStepSize(ST_SMALLEST);
      uint child_width = child_wid->smallest_x + child_wid->padding_left + child_wid->padding_right;
      if (step_size > 1 && child_width < cur_width) { // Small step sizes or already fitting children are not interesting.
        uint remainder = (cur_width - child_width) % step_size;
        if (remainder > 0) { // Child did not fit entirely, widen the container.
          cur_width += step_size - remainder;
          assert(cur_width < max_smallest); // Safeguard against infinite width expansion.
          /* Remaining children will adapt to the new cur_width, thus speeding up the computation. */
        }
      }
    }
    if (this->smallest_x == cur_width) break;
    this->smallest_x = cur_width; // Smallest width got changed, try again.
  }
  /* 2. For containers that must maintain equal width, extend children minimal size. */
  if (this->flags & NC_EQUALSIZE) {
    for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
      if (child_wid->fill_y == 1) child_wid->smallest_y = highest;
    }
  }
  /* 3. Move PIP space to the child, compute smallest, fill, and resize values of the container. */
  if (this->head != nullptr) this->head->padding_top += this->pip_pre;
  for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
    if (child_wid->next != nullptr) {
      child_wid->padding_bottom += this->pip_inter;
    } else {
      child_wid->padding_bottom += this->pip_post;
    }
 
    this->smallest_y += child_wid->smallest_y + child_wid->padding_top + child_wid->padding_bottom;
    if (child_wid->fill_y > 0) {
      if (this->fill_y == 0 || this->fill_y > child_wid->fill_y) this->fill_y = child_wid->fill_y;
    }
    this->fill_x = LeastCommonMultiple(this->fill_x, child_wid->fill_x);
 
    if (child_wid->resize_y > 0) {
      if (this->resize_y == 0 || this->resize_y > child_wid->resize_y) this->resize_y = child_wid->resize_y;
    }
    this->resize_x = LeastCommonMultiple(this->resize_x, child_wid->resize_x);
  }
  /* We need to zero the PIP settings so we can re-initialize the tree. */
  this->pip_pre = this->pip_inter = this->pip_post = 0;
}
 
void NWidgetVertical::AssignSizePosition(SizingType sizing, uint x, uint y, uint given_width, uint given_height, bool rtl)
{
  assert(given_width >= this->smallest_x && given_height >= this->smallest_y);
 
  /* Compute additional height given to us. */
  uint additional_length = given_height;
  if (sizing == ST_SMALLEST && (this->flags & NC_EQUALSIZE)) {
    /* For EQUALSIZE containers this does not sum to smallest_y during initialisation */
    for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
      additional_length -= child_wid->smallest_y + child_wid->padding_top + child_wid->padding_bottom;
    }
  } else {
    additional_length -= this->smallest_y;
  }
 
  this->StoreSizePosition(sizing, x, y, given_width, given_height);
 
  /* Like the horizontal container, the vertical container also distributes additional height evenly, starting with the children with the biggest resize steps.
   * It also stores computed widths and heights into current_x and current_y values of the child.
   */
 
  /* First loop: Find biggest stepsize, find number of children that want a piece of the pie, handle horizontal size for all children, handle vertical size for non-resizing child. */
  int num_changing_childs = 0; // Number of children that can change size.
  uint biggest_stepsize = 0;
  for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
    uint vert_step = child_wid->GetVerticalStepSize(sizing);
    if (vert_step > 0) {
      num_changing_childs++;
      biggest_stepsize = std::max(biggest_stepsize, vert_step);
    } else {
      child_wid->current_y = child_wid->smallest_y;
    }
 
    uint hor_step = (sizing == ST_SMALLEST) ? 1 : child_wid->GetHorizontalStepSize(sizing);
    child_wid->current_x = ComputeMaxSize(child_wid->smallest_x, given_width - child_wid->padding_left - child_wid->padding_right, hor_step);
  }
 
  /* Second loop: Allocate the additional vertical space over the resizing children, starting with the biggest resize steps. */
  while (biggest_stepsize > 0) {
    uint next_biggest_stepsize = 0;
    for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
      uint vert_step = child_wid->GetVerticalStepSize(sizing);
      if (vert_step > biggest_stepsize) continue; // Already done
      if (vert_step == biggest_stepsize) {
        uint increment = additional_length / num_changing_childs;
        num_changing_childs--;
        if (vert_step > 1) increment -= increment % vert_step;
        child_wid->current_y = child_wid->smallest_y + increment;
        additional_length -= increment;
        continue;
      }
      next_biggest_stepsize = std::max(next_biggest_stepsize, vert_step);
    }
    biggest_stepsize = next_biggest_stepsize;
  }
  assert(num_changing_childs == 0);
 
  /* Third loop: Compute position and call the child. */
  uint position = 0; // Place to put next child relative to origin of the container.
  for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
    uint child_x = x + (rtl ? child_wid->padding_right : child_wid->padding_left);
    uint child_height = child_wid->current_y;
 
    child_wid->AssignSizePosition(sizing, child_x, y + position + child_wid->padding_top, child_wid->current_x, child_height, rtl);
    position += child_height + child_wid->padding_top + child_wid->padding_bottom;
  }
}
 
NWidgetSpacer::NWidgetSpacer(int length, int height) : NWidgetResizeBase(NWID_SPACER, 0, 0)
{
  this->SetMinimalSize(length, height);
  this->SetResize(0, 0);
}
 
void NWidgetSpacer::SetupSmallestSize(Window *w, bool init_array)
{
  this->smallest_x = this->min_x;
  this->smallest_y = this->min_y;
}
 
void NWidgetSpacer::FillNestedArray(NWidgetBase **array, uint length)
{
}
 
void NWidgetSpacer::Draw(const Window *w)
{
  /* Spacer widget is never visible. */
}
 
void NWidgetSpacer::SetDirty(const Window *w) const
{
  /* Spacer widget never need repainting. */
}
 
NWidgetCore *NWidgetSpacer::GetWidgetFromPos(int x, int y)
{
  return nullptr;
}
 
NWidgetMatrix::NWidgetMatrix() : NWidgetPIPContainer(NWID_MATRIX, NC_EQUALSIZE), index(-1), clicked(-1), count(-1)
{
}
 
void NWidgetMatrix::SetIndex(int index)
{
  this->index = index;
}
 
void NWidgetMatrix::SetColour(Colours colour)
{
  this->colour = colour;
}
 
void NWidgetMatrix::SetClicked(int clicked)
{
  this->clicked = clicked;
  if (this->clicked >= 0 && this->sb != nullptr && this->widgets_x != 0) {
    int vpos = (this->clicked / this->widgets_x) * this->widget_h; // Vertical position of the top.
    /* Need to scroll down -> Scroll to the bottom.
     * However, last entry has no 'this->pip_inter' underneath, and we must stay below this->sb->GetCount() */
    if (this->sb->GetPosition() < vpos) vpos += this->widget_h - this->pip_inter - 1;
    this->sb->ScrollTowards(vpos);
  }
}
 
void NWidgetMatrix::SetCount(int count)
{
  this->count = count;
 
  if (this->sb == nullptr || this->widgets_x == 0) return;
 
  /* We need to get the number of pixels the matrix is high/wide.
   * So, determine the number of rows/columns based on the number of
   * columns/rows (one is constant/unscrollable).
   * Then multiply that by the height of a widget, and add the pre
   * and post spacing "offsets". */
  count = CeilDiv(count, this->sb->IsVertical() ? this->widgets_x : this->widgets_y);
  count *= (this->sb->IsVertical() ? this->head->smallest_y : this->head->smallest_x) + this->pip_inter;
  if (count > 0) count -= this->pip_inter; // We counted an inter too much in the multiplication above
  count += this->pip_pre + this->pip_post;
  this->sb->SetCount(count);
  this->sb->SetCapacity(this->sb->IsVertical() ? this->current_y : this->current_x);
  this->sb->SetStepSize(this->sb->IsVertical() ? this->widget_h  : this->widget_w);
}
 
void NWidgetMatrix::SetScrollbar(Scrollbar *sb)
{
  this->sb = sb;
}
 
void NWidgetMatrix::SetupSmallestSize(Window *w, bool init_array)
{
  assert(this->head != nullptr);
  assert(this->head->next == nullptr);
 
  if (this->index >= 0 && init_array) { // Fill w->nested_array[]
    assert(w->nested_array_size > (uint)this->index);
    w->nested_array[this->index] = this;
  }
 
