gfx.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 "gfx_layout.h"
#include "progress.h"
#include "zoom_func.h"
#include "blitter/factory.hpp"
#include "video/video_driver.hpp"
#include "strings_func.h"
#include "settings_type.h"
#include "network/network.h"
#include "network/network_func.h"
#include "window_gui.h"
#include "window_func.h"
#include "newgrf_debug.h"
#include "core/backup_type.hpp"
#include "core/container_func.hpp"
#include "viewport_func.h"
 
#include "table/string_colours.h"
#include "table/sprites.h"
#include "table/control_codes.h"
 
#include "safeguards.h"
 
byte _dirkeys;        
bool _fullscreen;
byte _support8bpp;
CursorVars _cursor;
bool _ctrl_pressed;   
bool _shift_pressed;  
uint16_t _game_speed = 100; 
bool _left_button_down;     
bool _left_button_clicked;  
bool _right_button_down;    
bool _right_button_clicked; 
DrawPixelInfo _screen;
bool _screen_disable_anim = false;   
std::atomic<bool> _exit_game;
GameMode _game_mode;
SwitchMode _switch_mode;  
PauseMode _pause_mode;
GameSessionStats _game_session_stats; 
 
static byte _stringwidth_table[FS_END][224]; 
DrawPixelInfo *_cur_dpi;
 
static void GfxMainBlitterViewport(const Sprite *sprite, int x, int y, BlitterMode mode, const SubSprite *sub = nullptr, SpriteID sprite_id = SPR_CURSOR_MOUSE);
static void GfxMainBlitter(const Sprite *sprite, int x, int y, BlitterMode mode, const SubSprite *sub = nullptr, SpriteID sprite_id = SPR_CURSOR_MOUSE, ZoomLevel zoom = ZOOM_LVL_NORMAL);
 
static ReusableBuffer<uint8_t> _cursor_backup;
 
ZoomLevel _gui_zoom  = ZOOM_LVL_OUT_4X;     
ZoomLevel _font_zoom = _gui_zoom;           
int _gui_scale       = MIN_INTERFACE_SCALE; 
int _gui_scale_cfg;                         
 
static Rect _invalid_rect;
static const byte *_colour_remap_ptr;
static byte _string_colourremap[3]; 
 
static const uint DIRTY_BLOCK_HEIGHT   = 8;
static const uint DIRTY_BLOCK_WIDTH    = 64;
 
static uint _dirty_bytes_per_line = 0;
static byte *_dirty_blocks = nullptr;
extern uint _dirty_block_colour;
 
void GfxScroll(int left, int top, int width, int height, int xo, int yo)
{
  Blitter *blitter = BlitterFactory::GetCurrentBlitter();
 
  if (xo == 0 && yo == 0) return;
 
  if (_cursor.visible) UndrawMouseCursor();
 
  if (_networking) NetworkUndrawChatMessage();
 
  blitter->ScrollBuffer(_screen.dst_ptr, left, top, width, height, xo, yo);
  /* This part of the screen is now dirty. */
  VideoDriver::GetInstance()->MakeDirty(left, top, width, height);
}
 
 
void GfxFillRect(int left, int top, int right, int bottom, int colour, FillRectMode mode)
{
  Blitter *blitter = BlitterFactory::GetCurrentBlitter();
  const DrawPixelInfo *dpi = _cur_dpi;
  void *dst;
  const int otop = top;
  const int oleft = left;
 
  if (dpi->zoom != ZOOM_LVL_NORMAL) return;
  if (left > right || top > bottom) return;
  if (right < dpi->left || left >= dpi->left + dpi->width) return;
  if (bottom < dpi->top || top >= dpi->top + dpi->height) return;
 
  if ( (left -= dpi->left) < 0) left = 0;
  right = right - dpi->left + 1;
  if (right > dpi->width) right = dpi->width;
  right -= left;
  assert(right > 0);
 
  if ( (top -= dpi->top) < 0) top = 0;
  bottom = bottom - dpi->top + 1;
  if (bottom > dpi->height) bottom = dpi->height;
  bottom -= top;
  assert(bottom > 0);
 
  dst = blitter->MoveTo(dpi->dst_ptr, left, top);
 
  switch (mode) {
    default: // FILLRECT_OPAQUE
      blitter->DrawRect(dst, right, bottom, (uint8_t)colour);
      break;
 
    case FILLRECT_RECOLOUR:
      blitter->DrawColourMappingRect(dst, right, bottom, GB(colour, 0, PALETTE_WIDTH));
      break;
 
    case FILLRECT_CHECKER: {
      byte bo = (oleft - left + dpi->left + otop - top + dpi->top) & 1;
      do {
        for (int i = (bo ^= 1); i < right; i += 2) blitter->SetPixel(dst, i, 0, (uint8_t)colour);
        dst = blitter->MoveTo(dst, 0, 1);
      } while (--bottom > 0);
      break;
    }
  }
}
 
typedef std::pair<Point, Point> LineSegment;
 
static std::vector<LineSegment> MakePolygonSegments(const std::vector<Point> &shape, Point offset)
{
  std::vector<LineSegment> segments;
  if (shape.size() < 3) return segments; // fewer than 3 will always result in an empty polygon
  segments.reserve(shape.size());
 
  /* Connect first and last point by having initial previous point be the last */
  Point prev = shape.back();
  prev.x -= offset.x;
  prev.y -= offset.y;
  for (Point pt : shape) {
    pt.x -= offset.x;
    pt.y -= offset.y;
    /* Create segments for all non-horizontal lines in the polygon.
     * The segments always have lowest Y coordinate first. */
    if (prev.y > pt.y) {
      segments.emplace_back(pt, prev);
    } else if (prev.y < pt.y) {
      segments.emplace_back(prev, pt);
    }
    prev = pt;
  }
 
  return segments;
}
 
void GfxFillPolygon(const std::vector<Point> &shape, int colour, FillRectMode mode)
{
  Blitter *blitter = BlitterFactory::GetCurrentBlitter();
  const DrawPixelInfo *dpi = _cur_dpi;
  if (dpi->zoom != ZOOM_LVL_NORMAL) return;
 
  std::vector<LineSegment> segments = MakePolygonSegments(shape, Point{ dpi->left, dpi->top });
 
  /* Remove segments appearing entirely above or below the clipping area. */
  segments.erase(std::remove_if(segments.begin(), segments.end(), [dpi](const LineSegment &s) { return s.second.y <= 0 || s.first.y >= dpi->height; }), segments.end());
 
  /* Check that this wasn't an empty shape (all points on a horizontal line or outside clipping.) */
  if (segments.empty()) return;
 
  /* Sort the segments by first point Y coordinate. */
  std::sort(segments.begin(), segments.end(), [](const LineSegment &a, const LineSegment &b) { return a.first.y < b.first.y; });
 
  /* Segments intersecting current scanline. */
  std::vector<LineSegment> active;
  /* Intersection points with a scanline.
   * Kept outside loop to avoid repeated re-allocations. */
  std::vector<int> intersections;
  /* Normal, reasonable polygons don't have many intersections per scanline. */
  active.reserve(4);
  intersections.reserve(4);
 
  /* Scan through the segments and paint each scanline. */
  int y = segments.front().first.y;
  std::vector<LineSegment>::iterator nextseg = segments.begin();
  while (!active.empty() || nextseg != segments.end()) {
    /* Clean up segments that have ended. */
    active.erase(std::remove_if(active.begin(), active.end(), [y](const LineSegment &s) { return s.second.y == y; }), active.end());
 
