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/*
* Copyright (c) 2012 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#define LOG_TAG "TextLayoutCache"
#include "HarfBuzzNGFaceSkia.h"
#include <stdlib.h>
#include <cutils/log.h>
#include <SkPaint.h>
#include <SkPath.h>
#include <SkPoint.h>
#include <SkRect.h>
#include <SkTypeface.h>
#include <hb.h>
namespace android {
static const bool kDebugGlyphs = false;
// Our implementation of the callbacks which Harfbuzz requires by using Skia
// calls. See the Harfbuzz source for references about what these callbacks do.
struct HarfBuzzFontData {
HarfBuzzFontData(SkPaint* paint) : m_paint(paint) { }
SkPaint* m_paint;
};
static void SkiaGetGlyphWidthAndExtents(SkPaint* paint, hb_codepoint_t codepoint, hb_position_t* width, hb_glyph_extents_t* extents)
{
ALOG_ASSERT(codepoint <= 0xFFFF);
paint->setTextEncoding(SkPaint::kGlyphID_TextEncoding);
SkScalar skWidth;
SkRect skBounds;
uint16_t glyph = codepoint;
paint->getTextWidths(&glyph, sizeof(glyph), &skWidth, &skBounds);
if (kDebugGlyphs) {
ALOGD("returned glyph for %i: width = %f", codepoint, skWidth);
}
if (width)
*width = SkScalarToHBFixed(skWidth);
if (extents) {
// Invert y-axis because Skia is y-grows-down but we set up harfbuzz to be y-grows-up.
extents->x_bearing = SkScalarToHBFixed(skBounds.fLeft);
extents->y_bearing = SkScalarToHBFixed(-skBounds.fTop);
extents->width = SkScalarToHBFixed(skBounds.width());
extents->height = SkScalarToHBFixed(-skBounds.height());
}
}
static hb_bool_t harfbuzzGetGlyph(hb_font_t* hbFont, void* fontData, hb_codepoint_t unicode, hb_codepoint_t variationSelector, hb_codepoint_t* glyph, void* userData)
{
HarfBuzzFontData* hbFontData = reinterpret_cast<HarfBuzzFontData*>(fontData);
SkPaint* paint = hbFontData->m_paint;
paint->setTextEncoding(SkPaint::kUTF32_TextEncoding);
if (unicode > 0x10ffff) {
unicode = 0xfffd;
}
SkUnichar unichar = unicode;
uint16_t glyph16;
paint->textToGlyphs(&unichar, sizeof(unichar), &glyph16);
*glyph = glyph16;
return !!*glyph;
}
static hb_position_t harfbuzzGetGlyphHorizontalAdvance(hb_font_t* hbFont, void* fontData, hb_codepoint_t glyph, void* userData)
{
HarfBuzzFontData* hbFontData = reinterpret_cast<HarfBuzzFontData*>(fontData);
hb_position_t advance = 0;
SkiaGetGlyphWidthAndExtents(hbFontData->m_paint, glyph, &advance, 0);
return advance;
}
static hb_bool_t harfbuzzGetGlyphHorizontalOrigin(hb_font_t* hbFont, void* fontData, hb_codepoint_t glyph, hb_position_t* x, hb_position_t* y, void* userData)
{
// Just return true, following the way that Harfbuzz-FreeType
// implementation does.
return true;
}
static hb_bool_t harfbuzzGetGlyphExtents(hb_font_t* hbFont, void* fontData, hb_codepoint_t glyph, hb_glyph_extents_t* extents, void* userData)
{
HarfBuzzFontData* hbFontData = reinterpret_cast<HarfBuzzFontData*>(fontData);
SkiaGetGlyphWidthAndExtents(hbFontData->m_paint, glyph, 0, extents);
return true;
}
static hb_font_funcs_t* harfbuzzSkiaGetFontFuncs()
{
static hb_font_funcs_t* harfbuzzSkiaFontFuncs = 0;
// We don't set callback functions which we can't support.
// Harfbuzz will use the fallback implementation if they aren't set.
if (!harfbuzzSkiaFontFuncs) {
harfbuzzSkiaFontFuncs = hb_font_funcs_create();
hb_font_funcs_set_glyph_func(harfbuzzSkiaFontFuncs, harfbuzzGetGlyph, 0, 0);
hb_font_funcs_set_glyph_h_advance_func(harfbuzzSkiaFontFuncs, harfbuzzGetGlyphHorizontalAdvance, 0, 0);
hb_font_funcs_set_glyph_h_origin_func(harfbuzzSkiaFontFuncs, harfbuzzGetGlyphHorizontalOrigin, 0, 0);
hb_font_funcs_set_glyph_extents_func(harfbuzzSkiaFontFuncs, harfbuzzGetGlyphExtents, 0, 0);
hb_font_funcs_make_immutable(harfbuzzSkiaFontFuncs);
}
return harfbuzzSkiaFontFuncs;
}
hb_blob_t* harfbuzzSkiaReferenceTable(hb_face_t* face, hb_tag_t tag, void* userData)
{
SkTypeface* typeface = reinterpret_cast<SkTypeface*>(userData);
const size_t tableSize = typeface->getTableSize(tag);
if (!tableSize)
return 0;
char* buffer = reinterpret_cast<char*>(malloc(tableSize));
if (!buffer)
return 0;
size_t actualSize = typeface->getTableData(tag, 0, tableSize, buffer);
if (tableSize != actualSize) {
free(buffer);
return 0;
}
return hb_blob_create(const_cast<char*>(buffer), tableSize,
HB_MEMORY_MODE_WRITABLE, buffer, free);
}
static void destroyHarfBuzzFontData(void* data) {
delete (HarfBuzzFontData*)data;
}
hb_font_t* createFont(hb_face_t* face, SkPaint* paint, float sizeX, float sizeY) {
hb_font_t* font = hb_font_create(face);
// Note: this needs to be reworked when we do subpixels
int x_ppem = floor(sizeX + 0.5);
int y_ppem = floor(sizeY + 0.5);
hb_font_set_ppem(font, x_ppem, y_ppem);
hb_font_set_scale(font, HBFloatToFixed(sizeX), HBFloatToFixed(sizeY));
HarfBuzzFontData* data = new HarfBuzzFontData(paint);
hb_font_set_funcs(font, harfbuzzSkiaGetFontFuncs(), data, destroyHarfBuzzFontData);
return font;
}
} // namespace android
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