  /* Reset the widget number. */
  NWidgetCore *nw = dynamic_cast<NWidgetCore *>(this->head);
  assert(nw != nullptr);
  SB(nw->index, 16, 16, 0);
  this->head->SetupSmallestSize(w, init_array);
 
  Dimension padding = { (uint)this->pip_pre + this->pip_post, (uint)this->pip_pre + this->pip_post};
  Dimension size    = {this->head->smallest_x + padding.width, this->head->smallest_y + padding.height};
  Dimension fill    = {0, 0};
  Dimension resize  = {this->pip_inter + this->head->smallest_x, this->pip_inter + this->head->smallest_y};
 
  if (this->index >= 0) w->UpdateWidgetSize(this->index, &size, padding, &fill, &resize);
 
  this->smallest_x = size.width;
  this->smallest_y = size.height;
  this->fill_x = fill.width;
  this->fill_y = fill.height;
  this->resize_x = resize.width;
  this->resize_y = resize.height;
}
 
void NWidgetMatrix::AssignSizePosition(SizingType sizing, uint x, uint y, uint given_width, uint given_height, bool rtl)
{
  assert(given_width >= this->smallest_x && given_height >= this->smallest_y);
 
  this->pos_x = x;
  this->pos_y = y;
  this->current_x = given_width;
  this->current_y = given_height;
 
  /* Determine the size of the widgets, and the number of visible widgets on each of the axis. */
  this->widget_w = this->head->smallest_x + this->pip_inter;
  this->widget_h = this->head->smallest_y + this->pip_inter;
 
  /* Account for the pip_inter is between widgets, so we need to account for that when
   * the division assumes pip_inter is used for all widgets. */
  this->widgets_x = CeilDiv(this->current_x - this->pip_pre - this->pip_post + this->pip_inter, this->widget_w);
  this->widgets_y = CeilDiv(this->current_y - this->pip_pre - this->pip_post + this->pip_inter, this->widget_h);
 
  /* When resizing, update the scrollbar's count. E.g. with a vertical
   * scrollbar becoming wider or narrower means the amount of rows in
   * the scrollbar becomes respectively smaller or higher. */
  this->SetCount(this->count);
}
 
void NWidgetMatrix::FillNestedArray(NWidgetBase **array, uint length)
{
  if (this->index >= 0 && (uint)(this->index) < length) array[this->index] = this;
  NWidgetContainer::FillNestedArray(array, length);
}
 
NWidgetCore *NWidgetMatrix::GetWidgetFromPos(int x, int y)
{
  /* Falls outside of the matrix widget. */
  if (!IsInsideBS(x, this->pos_x, this->current_x) || !IsInsideBS(y, this->pos_y, this->current_y)) return nullptr;
 
  int start_x, start_y, base_offs_x, base_offs_y;
  this->GetScrollOffsets(start_x, start_y, base_offs_x, base_offs_y);
 
  bool rtl = _current_text_dir == TD_RTL;
 
  int widget_col = (rtl ?
        -x + (int)this->pip_post + (int)this->pos_x + base_offs_x + (int)this->widget_w - 1 - (int)this->pip_inter :
         x - (int)this->pip_pre  - (int)this->pos_x - base_offs_x
      ) / this->widget_w;
 
  int widget_row = (y - base_offs_y - (int)this->pip_pre - (int)this->pos_y) / this->widget_h;
 
  int sub_wid = (widget_row + start_y) * this->widgets_x + start_x + widget_col;
  if (sub_wid >= this->count) return nullptr;
 
  NWidgetCore *child = dynamic_cast<NWidgetCore *>(this->head);
  assert(child != nullptr);
  child->AssignSizePosition(ST_RESIZE,
      this->pos_x + (rtl ? this->pip_post - widget_col * this->widget_w : this->pip_pre + widget_col * this->widget_w) + base_offs_x,
      this->pos_y + this->pip_pre + widget_row * this->widget_h + base_offs_y,
      child->smallest_x, child->smallest_y, rtl);
 
  SB(child->index, 16, 16, sub_wid);
 
  return child->GetWidgetFromPos(x, y);
}
 
/* virtual */ void NWidgetMatrix::Draw(const Window *w)
{
  /* Fill the background. */
  GfxFillRect(this->pos_x, this->pos_y, this->pos_x + this->current_x - 1, this->pos_y + this->current_y - 1, _colour_gradient[this->colour & 0xF][5]);
 
  /* Set up a clipping area for the previews. */
  bool rtl = _current_text_dir == TD_RTL;
  DrawPixelInfo tmp_dpi;
  if (!FillDrawPixelInfo(&tmp_dpi, this->pos_x + (rtl ? this->pip_post : this->pip_pre), this->pos_y + this->pip_pre, this->current_x - this->pip_pre - this->pip_post, this->current_y - this->pip_pre - this->pip_post)) return;
  DrawPixelInfo *old_dpi = _cur_dpi;
  _cur_dpi = &tmp_dpi;
 
  /* Get the appropriate offsets so we can draw the right widgets. */
  NWidgetCore *child = dynamic_cast<NWidgetCore *>(this->head);
  assert(child != nullptr);
  int start_x, start_y, base_offs_x, base_offs_y;
  this->GetScrollOffsets(start_x, start_y, base_offs_x, base_offs_y);
 
  int offs_y = base_offs_y;
  for (int y = start_y; y < start_y + this->widgets_y + 1; y++, offs_y += this->widget_h) {
    /* Are we within bounds? */
    if (offs_y + child->smallest_y <= 0) continue;
    if (offs_y >= (int)this->current_y) break;
 
    /* We've passed our amount of widgets. */
    if (y * this->widgets_x >= this->count) break;
 
    int offs_x = base_offs_x;
    for (int x = start_x; x < start_x + this->widgets_x + 1; x++, offs_x += rtl ? -this->widget_w : this->widget_w) {
      /* Are we within bounds? */
      if (offs_x + child->smallest_x <= 0) continue;
      if (offs_x >= (int)this->current_x) continue;
 
      /* Do we have this many widgets? */
      int sub_wid = y * this->widgets_x + x;
      if (sub_wid >= this->count) break;
 
      child->AssignSizePosition(ST_RESIZE, offs_x, offs_y, child->smallest_x, child->smallest_y, rtl);
      child->SetLowered(this->clicked == sub_wid);
      SB(child->index, 16, 16, sub_wid);
      child->Draw(w);
    }
  }
 
  /* Restore the clipping area. */
  _cur_dpi = old_dpi;
}
 
void NWidgetMatrix::GetScrollOffsets(int &start_x, int &start_y, int &base_offs_x, int &base_offs_y)
{
  base_offs_x = _current_text_dir == TD_RTL ? this->widget_w * (this->widgets_x - 1) : 0;
  base_offs_y = 0;
  start_x = 0;
  start_y = 0;
  if (this->sb != nullptr) {
    if (this->sb->IsVertical()) {
      start_y = this->sb->GetPosition() / this->widget_h;
      base_offs_y += -this->sb->GetPosition() + start_y * this->widget_h;
    } else {
      start_x = this->sb->GetPosition() / this->widget_w;
      int sub_x = this->sb->GetPosition() - start_x * this->widget_w;
      if (_current_text_dir == TD_RTL) {
        base_offs_x += sub_x;
      } else {
        base_offs_x -= sub_x;
      }
    }
  }
}
 
NWidgetBackground::NWidgetBackground(WidgetType tp, Colours colour, int index, NWidgetPIPContainer *child) : NWidgetCore(tp, colour, 1, 1, 0x0, STR_NULL)
{
  assert(tp == WWT_PANEL || tp == WWT_INSET || tp == WWT_FRAME);
  if (index >= 0) this->SetIndex(index);
  this->child = child;
}
 