    /* Activate all segments starting on this scanline. */
    while (nextseg != segments.end() && nextseg->first.y == y) {
      active.push_back(*nextseg);
      ++nextseg;
    }
 
    /* Check clipping. */
    if (y < 0) {
      ++y;
      continue;
    }
    if (y >= dpi->height) return;
 
    /*  Intersect scanline with all active segments. */
    intersections.clear();
    for (const LineSegment &s : active) {
      const int sdx = s.second.x - s.first.x;
      const int sdy = s.second.y - s.first.y;
      const int ldy = y - s.first.y;
      const int x = s.first.x + sdx * ldy / sdy;
      intersections.push_back(x);
    }
 
    /* Fill between pairs of intersections. */
    std::sort(intersections.begin(), intersections.end());
    for (size_t i = 1; i < intersections.size(); i += 2) {
      /* Check clipping. */
      const int x1 = std::max(0, intersections[i - 1]);
      const int x2 = std::min(intersections[i], dpi->width);
      if (x2 < 0) continue;
      if (x1 >= dpi->width) continue;
 
      /* Fill line y from x1 to x2. */
      void *dst = blitter->MoveTo(dpi->dst_ptr, x1, y);
      switch (mode) {
        default: // FILLRECT_OPAQUE
          blitter->DrawRect(dst, x2 - x1, 1, (uint8_t)colour);
          break;
        case FILLRECT_RECOLOUR:
          blitter->DrawColourMappingRect(dst, x2 - x1, 1, GB(colour, 0, PALETTE_WIDTH));
          break;
        case FILLRECT_CHECKER:
          /* Fill every other pixel, offset such that the sum of filled pixels' X and Y coordinates is odd.
           * This creates a checkerboard effect. */
          for (int x = (x1 + y) & 1; x < x2 - x1; x += 2) {
            blitter->SetPixel(dst, x, 0, (uint8_t)colour);
          }
          break;
      }
    }
 
    /* Next line */
    ++y;
  }
}
 
static inline void GfxDoDrawLine(void *video, int x, int y, int x2, int y2, int screen_width, int screen_height, uint8_t colour, int width, int dash = 0)
{
  Blitter *blitter = BlitterFactory::GetCurrentBlitter();
 
  assert(width > 0);
 
  if (y2 == y || x2 == x) {
    /* Special case: horizontal/vertical line. All checks already done in GfxPreprocessLine. */
    blitter->DrawLine(video, x, y, x2, y2, screen_width, screen_height, colour, width, dash);
    return;
  }
 
  int grade_y = y2 - y;
  int grade_x = x2 - x;
 
  /* Clipping rectangle. Slightly extended so we can ignore the width of the line. */
  int extra = (int)CeilDiv(3 * width, 4); // not less then "width * sqrt(2) / 2"
  Rect clip = { -extra, -extra, screen_width - 1 + extra, screen_height - 1 + extra };
 
  /* prevent integer overflows. */
  int margin = 1;
  while (INT_MAX / abs(grade_y) < std::max(abs(clip.left - x), abs(clip.right - x))) {
    grade_y /= 2;
    grade_x /= 2;
    margin  *= 2; // account for rounding errors
  }
 
  /* Imagine that the line is infinitely long and it intersects with
   * infinitely long left and right edges of the clipping rectangle.
   * If both intersection points are outside the clipping rectangle
   * and both on the same side of it, we don't need to draw anything. */
  int left_isec_y = y + (clip.left - x) * grade_y / grade_x;
  int right_isec_y = y + (clip.right - x) * grade_y / grade_x;
  if ((left_isec_y > clip.bottom + margin && right_isec_y > clip.bottom + margin) ||
      (left_isec_y < clip.top - margin && right_isec_y < clip.top - margin)) {
    return;
  }
 
  /* It is possible to use the line equation to further reduce the amount of
   * work the blitter has to do by shortening the effective line segment.
   * However, in order to get that right and prevent the flickering effects
   * of rounding errors so much additional code has to be run here that in
   * the general case the effect is not noticeable. */
 
  blitter->DrawLine(video, x, y, x2, y2, screen_width, screen_height, colour, width, dash);
}
 
static inline bool GfxPreprocessLine(DrawPixelInfo *dpi, int &x, int &y, int &x2, int &y2, int width)
{
  x -= dpi->left;
  x2 -= dpi->left;
  y -= dpi->top;
  y2 -= dpi->top;
 
  /* Check simple clipping */
  if (x + width / 2 < 0           && x2 + width / 2 < 0          ) return false;
  if (y + width / 2 < 0           && y2 + width / 2 < 0          ) return false;
  if (x - width / 2 > dpi->width  && x2 - width / 2 > dpi->width ) return false;
  if (y - width / 2 > dpi->height && y2 - width / 2 > dpi->height) return false;
  return true;
}
 
void GfxDrawLine(int x, int y, int x2, int y2, int colour, int width, int dash)
{
  DrawPixelInfo *dpi = _cur_dpi;
  if (GfxPreprocessLine(dpi, x, y, x2, y2, width)) {
    GfxDoDrawLine(dpi->dst_ptr, x, y, x2, y2, dpi->width, dpi->height, colour, width, dash);
  }
}
 
void GfxDrawLineUnscaled(int x, int y, int x2, int y2, int colour)
{
  DrawPixelInfo *dpi = _cur_dpi;
  if (GfxPreprocessLine(dpi, x, y, x2, y2, 1)) {
    GfxDoDrawLine(dpi->dst_ptr,
        UnScaleByZoom(x, dpi->zoom), UnScaleByZoom(y, dpi->zoom),
        UnScaleByZoom(x2, dpi->zoom), UnScaleByZoom(y2, dpi->zoom),
        UnScaleByZoom(dpi->width, dpi->zoom), UnScaleByZoom(dpi->height, dpi->zoom), colour, 1);
  }
}
 
void DrawBox(int x, int y, int dx1, int dy1, int dx2, int dy2, int dx3, int dy3)
{
  /*           ....
   *         ..    ....
   *       ..          ....
   *     ..                ^
   *   <--__(dx1,dy1)    /(dx2,dy2)
   *   :    --__       /   :
   *   :        --__ /     :
   *   :            *(x,y) :
   *   :            |      :
   *   :            |     ..
   *    ....        |(dx3,dy3)
   *        ....    | ..
   *            ....V.
   */
 
  static const byte colour = PC_WHITE;
 
  GfxDrawLineUnscaled(x, y, x + dx1, y + dy1, colour);
  GfxDrawLineUnscaled(x, y, x + dx2, y + dy2, colour);
  GfxDrawLineUnscaled(x, y, x + dx3, y + dy3, colour);
 
