src/gfx_layout.h

   1 /*
   2  * This file is part of OpenTTD.
   3  * 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.
   4  * 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.
   5  * 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/>.
   6  */
   7
   8 /** @file gfx_layout.h Functions related to laying out the texts. */
   9
  10 #ifndef GFX_LAYOUT_H
  11 #define GFX_LAYOUT_H
  12
  13 #include "fontcache.h"
  14 #include "gfx_func.h"
  15 #include "core/smallmap_type.hpp"
  16
  17 #include <map>
  18 #include <string>
  19 #include <stack>
  20 #include <vector>
  21
  22 #ifdef WITH_ICU_LX
  23 #include "layout/ParagraphLayout.h"
  24 #define ICU_FONTINSTANCE : public icu::LEFontInstance
  25 #else /* WITH_ICU_LX */
  26 #define ICU_FONTINSTANCE
  27 #endif /* WITH_ICU_LX */
  28
  29 /**
  30  * Text drawing parameters, which can change while drawing a line, but are kept between multiple parts
  31  * of the same text, e.g. on line breaks.
  32  */
  33 struct FontState {
  34         FontSize fontsize;       ///< Current font size.
  35         TextColour cur_colour;   ///< Current text colour.
  36
  37         std::stack<TextColour, std::vector<TextColour>> colour_stack; ///< Stack of colours to assist with colour switching.
  38
  39         FontState() : fontsize(FS_END), cur_colour(TC_INVALID) {}
  40         FontState(TextColour colour, FontSize fontsize) : fontsize(fontsize), cur_colour(colour) {}
  41
  42         /**
  43          * Switch to new colour \a c.
  44          * @param c New colour to use.
  45          */
  46         inline void SetColour(TextColour c)
  47         {
  48                 assert(c >= TC_BLUE && c <= TC_BLACK);
  49                 if ((this->cur_colour & TC_FORCED) == 0) this->cur_colour = c;
  50         }
  51
  52         /**
  53          * Switch to and pop the last saved colour on the stack.
  54          */
  55         inline void PopColour()
  56         {
  57                 if (colour_stack.empty()) return;
  58                 SetColour(colour_stack.top());
  59                 colour_stack.pop();
  60         }
  61
  62         /**
  63          * Push the current colour on to the stack.
  64          */
  65         inline void PushColour()
  66         {
  67                 colour_stack.push(this->cur_colour);
  68         }
  69
  70         /**
  71          * Switch to using a new font \a f.
  72          * @param f New font to use.
  73          */
  74         inline void SetFontSize(FontSize f)
  75         {
  76                 this->fontsize = f;
  77         }
  78 };
  79
  80 /**
  81  * Container with information about a font.
  82  */
  83 class Font ICU_FONTINSTANCE {
  84 public:
  85         FontCache *fc;     ///< The font we are using.
  86         TextColour colour; ///< The colour this font has to be.
  87
  88         Font(FontSize size, TextColour colour);
  89
  90 #ifdef WITH_ICU_LX
  91         /* Implementation details of LEFontInstance */
  92
  93         le_int32 getUnitsPerEM() const;
  94         le_int32 getAscent() const;
  95         le_int32 getDescent() const;
  96         le_int32 getLeading() const;
  97         float getXPixelsPerEm() const;
  98         float getYPixelsPerEm() const;
  99         float getScaleFactorX() const;
 100         float getScaleFactorY() const;
 101         const void *getFontTable(LETag tableTag) const;
 102         const void *getFontTable(LETag tableTag, size_t &length) const;
 103         LEGlyphID mapCharToGlyph(LEUnicode32 ch) const;
 104         void getGlyphAdvance(LEGlyphID glyph, LEPoint &advance) const;
 105         le_bool getGlyphPoint(LEGlyphID glyph, le_int32 pointNumber, LEPoint &point) const;
 106 #endif /* WITH_ICU_LX */
 107 };
 108
 109 /** Mapping from index to font. */
 110 typedef SmallMap<int, Font *> FontMap;
 111
 112 /**
 113  * Interface to glue fallback and normal layouter into one.
