The Tor Browser: comparison gfx/thebes/gfxFT2FontBase.cpp

--1:000000000000
+:75ad319e2f41
+/* -*- 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/. */
+#include "gfxFT2FontBase.h"
+#include "gfxFT2Utils.h"
+#include "harfbuzz/hb.h"
+#include "mozilla/Likely.h"
+#include "gfxFontConstants.h"
+#include "gfxFontUtils.h"
+using namespace mozilla::gfx;
+gfxFT2FontBase::gfxFT2FontBase(cairo_scaled_font_t *aScaledFont,
+gfxFontEntry *aFontEntry,
+const gfxFontStyle *aFontStyle)
+: gfxFont(aFontEntry, aFontStyle, kAntialiasDefault, aScaledFont),
+mSpaceGlyph(0),
+mHasMetrics(false)
+{
+cairo_scaled_font_reference(mScaledFont);
+ConstructFontOptions();
+}
+gfxFT2FontBase::~gfxFT2FontBase()
+{
+cairo_scaled_font_destroy(mScaledFont);
+}
+uint32_t
+gfxFT2FontBase::GetGlyph(uint32_t aCharCode)
+{
+// FcFreeTypeCharIndex needs to lock the FT_Face and can end up searching
+// through all the postscript glyph names in the font.  Therefore use a
+// lightweight cache, which is stored on the cairo_font_face_t.
+cairo_font_face_t *face =
+cairo_scaled_font_get_font_face(CairoScaledFont());
+if (cairo_font_face_status(face) != CAIRO_STATUS_SUCCESS)
+return 0;
+// This cache algorithm and size is based on what is done in
+// cairo_scaled_font_text_to_glyphs and pango_fc_font_real_get_glyph.  I
+// think the concept is that adjacent characters probably come mostly from
+// one Unicode block.  This assumption is probably not so valid with
+// scripts with large character sets as used for East Asian languages.
+struct CmapCacheSlot {
+uint32_t mCharCode;
+uint32_t mGlyphIndex;
+};
+const uint32_t kNumSlots = 256;
+static cairo_user_data_key_t sCmapCacheKey;
+CmapCacheSlot *slots = static_cast<CmapCacheSlot*>
+(cairo_font_face_get_user_data(face, &sCmapCacheKey));
+if (!slots) {
+// cairo's caches can keep some cairo_font_faces alive past our last
+// destroy, so the destroy function (free) for the cache must be
+// callable from cairo without any assumptions about what other
+// modules have not been shutdown.
+slots = static_cast<CmapCacheSlot*>
+(calloc(kNumSlots, sizeof(CmapCacheSlot)));
+if (!slots)
+return 0;
+cairo_status_t status =
+cairo_font_face_set_user_data(face, &sCmapCacheKey, slots, free);
+if (status != CAIRO_STATUS_SUCCESS) { // OOM
+free(slots);
+return 0;
+}
+// Invalidate slot 0 by setting its char code to something that would
+// never end up in slot 0.  All other slots are already invalid
+// because they have mCharCode = 0 and a glyph for char code 0 will
+// always be in the slot 0.
+slots[0].mCharCode = 1;
+}
+CmapCacheSlot *slot = &slots[aCharCode % kNumSlots];
+if (slot->mCharCode != aCharCode) {
+slot->mCharCode = aCharCode;
+slot->mGlyphIndex = gfxFT2LockedFace(this).GetGlyph(aCharCode);
+}
+return slot->mGlyphIndex;
+}
+void
+gfxFT2FontBase::GetGlyphExtents(uint32_t aGlyph, cairo_text_extents_t* aExtents)
+{
+NS_PRECONDITION(aExtents != nullptr, "aExtents must not be NULL");
+cairo_glyph_t glyphs[1];
+glyphs[0].index = aGlyph;
+glyphs[0].x = 0.0;
+glyphs[0].y = 0.0;
+// cairo does some caching for us here but perhaps a small gain could be
+// made by caching more.  It is usually only the advance that is needed,
+// so caching only the advance could allow many requests to be cached with
+// little memory use.  Ideally this cache would be merged with
+// gfxGlyphExtents.
+cairo_scaled_font_glyph_extents(CairoScaledFont(), glyphs, 1, aExtents);
+}
+const gfxFont::Metrics&
+gfxFT2FontBase::GetMetrics()
+{
+if (mHasMetrics)
+return mMetrics;
+if (MOZ_UNLIKELY(GetStyle()->size <= 0.0)) {
+new(&mMetrics) gfxFont::Metrics(); // zero initialize