  GfxDrawLineUnscaled(x + dx1, y + dy1, x + dx1 + dx2, y + dy1 + dy2, colour);
  GfxDrawLineUnscaled(x + dx1, y + dy1, x + dx1 + dx3, y + dy1 + dy3, colour);
  GfxDrawLineUnscaled(x + dx2, y + dy2, x + dx2 + dx1, y + dy2 + dy1, colour);
  GfxDrawLineUnscaled(x + dx2, y + dy2, x + dx2 + dx3, y + dy2 + dy3, colour);
  GfxDrawLineUnscaled(x + dx3, y + dy3, x + dx3 + dx1, y + dy3 + dy1, colour);
  GfxDrawLineUnscaled(x + dx3, y + dy3, x + dx3 + dx2, y + dy3 + dy2, colour);
}
 
void DrawRectOutline(const Rect &r, int colour, int width, int dash)
{
  GfxDrawLine(r.left,  r.top,    r.right, r.top,    colour, width, dash);
  GfxDrawLine(r.left,  r.top,    r.left,  r.bottom, colour, width, dash);
  GfxDrawLine(r.right, r.top,    r.right, r.bottom, colour, width, dash);
  GfxDrawLine(r.left,  r.bottom, r.right, r.bottom, colour, width, dash);
}
 
static void SetColourRemap(TextColour colour)
{
  if (colour == TC_INVALID) return;
 
  /* Black strings have no shading ever; the shading is black, so it
   * would be invisible at best, but it actually makes it illegible. */
  bool no_shade   = (colour & TC_NO_SHADE) != 0 || colour == TC_BLACK;
  bool raw_colour = (colour & TC_IS_PALETTE_COLOUR) != 0;
  colour &= ~(TC_NO_SHADE | TC_IS_PALETTE_COLOUR | TC_FORCED);
 
  _string_colourremap[1] = raw_colour ? (byte)colour : _string_colourmap[colour];
  _string_colourremap[2] = no_shade ? 0 : 1;
  _colour_remap_ptr = _string_colourremap;
}
 
static int DrawLayoutLine(const ParagraphLayouter::Line &line, int y, int left, int right, StringAlignment align, bool underline, bool truncation)
{
  if (line.CountRuns() == 0) return 0;
 
  int w = line.GetWidth();
  int h = line.GetLeading();
 
  /*
   * The following is needed for truncation.
   * Depending on the text direction, we either remove bits at the rear
   * or the front. For this we shift the entire area to draw so it fits
   * within the left/right bounds and the side we do not truncate it on.
   * Then we determine the truncation location, i.e. glyphs that fall
   * outside of the range min_x - max_x will not be drawn; they are thus
   * the truncated glyphs.
   *
   * At a later step we insert the dots.
   */
 
  int max_w = right - left + 1; // The maximum width.
 
  int offset_x = 0;  // The offset we need for positioning the glyphs
  int min_x = left;  // The minimum x position to draw normal glyphs on.
  int max_x = right; // The maximum x position to draw normal glyphs on.
 
  truncation &= max_w < w;         // Whether we need to do truncation.
  int dot_width = 0;               // Cache for the width of the dot.
  const Sprite *dot_sprite = nullptr; // Cache for the sprite of the dot.
  bool dot_has_shadow = false;     // Whether the dot's font requires shadows.
 
  if (truncation) {
    /*
     * Assumption may be made that all fonts of a run are of the same size.
     * In any case, we'll use these dots for the abbreviation, so even if
     * another size would be chosen it won't have truncated too little for
     * the truncation dots.
     */
    FontCache *fc = line.GetVisualRun(0).GetFont()->fc;
    dot_has_shadow = fc->GetDrawGlyphShadow();
    GlyphID dot_glyph = fc->MapCharToGlyph('.');
    dot_width = fc->GetGlyphWidth(dot_glyph);
    dot_sprite = fc->GetGlyph(dot_glyph);
 
    if (_current_text_dir == TD_RTL) {
      min_x += 3 * dot_width;
      offset_x = w - 3 * dot_width - max_w;
    } else {
      max_x -= 3 * dot_width;
    }
 
    w = max_w;
  }
 
  /* In case we have a RTL language we swap the alignment. */
  if (!(align & SA_FORCE) && _current_text_dir == TD_RTL && (align & SA_HOR_MASK) != SA_HOR_CENTER) align ^= SA_RIGHT;
 
  /* right is the right most position to draw on. In this case we want to do
   * calculations with the width of the string. In comparison right can be
   * seen as lastof(todraw) and width as lengthof(todraw). They differ by 1.
   * So most +1/-1 additions are to move from lengthof to 'indices'.
   */
  switch (align & SA_HOR_MASK) {
    case SA_LEFT:
      /* right + 1 = left + w */
      right = left + w - 1;
      break;
 
    case SA_HOR_CENTER:
      left  = RoundDivSU(right + 1 + left - w, 2);
      /* right + 1 = left + w */
      right = left + w - 1;
      break;
 
    case SA_RIGHT:
      left = right + 1 - w;
      break;
 
    default:
      NOT_REACHED();
  }
 
  const uint shadow_offset = ScaleGUITrad(1);
 
  /* Draw shadow, then foreground */
  for (bool do_shadow : { true, false }) {
    bool colour_has_shadow = false;
    for (int run_index = 0; run_index < line.CountRuns(); run_index++) {
      const ParagraphLayouter::VisualRun &run = line.GetVisualRun(run_index);
      const auto &glyphs = run.GetGlyphs();
      const auto &positions = run.GetPositions();
      const Font *f = run.GetFont();
 
      FontCache *fc = f->fc;
      TextColour colour = f->colour;
      colour_has_shadow = (colour & TC_NO_SHADE) == 0 && colour != TC_BLACK;
      SetColourRemap(do_shadow ? TC_BLACK : colour); // the last run also sets the colour for the truncation dots
      if (do_shadow && (!fc->GetDrawGlyphShadow() || !colour_has_shadow)) continue;
 
      DrawPixelInfo *dpi = _cur_dpi;
      int dpi_left  = dpi->left;
      int dpi_right = dpi->left + dpi->width - 1;
 
      for (int i = 0; i < run.GetGlyphCount(); i++) {
        GlyphID glyph = glyphs[i];
 
        /* Not a valid glyph (empty) */
        if (glyph == 0xFFFF) continue;
 
        int begin_x = positions[i].x     + left - offset_x;
        int end_x   = positions[i + 1].x + left - offset_x  - 1;
        int top     = positions[i].y + y;
 
        /* Truncated away. */
        if (truncation && (begin_x < min_x || end_x > max_x)) continue;
 
        const Sprite *sprite = fc->GetGlyph(glyph);
        /* Check clipping (the "+ 1" is for the shadow). */
        if (begin_x + sprite->x_offs > dpi_right || begin_x + sprite->x_offs + sprite->width /* - 1 + 1 */ < dpi_left) continue;
 
        if (do_shadow && (glyph & SPRITE_GLYPH) != 0) continue;
 
        GfxMainBlitter(sprite, begin_x + (do_shadow ? shadow_offset : 0), top + (do_shadow ? shadow_offset : 0), BM_COLOUR_REMAP);
      }
    }
 
    if (truncation && (!do_shadow || (dot_has_shadow && colour_has_shadow))) {
      int x = (_current_text_dir == TD_RTL) ? left : (right - 3 * dot_width);
      for (int i = 0; i < 3; i++, x += dot_width) {
        GfxMainBlitter(dot_sprite, x + (do_shadow ? shadow_offset : 0), y + (do_shadow ? shadow_offset : 0), BM_COLOUR_REMAP);
      }
    }
  }
 
  if (underline) {
    GfxFillRect(left, y + h, right, y + h + WidgetDimensions::scaled.bevel.top - 1, _string_colourremap[1]);
  }
 
  return (align & SA_HOR_MASK) == SA_RIGHT ? left : right;
}
 
int DrawString(int left, int right, int top, std::string_view str, TextColour colour, StringAlignment align, bool underline, FontSize fontsize)
{
  /* The string may contain control chars to change the font, just use the biggest font for clipping. */
  int max_height = std::max({GetCharacterHeight(FS_SMALL), GetCharacterHeight(FS_NORMAL), GetCharacterHeight(FS_LARGE), GetCharacterHeight(FS_MONO)});
 