 114  */
 115 class ParagraphLayouter {
 116 public:
 117         virtual ~ParagraphLayouter() {}
 118
 119         /** Visual run contains data about the bit of text with the same font. */
 120         class VisualRun {
 121         public:
 122                 virtual ~VisualRun() {}
 123                 virtual const Font *GetFont() const = 0;
 124                 virtual int GetGlyphCount() const = 0;
 125                 virtual const GlyphID *GetGlyphs() const = 0;
 126                 virtual const float *GetPositions() const = 0;
 127                 virtual int GetLeading() const = 0;
 128                 virtual const int *GetGlyphToCharMap() const = 0;
 129         };
 130
 131         /** A single line worth of VisualRuns. */
 132         class Line {
 133         public:
 134                 virtual ~Line() {}
 135                 virtual int GetLeading() const = 0;
 136                 virtual int GetWidth() const = 0;
 137                 virtual int CountRuns() const = 0;
 138                 virtual const VisualRun &GetVisualRun(int run) const = 0;
 139                 virtual int GetInternalCharLength(WChar c) const = 0;
 140         };
 141
 142         virtual void Reflow() = 0;
 143         virtual std::unique_ptr<const Line> NextLine(int max_width) = 0;
 144 };
 145
 146 /**
 147  * The layouter performs all the layout work.
 148  *
 149  * It also accounts for the memory allocations and frees.
 150  */
 151 class Layouter : public std::vector<std::unique_ptr<const ParagraphLayouter::Line>> {
 152         const char *string; ///< Pointer to the original string.
 153
 154         /** Key into the linecache */
 155         struct LineCacheKey {
 156                 FontState state_before;  ///< Font state at the beginning of the line.
 157                 std::string str;         ///< Source string of the line (including colour and font size codes).
 158
 159                 /** Comparison operator for std::map */
 160                 bool operator<(const LineCacheKey &other) const
 161                 {
 162                         if (this->state_before.fontsize != other.state_before.fontsize) return this->state_before.fontsize < other.state_before.fontsize;
 163                         if (this->state_before.cur_colour != other.state_before.cur_colour) return this->state_before.cur_colour < other.state_before.cur_colour;
 164                         if (this->state_before.colour_stack != other.state_before.colour_stack) return this->state_before.colour_stack < other.state_before.colour_stack;
 165                         return this->str < other.str;
 166                 }
 167         };
 168 public:
 169         /** Item in the linecache */
 170         struct LineCacheItem {
 171                 /* Stuff that cannot be freed until the ParagraphLayout is freed */
 172                 void *buffer;              ///< Accessed by both ICU's and our ParagraphLayout::nextLine.
 173                 FontMap runs;              ///< Accessed by our ParagraphLayout::nextLine.
 174
 175                 FontState state_after;     ///< Font state after the line.
 176                 ParagraphLayouter *layout; ///< Layout of the line.
 177
 178                 LineCacheItem() : buffer(nullptr), layout(nullptr) {}
 179                 ~LineCacheItem() { delete layout; free(buffer); }
 180         };
 181 private:
 182         typedef std::map<LineCacheKey, LineCacheItem> LineCache;
 183         static LineCache *linecache;
 184
 185         static LineCacheItem &GetCachedParagraphLayout(const char *str, size_t len, const FontState &state);
 186
 187         typedef SmallMap<TextColour, Font *> FontColourMap;
 188         static FontColourMap fonts[FS_END];
 189 public:
 190         static Font *GetFont(FontSize size, TextColour colour);
 191
 192         Layouter(const char *str, int maxw = INT32_MAX, TextColour colour = TC_FROMSTRING, FontSize fontsize = FS_NORMAL);
 193         Dimension GetBounds();
 194         Point GetCharPosition(const char *ch) const;
 195         const char *GetCharAtPosition(int x) const;
 196
 197         static void ResetFontCache(FontSize size);
 198         static void ResetLineCache();
 199         static void ReduceLineCache();
 200 };
 201
 202 #endif /* GFX_LAYOUT_H */