NWidgetBackground::~NWidgetBackground()
{
  if (this->child != nullptr) delete this->child;
}
 
void NWidgetBackground::Add(NWidgetBase *nwid)
{
  if (this->child == nullptr) {
    this->child = new NWidgetVertical();
  }
  this->child->Add(nwid);
}
 
void NWidgetBackground::SetPIP(uint8 pip_pre, uint8 pip_inter, uint8 pip_post)
{
  if (this->child == nullptr) {
    this->child = new NWidgetVertical();
  }
  this->child->SetPIP(pip_pre, pip_inter, pip_post);
}
 
void NWidgetBackground::SetupSmallestSize(Window *w, bool init_array)
{
  if (init_array && this->index >= 0) {
    assert(w->nested_array_size > (uint)this->index);
    w->nested_array[this->index] = this;
  }
  if (this->child != nullptr) {
    this->child->SetupSmallestSize(w, init_array);
 
    this->smallest_x = this->child->smallest_x;
    this->smallest_y = this->child->smallest_y;
    this->fill_x = this->child->fill_x;
    this->fill_y = this->child->fill_y;
    this->resize_x = this->child->resize_x;
    this->resize_y = this->child->resize_y;
 
    /* Account for the size of the frame's text if that exists */
    if (w != nullptr && this->type == WWT_FRAME) {
      this->child->padding_left   = WD_FRAMETEXT_LEFT;
      this->child->padding_right  = WD_FRAMETEXT_RIGHT;
      this->child->padding_top    = std::max((int)WD_FRAMETEXT_TOP, this->widget_data != STR_NULL ? FONT_HEIGHT_NORMAL + WD_FRAMETEXT_TOP / 2 : 0);
      this->child->padding_bottom = WD_FRAMETEXT_BOTTOM;
 
      this->smallest_x += this->child->padding_left + this->child->padding_right;
      this->smallest_y += this->child->padding_top + this->child->padding_bottom;
 
      if (this->index >= 0) w->SetStringParameters(this->index);
      this->smallest_x = std::max(this->smallest_x, GetStringBoundingBox(this->widget_data).width + WD_FRAMETEXT_LEFT + WD_FRAMETEXT_RIGHT);
    }
  } else {
    Dimension d = {this->min_x, this->min_y};
    Dimension fill = {this->fill_x, this->fill_y};
    Dimension resize  = {this->resize_x, this->resize_y};
    if (w != nullptr) { // A non-nullptr window pointer acts as switch to turn dynamic widget size on.
      if (this->type == WWT_FRAME || this->type == WWT_INSET) {
        if (this->index >= 0) w->SetStringParameters(this->index);
        Dimension background = GetStringBoundingBox(this->widget_data);
        background.width += (this->type == WWT_FRAME) ? (WD_FRAMETEXT_LEFT + WD_FRAMERECT_RIGHT) : (WD_INSET_LEFT + WD_INSET_RIGHT);
        d = maxdim(d, background);
      }
      if (this->index >= 0) {
        static const Dimension padding = {0, 0};
        w->UpdateWidgetSize(this->index, &d, padding, &fill, &resize);
      }
    }
    this->smallest_x = d.width;
    this->smallest_y = d.height;
    this->fill_x = fill.width;
    this->fill_y = fill.height;
    this->resize_x = resize.width;
    this->resize_y = resize.height;
  }
}
 
void NWidgetBackground::AssignSizePosition(SizingType sizing, uint x, uint y, uint given_width, uint given_height, bool rtl)
{
  this->StoreSizePosition(sizing, x, y, given_width, given_height);
 
  if (this->child != nullptr) {
    uint x_offset = (rtl ? this->child->padding_right : this->child->padding_left);
    uint width = given_width - this->child->padding_right - this->child->padding_left;
    uint height = given_height - this->child->padding_top - this->child->padding_bottom;
    this->child->AssignSizePosition(sizing, x + x_offset, y + this->child->padding_top, width, height, rtl);
  }
}
 
void NWidgetBackground::FillNestedArray(NWidgetBase **array, uint length)
{
  if (this->index >= 0 && (uint)(this->index) < length) array[this->index] = this;
  if (this->child != nullptr) this->child->FillNestedArray(array, length);
}
 
void NWidgetBackground::Draw(const Window *w)
{
  if (this->current_x == 0 || this->current_y == 0) return;
 
  Rect r;
  r.left = this->pos_x;
  r.right = this->pos_x + this->current_x - 1;
  r.top = this->pos_y;
  r.bottom = this->pos_y + this->current_y - 1;
 
  const DrawPixelInfo *dpi = _cur_dpi;
  if (dpi->left > r.right || dpi->left + dpi->width <= r.left || dpi->top > r.bottom || dpi->top + dpi->height <= r.top) return;
 
  switch (this->type) {
    case WWT_PANEL:
      assert(this->widget_data == 0);
      DrawFrameRect(r.left, r.top, r.right, r.bottom, this->colour, this->IsLowered() ? FR_LOWERED : FR_NONE);
      break;
 
    case WWT_FRAME:
      if (this->index >= 0) w->SetStringParameters(this->index);
      DrawFrame(r, this->colour, this->widget_data);
      break;
 
    case WWT_INSET:
      if (this->index >= 0) w->SetStringParameters(this->index);
      DrawInset(r, this->colour, this->widget_data);
      break;
 
    default:
      NOT_REACHED();
  }
 
  if (this->index >= 0) w->DrawWidget(r, this->index);
  if (this->child != nullptr) this->child->Draw(w);
 
  if (this->IsDisabled()) {
    GfxFillRect(r.left + 1, r.top + 1, r.right - 1, r.bottom - 1, _colour_gradient[this->colour & 0xF][2], FILLRECT_CHECKER);
  }
}
 
NWidgetCore *NWidgetBackground::GetWidgetFromPos(int x, int y)
{
  NWidgetCore *nwid = nullptr;
  if (IsInsideBS(x, this->pos_x, this->current_x) && IsInsideBS(y, this->pos_y, this->current_y)) {
    if (this->child != nullptr) nwid = this->child->GetWidgetFromPos(x, y);
    if (nwid == nullptr) nwid = this;
  }
  return nwid;
}
 
NWidgetBase *NWidgetBackground::GetWidgetOfType(WidgetType tp)
{
  NWidgetBase *nwid = nullptr;
  if (this->child != nullptr) nwid = this->child->GetWidgetOfType(tp);
  if (nwid == nullptr && this->type == tp) nwid = this;
  return nwid;
}
 
NWidgetViewport::NWidgetViewport(int index) : NWidgetCore(NWID_VIEWPORT, INVALID_COLOUR, 1, 1, 0x0, STR_NULL)
{
  this->SetIndex(index);
}
 
void NWidgetViewport::SetupSmallestSize(Window *w, bool init_array)
{
  if (init_array && this->index >= 0) {
    assert(w->nested_array_size > (uint)this->index);
    w->nested_array[this->index] = this;
  }
  this->smallest_x = this->min_x;
  this->smallest_y = this->min_y;
}
 
void NWidgetViewport::Draw(const Window *w)
{
  if (this->disp_flags & ND_NO_TRANSPARENCY) {
    TransparencyOptionBits to_backup = _transparency_opt;
    _transparency_opt &= (1 << TO_SIGNS) | (1 << TO_LOADING); // Disable all transparency, except textual stuff
    w->DrawViewport();
    _transparency_opt = to_backup;
  } else {
    w->DrawViewport();
  }
 