  /* Funny glyphs may extent outside the usual bounds, so relax the clipping somewhat. */
  int extra = max_height / 2;
 
  if (_cur_dpi->top + _cur_dpi->height + extra < top || _cur_dpi->top > top + max_height + extra ||
      _cur_dpi->left + _cur_dpi->width + extra < left || _cur_dpi->left > right + extra) {
    return 0;
  }
 
  Layouter layout(str, INT32_MAX, colour, fontsize);
  if (layout.empty()) return 0;
 
  return DrawLayoutLine(*layout.front(), top, left, right, align, underline, true);
}
 
int DrawString(int left, int right, int top, StringID str, TextColour colour, StringAlignment align, bool underline, FontSize fontsize)
{
  return DrawString(left, right, top, GetString(str), colour, align, underline, fontsize);
}
 
int GetStringHeight(std::string_view str, int maxw, FontSize fontsize)
{
  assert(maxw > 0);
  Layouter layout(str, maxw, TC_FROMSTRING, fontsize);
  return layout.GetBounds().height;
}
 
int GetStringHeight(StringID str, int maxw)
{
  return GetStringHeight(GetString(str), maxw);
}
 
int GetStringLineCount(StringID str, int maxw)
{
  Layouter layout(GetString(str), maxw);
  return (uint)layout.size();
}
 
Dimension GetStringMultiLineBoundingBox(StringID str, const Dimension &suggestion)
{
  Dimension box = {suggestion.width, (uint)GetStringHeight(str, suggestion.width)};
  return box;
}
 
Dimension GetStringMultiLineBoundingBox(std::string_view str, const Dimension &suggestion)
{
  Dimension box = {suggestion.width, (uint)GetStringHeight(str, suggestion.width)};
  return box;
}
 
int DrawStringMultiLine(int left, int right, int top, int bottom, std::string_view str, TextColour colour, StringAlignment align, bool underline, FontSize fontsize)
{
  int maxw = right - left + 1;
  int maxh = bottom - top + 1;
 
  /* It makes no sense to even try if it can't be drawn anyway, or
   * do we really want to support fonts of 0 or less pixels high? */
  if (maxh <= 0) return top;
 
  Layouter layout(str, maxw, colour, fontsize);
  int total_height = layout.GetBounds().height;
  int y;
  switch (align & SA_VERT_MASK) {
    case SA_TOP:
      y = top;
      break;
 
    case SA_VERT_CENTER:
      y = RoundDivSU(bottom + top - total_height, 2);
      break;
 
    case SA_BOTTOM:
      y = bottom - total_height;
      break;
 
    default: NOT_REACHED();
  }
 
  int last_line = top;
  int first_line = bottom;
 
  for (const auto &line : layout) {
 
    int line_height = line->GetLeading();
    if (y >= top && y + line_height - 1 <= bottom) {
      last_line = y + line_height;
      if (first_line > y) first_line = y;
 
      DrawLayoutLine(*line, y, left, right, align, underline, false);
    }
    y += line_height;
  }
 
  return ((align & SA_VERT_MASK) == SA_BOTTOM) ? first_line : last_line;
}
 
int DrawStringMultiLine(int left, int right, int top, int bottom, StringID str, TextColour colour, StringAlignment align, bool underline, FontSize fontsize)
{
  return DrawStringMultiLine(left, right, top, bottom, GetString(str), colour, align, underline, fontsize);
}
 
Dimension GetStringBoundingBox(std::string_view str, FontSize start_fontsize)
{
  Layouter layout(str, INT32_MAX, TC_FROMSTRING, start_fontsize);
  return layout.GetBounds();
}
 
Dimension GetStringBoundingBox(StringID strid, FontSize start_fontsize)
{
  return GetStringBoundingBox(GetString(strid), start_fontsize);
}
 
uint GetStringListWidth(const StringID *list, FontSize fontsize)
{
  uint width = 0;
  for (const StringID *str = list; *str != INVALID_STRING_ID; str++) {
    width = std::max(width, GetStringBoundingBox(*str, fontsize).width);
  }
  return width;
}
 
Point GetCharPosInString(std::string_view str, const char *ch, FontSize start_fontsize)
{
  /* Ensure "ch" is inside "str" or at the exact end. */
  assert(ch >= str.data() && (ch - str.data()) <= static_cast<ptrdiff_t>(str.size()));
  auto it_ch = str.begin() + (ch - str.data());
 
  Layouter layout(str, INT32_MAX, TC_FROMSTRING, start_fontsize);
  return layout.GetCharPosition(it_ch);
}
 
ptrdiff_t GetCharAtPosition(std::string_view str, int x, FontSize start_fontsize)
{
  if (x < 0) return -1;
 
  Layouter layout(str, INT32_MAX, TC_FROMSTRING, start_fontsize);
  return layout.GetCharAtPosition(x, 0);
}
 
void DrawCharCentered(char32_t c, const Rect &r, TextColour colour)
{
  SetColourRemap(colour);
  GfxMainBlitter(GetGlyph(FS_NORMAL, c),
    CenterBounds(r.left, r.right, GetCharacterWidth(FS_NORMAL, c)),
    CenterBounds(r.top, r.bottom, GetCharacterHeight(FS_NORMAL)),
    BM_COLOUR_REMAP);
}
 
Dimension GetSpriteSize(SpriteID sprid, Point *offset, ZoomLevel zoom)
{
  const Sprite *sprite = GetSprite(sprid, SpriteType::Normal);
 
  if (offset != nullptr) {
    offset->x = UnScaleByZoom(sprite->x_offs, zoom);
    offset->y = UnScaleByZoom(sprite->y_offs, zoom);
  }
 
  Dimension d;
  d.width  = std::max<int>(0, UnScaleByZoom(sprite->x_offs + sprite->width, zoom));
  d.height = std::max<int>(0, UnScaleByZoom(sprite->y_offs + sprite->height, zoom));
  return d;
}
 
static BlitterMode GetBlitterMode(PaletteID pal)
{
  switch (pal) {
    case PAL_NONE:          return BM_NORMAL;
    case PALETTE_CRASH:     return BM_CRASH_REMAP;
    case PALETTE_ALL_BLACK: return BM_BLACK_REMAP;
    default:                return BM_COLOUR_REMAP;
  }
}
 
void DrawSpriteViewport(SpriteID img, PaletteID pal, int x, int y, const SubSprite *sub)
{
  SpriteID real_sprite = GB(img, 0, SPRITE_WIDTH);
  if (HasBit(img, PALETTE_MODIFIER_TRANSPARENT)) {
    pal = GB(pal, 0, PALETTE_WIDTH);
    _colour_remap_ptr = GetNonSprite(pal, SpriteType::Recolour) + 1;
    GfxMainBlitterViewport(GetSprite(real_sprite, SpriteType::Normal), x, y, pal == PALETTE_TO_TRANSPARENT ? BM_TRANSPARENT : BM_TRANSPARENT_REMAP, sub, real_sprite);
  } else if (pal != PAL_NONE) {
    if (HasBit(pal, PALETTE_TEXT_RECOLOUR)) {
      SetColourRemap((TextColour)GB(pal, 0, PALETTE_WIDTH));
    } else {
      _colour_remap_ptr = GetNonSprite(GB(pal, 0, PALETTE_WIDTH), SpriteType::Recolour) + 1;
    }
    GfxMainBlitterViewport(GetSprite(real_sprite, SpriteType::Normal), x, y, GetBlitterMode(pal), sub, real_sprite);
  } else {
    GfxMainBlitterViewport(GetSprite(real_sprite, SpriteType::Normal), x, y, BM_NORMAL, sub, real_sprite);
  }
}
 
