mirror of
https://github.com/mozilla/gecko-dev.git
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844 lines
31 KiB
C++
844 lines
31 KiB
C++
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "gfxFT2FontBase.h"
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#include "gfxFT2Utils.h"
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#include "harfbuzz/hb.h"
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#include "mozilla/Likely.h"
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#include "mozilla/StaticPrefs_gfx.h"
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#include "gfxFontConstants.h"
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#include "gfxFontUtils.h"
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#include "gfxHarfBuzzShaper.h"
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#include <algorithm>
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#include <dlfcn.h>
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#include FT_TRUETYPE_TAGS_H
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#include FT_TRUETYPE_TABLES_H
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#include FT_ADVANCES_H
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#include FT_MULTIPLE_MASTERS_H
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#ifndef FT_LOAD_COLOR
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# define FT_LOAD_COLOR (1L << 20)
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#endif
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#ifndef FT_FACE_FLAG_COLOR
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# define FT_FACE_FLAG_COLOR (1L << 14)
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#endif
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using namespace mozilla;
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using namespace mozilla::gfx;
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gfxFT2FontBase::gfxFT2FontBase(
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const RefPtr<UnscaledFontFreeType>& aUnscaledFont,
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RefPtr<mozilla::gfx::SharedFTFace>&& aFTFace, gfxFontEntry* aFontEntry,
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const gfxFontStyle* aFontStyle, int aLoadFlags, bool aEmbolden)
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: gfxFont(aUnscaledFont, aFontEntry, aFontStyle, kAntialiasDefault),
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mFTFace(std::move(aFTFace)),
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mFTLoadFlags(aLoadFlags | FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH |
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FT_LOAD_COLOR),
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mEmbolden(aEmbolden),
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mFTSize(0.0) {}
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gfxFT2FontBase::~gfxFT2FontBase() { mFTFace->ForgetLockOwner(this); }
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FT_Face gfxFT2FontBase::LockFTFace() const
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MOZ_CAPABILITY_ACQUIRE(mFTFace) MOZ_NO_THREAD_SAFETY_ANALYSIS {
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if (!mFTFace->Lock(this)) {
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FT_Set_Transform(mFTFace->GetFace(), nullptr, nullptr);
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FT_F26Dot6 charSize = NS_lround(mFTSize * 64.0);
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FT_Set_Char_Size(mFTFace->GetFace(), charSize, charSize, 0, 0);
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}
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return mFTFace->GetFace();
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}
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void gfxFT2FontBase::UnlockFTFace() const
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MOZ_CAPABILITY_RELEASE(mFTFace) MOZ_NO_THREAD_SAFETY_ANALYSIS {
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mFTFace->Unlock();
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}
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static FT_ULong GetTableSizeFromFTFace(SharedFTFace* aFace,
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uint32_t aTableTag) {
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if (!aFace) {
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return 0;
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}
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FT_ULong len = 0;
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if (FT_Load_Sfnt_Table(aFace->GetFace(), aTableTag, 0, nullptr, &len) != 0) {
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return 0;
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}
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return len;
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}
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bool gfxFT2FontEntryBase::FaceHasTable(SharedFTFace* aFace,
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uint32_t aTableTag) {
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return GetTableSizeFromFTFace(aFace, aTableTag) > 0;
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}
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nsresult gfxFT2FontEntryBase::CopyFaceTable(SharedFTFace* aFace,
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uint32_t aTableTag,
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nsTArray<uint8_t>& aBuffer) {
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FT_ULong length = GetTableSizeFromFTFace(aFace, aTableTag);
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if (!length) {
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return NS_ERROR_NOT_AVAILABLE;
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}
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if (!aBuffer.SetLength(length, fallible)) {
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return NS_ERROR_OUT_OF_MEMORY;
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}
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if (FT_Load_Sfnt_Table(aFace->GetFace(), aTableTag, 0, aBuffer.Elements(),
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&length) != 0) {
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aBuffer.Clear();
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return NS_ERROR_FAILURE;
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}
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return NS_OK;
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}
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uint32_t gfxFT2FontEntryBase::GetGlyph(uint32_t aCharCode,
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gfxFT2FontBase* aFont) {
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const uint32_t slotIndex = aCharCode % kNumCmapCacheSlots;
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{
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// Try to read a cached entry without taking an exclusive lock.
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AutoReadLock lock(mLock);
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if (mCmapCache) {
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const auto& slot = mCmapCache[slotIndex];
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if (slot.mCharCode == aCharCode) {
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return slot.mGlyphIndex;
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}
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}
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}
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// Create/update the charcode-to-glyphid cache.
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AutoWriteLock lock(mLock);
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// This cache algorithm and size is based on what is done in
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// cairo_scaled_font_text_to_glyphs and pango_fc_font_real_get_glyph. I
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// think the concept is that adjacent characters probably come mostly from
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// one Unicode block. This assumption is probably not so valid with
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// scripts with large character sets as used for East Asian languages.
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if (!mCmapCache) {
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mCmapCache = mozilla::MakeUnique<CmapCacheSlot[]>(kNumCmapCacheSlots);
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// Invalidate slot 0 by setting its char code to something that would
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// never end up in slot 0. All other slots are already invalid
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// because they have mCharCode = 0 and a glyph for char code 0 will
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// always be in the slot 0.
