/*
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* Copyright 2006 The Android Open Source Project
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkGlyph_DEFINED
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#define SkGlyph_DEFINED
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#include "SkChecksum.h"
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#include "SkFixed.h"
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#include "SkMask.h"
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#include "SkPath.h"
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#include "SkTo.h"
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#include "SkTypes.h"
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class SkArenaAlloc;
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class SkStrike;
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class SkScalerContext;
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// needs to be != to any valid SkMask::Format
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#define MASK_FORMAT_UNKNOWN (0xFF)
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#define MASK_FORMAT_JUST_ADVANCE MASK_FORMAT_UNKNOWN
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#define kMaxGlyphWidth (1<<13)
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/** (glyph-index or unicode-point) + subpixel-pos */
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struct SkPackedID {
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static constexpr uint32_t kImpossibleID = ~0;
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enum {
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kSubBits = 2,
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kSubMask = ((1 << kSubBits) - 1),
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kSubShift = 24, // must be large enough for glyphs and unichars
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kCodeMask = ((1 << kSubShift) - 1),
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// relative offsets for X and Y subpixel bits
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kSubShiftX = kSubBits,
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kSubShiftY = 0
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};
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SkPackedID(uint32_t code) {
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SkASSERT(code <= kCodeMask);
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SkASSERT(code != kImpossibleID);
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fID = code;
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}
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SkPackedID(uint32_t code, SkFixed x, SkFixed y) {
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SkASSERT(code <= kCodeMask);
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x = FixedToSub(x);
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y = FixedToSub(y);
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uint32_t ID = (x << (kSubShift + kSubShiftX)) |
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(y << (kSubShift + kSubShiftY)) |
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code;
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SkASSERT(ID != kImpossibleID);
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fID = ID;
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}
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constexpr SkPackedID() : fID(kImpossibleID) {}
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bool operator==(const SkPackedID& that) const {
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return fID == that.fID;
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}
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bool operator!=(const SkPackedID& that) const {
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return !(*this == that);
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}
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bool operator<(SkPackedID that) const {
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return this->fID < that.fID;
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}
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uint32_t code() const {
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return fID & kCodeMask;
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}
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uint32_t value() const {
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return fID;
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}
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SkFixed getSubXFixed() const {
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return SubToFixed(ID2SubX(fID));
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}
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SkFixed getSubYFixed() const {
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return SubToFixed(ID2SubY(fID));
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}
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uint32_t hash() const {
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return SkChecksum::CheapMix(fID);
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}
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SkString dump() const {
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SkString str;
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str.appendf("code: %d, x: %d, y:%d", code(), getSubXFixed(), getSubYFixed());
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return str;
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}
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private:
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static unsigned ID2SubX(uint32_t id) {
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return id >> (kSubShift + kSubShiftX);
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}
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static unsigned ID2SubY(uint32_t id) {
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return (id >> (kSubShift + kSubShiftY)) & kSubMask;
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}
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static unsigned FixedToSub(SkFixed n) {
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return (n >> (16 - kSubBits)) & kSubMask;
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}
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static SkFixed SubToFixed(unsigned sub) {
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SkASSERT(sub <= kSubMask);
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return sub << (16 - kSubBits);
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}
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uint32_t fID;
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};
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struct SkPackedGlyphID : public SkPackedID {
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SkPackedGlyphID(SkGlyphID code) : SkPackedID(code) { }
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SkPackedGlyphID(SkGlyphID code, SkFixed x, SkFixed y) : SkPackedID(code, x, y) { }
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SkPackedGlyphID(SkGlyphID code, SkIPoint pt) : SkPackedID(code, pt.x(), pt.y()) { }
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constexpr SkPackedGlyphID() = default;
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SkGlyphID code() const {
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return SkTo<SkGlyphID>(SkPackedID::code());
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}
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};
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class SkGlyph {
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struct PathData;
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public:
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constexpr explicit SkGlyph(SkPackedGlyphID id) : fID{id} {}
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static constexpr SkFixed kSubpixelRound = SK_FixedHalf >> SkPackedID::kSubBits;
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bool isEmpty() const { return fWidth == 0 || fHeight == 0; }
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bool isJustAdvance() const { return MASK_FORMAT_JUST_ADVANCE == fMaskFormat; }
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bool isFullMetrics() const { return MASK_FORMAT_JUST_ADVANCE != fMaskFormat; }
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SkGlyphID getGlyphID() const { return fID.code(); }
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SkPackedGlyphID getPackedID() const { return fID; }
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SkFixed getSubXFixed() const { return fID.getSubXFixed(); }
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SkFixed getSubYFixed() const { return fID.getSubYFixed(); }
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size_t formatAlignment() const;
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size_t allocImage(SkArenaAlloc* alloc);
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size_t rowBytes() const;
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size_t computeImageSize() const;
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size_t rowBytesUsingFormat(SkMask::Format format) const;
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// Call this to set all of the metrics fields to 0 (e.g. if the scaler
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// encounters an error measuring a glyph). Note: this does not alter the
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// fImage, fPath, fID, fMaskFormat fields.
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void zeroMetrics();
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void toMask(SkMask* mask) const;
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SkPath* addPath(SkScalerContext*, SkArenaAlloc*);
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SkPath* path() const {
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return fPathData != nullptr && fPathData->fHasPath ? &fPathData->fPath : nullptr;
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}
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// Returns the size allocated on the arena.
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size_t copyImageData(const SkGlyph& from, SkArenaAlloc* alloc);
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void* fImage = nullptr;
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// Path data has tricky state. If the glyph isEmpty, then fPathData should always be nullptr,
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// else if fPathData is not null, then a path has been requested. The fPath field of fPathData
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// may still be null after the request meaning that there is no path for this glyph.
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PathData* fPathData = nullptr;
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// The advance for this glyph.
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float fAdvanceX = 0,
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fAdvanceY = 0;
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// The width and height of the glyph mask.
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uint16_t fWidth = 0,
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fHeight = 0;
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// The offset from the glyphs origin on the baseline to the top left of the glyph mask.
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int16_t fTop = 0,
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fLeft = 0;
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// Used by the GDI scaler to track state.
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int8_t fForceBW = 0;
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// This is a combination of SkMask::Format and SkGlyph state. The SkGlyph can be in one of two
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// states, just the advances have been calculated, and all the metrics are available. The
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// illegal mask format is used to signal that only the advances are available.
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uint8_t fMaskFormat = MASK_FORMAT_UNKNOWN;
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private:
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// Support horizontal and vertical skipping strike-through / underlines.
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// The caller walks the linked list looking for a match. For a horizontal underline,
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// the fBounds contains the top and bottom of the underline. The fInterval pair contains the
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// beginning and end of of the intersection of the bounds and the glyph's path.
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// If interval[0] >= interval[1], no intesection was found.
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struct Intercept {
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Intercept* fNext;
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SkScalar fBounds[2]; // for horz underlines, the boundaries in Y
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SkScalar fInterval[2]; // the outside intersections of the axis and the glyph
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};
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struct PathData {
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Intercept* fIntercept{nullptr};
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SkPath fPath;
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bool fHasPath{false};
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};
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// TODO(herb) remove friend statement after SkStrike cleanup.
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friend class SkStrike;
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SkPackedGlyphID fID;
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};
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#endif
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