/*
* 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 "SkMatrix.h"
#include "SkPaint.h"
#include "SkPath.h"
#include "SkPoint.h"
//#define SK_USE_COLOR_LUMINANCE
class SkDescriptor;
class SkMaskFilter;
class SkPathEffect;
class SkRasterizer;
// needs to be != to any valid SkMask::Format
#define MASK_FORMAT_UNKNOWN (0xFF)
#define MASK_FORMAT_JUST_ADVANCE MASK_FORMAT_UNKNOWN
#define kMaxGlyphWidth (1<<13)
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
void init(uint32_t id) {
fID = id;
fImage = NULL;
fPath = NULL;
fMaskFormat = MASK_FORMAT_UNKNOWN;
}
/**
* Compute the rowbytes for the specified width and mask-format.
*/
static unsigned ComputeRowBytes(unsigned width, SkMask::Format format) {
unsigned rb = width;
if (SkMask::kBW_Format == format) {
rb = (rb + 7) >> 3;
} else if (SkMask::kARGB32_Format == format ||
SkMask::kLCD32_Format == format)
{
rb <<= 2;
} else if (SkMask::kLCD16_Format == format) {
rb = SkAlign4(rb << 1);
} else {
rb = SkAlign4(rb);
}
return rb;
}
unsigned rowBytes() const {
return ComputeRowBytes(fWidth, (SkMask::Format)fMaskFormat);
}
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 Flags {
kFrameAndFill_Flag = 0x0001,
kDevKernText_Flag = 0x0002,
kEmbeddedBitmapText_Flag = 0x0004,
kEmbolden_Flag = 0x0008,
kSubpixelPositioning_Flag = 0x0010,
kAutohinting_Flag = 0x0020,
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,
// these should only ever be set 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), only meaningful if fMaskFormat is kA8
// Perhaps we can store this (instead) in fMaskFormat, in hight bit?
kGenA8FromLCD_Flag = 0x0800,
#ifdef SK_USE_COLOR_LUMINANCE
kLuminance_Bits = 3,
#else
// luminance : 0 for black text, kLuminance_Max for white text
kLuminance_Shift = 13, // shift to land in the high 3-bits of Flags
kLuminance_Bits = 3, // ensure Flags doesn't exceed 16bits
#endif
};
// computed values
enum {
kHinting_Mask = kHintingBit1_Flag | kHintingBit2_Flag,
#ifdef SK_USE_COLOR_LUMINANCE
#else
kLuminance_Max = (1 << kLuminance_Bits) - 1,
kLuminance_Mask = kLuminance_Max << kLuminance_Shift,
#endif
};
struct Rec {
uint32_t fOrigFontID;
uint32_t fFontID;
SkScalar fTextSize, fPreScaleX, fPreSkewX;
SkScalar fPost2x2[2][2];
SkScalar fFrameWidth, fMiterLimit;
#ifdef SK_USE_COLOR_LUMINANCE
uint32_t fLumBits;
#endif
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;
SkPaint::Hinting getHinting() const {
unsigned hint = (fFlags & kHinting_Mask) >> kHinting_Shift;
return static_cast<SkPaint::Hinting>(hint);
}
void setHinting(SkPaint::Hinting hinting) {
fFlags = (fFlags & ~kHinting_Mask) | (hinting << kHinting_Shift);
}
SkMask::Format getFormat() const {
return static_cast<SkMask::Format>(fMaskFormat);
}
#ifdef SK_USE_COLOR_LUMINANCE
SkColor getLuminanceColor() const {
return fLumBits;
}
void setLuminanceColor(SkColor c) {
fLumBits = c;
}
#else
unsigned getLuminanceBits() const {
return (fFlags & kLuminance_Mask) >> kLuminance_Shift;
}
void setLuminanceBits(unsigned lum) {
SkASSERT(lum <= kLuminance_Max);
fFlags = (fFlags & ~kLuminance_Mask) | (lum << kLuminance_Shift);
}
U8CPU getLuminanceByte() const {
SkASSERT(3 == kLuminance_Bits);
unsigned lum = this->getLuminanceBits();
lum |= (lum << kLuminance_Bits);
lum |= (lum << kLuminance_Bits*2);
return lum >> (4*kLuminance_Bits - 8);
}
#endif
};
SkScalerContext(const SkDescriptor* desc);
virtual ~SkScalerContext();
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* mX,
SkPaint::FontMetrics* mY);
#ifdef SK_BUILD_FOR_ANDROID
unsigned getBaseGlyphCount(SkUnichar charCode);
#endif
static inline void MakeRec(const SkPaint&, const SkMatrix*, Rec* rec);
static inline void PostMakeRec(Rec*);
static SkScalerContext* Create(const SkDescriptor*);
protected:
Rec fRec;
unsigned fBaseGlyphCount;
virtual unsigned generateGlyphCount() = 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;
// default impl returns 0, indicating failure.
virtual SkUnichar generateGlyphToChar(uint16_t);
void forceGenerateImageFromPath() { fGenerateImageFromPath = true; }
private:
SkPathEffect* fPathEffect;
SkMaskFilter* fMaskFilter;
SkRasterizer* fRasterizer;
SkScalar fDevFrameWidth;
// 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 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')
///////////////////////////////////////////////////////////////////////////////
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);
#endif