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      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 
     21 namespace android {
     22 namespace uirenderer {
     23 
     24 ///////////////////////////////////////////////////////////////////////////////
     25 // Utils
     26 ///////////////////////////////////////////////////////////////////////////////
     27 
     28 static 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 
     40 GammaFontRenderer* 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 
     56 GammaFontRenderer::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 
     90 GammaFontRenderer::~GammaFontRenderer() {
     91 }
     92 
     93 ///////////////////////////////////////////////////////////////////////////////
     94 // Shader-based renderer
     95 ///////////////////////////////////////////////////////////////////////////////
     96 
     97 ShaderGammaFontRenderer::ShaderGammaFontRenderer(bool multiGamma)
     98         : GammaFontRenderer() {
     99     INIT_LOGD("Creating shader gamma font renderer");
    100     mRenderer = nullptr;
    101     mMultiGamma = multiGamma;
    102 }
    103 
    104 void 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 
    124 void ShaderGammaFontRenderer::setupProgram(ProgramDescription& description,
    125         Program& program) const {
    126     if (description.hasGammaCorrection) {
    127         glUniform1f(program.getUniform("gamma"), description.gamma);
    128     }
    129 }
    130 
    131 void ShaderGammaFontRenderer::endPrecaching() {
    132     if (mRenderer) {
    133         mRenderer->endPrecaching();
    134     }
    135 }
    136 
    137 ///////////////////////////////////////////////////////////////////////////////
    138 // Lookup-based renderer
    139 ///////////////////////////////////////////////////////////////////////////////
    140 
    141 LookupGammaFontRenderer::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 
    155 void LookupGammaFontRenderer::endPrecaching() {
    156     if (mRenderer) {
    157         mRenderer->endPrecaching();
    158     }
    159 }
    160 
    161 ///////////////////////////////////////////////////////////////////////////////
    162 // Lookup-based renderer, using 3 different correction tables
    163 ///////////////////////////////////////////////////////////////////////////////
    164 
    165 Lookup3GammaFontRenderer::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 
    187 void Lookup3GammaFontRenderer::endPrecaching() {
    188     for (int i = 0; i < kGammaCount; i++) {
    189         if (mRenderers[i]) {
    190             mRenderers[i]->endPrecaching();
    191         }
    192     }
    193 }
    194 
    195 void Lookup3GammaFontRenderer::clear() {
    196     for (int i = 0; i < kGammaCount; i++) {
    197         mRenderers[i].release();
    198     }
    199 }
    200 
    201 void 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 
    228 FontRenderer* 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 
    237 FontRenderer& 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