src/gfx_layout.h

   1 /* $Id$ */
   2
   3 /*
   4  * This file is part of OpenTTD.
   5  * 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.
   6  * 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.
   7  * 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/>.
   8  */
   9
  10 /** @file gfx_layout.h Functions related to laying out the texts. */
  11
  12 #ifndef GFX_LAYOUT_H
  13 #define GFX_LAYOUT_H
  14
  15 #include "fontcache.h"
  16 #include "gfx_func.h"
  17 #include "core/smallmap_type.hpp"
  18
  19 #include <map>
  20 #include <string>
  21 #include <stack>
  22 #include <vector>
  23
  24 #ifdef WITH_ICU_LX
  25 #include "layout/ParagraphLayout.h"
  26 #define ICU_FONTINSTANCE : public icu::LEFontInstance
  27 #else /* WITH_ICU_LX */
  28 #define ICU_FONTINSTANCE
  29 #endif /* WITH_ICU_LX */
  30
  31 /**
  32  * Text drawing parameters, which can change while drawing a line, but are kept between multiple parts
  33  * of the same text, e.g. on line breaks.
  34  */
  35 struct FontState {
  36         FontSize fontsize;       ///< Current font size.
  37         TextColour cur_colour;   ///< Current text colour.
  38
  39         std::stack<TextColour, std::vector<TextColour>> colour_stack; ///< Stack of colours to assist with colour switching.
  40
  41         FontState() : fontsize(FS_END), cur_colour(TC_INVALID) {}
  42         FontState(TextColour colour, FontSize fontsize) : fontsize(fontsize), cur_colour(colour) {}
  43
  44         /**
  45          * Switch to new colour \a c.
  46          * @param c New colour to use.
  47          */
  48         inline void SetColour(TextColour c)
  49         {
  50                 assert(c >= TC_BLUE && c <= TC_BLACK);
  51                 this->cur_colour = c;
  52         }
  53
  54         /**
  55          * Switch to and pop the last saved colour on the stack.
  56          */
  57         inline void PopColour()
  58         {
  59                 if (colour_stack.empty()) return;
  60                 SetColour(colour_stack.top());
  61                 colour_stack.pop();
  62         }
  63
  64         /**
  65          * Push the current colour on to the stack.
  66          */
  67         inline void PushColour()
  68         {
  69                 colour_stack.push(this->cur_colour);
  70         }
  71
  72         /**
  73          * Switch to using a new font \a f.
  74          * @param f New font to use.
  75          */
  76         inline void SetFontSize(FontSize f)
  77         {
  78                 this->fontsize = f;
  79         }
  80 };
  81
  82 /**
  83  * Container with information about a font.
  84  */
  85 class Font ICU_FONTINSTANCE {
  86 public:
  87         FontCache *fc;     ///< The font we are using.
  88         TextColour colour; ///< The colour this font has to be.
  89
  90         Font(FontSize size, TextColour colour);
  91
  92 #ifdef WITH_ICU_LX
  93         /* Implementation details of LEFontInstance */
  94
  95         le_int32 getUnitsPerEM() const;
  96         le_int32 getAscent() const;
  97         le_int32 getDescent() const;
  98         le_int32 getLeading() const;
  99         float getXPixelsPerEm() const;
 100         float getYPixelsPerEm() const;
 101         float getScaleFactorX() const;
 102         float getScaleFactorY() const;
 103         const void *getFontTable(LETag tableTag) const;
 104         const void *getFontTable(LETag tableTag, size_t &length) const;
 105         LEGlyphID mapCharToGlyph(LEUnicode32 ch) const;
 106         void getGlyphAdvance(LEGlyphID glyph, LEPoint &advance) const;
 107         le_bool getGlyphPoint(LEGlyphID glyph, le_int32 pointNumber, LEPoint &point) const;
 108 #endif /* WITH_ICU_LX */
 109 };
 110
 111 /** Mapping from index to font. */
 112 typedef SmallMap<int, Font *> FontMap;
 113
 114 /**
 115  * Interface to glue fallback and normal layouter into one.
