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- /*
- * 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 <memory>
- #include "include/core/SkFont.h"
- #include "include/core/SkFontTypes.h"
- #include "include/core/SkMaskFilter.h"
- #include "include/core/SkMatrix.h"
- #include "include/core/SkPaint.h"
- #include "include/core/SkTypeface.h"
- #include "include/private/SkMacros.h"
- #include "src/core/SkGlyph.h"
- #include "src/core/SkMask.h"
- #include "src/core/SkMaskGamma.h"
- #include "src/core/SkStrikeInterface.h"
- #include "src/core/SkSurfacePriv.h"
- #include "src/core/SkWriteBuffer.h"
- class SkAutoDescriptor;
- class SkDescriptor;
- class SkMaskFilter;
- class SkPathEffect;
- class SkScalerContext;
- class SkScalerContext_DW;
- enum SkScalerContextFlags : uint32_t {
- kNone = 0,
- kFakeGamma = 1 << 0,
- kBoostContrast = 1 << 1,
- kFakeGammaAndBoostContrast = kFakeGamma | kBoostContrast,
- };
- enum SkAxisAlignment : uint32_t {
- kNone_SkAxisAlignment,
- kX_SkAxisAlignment,
- kY_SkAxisAlignment
- };
- /*
- * To allow this to be forward-declared, it must be its own typename, rather
- * than a nested struct inside SkScalerContext (where it started).
- *
- * SkScalerContextRec must be dense, and all bytes must be set to a know quantity because this
- * structure is used to calculate a checksum.
- */
- SK_BEGIN_REQUIRE_DENSE
- struct SkScalerContextRec {
- uint32_t fFontID;
- SkScalar fTextSize, fPreScaleX, fPreSkewX;
- SkScalar fPost2x2[2][2];
- SkScalar fFrameWidth, fMiterLimit;
- private:
- //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
- const uint8_t fReservedAlign{0};
- public:
- 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 {
- sk_ignore_unused_variable(fReservedAlign);
- 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 to be ignored, and the paint and device
- * gamma to be effectively 1.0
- */
- void ignoreGamma() {
- setLuminanceColor(SK_ColorTRANSPARENT);
- setPaintGamma(SK_Scalar1);
- setDeviceGamma(SK_Scalar1);
- }
- /**
- * Causes the luminance color and contrast to be ignored, and the
- * paint and device gamma to be effectively 1.0.
- */
- void ignorePreBlend() {
- ignoreGamma();
- setContrast(0);
- }
- uint8_t fMaskFormat;
- private:
- uint8_t fStrokeJoin : 4;
- uint8_t fStrokeCap : 4;
- public:
- 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::MakeRecAndEffects.
- SkString dump() const {
- SkString msg;
- msg.appendf("Rec\n");
- msg.appendf(" textsize %g prescale %g preskew %g post [%g %g %g %g]\n",
- fTextSize, fPreScaleX, fPreSkewX, fPost2x2[0][0],
- fPost2x2[0][1], fPost2x2[1][0], fPost2x2[1][1]);
- msg.appendf(" frame %g miter %g format %d join %d cap %d flags %#hx\n",
- fFrameWidth, fMiterLimit, fMaskFormat, fStrokeJoin, fStrokeCap, fFlags);
- msg.appendf(" lum bits %x, device gamma %d, paint gamma %d contrast %d\n", fLumBits,
- fDeviceGamma, fPaintGamma, fContrast);
- return msg;
- }
- void getMatrixFrom2x2(SkMatrix*) const;
- void getLocalMatrix(SkMatrix*) const;
- void getSingleMatrix(SkMatrix*) const;
- /** The kind of scale which will be applied by the underlying port (pre-matrix). */
- enum PreMatrixScale {
- kFull_PreMatrixScale, // The underlying port can apply both x and y scale.
- kVertical_PreMatrixScale, // The underlying port can only apply a y scale.
- kVerticalInteger_PreMatrixScale // The underlying port can only apply an integer y scale.
- };
- /**
- * Compute useful matrices for use with sizing in underlying libraries.
- *
- * There are two kinds of text size, a 'requested/logical size' which is like asking for size
- * '12' and a 'real' size which is the size after the matrix is applied. The matrices produced
- * by this method are based on the 'real' size. This method effectively finds the total device
- * matrix and decomposes it in various ways.
- *
- * The most useful decomposition is into 'scale' and 'remaining'. The 'scale' is applied first
- * and then the 'remaining' to fully apply the total matrix. This decomposition is useful when
- * the text size ('scale') may have meaning apart from the total matrix. This is true when
- * hinting, and sometimes true for other properties as well.
