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Cleanup SkPackedGlyphID

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Simplify lengths, positions and masks. The old code used to support
both unicode, and SkGlyphIDs; unicode support is not needed since
unicode->glyphID translation was moved to the typeface. Change the
glyph id field from 24 bits to 16.

Change-Id: I28524870c97a441159c5b00acfc2c43834924c8e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/240280
Commit-Queue: Herb Derby <herbderby@gmail.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
This commit is contained in:
Herb Derby 2019-09-09 15:13:57 -04:00 committed by Skia Commit-Bot
parent 9c173c8347
commit b831e26be3
1 changed files with 30 additions and 27 deletions
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57
src/core/SkGlyph.h
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@ -23,17 +23,28 @@ class SkScalerContext;
#define MASK_FORMAT_UNKNOWN (0xFF)
#define MASK_FORMAT_JUST_ADVANCE MASK_FORMAT_UNKNOWN
/** SkGlyphID + subpixel-pos */
// A combination of SkGlyphID and sub-pixel position information.
struct SkPackedGlyphID {
static constexpr uint32_t kImpossibleID = ~0u;
enum {
kSubBits = 2u,
kSubMask = ((1u << kSubBits) - 1),
kSubShift = 24u, // must be large enough for glyphs and unichars
kCodeMask = ((1u << kSubShift) - 1),
// relative offsets for X and Y subpixel bits
kSubShiftX = kSubBits,
kSubShiftY = 0
// Lengths
kGlyphIDLen = 16u,
kSubPixelPosLen = 2u,
// Bit positions
kGlyphID = 0u,
kSubPixelY = kGlyphIDLen,
kSubPixelX = kGlyphIDLen + kSubPixelPosLen,
kEndData = kGlyphIDLen + 2 * kSubPixelPosLen,
// Masks
kGlyphIDMask = (1u << kGlyphIDLen) - 1,
kSubPixelPosMask = (1u << kSubPixelPosLen) - 1,
kMaskAll = (1u << kEndData) - 1,
// Location of sub pixel info in a fixed pointer number.
kFixedPointBinaryPointPos = 16u,
kFixedPointSubPixelPosBits = kFixedPointBinaryPointPos - kSubPixelPosLen,
};
constexpr explicit SkPackedGlyphID(SkGlyphID glyphID)
@ -60,7 +71,7 @@ struct SkPackedGlyphID {
}
uint32_t code() const {
return fID & kCodeMask;
return fID & kGlyphIDMask;
}
uint32_t value() const {
@ -68,11 +79,11 @@ struct SkPackedGlyphID {
}
SkFixed getSubXFixed() const {
return SubToFixed(ID2SubX(fID));
return this->subToFixed(kSubPixelX);
}
SkFixed getSubYFixed() const {
return SubToFixed(ID2SubY(fID));
return this->subToFixed(kSubPixelY);
}
uint32_t hash() const {
@ -87,26 +98,18 @@ struct SkPackedGlyphID {
private:
static constexpr uint32_t PackIDXY(SkGlyphID glyphID, SkFixed x, SkFixed y) {
return (FixedToSub(x) << (kSubShift + kSubShiftX))
| (FixedToSub(y) << (kSubShift + kSubShiftY))
return (FixedToSub(x) << kSubPixelX)
| (FixedToSub(y) << kSubPixelY)
| glyphID;
}
static constexpr unsigned ID2SubX(uint32_t id) {
return id >> (kSubShift + kSubShiftX);
static constexpr uint32_t FixedToSub(SkFixed n) {
return ((uint32_t)n >> kFixedPointSubPixelPosBits) & kSubPixelPosMask;
}
static constexpr unsigned ID2SubY(uint32_t id) {
return (id >> (kSubShift + kSubShiftY)) & kSubMask;
}
static constexpr unsigned FixedToSub(SkFixed n) {
return (n >> (16 - kSubBits)) & kSubMask;
}
static constexpr SkFixed SubToFixed(uint32_t sub) {
SkASSERT(sub <= kSubMask);
return sub << (16u - kSubBits);
constexpr SkFixed subToFixed(uint32_t subPixelPosBit) const {
uint32_t subPixelPosition = (fID >> subPixelPosBit) & kSubPixelPosMask;
return subPixelPosition << kFixedPointSubPixelPosBits;
}
uint32_t fID;
@ -116,7 +119,7 @@ struct SkGlyphPrototype;
class SkGlyph {
public:
static constexpr SkFixed kSubpixelRound = SK_FixedHalf >> SkPackedGlyphID::kSubBits;
static constexpr SkFixed kSubpixelRound = SK_FixedHalf >> SkPackedGlyphID::kSubPixelPosLen;
constexpr explicit SkGlyph(SkPackedGlyphID id) : fID{id} { }
explicit SkGlyph(const SkGlyphPrototype& p);