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/*
* Copyright (C) 2006 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef SkScalerContext_DEFINED
#define SkScalerContext_DEFINED
#include "SkMask.h"
#include "SkMatrix.h"
#include "SkPaint.h"
#include "SkPath.h"
#include "SkPoint.h"
class SkDescriptor;
class SkMaskFilter;
class SkPathEffect;
class SkRasterizer;
// needs to be != to any valid SkMask::Format
#define MASK_FORMAT_JUST_ADVANCE (0xFF)
struct SkGlyph {
void* fImage;
SkPath* fPath;
SkFixed fAdvanceX, fAdvanceY;
uint32_t fID;
uint16_t fWidth, fHeight;
int16_t fTop, fLeft;
uint8_t fMaskFormat;
int8_t fRsbDelta, fLsbDelta; // used by auto-kerning
unsigned rowBytes() const {
unsigned rb = fWidth;
if (SkMask::kBW_Format == fMaskFormat) {
rb = (rb + 7) >> 3;
} else {
rb = SkAlign4(rb);
}
return rb;
}
bool isJustAdvance() const {
return MASK_FORMAT_JUST_ADVANCE == fMaskFormat;
}
bool isFullMetrics() const {
return MASK_FORMAT_JUST_ADVANCE != fMaskFormat;
}
uint16_t getGlyphID() const {
return ID2Code(fID);
}
unsigned getGlyphID(unsigned baseGlyphCount) const {
unsigned code = ID2Code(fID);
SkASSERT(code >= baseGlyphCount);
return code - baseGlyphCount;
}
unsigned getSubX() const {
return ID2SubX(fID);
}
SkFixed getSubXFixed() const {
return SubToFixed(ID2SubX(fID));
}
SkFixed getSubYFixed() const {
return SubToFixed(ID2SubY(fID));
}
size_t computeImageSize() const;
/** Call this to set all of the metrics fields to 0 (e.g. if the scaler
encounters an error measuring a glyph). Note: this does not alter the
fImage, fPath, fID, fMaskFormat fields.
*/
void zeroMetrics();
enum {
kSubBits = 2,
kSubMask = ((1 << kSubBits) - 1),
kSubShift = 24, // must be large enough for glyphs and unichars
kCodeMask = ((1 << kSubShift) - 1),
// relative offsets for X and Y subpixel bits
kSubShiftX = kSubBits,
kSubShiftY = 0
};
static unsigned ID2Code(uint32_t id) {
return id & kCodeMask;
}
static unsigned ID2SubX(uint32_t id) {
return id >> (kSubShift + kSubShiftX);
}
static unsigned ID2SubY(uint32_t id) {
return (id >> (kSubShift + kSubShiftY)) & kSubMask;
}
static unsigned FixedToSub(SkFixed n) {
return (n >> (16 - kSubBits)) & kSubMask;
}
static SkFixed SubToFixed(unsigned sub) {
SkASSERT(sub <= kSubMask);
return sub << (16 - kSubBits);
}
static uint32_t MakeID(unsigned code) {
return code;
}
static uint32_t MakeID(unsigned code, SkFixed x, SkFixed y) {
SkASSERT(code <= kCodeMask);
x = FixedToSub(x);
y = FixedToSub(y);
return (x << (kSubShift + kSubShiftX)) |
(y << (kSubShift + kSubShiftY)) |
code;
}
void toMask(SkMask* mask) const;
};
class SkScalerContext {
public:
enum Hints {
kNo_Hints,
kSubpixel_Hints,
kNormal_Hints
};
enum Flags {
kFrameAndFill_Flag = 0x01,
kDevKernText_Flag = 0x02,
kGammaForBlack_Flag = 0x04, // illegal to set both Gamma flags
kGammaForWhite_Flag = 0x08 // illegal to set both Gamma flags
};
struct Rec {
uint32_t fFontID;
SkScalar fTextSize, fPreScaleX, fPreSkewX;
SkScalar fPost2x2[2][2];
SkScalar fFrameWidth, fMiterLimit;
uint8_t fHints;
uint8_t fMaskFormat;
uint8_t fStrokeJoin;
uint8_t fFlags;
void getMatrixFrom2x2(SkMatrix*) const;
void getLocalMatrix(SkMatrix*) const;
void getSingleMatrix(SkMatrix*) const;
};
SkScalerContext(const SkDescriptor* desc);
virtual ~SkScalerContext();
// 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);
unsigned getGlyphCount() const { return this->generateGlyphCount(); }
void getAdvance(SkGlyph*);
void getMetrics(SkGlyph*);
void getImage(const SkGlyph&);
void getPath(const SkGlyph&, SkPath*);
void getFontMetrics(SkPaint::FontMetrics* mX,
SkPaint::FontMetrics* mY);
static inline void MakeRec(const SkPaint&, const SkMatrix*, Rec* rec);
static SkScalerContext* Create(const SkDescriptor*);
protected:
Rec fRec;
unsigned fBaseGlyphCount;
virtual unsigned generateGlyphCount() const = 0;
virtual uint16_t generateCharToGlyph(SkUnichar) = 0;
virtual void generateAdvance(SkGlyph*) = 0;
virtual void generateMetrics(SkGlyph*) = 0;
virtual void generateImage(const SkGlyph&) = 0;
virtual void generatePath(const SkGlyph&, SkPath*) = 0;
virtual void generateFontMetrics(SkPaint::FontMetrics* mX,
SkPaint::FontMetrics* mY) = 0;
private:
SkPathEffect* fPathEffect;
SkMaskFilter* fMaskFilter;
SkRasterizer* fRasterizer;
SkScalar fDevFrameWidth;
void internalGetPath(const SkGlyph& glyph, SkPath* fillPath,
SkPath* devPath, SkMatrix* fillToDevMatrix);
// 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);
// link-list of context, to handle missing chars. null-terminated.
SkScalerContext* fNextContext;
};
#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')
#endif
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