  /* Optionally shade the viewport. */
  if (this->disp_flags & (ND_SHADE_GREY | ND_SHADE_DIMMED)) {
    GfxFillRect(this->pos_x, this->pos_y, this->pos_x + this->current_x - 1, this->pos_y + this->current_y - 1,
        (this->disp_flags & ND_SHADE_DIMMED) ? PALETTE_TO_TRANSPARENT : PALETTE_NEWSPAPER, FILLRECT_RECOLOUR);
  }
}
 
void NWidgetViewport::InitializeViewport(Window *w, uint32 follow_flags, ZoomLevel zoom)
{
  InitializeWindowViewport(w, this->pos_x, this->pos_y, this->current_x, this->current_y, follow_flags, zoom);
}
 
void NWidgetViewport::UpdateViewportCoordinates(Window *w)
{
  Viewport *vp = w->viewport;
  if (vp != nullptr) {
    vp->left = w->left + this->pos_x;
    vp->top  = w->top + this->pos_y;
    vp->width  = this->current_x;
    vp->height = this->current_y;
 
    vp->virtual_width  = ScaleByZoom(vp->width, vp->zoom);
    vp->virtual_height = ScaleByZoom(vp->height, vp->zoom);
  }
}
 
int Scrollbar::GetScrolledRowFromWidget(int clickpos, const Window * const w, int widget, int padding, int line_height) const
{
  uint pos = w->GetRowFromWidget(clickpos, widget, padding, line_height);
  if (pos != INT_MAX) pos += this->GetPosition();
  return (pos >= this->GetCount()) ? INT_MAX : pos;
}
 
void Scrollbar::SetCapacityFromWidget(Window *w, int widget, int padding)
{
  NWidgetBase *nwid = w->GetWidget<NWidgetBase>(widget);
  if (this->IsVertical()) {
    this->SetCapacity(((int)nwid->current_y - padding) / (int)nwid->resize_y);
  } else {
    this->SetCapacity(((int)nwid->current_x - padding) / (int)nwid->resize_x);
  }
}
 
NWidgetScrollbar::NWidgetScrollbar(WidgetType tp, Colours colour, int index) : NWidgetCore(tp, colour, 1, 1, 0x0, STR_NULL), Scrollbar(tp != NWID_HSCROLLBAR)
{
  assert(tp == NWID_HSCROLLBAR || tp == NWID_VSCROLLBAR);
  this->SetIndex(index);
}
 
void NWidgetScrollbar::SetupSmallestSize(Window *w, bool init_array)
{
  if (init_array && this->index >= 0) {
    assert(w->nested_array_size > (uint)this->index);
    w->nested_array[this->index] = this;
  }
  this->min_x = 0;
  this->min_y = 0;
 
  switch (this->type) {
    case NWID_HSCROLLBAR:
      this->SetMinimalSize(NWidgetScrollbar::GetHorizontalDimension().width * 3, NWidgetScrollbar::GetHorizontalDimension().height);
      this->SetResize(1, 0);
      this->SetFill(1, 0);
      this->SetDataTip(0x0, STR_TOOLTIP_HSCROLL_BAR_SCROLLS_LIST);
      break;
 
    case NWID_VSCROLLBAR:
      this->SetMinimalSize(NWidgetScrollbar::GetVerticalDimension().width, NWidgetScrollbar::GetVerticalDimension().height * 3);
      this->SetResize(0, 1);
      this->SetFill(0, 1);
      this->SetDataTip(0x0, STR_TOOLTIP_VSCROLL_BAR_SCROLLS_LIST);
      break;
 
    default: NOT_REACHED();
  }
 
  this->smallest_x = this->min_x;
  this->smallest_y = this->min_y;
}
 
void NWidgetScrollbar::Draw(const Window *w)
{
  if (this->current_x == 0 || this->current_y == 0) return;
 
  Rect r;
  r.left = this->pos_x;
  r.right = this->pos_x + this->current_x - 1;
  r.top = this->pos_y;
  r.bottom = this->pos_y + this->current_y - 1;
 
  const DrawPixelInfo *dpi = _cur_dpi;
  if (dpi->left > r.right || dpi->left + dpi->width <= r.left || dpi->top > r.bottom || dpi->top + dpi->height <= r.top) return;
 
  bool up_lowered = HasBit(this->disp_flags, NDB_SCROLLBAR_UP);
  bool down_lowered = HasBit(this->disp_flags, NDB_SCROLLBAR_DOWN);
  bool middle_lowered = !(this->disp_flags & ND_SCROLLBAR_BTN) && w->mouse_capture_widget == this->index;
 
  if (this->type == NWID_HSCROLLBAR) {
    DrawHorizontalScrollbar(r, this->colour, up_lowered, middle_lowered, down_lowered, this);
  } else {
    DrawVerticalScrollbar(r, this->colour, up_lowered, middle_lowered, down_lowered, this);
  }
 
  if (this->IsDisabled()) {
    GfxFillRect(r.left + 1, r.top + 1, r.right - 1, r.bottom - 1, _colour_gradient[this->colour & 0xF][2], FILLRECT_CHECKER);
  }
}
 
/* static */ void NWidgetScrollbar::InvalidateDimensionCache()
{
  vertical_dimension.width   = vertical_dimension.height   = 0;
  horizontal_dimension.width = horizontal_dimension.height = 0;
}
 
/* static */ Dimension NWidgetScrollbar::GetVerticalDimension()
{
  static const Dimension extra = {WD_SCROLLBAR_LEFT + WD_SCROLLBAR_RIGHT, WD_SCROLLBAR_TOP + WD_SCROLLBAR_BOTTOM};
  if (vertical_dimension.width == 0) {
    vertical_dimension = maxdim(GetSpriteSize(SPR_ARROW_UP), GetSpriteSize(SPR_ARROW_DOWN));
    vertical_dimension.width += extra.width;
    vertical_dimension.height += extra.height;
  }
  return vertical_dimension;
}
 
/* static */ Dimension NWidgetScrollbar::GetHorizontalDimension()
{
  static const Dimension extra = {WD_SCROLLBAR_LEFT + WD_SCROLLBAR_RIGHT, WD_SCROLLBAR_TOP + WD_SCROLLBAR_BOTTOM};
  if (horizontal_dimension.width == 0) {
    horizontal_dimension = maxdim(GetSpriteSize(SPR_ARROW_LEFT), GetSpriteSize(SPR_ARROW_RIGHT));
    horizontal_dimension.width += extra.width;
    horizontal_dimension.height += extra.height;
  }
  return horizontal_dimension;
}
 
Dimension NWidgetScrollbar::vertical_dimension = {0, 0};
Dimension NWidgetScrollbar::horizontal_dimension = {0, 0};
 
/* static */ void NWidgetLeaf::InvalidateDimensionCache()
{
  shadebox_dimension.width   = shadebox_dimension.height   = 0;
  debugbox_dimension.width   = debugbox_dimension.height   = 0;
  defsizebox_dimension.width = defsizebox_dimension.height = 0;
  stickybox_dimension.width  = stickybox_dimension.height  = 0;
  resizebox_dimension.width  = resizebox_dimension.height  = 0;
  closebox_dimension.width   = closebox_dimension.height   = 0;
  dropdown_dimension.width   = dropdown_dimension.height   = 0;
}
 
Dimension NWidgetLeaf::shadebox_dimension   = {0, 0};
Dimension NWidgetLeaf::debugbox_dimension   = {0, 0};
Dimension NWidgetLeaf::defsizebox_dimension = {0, 0};
Dimension NWidgetLeaf::stickybox_dimension  = {0, 0};
Dimension NWidgetLeaf::resizebox_dimension  = {0, 0};
Dimension NWidgetLeaf::closebox_dimension   = {0, 0};
Dimension NWidgetLeaf::dropdown_dimension   = {0, 0};
 
