1/*
2 * Copyright (C) 2010 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 "Debug.h"
18#include "GammaFontRenderer.h"
19#include "Properties.h"
20
21namespace android {
22namespace uirenderer {
23
24///////////////////////////////////////////////////////////////////////////////
25// Utils
26///////////////////////////////////////////////////////////////////////////////
27
28static int luminance(const SkPaint* paint) {
29    uint32_t c = paint->getColor();
30    const int r = (c >> 16) & 0xFF;
31    const int g = (c >>  8) & 0xFF;
32    const int b = (c      ) & 0xFF;
33    return (r * 2 + g * 5 + b) >> 3;
34}
35
36///////////////////////////////////////////////////////////////////////////////
37// Base class GammaFontRenderer
38///////////////////////////////////////////////////////////////////////////////
39
40GammaFontRenderer* GammaFontRenderer::createRenderer() {
41    // Choose the best renderer
42    char property[PROPERTY_VALUE_MAX];
43    if (property_get(PROPERTY_TEXT_GAMMA_METHOD, property, DEFAULT_TEXT_GAMMA_METHOD) > 0) {
44        if (!strcasecmp(property, "lookup")) {
45            return new LookupGammaFontRenderer();
46        } else if (!strcasecmp(property, "shader")) {
47            return new ShaderGammaFontRenderer(false);
48        } else if (!strcasecmp(property, "shader3")) {
49            return new ShaderGammaFontRenderer(true);
50        }
51    }
52
53    return new Lookup3GammaFontRenderer();
54}
55
56GammaFontRenderer::GammaFontRenderer() {
57    // Get the renderer properties
58    char property[PROPERTY_VALUE_MAX];
59
60    // Get the gamma
61    mGamma = DEFAULT_TEXT_GAMMA;
62    if (property_get(PROPERTY_TEXT_GAMMA, property, nullptr) > 0) {
63        INIT_LOGD("  Setting text gamma to %s", property);
64        mGamma = atof(property);
65    } else {
66        INIT_LOGD("  Using default text gamma of %.2f", DEFAULT_TEXT_GAMMA);
67    }
68
69    // Get the black gamma threshold
70    mBlackThreshold = DEFAULT_TEXT_BLACK_GAMMA_THRESHOLD;
71    if (property_get(PROPERTY_TEXT_BLACK_GAMMA_THRESHOLD, property, nullptr) > 0) {
72        INIT_LOGD("  Setting text black gamma threshold to %s", property);
73        mBlackThreshold = atoi(property);
74    } else {
75        INIT_LOGD("  Using default text black gamma threshold of %d",
76                DEFAULT_TEXT_BLACK_GAMMA_THRESHOLD);
77    }
78
79    // Get the white gamma threshold
80    mWhiteThreshold = DEFAULT_TEXT_WHITE_GAMMA_THRESHOLD;
81    if (property_get(PROPERTY_TEXT_WHITE_GAMMA_THRESHOLD, property, nullptr) > 0) {
82        INIT_LOGD("  Setting text white gamma threshold to %s", property);
83        mWhiteThreshold = atoi(property);
84    } else {
85        INIT_LOGD("  Using default white black gamma threshold of %d",
86                DEFAULT_TEXT_WHITE_GAMMA_THRESHOLD);
87    }
88}
89
90GammaFontRenderer::~GammaFontRenderer() {
91}
92
93///////////////////////////////////////////////////////////////////////////////
94// Shader-based renderer
95///////////////////////////////////////////////////////////////////////////////
96
97ShaderGammaFontRenderer::ShaderGammaFontRenderer(bool multiGamma)
98        : GammaFontRenderer() {
99    INIT_LOGD("Creating shader gamma font renderer");
100    mRenderer = nullptr;
101    mMultiGamma = multiGamma;
102}
103
104void ShaderGammaFontRenderer::describe(ProgramDescription& description,
105        const SkPaint* paint) const {
106    if (paint->getShader() == nullptr) {
107        if (mMultiGamma) {
108            const int l = luminance(paint);
109
110            if (l <= mBlackThreshold) {
111                description.hasGammaCorrection = true;
112                description.gamma = mGamma;
113            } else if (l >= mWhiteThreshold) {
114                description.hasGammaCorrection = true;
115                description.gamma = 1.0f / mGamma;
116            }
117        } else {
118            description.hasGammaCorrection = true;
119            description.gamma = 1.0f / mGamma;
120        }
121    }
122}
123
124void ShaderGammaFontRenderer::setupProgram(ProgramDescription& description,