- *
- * The second (optional) decomposition is of 'remaining' into a non-rotational part
- * 'remainingWithoutRotation' and a rotational part 'remainingRotation'. The 'scale' is applied
- * first, then 'remainingWithoutRotation', then 'remainingRotation' to fully apply the total
- * matrix. This decomposition is helpful when only horizontal metrics can be trusted, so the
- * 'scale' and 'remainingWithoutRotation' will be handled by the underlying library, but
- * the final rotation 'remainingRotation' will be handled manually.
- *
- * The 'total' matrix is also (optionally) available. This is useful in cases where the
- * underlying library will not be used, often when working directly with font data.
- *
- * The parameters 'scale' and 'remaining' are required, the other pointers may be nullptr.
- *
- * @param preMatrixScale the kind of scale to extract from the total matrix.
- * @param scale the scale extracted from the total matrix (both values positive).
- * @param remaining apply after scale to apply the total matrix.
- * @param remainingWithoutRotation apply after scale to apply the total matrix sans rotation.
- * @param remainingRotation apply after remainingWithoutRotation to apply the total matrix.
- * @param total the total matrix.
- * @return false if the matrix was singular. The output will be valid but not invertible.
- */
- bool computeMatrices(PreMatrixScale preMatrixScale,
- SkVector* scale, SkMatrix* remaining,
- SkMatrix* remainingWithoutRotation = nullptr,
- SkMatrix* remainingRotation = nullptr,
- SkMatrix* total = nullptr);
- SkAxisAlignment computeAxisAlignmentForHText() const;
- inline SkFontHinting getHinting() const;
- inline void setHinting(SkFontHinting);
- SkMask::Format getFormat() const {
- return static_cast<SkMask::Format>(fMaskFormat);
- }
- SkColor getLuminanceColor() const {
- return fLumBits;
- }
- // setLuminanceColor forces the alpha to be 0xFF because the blitter that draws the glyph
- // will apply the alpha from the paint. Don't apply the alpha twice.
- void setLuminanceColor(SkColor c);
- private:
- // TODO: remove
- friend class SkScalerContext;
- };
- SK_END_REQUIRE_DENSE
- //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:
- enum Flags {
- kFrameAndFill_Flag = 0x0001,
- kUnused = 0x0002,
- kEmbeddedBitmapText_Flag = 0x0004,
- kEmbolden_Flag = 0x0008,
- kSubpixelPositioning_Flag = 0x0010,
- kForceAutohinting_Flag = 0x0020, // Use auto instead of bytcode hinting if hinting.
- // 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 kLCD16
- 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)
- kLinearMetrics_Flag = 0x1000,
- };
- // computed values
- enum {
- kHinting_Mask = kHintingBit1_Flag | kHintingBit2_Flag,
- };
- SkScalerContext(sk_sp<SkTypeface>, const SkScalerContextEffects&, 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);
- }
- bool isLinearMetrics() const {
- return SkToBool(fRec.fFlags & kLinearMetrics_Flag);
- }
- // DEPRECATED
- bool isVertical() const { return false; }
- unsigned getGlyphCount() { return this->generateGlyphCount(); }
- void getAdvance(SkGlyph*);
- void getMetrics(SkGlyph*);
- void getImage(const SkGlyph&);
- bool SK_WARN_UNUSED_RESULT getPath(SkPackedGlyphID, SkPath*);
- void getFontMetrics(SkFontMetrics*);
- /** Return the size in bytes of the associated gamma lookup table
- */
- static size_t GetGammaLUTSize(SkScalar contrast, SkScalar paintGamma, SkScalar deviceGamma,
- int* width, int* height);
- /** Get the associated gamma lookup table. The 'data' pointer must point to pre-allocated
- * memory, with size in bytes greater than or equal to the return value of getGammaLUTSize().
- *
- * If the lookup table hasn't been initialized (e.g., it's linear), this will return false.
- */
- static bool GetGammaLUTData(SkScalar contrast, SkScalar paintGamma, SkScalar deviceGamma,
- uint8_t* data);
- static void MakeRecAndEffects(const SkFont& font, const SkPaint& paint,
- const SkSurfaceProps& surfaceProps,
- SkScalerContextFlags scalerContextFlags,
- const SkMatrix& deviceMatrix,
- SkScalerContextRec* rec,
- SkScalerContextEffects* effects);
- // If we are creating rec and effects from a font only, then there is no device around either.