void DrawSprite(SpriteID img, PaletteID pal, int x, int y, const SubSprite *sub, ZoomLevel zoom)
{
  SpriteID real_sprite = GB(img, 0, SPRITE_WIDTH);
  if (HasBit(img, PALETTE_MODIFIER_TRANSPARENT)) {
    pal = GB(pal, 0, PALETTE_WIDTH);
    _colour_remap_ptr = GetNonSprite(pal, SpriteType::Recolour) + 1;
    GfxMainBlitter(GetSprite(real_sprite, SpriteType::Normal), x, y, pal == PALETTE_TO_TRANSPARENT ? BM_TRANSPARENT : BM_TRANSPARENT_REMAP, sub, real_sprite, zoom);
  } else if (pal != PAL_NONE) {
    if (HasBit(pal, PALETTE_TEXT_RECOLOUR)) {
      SetColourRemap((TextColour)GB(pal, 0, PALETTE_WIDTH));
    } else {
      _colour_remap_ptr = GetNonSprite(GB(pal, 0, PALETTE_WIDTH), SpriteType::Recolour) + 1;
    }
    GfxMainBlitter(GetSprite(real_sprite, SpriteType::Normal), x, y, GetBlitterMode(pal), sub, real_sprite, zoom);
  } else {
    GfxMainBlitter(GetSprite(real_sprite, SpriteType::Normal), x, y, BM_NORMAL, sub, real_sprite, zoom);
  }
}
 
template <int ZOOM_BASE, bool SCALED_XY>
static void GfxBlitter(const Sprite * const sprite, int x, int y, BlitterMode mode, const SubSprite * const sub, SpriteID sprite_id, ZoomLevel zoom, const DrawPixelInfo *dst = nullptr)
{
  const DrawPixelInfo *dpi = (dst != nullptr) ? dst : _cur_dpi;
  Blitter::BlitterParams bp;
 
  if (SCALED_XY) {
    /* Scale it */
    x = ScaleByZoom(x, zoom);
    y = ScaleByZoom(y, zoom);
  }
 
  /* Move to the correct offset */
  x += sprite->x_offs;
  y += sprite->y_offs;
 
  if (sub == nullptr) {
    /* No clipping. */
    bp.skip_left = 0;
    bp.skip_top = 0;
    bp.width = UnScaleByZoom(sprite->width, zoom);
    bp.height = UnScaleByZoom(sprite->height, zoom);
  } else {
    /* Amount of pixels to clip from the source sprite */
    int clip_left   = std::max(0,                   -sprite->x_offs +  sub->left        * ZOOM_BASE );
    int clip_top    = std::max(0,                   -sprite->y_offs +  sub->top         * ZOOM_BASE );
    int clip_right  = std::max(0, sprite->width  - (-sprite->x_offs + (sub->right + 1)  * ZOOM_BASE));
    int clip_bottom = std::max(0, sprite->height - (-sprite->y_offs + (sub->bottom + 1) * ZOOM_BASE));
 
    if (clip_left + clip_right >= sprite->width) return;
    if (clip_top + clip_bottom >= sprite->height) return;
 
    bp.skip_left = UnScaleByZoomLower(clip_left, zoom);
    bp.skip_top = UnScaleByZoomLower(clip_top, zoom);
    bp.width = UnScaleByZoom(sprite->width - clip_left - clip_right, zoom);
    bp.height = UnScaleByZoom(sprite->height - clip_top - clip_bottom, zoom);
 
    x += ScaleByZoom(bp.skip_left, zoom);
    y += ScaleByZoom(bp.skip_top, zoom);
  }
 
  /* Copy the main data directly from the sprite */
  bp.sprite = sprite->data;
  bp.sprite_width = sprite->width;
  bp.sprite_height = sprite->height;
  bp.top = 0;
  bp.left = 0;
 
  bp.dst = dpi->dst_ptr;
  bp.pitch = dpi->pitch;
  bp.remap = _colour_remap_ptr;
 
  assert(sprite->width > 0);
  assert(sprite->height > 0);
 
  if (bp.width <= 0) return;
  if (bp.height <= 0) return;
 
  y -= SCALED_XY ? ScaleByZoom(dpi->top, zoom) : dpi->top;
  int y_unscaled = UnScaleByZoom(y, zoom);
  /* Check for top overflow */
  if (y < 0) {
    bp.height -= -y_unscaled;
    if (bp.height <= 0) return;
    bp.skip_top += -y_unscaled;
    y = 0;
  } else {
    bp.top = y_unscaled;
  }
 
  /* Check for bottom overflow */
  y += SCALED_XY ? ScaleByZoom(bp.height - dpi->height, zoom) : ScaleByZoom(bp.height, zoom) - dpi->height;
  if (y > 0) {
    bp.height -= UnScaleByZoom(y, zoom);
    if (bp.height <= 0) return;
  }
 
  x -= SCALED_XY ? ScaleByZoom(dpi->left, zoom) : dpi->left;
  int x_unscaled = UnScaleByZoom(x, zoom);
  /* Check for left overflow */
  if (x < 0) {
    bp.width -= -x_unscaled;
    if (bp.width <= 0) return;
    bp.skip_left += -x_unscaled;
    x = 0;
  } else {
    bp.left = x_unscaled;
  }
 
  /* Check for right overflow */
  x += SCALED_XY ? ScaleByZoom(bp.width - dpi->width, zoom) : ScaleByZoom(bp.width, zoom) - dpi->width;
  if (x > 0) {
    bp.width -= UnScaleByZoom(x, zoom);
    if (bp.width <= 0) return;
  }
 
  assert(bp.skip_left + bp.width <= UnScaleByZoom(sprite->width, zoom));
  assert(bp.skip_top + bp.height <= UnScaleByZoom(sprite->height, zoom));
 
  /* We do not want to catch the mouse. However we also use that spritenumber for unknown (text) sprites. */
  if (_newgrf_debug_sprite_picker.mode == SPM_REDRAW && sprite_id != SPR_CURSOR_MOUSE) {
    Blitter *blitter = BlitterFactory::GetCurrentBlitter();
    void *topleft = blitter->MoveTo(bp.dst, bp.left, bp.top);
    void *bottomright = blitter->MoveTo(topleft, bp.width - 1, bp.height - 1);
 
    void *clicked = _newgrf_debug_sprite_picker.clicked_pixel;
 
    if (topleft <= clicked && clicked <= bottomright) {
      uint offset = (((size_t)clicked - (size_t)topleft) / (blitter->GetScreenDepth() / 8)) % bp.pitch;
      if (offset < (uint)bp.width) {
        include(_newgrf_debug_sprite_picker.sprites, sprite_id);
      }
    }
  }
 