NWidgetLeaf::NWidgetLeaf(WidgetType tp, Colours colour, int index, uint32 data, StringID tip) : NWidgetCore(tp, colour, 1, 1, data, tip)
{
  assert(index >= 0 || tp == WWT_LABEL || tp == WWT_TEXT || tp == WWT_CAPTION || tp == WWT_RESIZEBOX || tp == WWT_SHADEBOX || tp == WWT_DEFSIZEBOX || tp == WWT_DEBUGBOX || tp == WWT_STICKYBOX || tp == WWT_CLOSEBOX);
  if (index >= 0) this->SetIndex(index);
  this->min_x = 0;
  this->min_y = 0;
  this->SetResize(0, 0);
 
  switch (tp) {
    case WWT_EMPTY:
      break;
 
    case WWT_PUSHBTN:
    case WWT_IMGBTN:
    case WWT_PUSHIMGBTN:
    case WWT_IMGBTN_2:
    case WWT_TEXTBTN:
    case WWT_PUSHTXTBTN:
    case WWT_TEXTBTN_2:
    case WWT_LABEL:
    case WWT_TEXT:
    case WWT_MATRIX:
    case NWID_BUTTON_DROPDOWN:
    case NWID_PUSHBUTTON_DROPDOWN:
    case WWT_ARROWBTN:
    case WWT_PUSHARROWBTN:
      this->SetFill(0, 0);
      break;
 
    case WWT_EDITBOX:
      this->SetFill(0, 0);
      break;
 
    case WWT_CAPTION:
      this->SetFill(1, 0);
      this->SetResize(1, 0);
      this->min_y = WD_CAPTION_HEIGHT;
      this->SetDataTip(data, STR_TOOLTIP_WINDOW_TITLE_DRAG_THIS);
      break;
 
    case WWT_STICKYBOX:
      this->SetFill(0, 0);
      this->SetMinimalSize(WD_STICKYBOX_WIDTH, WD_CAPTION_HEIGHT);
      this->SetDataTip(STR_NULL, STR_TOOLTIP_STICKY);
      break;
 
    case WWT_SHADEBOX:
      this->SetFill(0, 0);
      this->SetMinimalSize(WD_SHADEBOX_TOP, WD_CAPTION_HEIGHT);
      this->SetDataTip(STR_NULL, STR_TOOLTIP_SHADE);
      break;
 
    case WWT_DEBUGBOX:
      this->SetFill(0, 0);
      this->SetMinimalSize(WD_DEBUGBOX_TOP, WD_CAPTION_HEIGHT);
      this->SetDataTip(STR_NULL, STR_TOOLTIP_DEBUG);
      break;
 
    case WWT_DEFSIZEBOX:
      this->SetFill(0, 0);
      this->SetMinimalSize(WD_DEFSIZEBOX_TOP, WD_CAPTION_HEIGHT);
      this->SetDataTip(STR_NULL, STR_TOOLTIP_DEFSIZE);
      break;
 
    case WWT_RESIZEBOX:
      this->SetFill(0, 0);
      this->SetMinimalSize(WD_RESIZEBOX_WIDTH, 12);
      this->SetDataTip(STR_NULL, STR_TOOLTIP_RESIZE);
      break;
 
    case WWT_CLOSEBOX:
      this->SetFill(0, 0);
      this->SetMinimalSize(WD_CLOSEBOX_WIDTH, WD_CAPTION_HEIGHT);
      this->SetDataTip(STR_NULL, STR_TOOLTIP_CLOSE_WINDOW);
      break;
 
    case WWT_DROPDOWN:
      this->SetFill(0, 0);
      this->min_y = WD_DROPDOWN_HEIGHT;
      break;
 
    default:
      NOT_REACHED();
  }
}
 
void NWidgetLeaf::SetupSmallestSize(Window *w, bool init_array)
{
  if (this->index >= 0 && init_array) { // Fill w->nested_array[]
    assert(w->nested_array_size > (uint)this->index);
    w->nested_array[this->index] = this;
  }
 
  Dimension size = {this->min_x, this->min_y};
  Dimension fill = {this->fill_x, this->fill_y};
  Dimension resize = {this->resize_x, this->resize_y};
  /* Get padding, and update size with the real content size if appropriate. */
  const Dimension *padding = nullptr;
  switch (this->type) {
    case WWT_EMPTY: {
      static const Dimension extra = {0, 0};
      padding = &extra;
      break;
    }
    case WWT_MATRIX: {
      static const Dimension extra = {WD_MATRIX_LEFT + WD_MATRIX_RIGHT, WD_MATRIX_TOP + WD_MATRIX_BOTTOM};
      padding = &extra;
      break;
    }
    case WWT_SHADEBOX: {
      static const Dimension extra = {WD_SHADEBOX_LEFT + WD_SHADEBOX_RIGHT, WD_SHADEBOX_TOP + WD_SHADEBOX_BOTTOM};
      padding = &extra;
      if (NWidgetLeaf::shadebox_dimension.width == 0) {
        NWidgetLeaf::shadebox_dimension = maxdim(GetSpriteSize(SPR_WINDOW_SHADE), GetSpriteSize(SPR_WINDOW_UNSHADE));
        NWidgetLeaf::shadebox_dimension.width += extra.width;
        NWidgetLeaf::shadebox_dimension.height += extra.height;
      }
      size = maxdim(size, NWidgetLeaf::shadebox_dimension);
      break;
    }
    case WWT_DEBUGBOX:
      if (_settings_client.gui.newgrf_developer_tools && w->IsNewGRFInspectable()) {
        static const Dimension extra = {WD_DEBUGBOX_LEFT + WD_DEBUGBOX_RIGHT, WD_DEBUGBOX_TOP + WD_DEBUGBOX_BOTTOM};
        padding = &extra;
        if (NWidgetLeaf::debugbox_dimension.width == 0) {
          NWidgetLeaf::debugbox_dimension = GetSpriteSize(SPR_WINDOW_DEBUG);
          NWidgetLeaf::debugbox_dimension.width += extra.width;
          NWidgetLeaf::debugbox_dimension.height += extra.height;
        }
        size = maxdim(size, NWidgetLeaf::debugbox_dimension);
      } else {
        /* If the setting is disabled we don't want to see it! */
        size.width = 0;
        fill.width = 0;
        resize.width = 0;
      }
      break;
 
    case WWT_STICKYBOX: {
      static const Dimension extra = {WD_STICKYBOX_LEFT + WD_STICKYBOX_RIGHT, WD_STICKYBOX_TOP + WD_STICKYBOX_BOTTOM};
      padding = &extra;
      if (NWidgetLeaf::stickybox_dimension.width == 0) {
        NWidgetLeaf::stickybox_dimension = maxdim(GetSpriteSize(SPR_PIN_UP), GetSpriteSize(SPR_PIN_DOWN));
        NWidgetLeaf::stickybox_dimension.width += extra.width;
        NWidgetLeaf::stickybox_dimension.height += extra.height;
      }
      size = maxdim(size, NWidgetLeaf::stickybox_dimension);
      break;
    }
 
    case WWT_DEFSIZEBOX: {
      static const Dimension extra = {WD_DEFSIZEBOX_LEFT + WD_DEFSIZEBOX_RIGHT, WD_DEFSIZEBOX_TOP + WD_DEFSIZEBOX_BOTTOM};
      padding = &extra;
      if (NWidgetLeaf::defsizebox_dimension.width == 0) {
        NWidgetLeaf::defsizebox_dimension = GetSpriteSize(SPR_WINDOW_DEFSIZE);
        NWidgetLeaf::defsizebox_dimension.width += extra.width;
        NWidgetLeaf::defsizebox_dimension.height += extra.height;
      }
      size = maxdim(size, NWidgetLeaf::defsizebox_dimension);
      break;
    }
 