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mCmapCache[0].mCharCode = 1;
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}
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auto& slot = mCmapCache[slotIndex];
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if (slot.mCharCode != aCharCode) {
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slot.mCharCode = aCharCode;
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slot.mGlyphIndex = gfxFT2LockedFace(aFont).GetGlyph(aCharCode);
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}
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return slot.mGlyphIndex;
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}
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// aScale is intended for a 16.16 x/y_scale of an FT_Size_Metrics
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static inline FT_Long ScaleRoundDesignUnits(FT_Short aDesignMetric,
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FT_Fixed aScale) {
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FT_Long fixed26dot6 = FT_MulFix(aDesignMetric, aScale);
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return ROUND_26_6_TO_INT(fixed26dot6);
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}
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// Snap a line to pixels while keeping the center and size of the line as
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// close to the original position as possible.
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//
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// Pango does similar snapping for underline and strikethrough when fonts are
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// hinted, but nsCSSRendering::GetTextDecorationRectInternal always snaps the
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// top and size of lines. Optimizing the distance between the line and
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// baseline is probably good for the gap between text and underline, but
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// optimizing the center of the line is better for positioning strikethough.
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static void SnapLineToPixels(gfxFloat& aOffset, gfxFloat& aSize) {
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gfxFloat snappedSize = std::max(floor(aSize + 0.5), 1.0);
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// Correct offset for change in size
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gfxFloat offset = aOffset - 0.5 * (aSize - snappedSize);
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// Snap offset
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aOffset = floor(offset + 0.5);
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aSize = snappedSize;
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}
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static inline gfxRect ScaleGlyphBounds(const IntRect& aBounds,
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gfxFloat aScale) {
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return gfxRect(FLOAT_FROM_26_6(aBounds.x) * aScale,
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FLOAT_FROM_26_6(aBounds.y) * aScale,
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FLOAT_FROM_26_6(aBounds.width) * aScale,
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FLOAT_FROM_26_6(aBounds.height) * aScale);
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}
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/**
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* Get extents for a simple character representable by a single glyph.
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* The return value is the glyph id of that glyph or zero if no such glyph
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* exists. aWidth/aBounds is only set when this returns a non-zero glyph id.
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* This is just for use during initialization, and doesn't use the width cache.
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*/
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uint32_t gfxFT2FontBase::GetCharExtents(uint32_t aChar, gfxFloat* aWidth,
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gfxRect* aBounds) {
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FT_UInt gid = GetGlyph(aChar);
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int32_t width;
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IntRect bounds;
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if (gid && GetFTGlyphExtents(gid, aWidth ? &width : nullptr,
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aBounds ? &bounds : nullptr)) {
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if (aWidth) {
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*aWidth = FLOAT_FROM_16_16(width);
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}
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if (aBounds) {
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*aBounds = ScaleGlyphBounds(bounds, GetAdjustedSize() / mFTSize);
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}
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return gid;
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} else {
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return 0;
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}
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}
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/**
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* Find the closest available fixed strike size, if applicable, to the
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* desired font size.
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*/
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static double FindClosestSize(FT_Face aFace, double aSize) {
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// FT size selection does not actually support sizes smaller than 1 and will
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// clamp this internally, regardless of what is requested. Do the clamp here
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// instead so that glyph extents/font matrix scaling will compensate it, as
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// Cairo normally would.
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if (aSize < 1.0) {
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aSize = 1.0;
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}
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if (FT_IS_SCALABLE(aFace)) {
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return aSize;
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}
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double bestDist = DBL_MAX;
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FT_Int bestSize = -1;
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for (FT_Int i = 0; i < aFace->num_fixed_sizes; i++) {
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double dist = aFace->available_sizes[i].y_ppem / 64.0 - aSize;
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// If the previous best is smaller than the desired size, prefer
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// a bigger size. Otherwise, just choose whatever size is closest.
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if (bestDist < 0 ? dist >= bestDist : fabs(dist) <= bestDist) {
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bestDist = dist;
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bestSize = i;
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}
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}
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if (bestSize < 0) {
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return aSize;
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}
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return aFace->available_sizes[bestSize].y_ppem / 64.0;
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}
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void gfxFT2FontBase::InitMetrics() {
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mFUnitsConvFactor = 0.0;
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if (MOZ_UNLIKELY(mStyle.AdjustedSizeMustBeZero())) {
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memset(&mMetrics, 0, sizeof(mMetrics)); // zero initialize
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mSpaceGlyph = GetGlyph(' ');
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return;
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}
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if (FontSizeAdjust::Tag(mStyle.sizeAdjustBasis) !=
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FontSizeAdjust::Tag::None &&
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mStyle.sizeAdjust >= 0.0 && GetAdjustedSize() > 0.0 && mFTSize == 0.0) {
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// If font-size-adjust is in effect, we need to get metrics in order to
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// determine the aspect ratio, then compute the final adjusted size and
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// re-initialize metrics.
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// Setting mFTSize nonzero here ensures we will not recurse again; the
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// actual value will be overridden by FindClosestSize below.
