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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/. */
#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;
}
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