    case WWT_RESIZEBOX: {
      static const Dimension extra = {WD_RESIZEBOX_LEFT + WD_RESIZEBOX_RIGHT, WD_RESIZEBOX_TOP + WD_RESIZEBOX_BOTTOM};
      padding = &extra;
      if (NWidgetLeaf::resizebox_dimension.width == 0) {
        NWidgetLeaf::resizebox_dimension = maxdim(GetSpriteSize(SPR_WINDOW_RESIZE_LEFT), GetSpriteSize(SPR_WINDOW_RESIZE_RIGHT));
        NWidgetLeaf::resizebox_dimension.width += extra.width;
        NWidgetLeaf::resizebox_dimension.height += extra.height;
      }
      size = maxdim(size, NWidgetLeaf::resizebox_dimension);
      break;
    }
    case WWT_EDITBOX: {
      Dimension sprite_size = GetSpriteSize(_current_text_dir == TD_RTL ? SPR_IMG_DELETE_RIGHT : SPR_IMG_DELETE_LEFT);
      size.width = std::max(size.width, 30 + sprite_size.width);
      size.height = std::max(sprite_size.height, GetStringBoundingBox("_").height + WD_FRAMERECT_TOP + WD_FRAMERECT_BOTTOM);
    }
    FALLTHROUGH;
    case WWT_PUSHBTN: {
      static const Dimension extra = {WD_FRAMERECT_LEFT + WD_FRAMERECT_RIGHT, WD_FRAMERECT_TOP + WD_FRAMERECT_BOTTOM};
      padding = &extra;
      break;
    }
    case WWT_IMGBTN:
    case WWT_IMGBTN_2:
    case WWT_PUSHIMGBTN: {
      static const Dimension extra = {WD_IMGBTN_LEFT + WD_IMGBTN_RIGHT,  WD_IMGBTN_TOP + WD_IMGBTN_BOTTOM};
      padding = &extra;
      Dimension d2 = GetSpriteSize(this->widget_data);
      if (this->type == WWT_IMGBTN_2) d2 = maxdim(d2, GetSpriteSize(this->widget_data + 1));
      d2.width += extra.width;
      d2.height += extra.height;
      size = maxdim(size, d2);
      break;
    }
    case WWT_ARROWBTN:
    case WWT_PUSHARROWBTN: {
      static const Dimension extra = {WD_IMGBTN_LEFT + WD_IMGBTN_RIGHT,  WD_IMGBTN_TOP + WD_IMGBTN_BOTTOM};
      padding = &extra;
      Dimension d2 = maxdim(GetSpriteSize(SPR_ARROW_LEFT), GetSpriteSize(SPR_ARROW_RIGHT));
      d2.width += extra.width;
      d2.height += extra.height;
      size = maxdim(size, d2);
      break;
    }
 
    case WWT_CLOSEBOX: {
      static const Dimension extra = {WD_CLOSEBOX_LEFT + WD_CLOSEBOX_RIGHT, WD_CLOSEBOX_TOP + WD_CLOSEBOX_BOTTOM};
      padding = &extra;
      if (NWidgetLeaf::closebox_dimension.width == 0) {
        NWidgetLeaf::closebox_dimension = GetSpriteSize(SPR_CLOSEBOX);
        NWidgetLeaf::closebox_dimension.width += extra.width;
        NWidgetLeaf::closebox_dimension.height += extra.height;
      }
      size = maxdim(size, NWidgetLeaf::closebox_dimension);
      break;
    }
    case WWT_TEXTBTN:
    case WWT_PUSHTXTBTN:
    case WWT_TEXTBTN_2: {
      static const Dimension extra = {WD_FRAMERECT_LEFT + WD_FRAMERECT_RIGHT,  WD_FRAMERECT_TOP + WD_FRAMERECT_BOTTOM};
      padding = &extra;
      if (this->index >= 0) w->SetStringParameters(this->index);
      Dimension d2 = GetStringBoundingBox(this->widget_data);
      d2.width += extra.width;
      d2.height += extra.height;
      size = maxdim(size, d2);
      break;
    }
    case WWT_LABEL:
    case WWT_TEXT: {
      static const Dimension extra = {0, 0};
      padding = &extra;
      if (this->index >= 0) w->SetStringParameters(this->index);
      size = maxdim(size, GetStringBoundingBox(this->widget_data));
      break;
    }
    case WWT_CAPTION: {
      static const Dimension extra = {WD_CAPTIONTEXT_LEFT + WD_CAPTIONTEXT_RIGHT, WD_CAPTIONTEXT_TOP + WD_CAPTIONTEXT_BOTTOM};
      padding = &extra;
      if (this->index >= 0) w->SetStringParameters(this->index);
      Dimension d2 = GetStringBoundingBox(this->widget_data);
      d2.width += extra.width;
      d2.height += extra.height;
      size = maxdim(size, d2);
      break;
    }
    case WWT_DROPDOWN:
    case NWID_BUTTON_DROPDOWN:
    case NWID_PUSHBUTTON_DROPDOWN: {
      static Dimension extra = {WD_DROPDOWNTEXT_LEFT + WD_DROPDOWNTEXT_RIGHT, WD_DROPDOWNTEXT_TOP + WD_DROPDOWNTEXT_BOTTOM};
      padding = &extra;
      if (NWidgetLeaf::dropdown_dimension.width == 0) {
        NWidgetLeaf::dropdown_dimension = GetSpriteSize(SPR_ARROW_DOWN);
        NWidgetLeaf::dropdown_dimension.width += WD_DROPDOWNTEXT_LEFT + WD_DROPDOWNTEXT_RIGHT;
        NWidgetLeaf::dropdown_dimension.height += WD_DROPDOWNTEXT_TOP + WD_DROPDOWNTEXT_BOTTOM;
        extra.width = WD_DROPDOWNTEXT_LEFT + WD_DROPDOWNTEXT_RIGHT + NWidgetLeaf::dropdown_dimension.width;
      }
      if (this->index >= 0) w->SetStringParameters(this->index);
      Dimension d2 = GetStringBoundingBox(this->widget_data);
      d2.width += extra.width;
      d2.height = std::max(d2.height, NWidgetLeaf::dropdown_dimension.height) + extra.height;
      size = maxdim(size, d2);
      break;
    }
    default:
      NOT_REACHED();
  }
 
  if (this->index >= 0) w->UpdateWidgetSize(this->index, &size, *padding, &fill, &resize);
 
  this->smallest_x = size.width;
  this->smallest_y = size.height;
  this->fill_x = fill.width;
  this->fill_y = fill.height;
  this->resize_x = resize.width;
  this->resize_y = resize.height;
}
 
void NWidgetLeaf::Draw(const Window *w)
{
  if (this->current_x == 0 || this->current_y == 0) return;
 
  /* Setup a clipping rectangle... */
  DrawPixelInfo new_dpi;
  if (!FillDrawPixelInfo(&new_dpi, this->pos_x, this->pos_y, this->current_x, this->current_y)) return;
  /* ...but keep coordinates relative to the window. */
  new_dpi.left += this->pos_x;
  new_dpi.top += this->pos_y;
 
  DrawPixelInfo *old_dpi = _cur_dpi;
  _cur_dpi = &new_dpi;
 
  Rect r;
  r.left = this->pos_x;
  r.right = this->pos_x + this->current_x - 1;
  r.top = this->pos_y;
  r.bottom = this->pos_y + this->current_y - 1;
 
  bool clicked = this->IsLowered();
  switch (this->type) {
    case WWT_EMPTY:
      break;
 
    case WWT_PUSHBTN:
      assert(this->widget_data == 0);
      DrawFrameRect(r.left, r.top, r.right, r.bottom, this->colour, (clicked) ? FR_LOWERED : FR_NONE);
      break;
 
    case WWT_IMGBTN:
    case WWT_PUSHIMGBTN:
    case WWT_IMGBTN_2:
      DrawImageButtons(r, this->type, this->colour, clicked, this->widget_data);
      break;
 
    case WWT_TEXTBTN:
    case WWT_PUSHTXTBTN:
    case WWT_TEXTBTN_2:
      if (this->index >= 0) w->SetStringParameters(this->index);
      DrawFrameRect(r.left, r.top, r.right, r.bottom, this->colour, (clicked) ? FR_LOWERED : FR_NONE);
      DrawLabel(r, this->type, clicked, this->widget_data);
      break;
 
    case WWT_ARROWBTN:
    case WWT_PUSHARROWBTN: {
      SpriteID sprite;
      switch (this->widget_data) {
        case AWV_DECREASE: sprite = _current_text_dir != TD_RTL ? SPR_ARROW_LEFT : SPR_ARROW_RIGHT; break;
        case AWV_INCREASE: sprite = _current_text_dir == TD_RTL ? SPR_ARROW_LEFT : SPR_ARROW_RIGHT; break;
        case AWV_LEFT:     sprite = SPR_ARROW_LEFT;  break;
        case AWV_RIGHT:    sprite = SPR_ARROW_RIGHT; break;
        default: NOT_REACHED();
      }
      DrawImageButtons(r, WWT_PUSHIMGBTN, this->colour, clicked, sprite);
      break;
    }
 