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mFTSize = 1.0;
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InitMetrics();
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// Now do the font-size-adjust calculation and set the final size.
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gfxFloat aspect;
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switch (FontSizeAdjust::Tag(mStyle.sizeAdjustBasis)) {
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default:
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MOZ_ASSERT_UNREACHABLE("unhandled sizeAdjustBasis?");
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aspect = 0.0;
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break;
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case FontSizeAdjust::Tag::ExHeight:
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aspect = mMetrics.xHeight / mAdjustedSize;
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break;
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case FontSizeAdjust::Tag::CapHeight:
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aspect = mMetrics.capHeight / mAdjustedSize;
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break;
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case FontSizeAdjust::Tag::ChWidth:
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aspect =
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mMetrics.zeroWidth > 0.0 ? mMetrics.zeroWidth / mAdjustedSize : 0.5;
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break;
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case FontSizeAdjust::Tag::IcWidth:
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case FontSizeAdjust::Tag::IcHeight: {
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bool vertical = FontSizeAdjust::Tag(mStyle.sizeAdjustBasis) ==
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FontSizeAdjust::Tag::IcHeight;
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gfxFloat advance = GetCharAdvance(kWaterIdeograph, vertical);
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aspect = advance > 0.0 ? advance / mAdjustedSize : 1.0;
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break;
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}
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}
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if (aspect > 0.0) {
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// If we created a shaper above (to measure glyphs), discard it so we
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// get a new one for the adjusted scaling.
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delete mHarfBuzzShaper.exchange(nullptr);
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mAdjustedSize = mStyle.GetAdjustedSize(aspect);
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// Ensure the FT_Face will be reconfigured for the new size next time we
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// need to use it.
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mFTFace->ForgetLockOwner(this);
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}
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}
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// Set mAdjustedSize if it hasn't already been set by a font-size-adjust
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// computation.
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mAdjustedSize = GetAdjustedSize();
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// Cairo metrics are normalized to em-space, so that whatever fixed size
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// might actually be chosen is factored out. They are then later scaled by
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// the font matrix to the target adjusted size. Stash the chosen closest
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// size here for later scaling of the metrics.
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mFTSize = FindClosestSize(mFTFace->GetFace(), GetAdjustedSize());
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// Explicitly lock the face so we can release it early before calling
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// back into Cairo below.
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FT_Face face = LockFTFace();
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if (MOZ_UNLIKELY(!face)) {
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// No face. This unfortunate situation might happen if the font
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// file is (re)moved at the wrong time.
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const gfxFloat emHeight = GetAdjustedSize();
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mMetrics.emHeight = emHeight;
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mMetrics.maxAscent = mMetrics.emAscent = 0.8 * emHeight;
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mMetrics.maxDescent = mMetrics.emDescent = 0.2 * emHeight;
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mMetrics.maxHeight = emHeight;
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mMetrics.internalLeading = 0.0;
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mMetrics.externalLeading = 0.2 * emHeight;
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const gfxFloat spaceWidth = 0.5 * emHeight;
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mMetrics.spaceWidth = spaceWidth;
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mMetrics.maxAdvance = spaceWidth;
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mMetrics.aveCharWidth = spaceWidth;
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mMetrics.zeroWidth = spaceWidth;
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mMetrics.ideographicWidth = emHeight;
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const gfxFloat xHeight = 0.5 * emHeight;
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mMetrics.xHeight = xHeight;
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mMetrics.capHeight = mMetrics.maxAscent;
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const gfxFloat underlineSize = emHeight / 14.0;
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mMetrics.underlineSize = underlineSize;
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mMetrics.underlineOffset = -underlineSize;
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mMetrics.strikeoutOffset = 0.25 * emHeight;
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mMetrics.strikeoutSize = underlineSize;
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SanitizeMetrics(&mMetrics, false);
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UnlockFTFace();
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return;
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}
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const FT_Size_Metrics& ftMetrics = face->size->metrics;
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mMetrics.maxAscent = FLOAT_FROM_26_6(ftMetrics.ascender);
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mMetrics.maxDescent = -FLOAT_FROM_26_6(ftMetrics.descender);
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mMetrics.maxAdvance = FLOAT_FROM_26_6(ftMetrics.max_advance);
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gfxFloat lineHeight = FLOAT_FROM_26_6(ftMetrics.height);
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gfxFloat emHeight;
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// Scale for vertical design metric conversion: pixels per design unit.
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// If this remains at 0.0, we can't use metrics from OS/2 etc.
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gfxFloat yScale = 0.0;
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if (FT_IS_SCALABLE(face)) {
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// Prefer FT_Size_Metrics::x_scale to x_ppem as x_ppem does not
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// have subpixel accuracy.
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//
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// FT_Size_Metrics::y_scale is in 16.16 fixed point format. Its
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// (fractional) value is a factor that converts vertical metrics from
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// design units to units of 1/64 pixels, so that the result may be
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// interpreted as pixels in 26.6 fixed point format.
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mFUnitsConvFactor = FLOAT_FROM_26_6(FLOAT_FROM_16_16(ftMetrics.x_scale));
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yScale = FLOAT_FROM_26_6(FLOAT_FROM_16_16(ftMetrics.y_scale));
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emHeight = face->units_per_EM * yScale;
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} else { // Not scalable.
