The Tor Browser: comparison gfx/skia/trunk/src/core/SkScalerContext.h

--1:000000000000
+:d0200295e1c0
+/*
+* Copyright 2006 The Android Open Source Project
+*
+* Use of this source code is governed by a BSD-style license that can be
+* found in the LICENSE file.
+*/
+#ifndef SkScalerContext_DEFINED
+#define SkScalerContext_DEFINED
+#include "SkMask.h"
+#include "SkMaskGamma.h"
+#include "SkMatrix.h"
+#include "SkPaint.h"
+#include "SkTypeface.h"
+#ifdef SK_BUILD_FOR_ANDROID
+#include "SkPaintOptionsAndroid.h"
+#endif
+struct SkGlyph;
+class SkDescriptor;
+class SkMaskFilter;
+class SkPathEffect;
+class SkRasterizer;
+/*
+*  To allow this to be forward-declared, it must be its own typename, rather
+*  than a nested struct inside SkScalerContext (where it started).
+*/
+struct SkScalerContextRec {
+uint32_t    fOrigFontID;
+uint32_t    fFontID;
+SkScalar    fTextSize, fPreScaleX, fPreSkewX;
+SkScalar    fPost2x2[2][2];
+SkScalar    fFrameWidth, fMiterLimit;
+//These describe the parameters to create (uniquely identify) the pre-blend.
+uint32_t    fLumBits;
+uint8_t     fDeviceGamma; //2.6, (0.0, 4.0) gamma, 0.0 for sRGB
+uint8_t     fPaintGamma;  //2.6, (0.0, 4.0) gamma, 0.0 for sRGB
+uint8_t     fContrast;    //0.8+1, [0.0, 1.0] artificial contrast
+uint8_t     fReservedAlign;
+SkScalar getDeviceGamma() const {
+return SkIntToScalar(fDeviceGamma) / (1 << 6);
+}
+void setDeviceGamma(SkScalar dg) {
+SkASSERT(0 <= dg && dg < SkIntToScalar(4));
+fDeviceGamma = SkScalarFloorToInt(dg * (1 << 6));
+}
+SkScalar getPaintGamma() const {
+return SkIntToScalar(fPaintGamma) / (1 << 6);
+}
+void setPaintGamma(SkScalar pg) {
+SkASSERT(0 <= pg && pg < SkIntToScalar(4));
+fPaintGamma = SkScalarFloorToInt(pg * (1 << 6));
+}
+SkScalar getContrast() const {
+return SkIntToScalar(fContrast) / ((1 << 8) - 1);
+}
+void setContrast(SkScalar c) {
+SkASSERT(0 <= c && c <= SK_Scalar1);
+fContrast = SkScalarRoundToInt(c * ((1 << 8) - 1));
+}
+/**
+*  Causes the luminance color and contrast to be ignored, and the
+*  paint and device gamma to be effectively 1.0.
+*/
+void ignorePreBlend() {
+setLuminanceColor(SK_ColorTRANSPARENT);
+setPaintGamma(SK_Scalar1);
+setDeviceGamma(SK_Scalar1);
+setContrast(0);
+}
+uint8_t     fMaskFormat;
+uint8_t     fStrokeJoin;
+uint16_t    fFlags;
+// Warning: when adding members note that the size of this structure
+// must be a multiple of 4. SkDescriptor requires that its arguments be
+// multiples of four and this structure is put in an SkDescriptor in
+// SkPaint::MakeRec.
+void    getMatrixFrom2x2(SkMatrix*) const;
+void    getLocalMatrix(SkMatrix*) const;
+void    getSingleMatrix(SkMatrix*) const;
+inline SkPaint::Hinting getHinting() const;
+inline void setHinting(SkPaint::Hinting);
+SkMask::Format getFormat() const {
+return static_cast<SkMask::Format>(fMaskFormat);
+}
+SkColor getLuminanceColor() const {
+return fLumBits;
+}
+void setLuminanceColor(SkColor c) {
+fLumBits = c;
+}
+};
+//The following typedef hides from the rest of the implementation the number of
+//most significant bits to consider when creating mask gamma tables. Two bits
+//per channel was chosen as a balance between fidelity (more bits) and cache
+//sizes (fewer bits). Three bits per channel was chosen when #303942; (used by
+//the Chrome UI) turned out too green.
+typedef SkTMaskGamma<3, 3, 3> SkMaskGamma;
+class SkScalerContext {
+public:
+typedef SkScalerContextRec Rec;
+enum Flags {
+kFrameAndFill_Flag        = 0x0001,
+kDevKernText_Flag         = 0x0002,
+kEmbeddedBitmapText_Flag  = 0x0004,
+kEmbolden_Flag            = 0x0008,
+kSubpixelPositioning_Flag = 0x0010,
+kForceAutohinting_Flag    = 0x0020,  // Use auto instead of bytcode hinting if hinting.