 116  */
 117 class ParagraphLayouter {
 118 public:
 119         virtual ~ParagraphLayouter() {}
 120
 121         /** Visual run contains data about the bit of text with the same font. */
 122         class VisualRun {
 123         public:
 124                 virtual ~VisualRun() {}
 125                 virtual const Font *GetFont() const = 0;
 126                 virtual int GetGlyphCount() const = 0;
 127                 virtual const GlyphID *GetGlyphs() const = 0;
 128                 virtual const float *GetPositions() const = 0;
 129                 virtual int GetLeading() const = 0;
 130                 virtual const int *GetGlyphToCharMap() const = 0;
 131         };
 132
 133         /** A single line worth of VisualRuns. */
 134         class Line {
 135         public:
 136                 virtual ~Line() {}
 137                 virtual int GetLeading() const = 0;
 138                 virtual int GetWidth() const = 0;
 139                 virtual int CountRuns() const = 0;
 140                 virtual const VisualRun &GetVisualRun(int run) const = 0;
 141                 virtual int GetInternalCharLength(WChar c) const = 0;
 142         };
 143
 144         virtual void Reflow() = 0;
 145         virtual std::unique_ptr<const Line> NextLine(int max_width) = 0;
 146 };
 147
 148 /**
 149  * The layouter performs all the layout work.
 150  *
 151  * It also accounts for the memory allocations and frees.
 152  */
 153 class Layouter : public std::vector<std::unique_ptr<const ParagraphLayouter::Line>> {
 154         const char *string; ///< Pointer to the original string.
 155
 156         /** Key into the linecache */
 157         struct LineCacheKey {
 158                 FontState state_before;  ///< Font state at the beginning of the line.
 159                 std::string str;         ///< Source string of the line (including colour and font size codes).
 160
 161                 /** Comparison operator for std::map */
 162                 bool operator<(const LineCacheKey &other) const
 163                 {
 164                         if (this->state_before.fontsize != other.state_before.fontsize) return this->state_before.fontsize < other.state_before.fontsize;
 165                         if (this->state_before.cur_colour != other.state_before.cur_colour) return this->state_before.cur_colour < other.state_before.cur_colour;
 166                         if (this->state_before.colour_stack != other.state_before.colour_stack) return this->state_before.colour_stack < other.state_before.colour_stack;
 167                         return this->str < other.str;
 168                 }
 169         };
 170 public:
 171         /** Item in the linecache */
 172         struct LineCacheItem {
 173                 /* Stuff that cannot be freed until the ParagraphLayout is freed */
 174                 void *buffer;              ///< Accessed by both ICU's and our ParagraphLayout::nextLine.
 175                 FontMap runs;              ///< Accessed by our ParagraphLayout::nextLine.
 176
 177                 FontState state_after;     ///< Font state after the line.
 178                 ParagraphLayouter *layout; ///< Layout of the line.
 179
 180                 LineCacheItem() : buffer(nullptr), layout(nullptr) {}
 181                 ~LineCacheItem() { delete layout; free(buffer); }
 182         };
 183 private:
 184         typedef std::map<LineCacheKey, LineCacheItem> LineCache;
 185         static LineCache *linecache;
 186
 187         static LineCacheItem &GetCachedParagraphLayout(const char *str, size_t len, const FontState &state);
 188
 189         typedef SmallMap<TextColour, Font *> FontColourMap;
 190         static FontColourMap fonts[FS_END];
 191 public:
 192         static Font *GetFont(FontSize size, TextColour colour);
 193
 194         Layouter(const char *str, int maxw = INT32_MAX, TextColour colour = TC_FROMSTRING, FontSize fontsize = FS_NORMAL);
 195         Dimension GetBounds();
 196         Point GetCharPosition(const char *ch) const;
 197         const char *GetCharAtPosition(int x) const;
 198
 199         static void ResetFontCache(FontSize size);
 200         static void ResetLineCache();
 201         static void ReduceLineCache();
 202 };
 203
 204 #endif /* GFX_LAYOUT_H */