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emHeight = ftMetrics.y_ppem;
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// FT_Face doc says units_per_EM and a bunch of following fields
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// are "only relevant to scalable outlines". If it's an sfnt,
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// we can get units_per_EM from the 'head' table instead; otherwise,
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// we don't have a unitsPerEm value so we can't compute/use yScale or
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// mFUnitsConvFactor (x scale).
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const TT_Header* head =
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static_cast<TT_Header*>(FT_Get_Sfnt_Table(face, ft_sfnt_head));
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if (head) {
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// Bug 1267909 - Even if the font is not explicitly scalable,
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// if the face has color bitmaps, it should be treated as scalable
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// and scaled to the desired size. Metrics based on y_ppem need
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// to be rescaled for the adjusted size. This makes metrics agree
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// with the scales we pass to Cairo for Fontconfig fonts.
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if (face->face_flags & FT_FACE_FLAG_COLOR) {
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emHeight = GetAdjustedSize();
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gfxFloat adjustScale = emHeight / ftMetrics.y_ppem;
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mMetrics.maxAscent *= adjustScale;
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mMetrics.maxDescent *= adjustScale;
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mMetrics.maxAdvance *= adjustScale;
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lineHeight *= adjustScale;
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}
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gfxFloat emUnit = head->Units_Per_EM;
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mFUnitsConvFactor = ftMetrics.x_ppem / emUnit;
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yScale = emHeight / emUnit;
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}
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}
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TT_OS2* os2 = static_cast<TT_OS2*>(FT_Get_Sfnt_Table(face, ft_sfnt_os2));
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if (os2 && os2->sTypoAscender && yScale > 0.0) {
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mMetrics.emAscent = os2->sTypoAscender * yScale;
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mMetrics.emDescent = -os2->sTypoDescender * yScale;
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FT_Short typoHeight =
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os2->sTypoAscender - os2->sTypoDescender + os2->sTypoLineGap;
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lineHeight = typoHeight * yScale;
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// If the OS/2 fsSelection USE_TYPO_METRICS bit is set,
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// set maxAscent/Descent from the sTypo* fields instead of hhea.
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const uint16_t kUseTypoMetricsMask = 1 << 7;
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if ((os2->fsSelection & kUseTypoMetricsMask) ||
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// maxAscent/maxDescent get used for frame heights, and some fonts
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// don't have the HHEA table ascent/descent set (bug 279032).
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(mMetrics.maxAscent == 0.0 && mMetrics.maxDescent == 0.0)) {
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// We use NS_round here to parallel the pixel-rounded values that
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// freetype gives us for ftMetrics.ascender/descender.
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mMetrics.maxAscent = NS_round(mMetrics.emAscent);
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mMetrics.maxDescent = NS_round(mMetrics.emDescent);
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}
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} else {
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mMetrics.emAscent = mMetrics.maxAscent;
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mMetrics.emDescent = mMetrics.maxDescent;
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}
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// gfxFont::Metrics::underlineOffset is the position of the top of the
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// underline.
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//
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// FT_FaceRec documentation describes underline_position as "the
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// center of the underlining stem". This was the original definition
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// of the PostScript metric, but in the PostScript table of OpenType
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// fonts the metric is "the top of the underline"
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// (http://www.microsoft.com/typography/otspec/post.htm), and FreeType
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// (up to version 2.3.7) doesn't make any adjustment.
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//
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// Therefore get the underline position directly from the table
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// ourselves when this table exists. Use FreeType's metrics for
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// other (including older PostScript) fonts.
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if (face->underline_position && face->underline_thickness && yScale > 0.0) {
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mMetrics.underlineSize = face->underline_thickness * yScale;
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TT_Postscript* post =
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static_cast<TT_Postscript*>(FT_Get_Sfnt_Table(face, ft_sfnt_post));
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if (post && post->underlinePosition) {
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mMetrics.underlineOffset = post->underlinePosition * yScale;
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} else {
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mMetrics.underlineOffset =
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face->underline_position * yScale + 0.5 * mMetrics.underlineSize;
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}
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} else { // No underline info.
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// Imitate Pango.
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mMetrics.underlineSize = emHeight / 14.0;
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mMetrics.underlineOffset = -mMetrics.underlineSize;
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}
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if (os2 && os2->yStrikeoutSize && os2->yStrikeoutPosition && yScale > 0.0) {
|
|
mMetrics.strikeoutSize = os2->yStrikeoutSize * yScale;
|
|
mMetrics.strikeoutOffset = os2->yStrikeoutPosition * yScale;
|
|
} else { // No strikeout info.
|
|
mMetrics.strikeoutSize = mMetrics.underlineSize;
|
|
// Use OpenType spec's suggested position for Roman font.