  BlitterFactory::GetCurrentBlitter()->Draw(&bp, mode, zoom);
}
 
std::unique_ptr<uint32_t[]> DrawSpriteToRgbaBuffer(SpriteID spriteId, ZoomLevel zoom)
{
  /* Invalid zoom level requested? */
  if (zoom < _settings_client.gui.zoom_min || zoom > _settings_client.gui.zoom_max) return nullptr;
 
  Blitter *blitter = BlitterFactory::GetCurrentBlitter();
  if (blitter->GetScreenDepth() != 8 && blitter->GetScreenDepth() != 32) return nullptr;
 
  /* Gather information about the sprite to write, reserve memory */
  const SpriteID real_sprite = GB(spriteId, 0, SPRITE_WIDTH);
  const Sprite *sprite = GetSprite(real_sprite, SpriteType::Normal);
  Dimension dim = GetSpriteSize(real_sprite, nullptr, zoom);
  size_t dim_size = static_cast<size_t>(dim.width) * dim.height;
  std::unique_ptr<uint32_t[]> result(new uint32_t[dim_size]);
  /* Set buffer to fully transparent. */
  MemSetT(result.get(), 0, dim_size);
 
  /* Prepare new DrawPixelInfo - Normally this would be the screen but we want to draw to another buffer here.
   * Normally, pitch would be scaled screen width, but in our case our "screen" is only the sprite width wide. */
  DrawPixelInfo dpi;
  dpi.dst_ptr = result.get();
  dpi.pitch = dim.width;
  dpi.left = 0;
  dpi.top = 0;
  dpi.width = dim.width;
  dpi.height = dim.height;
  dpi.zoom = zoom;
 
  dim_size = static_cast<size_t>(dim.width) * dim.height;
 
  /* If the current blitter is a paletted blitter, we have to render to an extra buffer and resolve the palette later. */
  std::unique_ptr<byte[]> pal_buffer{};
  if (blitter->GetScreenDepth() == 8) {
    pal_buffer.reset(new byte[dim_size]);
    MemSetT(pal_buffer.get(), 0, dim_size);
 
    dpi.dst_ptr = pal_buffer.get();
  }
 
  /* Temporarily disable screen animations while blitting - This prevents 40bpp_anim from writing to the animation buffer. */
  Backup<bool> disable_anim(_screen_disable_anim, true, FILE_LINE);
  GfxBlitter<1, true>(sprite, 0, 0, BM_NORMAL, nullptr, real_sprite, zoom, &dpi);
  disable_anim.Restore();
 
  if (blitter->GetScreenDepth() == 8) {
    /* Resolve palette. */
    uint32_t *dst = result.get();
    const byte *src = pal_buffer.get();
    for (size_t i = 0; i < dim_size; ++i) {
      *dst++ = _cur_palette.palette[*src++].data;
    }
  }
 
  return result;
}
 
static void GfxMainBlitterViewport(const Sprite *sprite, int x, int y, BlitterMode mode, const SubSprite *sub, SpriteID sprite_id)
{
  GfxBlitter<ZOOM_LVL_BASE, false>(sprite, x, y, mode, sub, sprite_id, _cur_dpi->zoom);
}
 
static void GfxMainBlitter(const Sprite *sprite, int x, int y, BlitterMode mode, const SubSprite *sub, SpriteID sprite_id, ZoomLevel zoom)
{
  GfxBlitter<1, true>(sprite, x, y, mode, sub, sprite_id, zoom);
}
 
void LoadStringWidthTable(bool monospace)
{
  ClearFontCache();
 
  for (FontSize fs = monospace ? FS_MONO : FS_BEGIN; fs < (monospace ? FS_END : FS_MONO); fs++) {
    for (uint i = 0; i != 224; i++) {
      _stringwidth_table[fs][i] = GetGlyphWidth(fs, i + 32);
    }
  }
}
 
byte GetCharacterWidth(FontSize size, char32_t key)
{
  /* Use _stringwidth_table cache if possible */
  if (key >= 32 && key < 256) return _stringwidth_table[size][key - 32];
 
  return GetGlyphWidth(size, key);
}
 
byte GetDigitWidth(FontSize size)
{
  byte width = 0;
  for (char c = '0'; c <= '9'; c++) {
    width = std::max(GetCharacterWidth(size, c), width);
  }
  return width;
}
 
void GetBroadestDigit(uint *front, uint *next, FontSize size)
{
  int width = -1;
  for (char c = '9'; c >= '0'; c--) {
    int w = GetCharacterWidth(size, c);
    if (w > width) {
      width = w;
      *next = c - '0';
      if (c != '0') *front = c - '0';
    }
  }
}
 
void ScreenSizeChanged()
{
  _dirty_bytes_per_line = CeilDiv(_screen.width, DIRTY_BLOCK_WIDTH);
  _dirty_blocks = ReallocT<byte>(_dirty_blocks, static_cast<size_t>(_dirty_bytes_per_line) * CeilDiv(_screen.height, DIRTY_BLOCK_HEIGHT));
 
  /* check the dirty rect */
  if (_invalid_rect.right >= _screen.width) _invalid_rect.right = _screen.width;
  if (_invalid_rect.bottom >= _screen.height) _invalid_rect.bottom = _screen.height;
 
  /* screen size changed and the old bitmap is invalid now, so we don't want to undraw it */
  _cursor.visible = false;
}
 
void UndrawMouseCursor()
{
  /* Don't undraw mouse cursor if it is handled by the video driver. */
  if (VideoDriver::GetInstance()->UseSystemCursor()) return;
 
  /* Don't undraw the mouse cursor if the screen is not ready */
  if (_screen.dst_ptr == nullptr) return;
 
  if (_cursor.visible) {
    Blitter *blitter = BlitterFactory::GetCurrentBlitter();
    _cursor.visible = false;
    blitter->CopyFromBuffer(blitter->MoveTo(_screen.dst_ptr, _cursor.draw_pos.x, _cursor.draw_pos.y), _cursor_backup.GetBuffer(), _cursor.draw_size.x, _cursor.draw_size.y);
    VideoDriver::GetInstance()->MakeDirty(_cursor.draw_pos.x, _cursor.draw_pos.y, _cursor.draw_size.x, _cursor.draw_size.y);
  }
}
 
void DrawMouseCursor()
{
  /* Don't draw mouse cursor if it is handled by the video driver. */
  if (VideoDriver::GetInstance()->UseSystemCursor()) return;
 
  /* Don't draw the mouse cursor if the screen is not ready */
  if (_screen.dst_ptr == nullptr) return;
 
  Blitter *blitter = BlitterFactory::GetCurrentBlitter();
 
  /* Redraw mouse cursor but only when it's inside the window */
  if (!_cursor.in_window) return;
 
  /* Don't draw the mouse cursor if it's already drawn */
  if (_cursor.visible) {
    if (!_cursor.dirty) return;
    UndrawMouseCursor();
  }
 
  /* Determine visible area */
  int left = _cursor.pos.x + _cursor.total_offs.x;
  int width = _cursor.total_size.x;
  if (left < 0) {
    width += left;
    left = 0;
  }
  if (left + width > _screen.width) {
    width = _screen.width - left;
  }
  if (width <= 0) return;
 
  int top = _cursor.pos.y + _cursor.total_offs.y;
  int height = _cursor.total_size.y;
  if (top < 0) {
    height += top;
    top = 0;
  }
  if (top + height > _screen.height) {
    height = _screen.height - top;
  }
  if (height <= 0) return;
 
