layout/mathml/nsMathMLChar.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef nsMathMLChar_h___
   8 #define nsMathMLChar_h___
   9
  10 #include "nsColor.h"
  11 #include "nsMathMLOperators.h"
  12 #include "nsPoint.h"
  13 #include "nsRect.h"
  14 #include "nsString.h"
  15 #include "nsBoundingMetrics.h"
  16 #include "gfxTextRun.h"
  17
  18 class gfxContext;
  19 class nsGlyphTable;
  20 class nsIFrame;
  21 class nsPresContext;
  22 struct nsBoundingMetrics;
  23 struct nsFont;
  24
  25 namespace mozilla {
  26 class nsDisplayListBuilder;
  27 class nsDisplayListSet;
  28 class ComputedStyle;
  29 }  // namespace mozilla
  30
  31 // Hints for Stretch() to indicate criteria for stretching
  32 enum {
  33   // Don't stretch
  34   NS_STRETCH_NONE = 0x00,
  35   // Variable size stretches
  36   NS_STRETCH_VARIABLE_MASK = 0x0F,
  37   NS_STRETCH_NORMAL = 0x01,   // try to stretch to requested size
  38   NS_STRETCH_NEARER = 0x02,   // stretch very close to requested size
  39   NS_STRETCH_SMALLER = 0x04,  // don't stretch more than requested size
  40   NS_STRETCH_LARGER = 0x08,   // don't stretch less than requested size
  41   // A largeop in displaystyle
  42   NS_STRETCH_LARGEOP = 0x10,
  43
  44   // Intended for internal use:
  45   // Find the widest metrics that might be returned from a vertical stretch
  46   NS_STRETCH_MAXWIDTH = 0x20
  47 };
  48
  49 // A single glyph in our internal representation is either
  50 // 1) a 'code@font' pair from the mathfontFONTFAMILY.properties table. The
  51 // 'code' is interpreted as a Unicode point. The 'font' is a numeric
  52 // identifier given to the font to which the glyph belongs, which is 0 for the
  53 // FONTFAMILY and > 0 for 'external' fonts.
  54 // 2) a glyph index from the Open Type MATH table. In that case, all the glyphs
  55 // come from the font containing that table and 'font' is just set to -1.
  56 struct nsGlyphCode {
  57   union {
  58     char16_t code[2];
  59     uint32_t glyphID;
  60   };
  61   int8_t font;
  62
  63   bool IsGlyphID() const { return font == -1; }
  64
  65   int32_t Length() const {
  66     return (IsGlyphID() || code[1] == char16_t('\0') ? 1 : 2);
  67   }
  68   bool Exists() const { return IsGlyphID() ? glyphID != 0 : code[0] != 0; }
  69   bool operator==(const nsGlyphCode& other) const {
  70     return (other.font == font && ((IsGlyphID() && other.glyphID == glyphID) ||
  71                                    (!IsGlyphID() && other.code[0] == code[0] &&
  72                                     other.code[1] == code[1])));
  73   }
  74   bool operator!=(const nsGlyphCode& other) const { return !operator==(other); }
  75 };
  76
  77 // Class used to handle stretchy symbols (accent, delimiter and boundary
  78 // symbols).
  79 class nsMathMLChar {
  80  public:
  81   typedef gfxTextRun::Range Range;
  82   typedef mozilla::gfx::DrawTarget DrawTarget;
  83
  84   // constructor and destructor
  85   nsMathMLChar() : mDirection(NS_STRETCH_DIRECTION_DEFAULT) {
  86     MOZ_COUNT_CTOR(nsMathMLChar);
  87     mComputedStyle = nullptr;
  88     mUnscaledAscent = 0;
  89     mScaleX = mScaleY = 1.0;
  90     mDraw = DRAW_NORMAL;
  91     mMirrored = false;
  92   }
  93
  94   // not a virtual destructor: this class is not intended to be subclassed
  95   ~nsMathMLChar();
  96
  97   void Display(mozilla::nsDisplayListBuilder* aBuilder, nsIFrame* aForFrame,
  98                const mozilla::nsDisplayListSet& aLists, uint32_t aIndex,
  99                const nsRect* aSelectedRect = nullptr);
 100
 101   void PaintForeground(nsIFrame* aForFrame, gfxContext& aRenderingContext,
 102                        nsPoint aPt, bool aIsSelected);
 103
 104   // This is the method called to ask the char to stretch itself.
 105   // @param aContainerSize - IN - suggested size for the stretched char
 106   // @param aDesiredStretchSize - OUT - the size that the char wants
 107   nsresult Stretch(nsIFrame* aForFrame, DrawTarget* aDrawTarget,
 108                    float aFontSizeInflation,
 109                    nsStretchDirection aStretchDirection,
 110                    const nsBoundingMetrics& aContainerSize,
 111                    nsBoundingMetrics& aDesiredStretchSize,
 112                    uint32_t aStretchHint, bool aRTL);
 113
 114   void SetData(nsString& aData);
 115
 116   void GetData(nsString& aData) { aData = mData; }
 117
 118   int32_t Length() { return mData.Length(); }
 119
 120   nsStretchDirection GetStretchDirection() { return mDirection; }
 121
 122   // Sometimes we only want to pass the data to another routine,
 123   // this function helps to avoid copying
 124   const char16_t* get() { return mData.get(); }
 125
 126   void GetRect(nsRect& aRect) { aRect = mRect; }
 127
 128   void SetRect(const nsRect& aRect) { mRect = aRect; }
 129
 130   // Get the maximum width that the character might have after a vertical
 131   // Stretch().