|
|
mMetrics.strikeoutOffset =
|
|
emHeight * 409.0 / 2048.0 + 0.5 * mMetrics.strikeoutSize;
|
|
}
|
|
SnapLineToPixels(mMetrics.strikeoutOffset, mMetrics.strikeoutSize);
|
|
|
|
if (os2 && os2->sxHeight && yScale > 0.0) {
|
|
mMetrics.xHeight = os2->sxHeight * yScale;
|
|
} else {
|
|
// CSS 2.1, section 4.3.2 Lengths: "In the cases where it is
|
|
// impossible or impractical to determine the x-height, a value of
|
|
// 0.5em should be used."
|
|
mMetrics.xHeight = 0.5 * emHeight;
|
|
}
|
|
|
|
// aveCharWidth is used for the width of text input elements so be
|
|
// liberal rather than conservative in the estimate.
|
|
if (os2 && os2->xAvgCharWidth) {
|
|
// Round to pixels as this is compared with maxAdvance to guess
|
|
// whether this is a fixed width font.
|
|
mMetrics.aveCharWidth =
|
|
ScaleRoundDesignUnits(os2->xAvgCharWidth, ftMetrics.x_scale);
|
|
} else {
|
|
mMetrics.aveCharWidth = 0.0; // updated below
|
|
}
|
|
|
|
if (os2 && os2->sCapHeight && yScale > 0.0) {
|
|
mMetrics.capHeight = os2->sCapHeight * yScale;
|
|
} else {
|
|
mMetrics.capHeight = mMetrics.maxAscent;
|
|
}
|
|
|
|
// Release the face lock to safely load glyphs with GetCharExtents if
|
|
// necessary without recursively locking.
|
|
UnlockFTFace();
|
|
|
|
gfxFloat width;
|
|
mSpaceGlyph = GetCharExtents(' ', &width);
|
|
if (mSpaceGlyph) {
|
|
mMetrics.spaceWidth = width;
|
|
} else {
|
|
mMetrics.spaceWidth = mMetrics.maxAdvance; // guess
|
|
}
|
|
|
|
if (GetCharExtents('0', &width)) {
|
|
mMetrics.zeroWidth = width;
|
|
} else {
|
|
mMetrics.zeroWidth = -1.0; // indicates not found
|
|
}
|
|
|
|
if (GetCharExtents(kWaterIdeograph, &width)) {
|
|
mMetrics.ideographicWidth = width;
|
|
} else {
|
|
mMetrics.ideographicWidth = -1.0;
|
|
}
|
|
|
|
// If we didn't get a usable x-height or cap-height above, try measuring
|
|
// specific glyphs. This can be affected by hinting, leading to erratic
|
|
// behavior across font sizes and system configuration, so we prefer to
|
|
// use the metrics directly from the font if possible.
|
|
// Using glyph bounds for x-height or cap-height may not really be right,
|
|
// if fonts have fancy swashes etc. For x-height, CSS 2.1 suggests possibly
|
|
// using the height of an "o", which may be more consistent across fonts,
|
|
// but then curve-overshoot should also be accounted for.
|
|
gfxFloat xWidth;
|
|
gfxRect xBounds;
|
|
if (mMetrics.xHeight == 0.0) {
|
|
if (GetCharExtents('x', &xWidth, &xBounds) && xBounds.y < 0.0) {
|
|
mMetrics.xHeight = -xBounds.y;
|
|
mMetrics.aveCharWidth = std::max(mMetrics.aveCharWidth, xWidth);
|
|
}
|
|
}
|
|
|
|
if (mMetrics.capHeight == 0.0) {
|
|
if (GetCharExtents('H', nullptr, &xBounds) && xBounds.y < 0.0) {
|
|
mMetrics.capHeight = -xBounds.y;
|
|
}
|
|
}
|
|
|
|
mMetrics.aveCharWidth = std::max(mMetrics.aveCharWidth, mMetrics.zeroWidth);
|
|
if (mMetrics.aveCharWidth == 0.0) {
|
|
mMetrics.aveCharWidth = mMetrics.spaceWidth;
|
|
}
|
|
// Apparently hinting can mean that max_advance is not always accurate.
|
|
mMetrics.maxAdvance = std::max(mMetrics.maxAdvance, mMetrics.aveCharWidth);
|
|
|
|
mMetrics.maxHeight = mMetrics.maxAscent + mMetrics.maxDescent;
|
|
|
|
// Make the line height an integer number of pixels so that lines will be
|
|
// equally spaced (rather than just being snapped to pixels, some up and
|
|
// some down). Layout calculates line height from the emHeight +
|
|
// internalLeading + externalLeading, but first each of these is rounded
|
|
// to layout units. To ensure that the result is an integer number of
|
|
// pixels, round each of the components to pixels.
|
|
mMetrics.emHeight = floor(emHeight + 0.5);
|
|
|
|
// maxHeight will normally be an integer, but round anyway in case
|
|
// FreeType is configured differently.
|
|
mMetrics.internalLeading =
|
|
floor(mMetrics.maxHeight - mMetrics.emHeight + 0.5);
|
|
|
|
// Text input boxes currently don't work well with lineHeight
|
|
// significantly less than maxHeight (with Verdana, for example).