  _cursor.draw_pos.x = left;
  _cursor.draw_pos.y = top;
  _cursor.draw_size.x = width;
  _cursor.draw_size.y = height;
 
  uint8_t *buffer = _cursor_backup.Allocate(blitter->BufferSize(_cursor.draw_size.x, _cursor.draw_size.y));
 
  /* Make backup of stuff below cursor */
  blitter->CopyToBuffer(blitter->MoveTo(_screen.dst_ptr, _cursor.draw_pos.x, _cursor.draw_pos.y), buffer, _cursor.draw_size.x, _cursor.draw_size.y);
 
  /* Draw cursor on screen */
  _cur_dpi = &_screen;
  for (uint i = 0; i < _cursor.sprite_count; ++i) {
    DrawSprite(_cursor.sprite_seq[i].sprite, _cursor.sprite_seq[i].pal, _cursor.pos.x + _cursor.sprite_pos[i].x, _cursor.pos.y + _cursor.sprite_pos[i].y);
  }
 
  VideoDriver::GetInstance()->MakeDirty(_cursor.draw_pos.x, _cursor.draw_pos.y, _cursor.draw_size.x, _cursor.draw_size.y);
 
  _cursor.visible = true;
  _cursor.dirty = false;
}
 
void RedrawScreenRect(int left, int top, int right, int bottom)
{
  assert(right <= _screen.width && bottom <= _screen.height);
  if (_cursor.visible) {
    if (right > _cursor.draw_pos.x &&
        left < _cursor.draw_pos.x + _cursor.draw_size.x &&
        bottom > _cursor.draw_pos.y &&
        top < _cursor.draw_pos.y + _cursor.draw_size.y) {
      UndrawMouseCursor();
    }
  }
 
  if (_networking) NetworkUndrawChatMessage();
 
  DrawOverlappedWindowForAll(left, top, right, bottom);
 
  VideoDriver::GetInstance()->MakeDirty(left, top, right - left, bottom - top);
}
 
void DrawDirtyBlocks()
{
  byte *b = _dirty_blocks;
  const int w = Align(_screen.width,  DIRTY_BLOCK_WIDTH);
  const int h = Align(_screen.height, DIRTY_BLOCK_HEIGHT);
  int x;
  int y;
 
  y = 0;
  do {
    x = 0;
    do {
      if (*b != 0) {
        int left;
        int top;
        int right = x + DIRTY_BLOCK_WIDTH;
        int bottom = y;
        byte *p = b;
        int h2;
 
        /* First try coalescing downwards */
        do {
          *p = 0;
          p += _dirty_bytes_per_line;
          bottom += DIRTY_BLOCK_HEIGHT;
        } while (bottom != h && *p != 0);
 
        /* Try coalescing to the right too. */
        h2 = (bottom - y) / DIRTY_BLOCK_HEIGHT;
        assert(h2 > 0);
        p = b;
 
        while (right != w) {
          byte *p2 = ++p;
          int i = h2;
          /* Check if a full line of dirty flags is set. */
          do {
            if (!*p2) goto no_more_coalesc;
            p2 += _dirty_bytes_per_line;
          } while (--i != 0);
 
          /* Wohoo, can combine it one step to the right!
           * Do that, and clear the bits. */
          right += DIRTY_BLOCK_WIDTH;
 
          i = h2;
          p2 = p;
          do {
            *p2 = 0;
            p2 += _dirty_bytes_per_line;
          } while (--i != 0);
        }
        no_more_coalesc:
 
        left = x;
        top = y;
 
        if (left   < _invalid_rect.left  ) left   = _invalid_rect.left;
        if (top    < _invalid_rect.top   ) top    = _invalid_rect.top;
        if (right  > _invalid_rect.right ) right  = _invalid_rect.right;
        if (bottom > _invalid_rect.bottom) bottom = _invalid_rect.bottom;
 
        if (left < right && top < bottom) {
          RedrawScreenRect(left, top, right, bottom);
        }
 
      }
    } while (b++, (x += DIRTY_BLOCK_WIDTH) != w);
  } while (b += -(int)(w / DIRTY_BLOCK_WIDTH) + _dirty_bytes_per_line, (y += DIRTY_BLOCK_HEIGHT) != h);
 
  ++_dirty_block_colour;
  _invalid_rect.left = w;
  _invalid_rect.top = h;
  _invalid_rect.right = 0;
  _invalid_rect.bottom = 0;
}
 
void AddDirtyBlock(int left, int top, int right, int bottom)
{
  byte *b;
  int width;
  int height;
 
  if (left < 0) left = 0;
  if (top < 0) top = 0;
  if (right > _screen.width) right = _screen.width;
  if (bottom > _screen.height) bottom = _screen.height;
 
  if (left >= right || top >= bottom) return;
 
  if (left   < _invalid_rect.left  ) _invalid_rect.left   = left;
  if (top    < _invalid_rect.top   ) _invalid_rect.top    = top;
  if (right  > _invalid_rect.right ) _invalid_rect.right  = right;
  if (bottom > _invalid_rect.bottom) _invalid_rect.bottom = bottom;
 
  left /= DIRTY_BLOCK_WIDTH;
  top  /= DIRTY_BLOCK_HEIGHT;
 
  b = _dirty_blocks + top * _dirty_bytes_per_line + left;
 
  width  = ((right  - 1) / DIRTY_BLOCK_WIDTH)  - left + 1;
  height = ((bottom - 1) / DIRTY_BLOCK_HEIGHT) - top  + 1;
 
  assert(width > 0 && height > 0);
 
  do {
    int i = width;
 
    do b[--i] = 0xFF; while (i != 0);
 
    b += _dirty_bytes_per_line;
  } while (--height != 0);
}
 
void MarkWholeScreenDirty()
{
  AddDirtyBlock(0, 0, _screen.width, _screen.height);
}
 
bool FillDrawPixelInfo(DrawPixelInfo *n, int left, int top, int width, int height)
{
  Blitter *blitter = BlitterFactory::GetCurrentBlitter();
  const DrawPixelInfo *o = _cur_dpi;
 
  n->zoom = ZOOM_LVL_NORMAL;
 
  assert(width > 0);
  assert(height > 0);
 
  if ((left -= o->left) < 0) {
    width += left;
    if (width <= 0) return false;
    n->left = -left;
    left = 0;
  } else {
    n->left = 0;
  }
 
  if (width > o->width - left) {
    width = o->width - left;
    if (width <= 0) return false;
  }
  n->width = width;
 
  if ((top -= o->top) < 0) {
    height += top;
    if (height <= 0) return false;
    n->top = -top;
    top = 0;
  } else {
    n->top = 0;
  }
 
  n->dst_ptr = blitter->MoveTo(o->dst_ptr, left, top);
  n->pitch = o->pitch;
 
  if (height > o->height - top) {
    height = o->height - top;
    if (height <= 0) return false;
  }
  n->height = height;
 
  return true;
}
 
void UpdateCursorSize()
{
  /* Ignore setting any cursor before the sprites are loaded. */
  if (GetMaxSpriteID() == 0) return;
 
