/* -*- 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); gfxFT2LockedFace face(this); mFUnitsConvFactor = face.XScale(); } 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::GetHorizontalMetrics() { if (mHasMetrics) return mMetrics; if (MOZ_UNLIKELY(GetStyle()->size <= 0.0) || MOZ_UNLIKELY(GetStyle()->sizeAdjust == 0.0)) { new(&mMetrics) gfxFont::Metrics(); // zero initialize mSpaceGlyph = GetGlyph(' '); } else { gfxFT2LockedFace face(this); 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\n", mMetrics.underlineOffset, mMetrics.underlineSize, mMetrics.strikeoutOffset, mMetrics.strikeoutSize); #endif mHasMetrics = true; return mMetrics; } // Get the glyphID of a space uint32_t gfxFT2FontBase::GetSpaceGlyph() { GetHorizontalMetrics(); 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; } unicode = gfxFontUtils::GetUVSFallback(unicode, variation_selector); if (unicode) { return GetGlyph(unicode); } return 0; } return GetGlyph(unicode); } int32_t gfxFT2FontBase::GetGlyphWidth(DrawTarget& aDrawTarget, 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(DrawTarget* aDrawTarget) { // 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(gfxFont::RefCairo(aDrawTarget), cairoFont); return true; }