    case WWT_LABEL:
      if (this->index >= 0) w->SetStringParameters(this->index);
      DrawLabel(r, this->type, clicked, this->widget_data);
      break;
 
    case WWT_TEXT:
      if (this->index >= 0) w->SetStringParameters(this->index);
      DrawText(r, (TextColour)this->colour, this->widget_data);
      break;
 
    case WWT_MATRIX:
      DrawMatrix(r, this->colour, clicked, this->widget_data, this->resize_x, this->resize_y);
      break;
 
    case WWT_EDITBOX: {
      const QueryString *query = w->GetQueryString(this->index);
      if (query != nullptr) query->DrawEditBox(w, this->index);
      break;
    }
 
    case WWT_CAPTION:
      if (this->index >= 0) w->SetStringParameters(this->index);
      DrawCaption(r, this->colour, w->owner, this->widget_data);
      break;
 
    case WWT_SHADEBOX:
      assert(this->widget_data == 0);
      DrawShadeBox(r, this->colour, w->IsShaded());
      break;
 
    case WWT_DEBUGBOX:
      DrawDebugBox(r, this->colour, clicked);
      break;
 
    case WWT_STICKYBOX:
      assert(this->widget_data == 0);
      DrawStickyBox(r, this->colour, !!(w->flags & WF_STICKY));
      break;
 
    case WWT_DEFSIZEBOX:
      assert(this->widget_data == 0);
      DrawDefSizeBox(r, this->colour, clicked);
      break;
 
    case WWT_RESIZEBOX:
      assert(this->widget_data == 0);
      DrawResizeBox(r, this->colour, this->pos_x < (w->width / 2), !!(w->flags & WF_SIZING));
      break;
 
    case WWT_CLOSEBOX:
      DrawCloseBox(r, this->colour);
      break;
 
    case WWT_DROPDOWN:
      if (this->index >= 0) w->SetStringParameters(this->index);
      DrawDropdown(r, this->colour, clicked, this->widget_data);
      break;
 
    case NWID_BUTTON_DROPDOWN:
    case NWID_PUSHBUTTON_DROPDOWN:
      if (this->index >= 0) w->SetStringParameters(this->index);
      DrawButtonDropdown(r, this->colour, clicked, (this->disp_flags & ND_DROPDOWN_ACTIVE) != 0, this->widget_data);
      break;
 
    default:
      NOT_REACHED();
  }
  if (this->index >= 0) w->DrawWidget(r, this->index);
 
  if (this->IsDisabled()) {
    GfxFillRect(r.left + 1, r.top + 1, r.right - 1, r.bottom - 1, _colour_gradient[this->colour & 0xF][2], FILLRECT_CHECKER);
  }
 
  _cur_dpi = old_dpi;
}
 
bool NWidgetLeaf::ButtonHit(const Point &pt)
{
  if (_current_text_dir == TD_LTR) {
    int button_width = this->pos_x + this->current_x - NWidgetLeaf::dropdown_dimension.width;
    return pt.x < button_width;
  } else {
    int button_left = this->pos_x + NWidgetLeaf::dropdown_dimension.width;
    return pt.x >= button_left;
  }
}
 
/* == Conversion code from NWidgetPart array to NWidgetBase* tree == */
 
static int MakeNWidget(const NWidgetPart *parts, int count, NWidgetBase **dest, bool *fill_dest, int *biggest_index)
{
  int num_used = 0;
 
  *dest = nullptr;
  *fill_dest = false;
 
  while (count > num_used) {
    switch (parts->type) {
      case NWID_SPACER:
        if (*dest != nullptr) return num_used;
        *dest = new NWidgetSpacer(0, 0);
        break;
 
      case NWID_HORIZONTAL:
        if (*dest != nullptr) return num_used;
        *dest = new NWidgetHorizontal(parts->u.cont_flags);
        *fill_dest = true;
        break;
 
      case NWID_HORIZONTAL_LTR:
        if (*dest != nullptr) return num_used;
        *dest = new NWidgetHorizontalLTR(parts->u.cont_flags);
        *fill_dest = true;
        break;
 
      case WWT_PANEL:
      case WWT_INSET:
      case WWT_FRAME:
        if (*dest != nullptr) return num_used;
        *dest = new NWidgetBackground(parts->type, parts->u.widget.colour, parts->u.widget.index);
        *biggest_index = std::max(*biggest_index, (int)parts->u.widget.index);
        *fill_dest = true;
        break;
 
      case NWID_VERTICAL:
        if (*dest != nullptr) return num_used;
        *dest = new NWidgetVertical(parts->u.cont_flags);
        *fill_dest = true;
        break;
 
      case NWID_MATRIX: {
        if (*dest != nullptr) return num_used;
        NWidgetMatrix *nwm = new NWidgetMatrix();
        *dest = nwm;
        *fill_dest = true;
        nwm->SetIndex(parts->u.widget.index);
        nwm->SetColour(parts->u.widget.colour);
        *biggest_index = std::max(*biggest_index, (int)parts->u.widget.index);
        break;
      }
 
      case WPT_FUNCTION: {
        if (*dest != nullptr) return num_used;
        /* Ensure proper functioning even when the called code simply writes its largest index. */
        int biggest = -1;
        *dest = parts->u.func_ptr(&biggest);
        *biggest_index = std::max(*biggest_index, biggest);
        *fill_dest = false;
        break;
      }
 
      case WPT_RESIZE: {
        NWidgetResizeBase *nwrb = dynamic_cast<NWidgetResizeBase *>(*dest);
        if (nwrb != nullptr) {
          assert(parts->u.xy.x >= 0 && parts->u.xy.y >= 0);
          nwrb->SetResize(parts->u.xy.x, parts->u.xy.y);
        }
        break;
      }
 
      case WPT_MINSIZE: {
        NWidgetResizeBase *nwrb = dynamic_cast<NWidgetResizeBase *>(*dest);
        if (nwrb != nullptr) {
          assert(parts->u.xy.x >= 0 && parts->u.xy.y >= 0);
          nwrb->SetMinimalSize(ScaleGUITrad(parts->u.xy.x), ScaleGUITrad(parts->u.xy.y));
        }
        break;
      }
 
      case WPT_MINTEXTLINES: {
        NWidgetResizeBase *nwrb = dynamic_cast<NWidgetResizeBase *>(*dest);
        if (nwrb != nullptr) {
          assert(parts->u.text_lines.size >= FS_BEGIN && parts->u.text_lines.size < FS_END);
          nwrb->SetMinimalTextLines(parts->u.text_lines.lines, parts->u.text_lines.spacing, parts->u.text_lines.size);
        }
        break;
      }
 
      case WPT_FILL: {
        NWidgetResizeBase *nwrb = dynamic_cast<NWidgetResizeBase *>(*dest);
        if (nwrb != nullptr) nwrb->SetFill(parts->u.xy.x, parts->u.xy.y);
        break;
      }
 
      case WPT_DATATIP: {
        NWidgetCore *nwc = dynamic_cast<NWidgetCore *>(*dest);
        if (nwc != nullptr) {
          nwc->widget_data = parts->u.data_tip.data;
          nwc->tool_tip = parts->u.data_tip.tooltip;
        }
        break;
      }
 
      case WPT_PADDING:
        if (*dest != nullptr) (*dest)->SetPadding(ScaleGUITrad(parts->u.padding.top), ScaleGUITrad(parts->u.padding.right), ScaleGUITrad(parts->u.padding.bottom), ScaleGUITrad(parts->u.padding.left));
        break;
 
      case WPT_PIPSPACE: {
        NWidgetPIPContainer *nwc = dynamic_cast<NWidgetPIPContainer *>(*dest);
        if (nwc != nullptr) nwc->SetPIP(parts->u.pip.pre,  parts->u.pip.inter, parts->u.pip.post);
 