- static void MakeRecAndEffectsFromFont(const SkFont& font,
- SkScalerContextRec* rec,
- SkScalerContextEffects* effects) {
- SkPaint paint;
- return MakeRecAndEffects(
- font, paint, SkSurfaceProps(SkSurfaceProps::kLegacyFontHost_InitType),
- SkScalerContextFlags::kNone, SkMatrix::I(), rec, effects);
- }
- static SkDescriptor* MakeDescriptorForPaths(SkFontID fontID,
- SkAutoDescriptor* ad);
- static SkDescriptor* AutoDescriptorGivenRecAndEffects(
- const SkScalerContextRec& rec,
- const SkScalerContextEffects& effects,
- SkAutoDescriptor* ad);
- static std::unique_ptr<SkDescriptor> DescriptorGivenRecAndEffects(
- const SkScalerContextRec& rec,
- const SkScalerContextEffects& effects);
- static void DescriptorBufferGiveRec(const SkScalerContextRec& rec, void* buffer);
- static bool CheckBufferSizeForRec(const SkScalerContextRec& rec,
- const SkScalerContextEffects& effects,
- size_t size);
- static SkMaskGamma::PreBlend GetMaskPreBlend(const SkScalerContextRec& rec);
- const SkScalerContextRec& getRec() const { return fRec; }
- SkScalerContextEffects getEffects() const {
- return { fPathEffect.get(), fMaskFilter.get() };
- }
- /**
- * Return the axis (if any) that the baseline for horizontal text should land on.
- * As an example, the identity matrix will return kX_SkAxisAlignment
- */
- SkAxisAlignment computeAxisAlignmentForHText() const;
- static SkDescriptor* CreateDescriptorAndEffectsUsingPaint(
- const SkFont&, const SkPaint&, const SkSurfaceProps&,
- SkScalerContextFlags scalerContextFlags,
- const SkMatrix& deviceMatrix, SkAutoDescriptor* ad,
- SkScalerContextEffects* effects);
- protected:
- SkScalerContextRec fRec;
- /** Generates the contents of glyph.fAdvanceX and glyph.fAdvanceY if it can do so quickly.
- * Returns true if it could, false otherwise.
- */
- virtual bool 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.imageSize().
- * This method may change glyph.fMaskFormat if the new image size is
- * less than or equal to the old image size.
- *
- * Because glyph.imageSize() 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;
- * @return false if this glyph does not have any path.
- */
- virtual bool SK_WARN_UNUSED_RESULT generatePath(SkGlyphID glyphId, SkPath* path) = 0;
- /** Retrieves font metrics. */
- virtual void generateFontMetrics(SkFontMetrics*) = 0;
- /** Returns the number of glyphs in the font. */
- virtual unsigned generateGlyphCount() = 0;
- void forceGenerateImageFromPath() { fGenerateImageFromPath = true; }
- void forceOffGenerateImageFromPath() { fGenerateImageFromPath = false; }
- private:
- friend class RandomScalerContext; // For debug purposes
- static SkScalerContextRec PreprocessRec(const SkTypeface& typeface,
- const SkScalerContextEffects& effects,
- const SkDescriptor& desc);
- // never null
- sk_sp<SkTypeface> fTypeface;
- // optional objects, which may be null
- sk_sp<SkPathEffect> fPathEffect;
- sk_sp<SkMaskFilter> fMaskFilter;
- // if this is set, we draw the image from a path, rather than
- // calling generateImage.
- bool fGenerateImageFromPath;
- /** Returns false if the glyph has no path at all. */
- bool internalGetPath(SkPackedGlyphID id, SkPath* devPath);
- // 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;
- };
- #define kRec_SkDescriptorTag SkSetFourByteTag('s', 'r', 'e', 'c')
- #define kEffects_SkDescriptorTag SkSetFourByteTag('e', 'f', 'c', 't')
- ///////////////////////////////////////////////////////////////////////////////
- SkFontHinting SkScalerContextRec::getHinting() const {
- unsigned hint = (fFlags & SkScalerContext::kHinting_Mask) >>
- SkScalerContext::kHinting_Shift;
- return static_cast<SkFontHinting>(hint);
- }
- void SkScalerContextRec::setHinting(SkFontHinting hinting) {
- fFlags = (fFlags & ~SkScalerContext::kHinting_Mask) |
- (static_cast<unsigned>(hinting) << SkScalerContext::kHinting_Shift);
- }
- #endif
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