MinikinSkia.cpp revision 9ff994d98846d24bc488939af6e7dc440149a4bc 
1/*
2 * Copyright (C) 2013 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "MinikinSkia.h"
18
19#include <log/log.h>
20#include <SkFontDescriptor.h>
21#include <SkFontMgr.h>
22#include <SkPaint.h>
23#include <SkTypeface.h>
24
25namespace android {
26
27MinikinFontSkia::MinikinFontSkia(sk_sp<SkTypeface> typeface, const void* fontData, size_t fontSize,
28        int ttcIndex) :
29    minikin::MinikinFont(typeface->uniqueID()), mTypeface(std::move(typeface)), mFontData(fontData),
30    mFontSize(fontSize), mTtcIndex(ttcIndex) {
31}
32
33static void MinikinFontSkia_SetSkiaPaint(const minikin::MinikinFont* font, SkPaint* skPaint,
34        const minikin::MinikinPaint& paint) {
35    skPaint->setTextEncoding(SkPaint::kGlyphID_TextEncoding);
36    skPaint->setTextSize(paint.size);
37    skPaint->setTextScaleX(paint.scaleX);
38    skPaint->setTextSkewX(paint.skewX);
39    MinikinFontSkia::unpackPaintFlags(skPaint, paint.paintFlags);
40    // Apply font fakery on top of user-supplied flags.
41    MinikinFontSkia::populateSkPaint(skPaint, font, paint.fakery);
42}
43
44float MinikinFontSkia::GetHorizontalAdvance(uint32_t glyph_id,
45        const minikin::MinikinPaint &paint) const {
46    SkPaint skPaint;
47    uint16_t glyph16 = glyph_id;
48    SkScalar skWidth;
49    MinikinFontSkia_SetSkiaPaint(this, &skPaint, paint);
50    skPaint.getTextWidths(&glyph16, sizeof(glyph16), &skWidth, NULL);
51#ifdef VERBOSE
52    ALOGD("width for typeface %d glyph %d = %f", mTypeface->uniqueID(), glyph_id, skWidth);
53#endif
54    return skWidth;
55}
56
57void MinikinFontSkia::GetBounds(minikin::MinikinRect* bounds, uint32_t glyph_id,
58        const minikin::MinikinPaint& paint) const {
59    SkPaint skPaint;
60    uint16_t glyph16 = glyph_id;
61    SkRect skBounds;
62    MinikinFontSkia_SetSkiaPaint(this, &skPaint, paint);
63    skPaint.getTextWidths(&glyph16, sizeof(glyph16), NULL, &skBounds);
64    bounds->mLeft = skBounds.fLeft;
65    bounds->mTop = skBounds.fTop;
66    bounds->mRight = skBounds.fRight;
67    bounds->mBottom = skBounds.fBottom;
68}
69
70SkTypeface *MinikinFontSkia::GetSkTypeface() const {
71    return mTypeface.get();
72}
73
74sk_sp<SkTypeface> MinikinFontSkia::RefSkTypeface() const {
75    return mTypeface;
76}
77
78const void* MinikinFontSkia::GetFontData() const {
79    return mFontData;
80}
81
82size_t MinikinFontSkia::GetFontSize() const {
83    return mFontSize;
84}
85
86int MinikinFontSkia::GetFontIndex() const {
87    return mTtcIndex;
88}
89
90minikin::MinikinFont* MinikinFontSkia::createFontWithVariation(
91        const std::vector<minikin::FontVariation>& variations) const {
92    SkFontMgr::FontParameters params;
93
94    int ttcIndex;
95    SkStreamAsset* stream = mTypeface->openStream(&ttcIndex);
96    LOG_ALWAYS_FATAL_IF(stream == nullptr, "openStream failed");
97
98    params.setCollectionIndex(ttcIndex);
99    std::vector<SkFontMgr::FontParameters::Axis> skAxes;
100    skAxes.resize(variations.size());
101    for (size_t i = 0; i < variations.size(); i++) {
102        skAxes[i].fTag = variations[i].axisTag;
103        skAxes[i].fStyleValue = SkFloatToScalar(variations[i].value);
104    }
105    params.setAxes(skAxes.data(), skAxes.size());
106    sk_sp<SkFontMgr> fm(SkFontMgr::RefDefault());
107    sk_sp<SkTypeface> face(fm->createFromStream(stream, params));
108
109    return new MinikinFontSkia(std::move(face), mFontData, mFontSize, ttcIndex);
110}
111
112uint32_t MinikinFontSkia::packPaintFlags(const SkPaint* paint) {
113    uint32_t flags = paint->getFlags();
114    SkPaint::Hinting hinting = paint->getHinting();
115    // select only flags that might affect text layout
116    flags &= (SkPaint::kAntiAlias_Flag | SkPaint::kFakeBoldText_Flag | SkPaint::kLinearText_Flag |
117            SkPaint::kSubpixelText_Flag | SkPaint::kDevKernText_Flag |
118            SkPaint::kEmbeddedBitmapText_Flag | SkPaint::kAutoHinting_Flag |
119            SkPaint::kVerticalText_Flag);
120    flags |= (hinting << 16);
121    return flags;
122}
123
124void MinikinFontSkia::unpackPaintFlags(SkPaint* paint, uint32_t paintFlags) {
125    paint->setFlags(paintFlags & SkPaint::kAllFlags);
126    paint->setHinting(static_cast<SkPaint::Hinting>(paintFlags >> 16));
127}
128
129void MinikinFontSkia::populateSkPaint(SkPaint* paint, const MinikinFont* font,
130        minikin::FontFakery fakery) {
131    paint->setTypeface(reinterpret_cast<const MinikinFontSkia*>(font)->RefSkTypeface());
132    paint->setFakeBoldText(paint->isFakeBoldText() || fakery.isFakeBold());
133    if (fakery.isFakeItalic()) {
134        paint->setTextSkewX(paint->getTextSkewX() - 0.25f);
135    }
136}
137
138}
139