+mSpaceGlyph = 0;
+} else {
+gfxFT2LockedFace face(this);
+mFUnitsConvFactor = face.XScale();
+face.GetMetrics(&mMetrics, &mSpaceGlyph);
+}
+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", NS_ConvertUTF16toUTF8(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, "    uOff: %f uSize: %f stOff: %f stSize: %f suOff: %f suSize: %f\n", mMetrics.underlineOffset, mMetrics.underlineSize, mMetrics.strikeoutOffset, mMetrics.strikeoutSize, mMetrics.superscriptOffset, mMetrics.subscriptOffset);
+#endif
+mHasMetrics = true;
+return mMetrics;
+}
+// Get the glyphID of a space
+uint32_t
+gfxFT2FontBase::GetSpaceGlyph()
+{
+NS_ASSERTION(GetStyle()->size != 0,
+"forgot to short-circuit a text run with zero-sized font?");
+GetMetrics();
+return mSpaceGlyph;
+}
+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;
+id = gfxFontUtils::GetUVSFallback(unicode, variation_selector);
+if (id) {
+unicode = id;
+}
+}
+return GetGlyph(unicode);
+}
+int32_t
+gfxFT2FontBase::GetGlyphWidth(gfxContext *aCtx, uint16_t aGID)
+{
+cairo_text_extents_t extents;
+GetGlyphExtents(aGID, &extents);
+// convert to 16.16 fixed point
+return NS_lround(0x10000 * extents.x_advance);
+}
+bool
+gfxFT2FontBase::SetupCairoFont(gfxContext *aContext)
+{
+cairo_t *cr = aContext->GetCairo();
+// The scaled font ctm is not relevant right here because
+// cairo_set_scaled_font does not record the scaled font itself, but
+// merely the font_face, font_matrix, font_options.  The scaled_font used
+// for the target can be different from the scaled_font passed to
+// cairo_set_scaled_font.  (Unfortunately we have measured only for an
+// identity ctm.)
+cairo_scaled_font_t *cairoFont = CairoScaledFont();
+if (cairo_scaled_font_status(cairoFont) != CAIRO_STATUS_SUCCESS) {
+// Don't cairo_set_scaled_font as that would propagate the error to
+// the cairo_t, precluding any further drawing.
+return false;
+}
+// Thoughts on which font_options to set on the context:
+//
+// cairoFont has been created for screen rendering.
+//
+// When the context is being used for screen rendering, we should set
+// font_options such that the same scaled_font gets used (when the ctm is
+// the same).  The use of explicit font_options recorded in
+// CreateScaledFont ensures that this will happen.
+//
+// XXXkt: For pdf and ps surfaces, I don't know whether it's better to
+// remove surface-specific options, or try to draw with the same
+// scaled_font that was used to measure.  As the same font_face is being
+// used, its font_options will often override some values anyway (unless
+// perhaps we remove those from the FcPattern at face creation).
+//
+// I can't see any significant difference in printing, irrespective of
+// what is set here.  It's too late to change things here as measuring has
+// already taken place.  We should really be measuring with a different
+// font for pdf and ps surfaces (bug 403513).
+cairo_set_scaled_font(cr, cairoFont);
+return true;
+}
+void
+gfxFT2FontBase::ConstructFontOptions()
+{
+NS_LossyConvertUTF16toASCII name(this->GetName());
+mFontOptions.mName = name.get();
+const gfxFontStyle* style = this->GetStyle();
+if (style->style == NS_FONT_STYLE_ITALIC) {
+if (style->weight == NS_FONT_WEIGHT_BOLD) {
+mFontOptions.mStyle = FontStyle::BOLD_ITALIC;
+} else {
+mFontOptions.mStyle = FontStyle::ITALIC;
+}
+} else {
+if (style->weight == NS_FONT_WEIGHT_BOLD) {
+mFontOptions.mStyle = FontStyle::BOLD;
+} else {
+mFontOptions.mStyle = FontStyle::NORMAL;
+}
+}
+}

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comparison: gfx/thebes/gfxFT2FontBase.cpp

gfx/thebes/gfxFT2FontBase.cpp