+kVertical_Flag            = 0x0040,
+// together, these two flags resulting in a two bit value which matches
+// up with the SkPaint::Hinting enum.
+kHinting_Shift            = 7, // to shift into the other flags above
+kHintingBit1_Flag         = 0x0080,
+kHintingBit2_Flag         = 0x0100,
+// Pixel geometry information.
+// only meaningful if fMaskFormat is LCD16 or LCD32
+kLCD_Vertical_Flag        = 0x0200,    // else Horizontal
+kLCD_BGROrder_Flag        = 0x0400,    // else RGB order
+// Generate A8 from LCD source (for GDI and CoreGraphics).
+// only meaningful if fMaskFormat is kA8
+kGenA8FromLCD_Flag        = 0x0800, // could be 0x200 (bit meaning dependent on fMaskFormat)
+};
+// computed values
+enum {
+kHinting_Mask   = kHintingBit1_Flag | kHintingBit2_Flag,
+};
+SkScalerContext(SkTypeface*, const SkDescriptor*);
+virtual ~SkScalerContext();
+SkTypeface* getTypeface() const { return fTypeface.get(); }
+SkMask::Format getMaskFormat() const {
+return (SkMask::Format)fRec.fMaskFormat;
+}
+bool isSubpixel() const {
+return SkToBool(fRec.fFlags & kSubpixelPositioning_Flag);
+}
+// remember our glyph offset/base
+void setBaseGlyphCount(unsigned baseGlyphCount) {
+fBaseGlyphCount = baseGlyphCount;
+}
+/** Return the corresponding glyph for the specified unichar. Since contexts
+may be chained (under the hood), the glyphID that is returned may in
+fact correspond to a different font/context. In that case, we use the
+base-glyph-count to know how to translate back into local glyph space.
+*/
+uint16_t charToGlyphID(SkUnichar uni);
+/** Map the glyphID to its glyph index, and then to its char code. Unmapped
+glyphs return zero.
+*/
+SkUnichar glyphIDToChar(uint16_t glyphID);
+unsigned    getGlyphCount() { return this->generateGlyphCount(); }
+void        getAdvance(SkGlyph*);
+void        getMetrics(SkGlyph*);
+void        getImage(const SkGlyph&);
+void        getPath(const SkGlyph&, SkPath*);
+void        getFontMetrics(SkPaint::FontMetrics*);
+#ifdef SK_BUILD_FOR_ANDROID
+unsigned getBaseGlyphCount(SkUnichar charCode);
+// This function must be public for SkTypeface_android.h, but should not be
+// called by other callers
+SkFontID findTypefaceIdForChar(SkUnichar uni);
+#endif
+static inline void MakeRec(const SkPaint&, const SkDeviceProperties* deviceProperties,
+const SkMatrix*, Rec* rec);
+static inline void PostMakeRec(const SkPaint&, Rec*);
+static SkMaskGamma::PreBlend GetMaskPreBlend(const Rec& rec);
+protected:
+Rec         fRec;
+unsigned    fBaseGlyphCount;
+/** Generates the contents of glyph.fAdvanceX and glyph.fAdvanceY.
+*  May call getMetrics if that would be just as fast.
+*/
+virtual void generateAdvance(SkGlyph* glyph) = 0;
+/** Generates the contents of glyph.fWidth, fHeight, fTop, fLeft,
+*  as well as fAdvanceX and fAdvanceY if not already set.
+*
+*  TODO: fMaskFormat is set by getMetrics later; cannot be set here.
+*/
+virtual void generateMetrics(SkGlyph* glyph) = 0;
+/** Generates the contents of glyph.fImage.
+*  When called, glyph.fImage will be pointing to a pre-allocated,
+*  uninitialized region of memory of size glyph.computeImageSize().
+*  This method may change glyph.fMaskFormat if the new image size is
+*  less than or equal to the old image size.
+*
+*  Because glyph.computeImageSize() will determine the size of fImage,
+*  generateMetrics will be called before generateImage.
+*/
+virtual void generateImage(const SkGlyph& glyph) = 0;
+/** Sets the passed path to the glyph outline.
+*  If this cannot be done the path is set to empty;
+*  this is indistinguishable from a glyph with an empty path.
+*  This does not set glyph.fPath.
+*
+*  TODO: path is always glyph.fPath, no reason to pass separately.
+*/
+virtual void generatePath(const SkGlyph& glyph, SkPath* path) = 0;
+/** Retrieves font metrics.