|
|
lineHeight = floor(std::max(lineHeight, mMetrics.maxHeight) + 0.5);
|
|
mMetrics.externalLeading =
|
|
lineHeight - mMetrics.internalLeading - mMetrics.emHeight;
|
|
|
|
// Ensure emAscent + emDescent == emHeight
|
|
gfxFloat sum = mMetrics.emAscent + mMetrics.emDescent;
|
|
mMetrics.emAscent =
|
|
sum > 0.0 ? mMetrics.emAscent * mMetrics.emHeight / sum : 0.0;
|
|
mMetrics.emDescent = mMetrics.emHeight - mMetrics.emAscent;
|
|
|
|
SanitizeMetrics(&mMetrics, false);
|
|
|
|
#if 0
|
|
// printf("font name: %s %f\n", NS_ConvertUTF16toUTF8(GetName()).get(), GetStyle()->size);
|
|
// printf ("pango font %s\n", pango_font_description_to_string (pango_font_describe (font)));
|
|
|
|
fprintf (stderr, "Font: %s\n", GetName().get());
|
|
fprintf (stderr, " emHeight: %f emAscent: %f emDescent: %f\n", mMetrics.emHeight, mMetrics.emAscent, mMetrics.emDescent);
|
|
fprintf (stderr, " maxAscent: %f maxDescent: %f\n", mMetrics.maxAscent, mMetrics.maxDescent);
|
|
fprintf (stderr, " internalLeading: %f externalLeading: %f\n", mMetrics.externalLeading, mMetrics.internalLeading);
|
|
fprintf (stderr, " spaceWidth: %f aveCharWidth: %f xHeight: %f\n", mMetrics.spaceWidth, mMetrics.aveCharWidth, mMetrics.xHeight);
|
|
fprintf (stderr, " ideographicWidth: %f\n", mMetrics.ideographicWidth);
|
|
fprintf (stderr, " uOff: %f uSize: %f stOff: %f stSize: %f\n", mMetrics.underlineOffset, mMetrics.underlineSize, mMetrics.strikeoutOffset, mMetrics.strikeoutSize);
|
|
#endif
|
|
}
|
|
|
|
uint32_t gfxFT2FontBase::GetGlyph(uint32_t unicode,
|
|
uint32_t variation_selector) {
|
|
if (variation_selector) {
|
|
uint32_t id =
|
|
gfxFT2LockedFace(this).GetUVSGlyph(unicode, variation_selector);
|
|
if (id) {
|
|
return id;
|
|
}
|
|
unicode = gfxFontUtils::GetUVSFallback(unicode, variation_selector);
|
|
if (unicode) {
|
|
return GetGlyph(unicode);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
return GetGlyph(unicode);
|
|
}
|
|
|
|
bool gfxFT2FontBase::ShouldRoundXOffset(cairo_t* aCairo) const {
|
|
// Force rounding if outputting to a Cairo context or if requested by pref to
|
|
// disable subpixel positioning. Otherwise, allow subpixel positioning (no
|
|
// rounding) if rendering a scalable outline font with anti-aliasing.
|
|
// Monochrome rendering or some bitmap fonts can become too distorted with
|
|
// subpixel positioning, so force rounding in those cases. Also be careful not
|
|
// to use subpixel positioning if the user requests full hinting via
|
|
// Fontconfig, which we detect by checking that neither hinting was disabled
|
|
// nor light hinting was requested. Allow pref to force subpixel positioning
|
|
// on even if full hinting was requested.
|
|
return MOZ_UNLIKELY(
|
|
StaticPrefs::
|
|
gfx_text_subpixel_position_force_disabled_AtStartup()) ||
|
|
aCairo != nullptr || !mFTFace || !FT_IS_SCALABLE(mFTFace->GetFace()) ||
|
|
(mFTLoadFlags & FT_LOAD_MONOCHROME) ||
|
|
!((mFTLoadFlags & FT_LOAD_NO_HINTING) ||
|
|
FT_LOAD_TARGET_MODE(mFTLoadFlags) == FT_RENDER_MODE_LIGHT ||
|
|
MOZ_UNLIKELY(
|
|
StaticPrefs::
|
|
gfx_text_subpixel_position_force_enabled_AtStartup()));
|
|
}
|
|
|
|
FT_Vector gfxFT2FontBase::GetEmboldenStrength(FT_Face aFace) const {
|
|
FT_Vector strength = {0, 0};
|
|
if (!mEmbolden) {
|
|
return strength;
|
|
}
|
|
|
|
// If it's an outline glyph, we'll be using mozilla_glyphslot_embolden_less
|
|
// (see gfx/wr/webrender/src/platform/unix/font.rs), so we need to match its
|
|
// emboldening strength here.
|
|
if (aFace->glyph->format == FT_GLYPH_FORMAT_OUTLINE) {
|
|
strength.x =
|
|
FT_MulFix(aFace->units_per_EM, aFace->size->metrics.y_scale) / 48;
|
|
strength.y = strength.x;
|
|
return strength;
|
|
}
|
|
|
|
// This is the embolden "strength" used by FT_GlyphSlot_Embolden.