 132   //
 133   // @param aStretchHint can be the value that will be passed to Stretch().
 134   // It is used to determine whether the operator is stretchy or a largeop.
 135   nscoord GetMaxWidth(nsIFrame* aForFrame, DrawTarget* aDrawTarget,
 136                       float aFontSizeInflation,
 137                       uint32_t aStretchHint = NS_STRETCH_NORMAL);
 138
 139   // Metrics that _exactly_ enclose the char. The char *must* have *already*
 140   // being stretched before you can call the GetBoundingMetrics() method.
 141   // IMPORTANT: since chars have their own ComputedStyles, and may be rendered
 142   // with glyphs that are not in the parent font, just calling the default
 143   // aRenderingContext.GetBoundingMetrics(aChar) can give incorrect results.
 144   void GetBoundingMetrics(nsBoundingMetrics& aBoundingMetrics) {
 145     aBoundingMetrics = mBoundingMetrics;
 146   }
 147
 148   void SetBoundingMetrics(nsBoundingMetrics& aBoundingMetrics) {
 149     mBoundingMetrics = aBoundingMetrics;
 150   }
 151
 152   // Hooks to access the extra leaf ComputedStyles given to the MathMLChars.
 153   // They provide an interface to make them accessible to the Style System via
 154   // the Get/Set AdditionalComputedStyle() APIs. Owners of MathMLChars
 155   // should honor these APIs.
 156   mozilla::ComputedStyle* GetComputedStyle() const;
 157
 158   void SetComputedStyle(mozilla::ComputedStyle* aComputedStyle);
 159
 160  protected:
 161   friend class nsGlyphTable;
 162   friend class nsPropertiesTable;
 163   friend class nsOpenTypeTable;
 164   nsString mData;
 165
 166  private:
 167   nsRect mRect;
 168   nsStretchDirection mDirection;
 169   nsBoundingMetrics mBoundingMetrics;
 170   RefPtr<mozilla::ComputedStyle> mComputedStyle;
 171   // mGlyphs/mBmData are arrays describing the glyphs used to draw the operator.
 172   // See the drawing methods below.
 173   RefPtr<gfxTextRun> mGlyphs[4];
 174   nsBoundingMetrics mBmData[4];
 175   // mUnscaledAscent is the actual ascent of the char.
 176   nscoord mUnscaledAscent;
 177   // mScaleX, mScaleY are the factors by which we scale the char.
 178   float mScaleX, mScaleY;
 179
 180   // mDraw indicates how we draw the stretchy operator:
 181   // - DRAW_NORMAL: we render the mData string normally.
 182   // - DRAW_VARIANT: we draw a larger size variant given by mGlyphs[0].
 183   // - DRAW_PARTS: we assemble several parts given by mGlyphs[0], ... mGlyphs[4]
 184   // XXXfredw: the MATH table can have any numbers of parts and extenders.
 185   enum DrawingMethod { DRAW_NORMAL, DRAW_VARIANT, DRAW_PARTS };
 186   DrawingMethod mDraw;
 187
 188   // mMirrored indicates whether the character is mirrored.
 189   bool mMirrored;
 190
 191   class StretchEnumContext;
 192   friend class StretchEnumContext;
 193
 194   // helper methods
 195   bool SetFontFamily(nsPresContext* aPresContext,
 196                      const nsGlyphTable* aGlyphTable,
 197                      const nsGlyphCode& aGlyphCode,
 198                      const mozilla::StyleFontFamilyList& aDefaultFamily,
 199                      nsFont& aFont, RefPtr<gfxFontGroup>* aFontGroup);
 200
 201   nsresult StretchInternal(nsIFrame* aForFrame, DrawTarget* aDrawTarget,
 202                            float aFontSizeInflation,
 203                            nsStretchDirection& aStretchDirection,
 204                            const nsBoundingMetrics& aContainerSize,
 205                            nsBoundingMetrics& aDesiredStretchSize,
 206                            uint32_t aStretchHint,
 207                            float aMaxSize = NS_MATHML_OPERATOR_SIZE_INFINITY,
 208                            bool aMaxSizeIsAbsolute = false);
 209
 210   nsresult PaintVertically(nsPresContext* aPresContext,
 211                            gfxContext* aThebesContext, nsRect& aRect,
 212                            nscolor aColor);
 213
 214   nsresult PaintHorizontally(nsPresContext* aPresContext,
 215                              gfxContext* aThebesContext, nsRect& aRect,
 216                              nscolor aColor);
 217
 218   void ApplyTransforms(gfxContext* aThebesContext, int32_t aAppUnitsPerGfxUnit,
 219                        nsRect& r);
 220 };
 221
 222 #endif /* nsMathMLChar_h___ */