  static_assert(lengthof(_cursor.sprite_seq) == lengthof(_cursor.sprite_pos));
  assert(_cursor.sprite_count <= lengthof(_cursor.sprite_seq));
  for (uint i = 0; i < _cursor.sprite_count; ++i) {
    const Sprite *p = GetSprite(GB(_cursor.sprite_seq[i].sprite, 0, SPRITE_WIDTH), SpriteType::Normal);
    Point offs, size;
    offs.x = UnScaleGUI(p->x_offs) + _cursor.sprite_pos[i].x;
    offs.y = UnScaleGUI(p->y_offs) + _cursor.sprite_pos[i].y;
    size.x = UnScaleGUI(p->width);
    size.y = UnScaleGUI(p->height);
 
    if (i == 0) {
      _cursor.total_offs = offs;
      _cursor.total_size = size;
    } else {
      int right  = std::max(_cursor.total_offs.x + _cursor.total_size.x, offs.x + size.x);
      int bottom = std::max(_cursor.total_offs.y + _cursor.total_size.y, offs.y + size.y);
      if (offs.x < _cursor.total_offs.x) _cursor.total_offs.x = offs.x;
      if (offs.y < _cursor.total_offs.y) _cursor.total_offs.y = offs.y;
      _cursor.total_size.x = right  - _cursor.total_offs.x;
      _cursor.total_size.y = bottom - _cursor.total_offs.y;
    }
  }
 
  _cursor.dirty = true;
}
 
static void SetCursorSprite(CursorID cursor, PaletteID pal)
{
  if (_cursor.sprite_count == 1 && _cursor.sprite_seq[0].sprite == cursor && _cursor.sprite_seq[0].pal == pal) return;
 
  _cursor.sprite_count = 1;
  _cursor.sprite_seq[0].sprite = cursor;
  _cursor.sprite_seq[0].pal = pal;
  _cursor.sprite_pos[0].x = 0;
  _cursor.sprite_pos[0].y = 0;
 
  UpdateCursorSize();
}
 
static void SwitchAnimatedCursor()
{
  const AnimCursor *cur = _cursor.animate_cur;
 
  if (cur == nullptr || cur->sprite == AnimCursor::LAST) cur = _cursor.animate_list;
 
  SetCursorSprite(cur->sprite, _cursor.sprite_seq[0].pal);
 
  _cursor.animate_timeout = cur->display_time;
  _cursor.animate_cur     = cur + 1;
}
 
void CursorTick()
{
  if (_cursor.animate_timeout != 0 && --_cursor.animate_timeout == 0) {
    SwitchAnimatedCursor();
  }
}
 
void SetMouseCursorBusy(bool busy)
{
  if (busy) {
    if (_cursor.sprite_seq[0].sprite == SPR_CURSOR_MOUSE) SetMouseCursor(SPR_CURSOR_ZZZ, PAL_NONE);
  } else {
    if (_cursor.sprite_seq[0].sprite == SPR_CURSOR_ZZZ) SetMouseCursor(SPR_CURSOR_MOUSE, PAL_NONE);
  }
}
 
void SetMouseCursor(CursorID sprite, PaletteID pal)
{
  /* Turn off animation */
  _cursor.animate_timeout = 0;
  /* Set cursor */
  SetCursorSprite(sprite, pal);
}
 
void SetAnimatedMouseCursor(const AnimCursor *table)
{
  _cursor.animate_list = table;
  _cursor.animate_cur = nullptr;
  _cursor.sprite_seq[0].pal = PAL_NONE;
  SwitchAnimatedCursor();
}
 
void CursorVars::UpdateCursorPositionRelative(int delta_x, int delta_y)
{
  assert(this->fix_at);
 
  this->delta.x = delta_x;
  this->delta.y = delta_y;
}
 
bool CursorVars::UpdateCursorPosition(int x, int y)
{
  this->delta.x = x - this->pos.x;
  this->delta.y = y - this->pos.y;
 
  if (this->fix_at) {
    return this->delta.x != 0 || this->delta.y != 0;
  } else if (this->pos.x != x || this->pos.y != y) {
    this->dirty = true;
    this->pos.x = x;
    this->pos.y = y;
  }
 
  return false;
}
 
bool ChangeResInGame(int width, int height)
{
  return (_screen.width == width && _screen.height == height) || VideoDriver::GetInstance()->ChangeResolution(width, height);
}
 
bool ToggleFullScreen(bool fs)
{
  bool result = VideoDriver::GetInstance()->ToggleFullscreen(fs);
  if (_fullscreen != fs && _resolutions.empty()) {
    Debug(driver, 0, "Could not find a suitable fullscreen resolution");
  }
  return result;
}
 
void SortResolutions()
{
  std::sort(_resolutions.begin(), _resolutions.end());
 
  /* Remove any duplicates from the list. */
  auto last = std::unique(_resolutions.begin(), _resolutions.end());
  _resolutions.erase(last, _resolutions.end());
}
 
void UpdateGUIZoom()
{
  /* Determine real GUI zoom to use. */
  if (_gui_scale_cfg == -1) {
    _gui_scale = VideoDriver::GetInstance()->GetSuggestedUIScale();
  } else {
    _gui_scale = Clamp(_gui_scale_cfg, MIN_INTERFACE_SCALE, MAX_INTERFACE_SCALE);
  }
 
  int8_t new_zoom = ScaleGUITrad(1) <= 1 ? ZOOM_LVL_OUT_4X : ScaleGUITrad(1) >= 4 ? ZOOM_LVL_MIN : ZOOM_LVL_OUT_2X;
  /* Font glyphs should not be clamped to min/max zoom. */
  _font_zoom = static_cast<ZoomLevel>(new_zoom);
  /* Ensure the gui_zoom is clamped between min/max. */
  new_zoom = Clamp(new_zoom, _settings_client.gui.zoom_min, _settings_client.gui.zoom_max);
  _gui_zoom = static_cast<ZoomLevel>(new_zoom);
}
 
bool AdjustGUIZoom(bool automatic)
{
  ZoomLevel old_gui_zoom = _gui_zoom;
  ZoomLevel old_font_zoom = _font_zoom;
  int old_scale = _gui_scale;
  UpdateGUIZoom();
  if (old_scale == _gui_scale && old_gui_zoom == _gui_zoom) return false;
 
  /* Update cursors if sprite zoom level has changed. */
  if (old_gui_zoom != _gui_zoom) {
    VideoDriver::GetInstance()->ClearSystemSprites();
    UpdateCursorSize();
  }
  if (old_font_zoom != _font_zoom) {
    GfxClearFontSpriteCache();
  }
  ClearFontCache();
  LoadStringWidthTable();
 
  SetupWidgetDimensions();
  UpdateAllVirtCoords();
 
  /* Adjust all window sizes to match the new zoom level, so that they don't appear
     to move around when the application is moved to a screen with different DPI. */
  auto zoom_shift = old_gui_zoom - _gui_zoom;
  for (Window *w : Window::Iterate()) {
    if (automatic) {
      w->left   = (w->left   * _gui_scale) / old_scale;
      w->top    = (w->top    * _gui_scale) / old_scale;
    }
    if (w->viewport != nullptr) {
      w->viewport->zoom = static_cast<ZoomLevel>(Clamp(w->viewport->zoom - zoom_shift, _settings_client.gui.zoom_min, _settings_client.gui.zoom_max));
    }
  }
 
  return true;
}
 
void ChangeGameSpeed(bool enable_fast_forward)
{
  if (enable_fast_forward) {
    _game_speed = _settings_client.gui.fast_forward_speed_limit;
  } else {
    _game_speed = 100;
  }
}