/*
|
* 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 "SkFont.h"
|
#include "SkFontTypes.h"
|
#include "SkGlyph.h"
|
#include "SkMacros.h"
|
#include "SkMask.h"
|
#include "SkMaskFilter.h"
|
#include "SkMaskGamma.h"
|
#include "SkMatrix.h"
|
#include "SkPaint.h"
|
#include "SkStrikeInterface.h"
|
#include "SkSurfacePriv.h"
|
#include "SkTypeface.h"
|
#include "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) {
|
fLumBits = SkColorSetRGB(SkColorGetR(c), SkColorGetG(c), SkColorGetB(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)
|
};
|
|
// 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);
|
}
|
|
// DEPRECATED
|
bool isVertical() const { return false; }
|
|
/** 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) {
|
return generateCharToGlyph(uni);
|
}
|
|
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.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;
|
* @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;
|
|
/** 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;
|
|
void forceGenerateImageFromPath() { fGenerateImageFromPath = true; }
|
void forceOffGenerateImageFromPath() { fGenerateImageFromPath = false; }
|
|
private:
|
friend class SkRandomScalerContext; // 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
|
