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-rw-r--r--gfx/thebes/gfxGlyphExtents.h151
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diff --git a/gfx/thebes/gfxGlyphExtents.h b/gfx/thebes/gfxGlyphExtents.h
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+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GFX_GLYPHEXTENTS_H
+#define GFX_GLYPHEXTENTS_H
+
+#include "gfxFont.h"
+#include "nsTHashtable.h"
+#include "nsHashKeys.h"
+#include "nsTArray.h"
+#include "mozilla/MemoryReporting.h"
+
+class gfxContext;
+struct gfxRect;
+
+namespace mozilla {
+namespace gfx {
+class DrawTarget;
+} // namespace gfx
+} // namespace mozilla
+
+/**
+ * This stores glyph bounds information for a particular gfxFont, at
+ * a particular appunits-per-dev-pixel ratio (because the compressed glyph
+ * width array is stored in appunits).
+ *
+ * We store a hashtable from glyph IDs to float bounding rects. For the
+ * common case where the glyph has no horizontal left bearing, and no
+ * y overflow above the font ascent or below the font descent, and tight
+ * bounding boxes are not required, we avoid storing the glyph ID in the hashtable
+ * and instead consult an array of 16-bit glyph XMost values (in appunits).
+ * This array always has an entry for the font's space glyph --- the width is
+ * assumed to be zero.
+ */
+class gfxGlyphExtents {
+ typedef mozilla::gfx::DrawTarget DrawTarget;
+
+public:
+ explicit gfxGlyphExtents(int32_t aAppUnitsPerDevUnit) :
+ mAppUnitsPerDevUnit(aAppUnitsPerDevUnit) {
+ MOZ_COUNT_CTOR(gfxGlyphExtents);
+ }
+ ~gfxGlyphExtents();
+
+ enum { INVALID_WIDTH = 0xFFFF };
+
+ void NotifyGlyphsChanged() {
+ mTightGlyphExtents.Clear();
+ }
+
+ // returns INVALID_WIDTH => not a contained glyph
+ // Otherwise the glyph has no before-bearing or vertical bearings,
+ // and the result is its width measured from the baseline origin, in
+ // appunits.
+ uint16_t GetContainedGlyphWidthAppUnits(uint32_t aGlyphID) const {
+ return mContainedGlyphWidths.Get(aGlyphID);
+ }
+
+ bool IsGlyphKnown(uint32_t aGlyphID) const {
+ return mContainedGlyphWidths.Get(aGlyphID) != INVALID_WIDTH ||
+ mTightGlyphExtents.GetEntry(aGlyphID) != nullptr;
+ }
+
+ bool IsGlyphKnownWithTightExtents(uint32_t aGlyphID) const {
+ return mTightGlyphExtents.GetEntry(aGlyphID) != nullptr;
+ }
+
+ // Get glyph extents; a rectangle relative to the left baseline origin
+ // Returns true on success. Can fail on OOM or when aContext is null
+ // and extents were not (successfully) prefetched.
+ bool GetTightGlyphExtentsAppUnits(gfxFont* aFont,
+ DrawTarget* aDrawTarget, uint32_t aGlyphID, gfxRect* aExtents);
+
+ void SetContainedGlyphWidthAppUnits(uint32_t aGlyphID, uint16_t aWidth) {
+ mContainedGlyphWidths.Set(aGlyphID, aWidth);
+ }
+ void SetTightGlyphExtents(uint32_t aGlyphID, const gfxRect& aExtentsAppUnits);
+
+ int32_t GetAppUnitsPerDevUnit() { return mAppUnitsPerDevUnit; }
+
+ size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
+ size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
+
+private:
+ class HashEntry : public nsUint32HashKey {
+ public:
+ // When constructing a new entry in the hashtable, we'll leave this
+ // blank. The caller of Put() will fill this in.
+ explicit HashEntry(KeyTypePointer aPtr) : nsUint32HashKey(aPtr) {}
+ HashEntry(const HashEntry& toCopy) : nsUint32HashKey(toCopy) {
+ x = toCopy.x; y = toCopy.y; width = toCopy.width; height = toCopy.height;
+ }
+
+ float x, y, width, height;
+ };
+
+ enum { BLOCK_SIZE_BITS = 7, BLOCK_SIZE = 1 << BLOCK_SIZE_BITS }; // 128-glyph blocks
+
+ class GlyphWidths {
+ public:
+ void Set(uint32_t aIndex, uint16_t aValue);
+ uint16_t Get(uint32_t aIndex) const {
+ uint32_t block = aIndex >> BLOCK_SIZE_BITS;
+ if (block >= mBlocks.Length())
+ return INVALID_WIDTH;
+ uintptr_t bits = mBlocks[block];
+ if (!bits)
+ return INVALID_WIDTH;
+ uint32_t indexInBlock = aIndex & (BLOCK_SIZE - 1);
+ if (bits & 0x1) {
+ if (GetGlyphOffset(bits) != indexInBlock)
+ return INVALID_WIDTH;
+ return GetWidth(bits);
+ }
+ uint16_t *widths = reinterpret_cast<uint16_t *>(bits);
+ return widths[indexInBlock];
+ }
+
+ uint32_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
+
+ ~GlyphWidths();
+
+ private:
+ static uint32_t GetGlyphOffset(uintptr_t aBits) {
+ NS_ASSERTION(aBits & 0x1, "This is really a pointer...");
+ return (aBits >> 1) & ((1 << BLOCK_SIZE_BITS) - 1);
+ }
+ static uint32_t GetWidth(uintptr_t aBits) {
+ NS_ASSERTION(aBits & 0x1, "This is really a pointer...");
+ return aBits >> (1 + BLOCK_SIZE_BITS);
+ }
+ static uintptr_t MakeSingle(uint32_t aGlyphOffset, uint16_t aWidth) {
+ return (aWidth << (1 + BLOCK_SIZE_BITS)) + (aGlyphOffset << 1) + 1;
+ }
+
+ nsTArray<uintptr_t> mBlocks;
+ };
+
+ GlyphWidths mContainedGlyphWidths;
+ nsTHashtable<HashEntry> mTightGlyphExtents;
+ int32_t mAppUnitsPerDevUnit;
+
+private:
+ // not implemented:
+ gfxGlyphExtents(const gfxGlyphExtents& aOther) = delete;
+ gfxGlyphExtents& operator=(const gfxGlyphExtents& aOther) = delete;
+};
+
+#endif