|
|
strength.x =
|
|
FT_MulFix(aFace->units_per_EM, aFace->size->metrics.y_scale) / 24;
|
|
strength.y = strength.x;
|
|
if (aFace->glyph->format == FT_GLYPH_FORMAT_BITMAP) {
|
|
strength.x &= -64;
|
|
if (!strength.x) {
|
|
strength.x = 64;
|
|
}
|
|
strength.y &= -64;
|
|
}
|
|
return strength;
|
|
}
|
|
|
|
bool gfxFT2FontBase::GetFTGlyphExtents(uint16_t aGID, int32_t* aAdvance,
|
|
IntRect* aBounds) {
|
|
gfxFT2LockedFace face(this);
|
|
MOZ_ASSERT(face.get());
|
|
if (!face.get()) {
|
|
// Failed to get the FT_Face? Give up already.
|
|
NS_WARNING("failed to get FT_Face!");
|
|
return false;
|
|
}
|
|
|
|
FT_Int32 flags = mFTLoadFlags;
|
|
if (!aBounds) {
|
|
flags |= FT_LOAD_ADVANCE_ONLY;
|
|
}
|
|
|
|
// Whether to disable subpixel positioning
|
|
bool roundX = ShouldRoundXOffset(nullptr);
|
|
|
|
// Workaround for FT_Load_Glyph not setting linearHoriAdvance for SVG glyphs.
|
|
// See https://gitlab.freedesktop.org/freetype/freetype/-/issues/1156.
|
|
if (!roundX &&
|
|
GetFontEntry()->HasFontTable(TRUETYPE_TAG('S', 'V', 'G', ' '))) {
|
|
flags &= ~FT_LOAD_COLOR;
|
|
}
|
|
|
|
if (Factory::LoadFTGlyph(face.get(), aGID, flags) != FT_Err_Ok) {
|
|
// FT_Face was somehow broken/invalid? Don't try to access glyph slot.
|
|
// This probably shouldn't happen, but does: see bug 1440938.
|
|
NS_WARNING("failed to load glyph!");
|
|
return false;
|
|
}
|
|
|
|
// Whether to interpret hinting settings (i.e. not printing)
|
|
bool hintMetrics = ShouldHintMetrics();
|
|
// No hinting disables X and Y hinting. Light disables only X hinting.
|
|
bool unhintedY = (mFTLoadFlags & FT_LOAD_NO_HINTING) != 0;
|
|
bool unhintedX =
|
|
unhintedY || FT_LOAD_TARGET_MODE(mFTLoadFlags) == FT_RENDER_MODE_LIGHT;
|
|
|
|
// Normalize out the loaded FT glyph size and then scale to the actually
|
|
// desired size, in case these two sizes differ.
|
|
gfxFloat extentsScale = GetAdjustedSize() / mFTSize;
|
|
|
|
FT_Vector bold = GetEmboldenStrength(face.get());
|
|
|
|
// Due to freetype bug 52683 we MUST use the linearHoriAdvance field when
|
|
// dealing with a variation font; also use it for scalable fonts when not
|
|
// applying hinting. Otherwise, prefer hinted width from glyph->advance.x.
|
|
if (aAdvance) {
|
|
FT_Fixed advance;
|
|
if (!roundX || FT_HAS_MULTIPLE_MASTERS(face.get())) {
|
|
advance = face.get()->glyph->linearHoriAdvance;
|
|
} else {
|
|
advance = face.get()->glyph->advance.x << 10; // convert 26.6 to 16.16
|
|
}
|
|
if (advance) {
|
|
advance += bold.x << 10; // convert 26.6 to 16.16
|
|
}
|
|
// Hinting was requested, but FT did not apply any hinting to the metrics.
|
|
// Round the advance here to approximate hinting as Cairo does. This must
|
|
// happen BEFORE we apply the glyph extents scale, just like FT hinting
|
|
// would.
|
|
if (hintMetrics && roundX && unhintedX) {
|
|
advance = (advance + 0x8000) & 0xffff0000u;
|
|
}
|
|
*aAdvance = NS_lround(advance * extentsScale);
|
|
}
|
|
|
|
if (aBounds) {
|
|
const FT_Glyph_Metrics& metrics = face.get()->glyph->metrics;
|
|
FT_F26Dot6 x = metrics.horiBearingX;
|
|
FT_F26Dot6 y = -metrics.horiBearingY;
|
|
FT_F26Dot6 x2 = x + metrics.width;
|
|
FT_F26Dot6 y2 = y + metrics.height;
|
|
// Synthetic bold moves the glyph top and right boundaries.
|
|
y -= bold.y;
|
|
x2 += bold.x;
|
|
if (hintMetrics) {
|
|
if (roundX && unhintedX) {
|
|
x &= -64;
|
|
x2 = (x2 + 63) & -64;
|
|
}
|
|
if (unhintedY) {
|
|
y &= -64;
|
|
y2 = (y2 + 63) & -64;
|
|
}
|
|
}
|
|
*aBounds = IntRect(x, y, x2 - x, y2 - y);
|
|
|
|
// Color fonts may not have reported the right bounds here, if there wasn't
|
|
// an outline for the nominal glyph ID.
|
|
// In principle we could use COLRFonts::GetColorGlyphBounds to retrieve the
|
|
// true bounds of the rendering, but that's more expensive; probably better
|
|
// to just use the font-wide ascent/descent as a heuristic that will
|
|
// generally ensure everything gets rendered.