+*  TODO: there is now a vertical bit, no need for two parameters.
+*/
+virtual void generateFontMetrics(SkPaint::FontMetrics* mX,
+SkPaint::FontMetrics* mY) = 0;
+/** Returns the number of glyphs in the font. */
+virtual unsigned generateGlyphCount() = 0;
+/** Returns the glyph id for the given unichar.
+*  If there is no 1:1 mapping from the unichar to a glyph id, returns 0.
+*/
+virtual uint16_t generateCharToGlyph(SkUnichar unichar) = 0;
+/** Returns the unichar for the given glyph id.
+*  If there is no 1:1 mapping from the glyph id to a unichar, returns 0.
+*  The default implementation always returns 0, indicating failure.
+*/
+virtual SkUnichar generateGlyphToChar(uint16_t glyphId);
+void forceGenerateImageFromPath() { fGenerateImageFromPath = true; }
+private:
+// never null
+SkAutoTUnref<SkTypeface> fTypeface;
+#ifdef SK_BUILD_FOR_ANDROID
+SkPaintOptionsAndroid fPaintOptionsAndroid;
+#endif
+// optional object, which may be null
+SkPathEffect*   fPathEffect;
+SkMaskFilter*   fMaskFilter;
+SkRasterizer*   fRasterizer;
+// if this is set, we draw the image from a path, rather than
+// calling generateImage.
+bool fGenerateImageFromPath;
+void internalGetPath(const SkGlyph& glyph, SkPath* fillPath,
+SkPath* devPath, SkMatrix* fillToDevMatrix);
+// Return the context associated with the next logical typeface, or NULL if
+// there are no more entries in the fallback chain.
+SkScalerContext* allocNextContext() const;
+// return the next context, treating fNextContext as a cache of the answer
+SkScalerContext* getNextContext();
+// returns the right context from our link-list for this glyph. If no match
+// is found, just returns the original context (this)
+SkScalerContext* getGlyphContext(const SkGlyph& glyph);
+// returns the right context from our link-list for this char. If no match
+// is found it returns NULL. If a match is found then the glyphID param is
+// set to the glyphID that maps to the provided char.
+SkScalerContext* getContextFromChar(SkUnichar uni, uint16_t* glyphID);
+// link-list of context, to handle missing chars. null-terminated.
+SkScalerContext* fNextContext;
+// SkMaskGamma::PreBlend converts linear masks to gamma correcting masks.
+protected:
+// Visible to subclasses so that generateImage can apply the pre-blend directly.
+const SkMaskGamma::PreBlend fPreBlend;
+private:
+// When there is a filter, previous steps must create a linear mask
+// and the pre-blend applied as a final step.
+const SkMaskGamma::PreBlend fPreBlendForFilter;
+};
+#define kRec_SkDescriptorTag            SkSetFourByteTag('s', 'r', 'e', 'c')
+#define kPathEffect_SkDescriptorTag     SkSetFourByteTag('p', 't', 'h', 'e')
+#define kMaskFilter_SkDescriptorTag     SkSetFourByteTag('m', 's', 'k', 'f')
+#define kRasterizer_SkDescriptorTag     SkSetFourByteTag('r', 'a', 's', 't')
+#ifdef SK_BUILD_FOR_ANDROID
+#define kAndroidOpts_SkDescriptorTag    SkSetFourByteTag('a', 'n', 'd', 'r')
+#endif
+///////////////////////////////////////////////////////////////////////////////
+enum SkAxisAlignment {
+kNone_SkAxisAlignment,
+kX_SkAxisAlignment,
+kY_SkAxisAlignment
+};
+/**
+*  Return the axis (if any) that the baseline for horizontal text will land on
+*  after running through the specified matrix.
+*
+*  As an example, the identity matrix will return kX_SkAxisAlignment
+*/
+SkAxisAlignment SkComputeAxisAlignmentForHText(const SkMatrix& matrix);
+///////////////////////////////////////////////////////////////////////////////
+SkPaint::Hinting SkScalerContextRec::getHinting() const {
+unsigned hint = (fFlags & SkScalerContext::kHinting_Mask) >>
+SkScalerContext::kHinting_Shift;
+return static_cast<SkPaint::Hinting>(hint);
+}
+void SkScalerContextRec::setHinting(SkPaint::Hinting hinting) {
+fFlags = (fFlags & ~SkScalerContext::kHinting_Mask) |
+(hinting << SkScalerContext::kHinting_Shift);
+}
+#endif

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comparison: gfx/skia/trunk/src/core/SkScalerContext.h

gfx/skia/trunk/src/core/SkScalerContext.h