125        Program& program) const {
126    if (description.hasGammaCorrection) {
127        glUniform1f(program.getUniform("gamma"), description.gamma);
128    }
129}
130
131void ShaderGammaFontRenderer::endPrecaching() {
132    if (mRenderer) {
133        mRenderer->endPrecaching();
134    }
135}
136
137///////////////////////////////////////////////////////////////////////////////
138// Lookup-based renderer
139///////////////////////////////////////////////////////////////////////////////
140
141LookupGammaFontRenderer::LookupGammaFontRenderer()
142        : GammaFontRenderer() {
143    INIT_LOGD("Creating lookup gamma font renderer");
144
145    // Compute the gamma tables
146    const float gamma = 1.0f / mGamma;
147
148    for (uint32_t i = 0; i <= 255; i++) {
149        mGammaTable[i] = uint8_t((float)::floor(pow(i / 255.0f, gamma) * 255.0f + 0.5f));
150    }
151
152    mRenderer = nullptr;
153}
154
155void LookupGammaFontRenderer::endPrecaching() {
156    if (mRenderer) {
157        mRenderer->endPrecaching();
158    }
159}
160
161///////////////////////////////////////////////////////////////////////////////
162// Lookup-based renderer, using 3 different correction tables
163///////////////////////////////////////////////////////////////////////////////
164
165Lookup3GammaFontRenderer::Lookup3GammaFontRenderer()
166        : GammaFontRenderer() {
167    INIT_LOGD("Creating lookup3 gamma font renderer");
168
169    // Compute the gamma tables
170    const float blackGamma = mGamma;
171    const float whiteGamma = 1.0f / mGamma;
172
173    for (uint32_t i = 0; i <= 255; i++) {
174        const float v = i / 255.0f;
175        const float black = pow(v, blackGamma);
176        const float white = pow(v, whiteGamma);
177
178        mGammaTable[i] = i;
179        mGammaTable[256 + i] = uint8_t((float)::floor(black * 255.0f + 0.5f));
180        mGammaTable[512 + i] = uint8_t((float)::floor(white * 255.0f + 0.5f));
181    }
182
183    memset(mRenderers, 0, sizeof(FontRenderer*) * kGammaCount);
184    memset(mRenderersUsageCount, 0, sizeof(uint32_t) * kGammaCount);
185}
186
187void Lookup3GammaFontRenderer::endPrecaching() {
188    for (int i = 0; i < kGammaCount; i++) {
189        if (mRenderers[i]) {
190            mRenderers[i]->endPrecaching();
191        }
192    }
193}
194
195void Lookup3GammaFontRenderer::clear() {
196    for (int i = 0; i < kGammaCount; i++) {
197        mRenderers[i].release();
198    }
199}
200
201void Lookup3GammaFontRenderer::flush() {
202    int count = 0;
203    int min = -1;
204    uint32_t minCount = UINT_MAX;
205
206    for (int i = 0; i < kGammaCount; i++) {
207        if (mRenderers[i]) {
208            count++;
209            if (mRenderersUsageCount[i] < minCount) {
210                minCount = mRenderersUsageCount[i];
211                min = i;
212            }
213        }
214    }
215
216    if (count <= 1 || min < 0) return;
217
218    mRenderers[min].release();
219
220    // Also eliminate the caches for large glyphs, as they consume significant memory
221    for (int i = 0; i < kGammaCount; ++i) {
222        if (mRenderers[i]) {
223            mRenderers[i]->flushLargeCaches();
224        }
225    }
226}
227
228FontRenderer* Lookup3GammaFontRenderer::getRenderer(Gamma gamma) {
229    if (!mRenderers[gamma]) {
230        mRenderers[gamma].reset(new FontRenderer());
231        mRenderers[gamma]->setGammaTable(&mGammaTable[gamma * 256]);
232    }
233    mRenderersUsageCount[gamma]++;
234    return mRenderers[gamma].get();
235}
236
237FontRenderer& Lookup3GammaFontRenderer::getFontRenderer(const SkPaint* paint) {
238    if (paint->getShader() == nullptr) {
239        const int l = luminance(paint);
240
241        if (l <= mBlackThreshold) {
242            return *getRenderer(kGammaBlack);
243        } else if (l >= mWhiteThreshold) {
244            return *getRenderer(kGammaWhite);
245        }
246    }
247    return *getRenderer(kGammaDefault);
248}
249
250}; // namespace uirenderer
251}; // namespace android
252