|
|
if (aBounds->IsEmpty() &&
|
|
GetFontEntry()->HasFontTable(TRUETYPE_TAG('C', 'O', 'L', 'R'))) {
|
|
const auto& fm = GetMetrics(nsFontMetrics::eHorizontal);
|
|
// aBounds is stored as FT_F26Dot6, so scale values from `fm` by 64.
|
|
aBounds->y = int32_t(-NS_round(fm.maxAscent * 64.0));
|
|
aBounds->height =
|
|
int32_t(NS_round((fm.maxAscent + fm.maxDescent) * 64.0));
|
|
aBounds->x = 0;
|
|
aBounds->width =
|
|
int32_t(aAdvance ? *aAdvance : NS_round(fm.maxAdvance * 64.0));
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Get the cached glyph metrics for the glyph id if available. Otherwise, query
|
|
* FreeType for the glyph extents and initialize the glyph metrics.
|
|
*/
|
|
const gfxFT2FontBase::GlyphMetrics& gfxFT2FontBase::GetCachedGlyphMetrics(
|
|
uint16_t aGID, IntRect* aBounds) {
|
|
{
|
|
// Try to read cached metrics without exclusive locking.
|
|
AutoReadLock lock(mLock);
|
|
if (mGlyphMetrics) {
|
|
if (auto metrics = mGlyphMetrics->Lookup(aGID)) {
|
|
return metrics.Data();
|
|
}
|
|
}
|
|
}
|
|
|
|
// We need to create/update the cache.
|
|
AutoWriteLock lock(mLock);
|
|
if (!mGlyphMetrics) {
|
|
mGlyphMetrics =
|
|
mozilla::MakeUnique<nsTHashMap<nsUint32HashKey, GlyphMetrics>>(128);
|
|
}
|
|
|
|
return mGlyphMetrics->LookupOrInsertWith(aGID, [&] {
|
|
GlyphMetrics metrics;
|
|
IntRect bounds;
|
|
if (GetFTGlyphExtents(aGID, &metrics.mAdvance, &bounds)) {
|
|
metrics.SetBounds(bounds);
|
|
if (aBounds) {
|
|
*aBounds = bounds;
|
|
}
|
|
}
|
|
return metrics;
|
|
});
|
|
}
|
|
|
|
bool gfxFT2FontBase::GetGlyphBounds(uint16_t aGID, gfxRect* aBounds,
|
|
bool aTight) {
|
|
IntRect bounds;
|
|
const GlyphMetrics& metrics = GetCachedGlyphMetrics(aGID, &bounds);
|
|
if (!metrics.HasValidBounds()) {
|
|
return false;
|
|
}
|
|
// Check if there are cached bounds and use those if available. Otherwise,
|
|
// fall back to directly querying the glyph extents.
|
|
if (metrics.HasCachedBounds()) {
|
|
bounds = metrics.GetBounds();
|
|
} else if (bounds.IsEmpty() && !GetFTGlyphExtents(aGID, nullptr, &bounds)) {
|
|
return false;
|
|
}
|
|
// The bounds are stored unscaled, so must be scaled to the adjusted size.
|
|
*aBounds = ScaleGlyphBounds(bounds, GetAdjustedSize() / mFTSize);
|
|
return true;
|
|
}
|
|
|
|
// For variation fonts, figure out the variation coordinates to be applied
|
|
// for each axis, in freetype's order (which may not match the order of
|
|
// axes in mStyle.variationSettings, so we need to search by axis tag).
|
|
/*static*/
|
|
void gfxFT2FontBase::SetupVarCoords(
|
|
FT_MM_Var* aMMVar, const nsTArray<gfxFontVariation>& aVariations,
|
|
FT_Face aFTFace) {
|
|
if (!aMMVar) {
|
|
return;
|
|
}
|
|
|
|
nsTArray<FT_Fixed> coords;
|
|
for (unsigned i = 0; i < aMMVar->num_axis; ++i) {
|
|
coords.AppendElement(aMMVar->axis[i].def);
|
|
for (const auto& v : aVariations) {
|
|
if (aMMVar->axis[i].tag == v.mTag) {
|
|
FT_Fixed val = v.mValue * 0x10000;
|
|
val = std::min(val, aMMVar->axis[i].maximum);
|
|
val = std::max(val, aMMVar->axis[i].minimum);
|
|
coords[i] = val;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (!coords.IsEmpty()) {
|
|
#if MOZ_TREE_FREETYPE
|
|
FT_Set_Var_Design_Coordinates(aFTFace, coords.Length(), coords.Elements());
|
|
#else
|
|
typedef FT_Error (*SetCoordsFunc)(FT_Face, FT_UInt, FT_Fixed*);
|
|
static SetCoordsFunc setCoords;
|
|
static bool firstTime = true;
|
|
if (firstTime) {
|
|
firstTime = false;
|
|
setCoords =
|
|
(SetCoordsFunc)dlsym(RTLD_DEFAULT, "FT_Set_Var_Design_Coordinates");
|
|
}
|
|
if (setCoords) {
|
|
(*setCoords)(aFTFace, coords.Length(), coords.Elements());
|
|
}
|
|
#endif
|
|
}
|
|
}
|