        NWidgetBackground *nwb = dynamic_cast<NWidgetBackground *>(*dest);
        if (nwb != nullptr) nwb->SetPIP(parts->u.pip.pre,  parts->u.pip.inter, parts->u.pip.post);
        break;
      }
 
      case WPT_SCROLLBAR: {
        NWidgetCore *nwc = dynamic_cast<NWidgetCore *>(*dest);
        if (nwc != nullptr) {
          nwc->scrollbar_index = parts->u.widget.index;
        }
        break;
      }
 
      case WPT_ENDCONTAINER:
        return num_used;
 
      case NWID_VIEWPORT:
        if (*dest != nullptr) return num_used;
        *dest = new NWidgetViewport(parts->u.widget.index);
        *biggest_index = std::max(*biggest_index, (int)parts->u.widget.index);
        break;
 
      case NWID_HSCROLLBAR:
      case NWID_VSCROLLBAR:
        if (*dest != nullptr) return num_used;
        *dest = new NWidgetScrollbar(parts->type, parts->u.widget.colour, parts->u.widget.index);
        *biggest_index = std::max(*biggest_index, (int)parts->u.widget.index);
        break;
 
      case NWID_SELECTION: {
        if (*dest != nullptr) return num_used;
        NWidgetStacked *nws = new NWidgetStacked();
        *dest = nws;
        *fill_dest = true;
        nws->SetIndex(parts->u.widget.index);
        *biggest_index = std::max(*biggest_index, (int)parts->u.widget.index);
        break;
      }
 
      default:
        if (*dest != nullptr) return num_used;
        assert((parts->type & WWT_MASK) < WWT_LAST || (parts->type & WWT_MASK) == NWID_BUTTON_DROPDOWN);
        *dest = new NWidgetLeaf(parts->type, parts->u.widget.colour, parts->u.widget.index, 0x0, STR_NULL);
        *biggest_index = std::max(*biggest_index, (int)parts->u.widget.index);
        break;
    }
    num_used++;
    parts++;
  }
 
  return num_used;
}
 
static int MakeWidgetTree(const NWidgetPart *parts, int count, NWidgetBase **parent, int *biggest_index)
{
  /* If *parent == nullptr, only the first widget is read and returned. Otherwise, *parent must point to either
   * a #NWidgetContainer or a #NWidgetBackground object, and parts are added as much as possible. */
  NWidgetContainer *nwid_cont = dynamic_cast<NWidgetContainer *>(*parent);
  NWidgetBackground *nwid_parent = dynamic_cast<NWidgetBackground *>(*parent);
  assert(*parent == nullptr || (nwid_cont != nullptr && nwid_parent == nullptr) || (nwid_cont == nullptr && nwid_parent != nullptr));
 
  int total_used = 0;
  for (;;) {
    NWidgetBase *sub_widget = nullptr;
    bool fill_sub = false;
    int num_used = MakeNWidget(parts, count - total_used, &sub_widget, &fill_sub, biggest_index);
    parts += num_used;
    total_used += num_used;
 
    /* Break out of loop when end reached */
    if (sub_widget == nullptr) break;
 
    /* If sub-widget is a container, recursively fill that container. */
    WidgetType tp = sub_widget->type;
    if (fill_sub && (tp == NWID_HORIZONTAL || tp == NWID_HORIZONTAL_LTR || tp == NWID_VERTICAL || tp == NWID_MATRIX
              || tp == WWT_PANEL || tp == WWT_FRAME || tp == WWT_INSET || tp == NWID_SELECTION)) {
      NWidgetBase *sub_ptr = sub_widget;
      int num_used = MakeWidgetTree(parts, count - total_used, &sub_ptr, biggest_index);
      parts += num_used;
      total_used += num_used;
    }
 
    /* Add sub_widget to parent container if available, otherwise return the widget to the caller. */
    if (nwid_cont != nullptr) nwid_cont->Add(sub_widget);
    if (nwid_parent != nullptr) nwid_parent->Add(sub_widget);
    if (nwid_cont == nullptr && nwid_parent == nullptr) {
      *parent = sub_widget;
      return total_used;
    }
  }
 
  if (count == total_used) return total_used; // Reached the end of the array of parts?
 
  assert(total_used < count);
  assert(parts->type == WPT_ENDCONTAINER);
  return total_used + 1; // *parts is also 'used'
}
 
NWidgetContainer *MakeNWidgets(const NWidgetPart *parts, int count, int *biggest_index, NWidgetContainer *container)
{
  *biggest_index = -1;
  if (container == nullptr) container = new NWidgetVertical();
  NWidgetBase *cont_ptr = container;
  MakeWidgetTree(parts, count, &cont_ptr, biggest_index);
  return container;
}
 
NWidgetContainer *MakeWindowNWidgetTree(const NWidgetPart *parts, int count, int *biggest_index, NWidgetStacked **shade_select)
{
  *biggest_index = -1;
 
  /* Read the first widget recursively from the array. */
  NWidgetBase *nwid = nullptr;
  int num_used = MakeWidgetTree(parts, count, &nwid, biggest_index);
  assert(nwid != nullptr);
  parts += num_used;
  count -= num_used;
 
  NWidgetContainer *root = new NWidgetVertical;
  root->Add(nwid);
  if (count == 0) { // There is no body at all.
    *shade_select = nullptr;
    return root;
  }
 
  /* If the first widget looks like a titlebar, treat it as such.
   * If it has a shading box, silently add a shade selection widget in the tree. */
  NWidgetHorizontal *hor_cont = dynamic_cast<NWidgetHorizontal *>(nwid);
  NWidgetContainer *body;
  if (hor_cont != nullptr && hor_cont->GetWidgetOfType(WWT_CAPTION) != nullptr && hor_cont->GetWidgetOfType(WWT_SHADEBOX) != nullptr) {
    *shade_select = new NWidgetStacked;
    root->Add(*shade_select);
    body = new NWidgetVertical;
    (*shade_select)->Add(body);
  } else {
    *shade_select = nullptr;
    body = root;
  }
 
  /* Load the remaining parts into 'body'. */
  int biggest2 = -1;
  MakeNWidgets(parts, count, &biggest2, body);
 
  *biggest_index = std::max(*biggest_index, biggest2);
  return root;
}
 
NWidgetBase *MakeCompanyButtonRows(int *biggest_index, int widget_first, int widget_last, int max_length, StringID button_tooltip)
{
  assert(max_length >= 1);
  NWidgetVertical *vert = nullptr; // Storage for all rows.
  NWidgetHorizontal *hor = nullptr; // Storage for buttons in one row.
  int hor_length = 0;
 
  Dimension sprite_size = GetSpriteSize(SPR_COMPANY_ICON);
  sprite_size.width  += WD_MATRIX_LEFT + WD_MATRIX_RIGHT;
  sprite_size.height += WD_MATRIX_TOP + WD_MATRIX_BOTTOM + 1; // 1 for the 'offset' of being pressed
 
  for (int widnum = widget_first; widnum <= widget_last; widnum++) {
    /* Ensure there is room in 'hor' for another button. */
    if (hor_length == max_length) {
      if (vert == nullptr) vert = new NWidgetVertical();
      vert->Add(hor);
      hor = nullptr;
      hor_length = 0;
    }
    if (hor == nullptr) {
      hor = new NWidgetHorizontal();
      hor_length = 0;
    }
 
    NWidgetBackground *panel = new NWidgetBackground(WWT_PANEL, COLOUR_GREY, widnum);
    panel->SetMinimalSize(sprite_size.width, sprite_size.height);
    panel->SetFill(1, 1);
    panel->SetResize(1, 0);
    panel->SetDataTip(0x0, button_tooltip);
    hor->Add(panel);
    hor_length++;
  }
  *biggest_index = widget_last;
  if (vert == nullptr) return hor; // All buttons fit in a single row.
 
  if (hor_length > 0 && hor_length < max_length) {
    /* Last row is partial, add a spacer at the end to force all buttons to the left. */
    NWidgetSpacer *spc = new NWidgetSpacer(sprite_size.width, sprite_size.height);
    spc->SetFill(1, 1);
    spc->SetResize(1, 0);
    hor->Add(spc);
  }
  if (hor != nullptr) vert->Add(hor);
  return vert;
}