GammaFontRenderer.cpp revision b1d0a4ed21168fefcb82232c8f22cb95d60acb85 
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#define LOG_TAG "OpenGLRenderer"
18
19#include "Debug.h"
20#include "GammaFontRenderer.h"
21#include "Properties.h"
22
23namespace android {
24namespace uirenderer {
25
26///////////////////////////////////////////////////////////////////////////////
27// Base class GammaFontRenderer
28///////////////////////////////////////////////////////////////////////////////
29
30GammaFontRenderer* GammaFontRenderer::createRenderer() {
31    // Choose the best renderer
32    char property[PROPERTY_VALUE_MAX];
33    if (property_get(PROPERTY_TEXT_GAMMA_SHADER, property, DEFAULT_TEXT_GAMMA_SHADER) > 0) {
34        if (!strcasecmp(property, "true")) {
35            return new ShaderGammaFontRenderer();
36        }
37    }
38
39    return new LookupGammaFontRenderer();
40}
41
42GammaFontRenderer::GammaFontRenderer() {
43    // Get the renderer properties
44    char property[PROPERTY_VALUE_MAX];
45
46    // Get the gamma
47    mGamma = DEFAULT_TEXT_GAMMA;
48    if (property_get(PROPERTY_TEXT_GAMMA, property, NULL) > 0) {
49        INIT_LOGD("  Setting text gamma to %s", property);
50        mGamma = atof(property);
51    } else {
52        INIT_LOGD("  Using default text gamma of %.2f", DEFAULT_TEXT_GAMMA);
53    }
54
55    // Get the black gamma threshold
56    mBlackThreshold = DEFAULT_TEXT_BLACK_GAMMA_THRESHOLD;
57    if (property_get(PROPERTY_TEXT_BLACK_GAMMA_THRESHOLD, property, NULL) > 0) {
58        INIT_LOGD("  Setting text black gamma threshold to %s", property);
59        mBlackThreshold = atoi(property);
60    } else {
61        INIT_LOGD("  Using default text black gamma threshold of %d",
62                DEFAULT_TEXT_BLACK_GAMMA_THRESHOLD);
63    }
64
65    // Get the white gamma threshold
66    mWhiteThreshold = DEFAULT_TEXT_WHITE_GAMMA_THRESHOLD;
67    if (property_get(PROPERTY_TEXT_WHITE_GAMMA_THRESHOLD, property, NULL) > 0) {
68        INIT_LOGD("  Setting text white gamma threshold to %s", property);
69        mWhiteThreshold = atoi(property);
70    } else {
71        INIT_LOGD("  Using default white black gamma threshold of %d",
72                DEFAULT_TEXT_WHITE_GAMMA_THRESHOLD);
73    }
74}
75
76GammaFontRenderer::~GammaFontRenderer() {
77}
78
79///////////////////////////////////////////////////////////////////////////////
80// Shader-based renderer
81///////////////////////////////////////////////////////////////////////////////
82
83ShaderGammaFontRenderer::ShaderGammaFontRenderer(): GammaFontRenderer() {
84    INIT_LOGD("Creating shader gamma font renderer");
85}
86
87///////////////////////////////////////////////////////////////////////////////
88// Lookup-based renderer
89///////////////////////////////////////////////////////////////////////////////
90
91LookupGammaFontRenderer::LookupGammaFontRenderer(): GammaFontRenderer() {
92    INIT_LOGD("Creating lookup gamma font renderer");
93
94    // Compute the gamma tables
95    const float blackGamma = mGamma;
96    const float whiteGamma = 1.0f / mGamma;
97
98    for (uint32_t i = 0; i <= 255; i++) {
99        mGammaTable[i] = i;
100
101        const float v = i / 255.0f;
102        const float black = pow(v, blackGamma);
103        const float white = pow(v, whiteGamma);
104
105        mGammaTable[256 + i] = uint8_t((float)::floor(black * 255.0f + 0.5f));
106        mGammaTable[512 + i] = uint8_t((float)::floor(white * 255.0f + 0.5f));
107    }
108
109    memset(mRenderers, 0, sizeof(FontRenderer*) * kGammaCount);
110    memset(mRenderersUsageCount, 0, sizeof(uint32_t) * kGammaCount);
111}
112
113LookupGammaFontRenderer::~LookupGammaFontRenderer() {
114    for (int i = 0; i < kGammaCount; i++) {
115        delete mRenderers[i];
116    }
117}
118
119void LookupGammaFontRenderer::clear() {
120    for (int i = 0; i < kGammaCount; i++) {
121        delete mRenderers[i];
122        mRenderers[i] = NULL;
123    }
124}
125
126void LookupGammaFontRenderer::flush() {
127    int count = 0;
128    int min = -1;
129    uint32_t minCount = UINT_MAX;
130
131    for (int i = 0; i < kGammaCount; i++) {
132        if (mRenderers[i]) {
133            count++;
134            if (mRenderersUsageCount[i] < minCount) {
135                minCount = mRenderersUsageCount[i];
136                min = i;
137            }
138        }
139    }
140
141    if (count <= 1 || min < 0) return;
142
143    delete mRenderers[min];
144    mRenderers[min] = NULL;
145
146    // Also eliminate the caches for large glyphs, as they consume significant memory
147    for (int i = 0; i < kGammaCount; ++i) {
148        if (mRenderers[i]) {
149            mRenderers[i]->flushLargeCaches();
150        }
151    }
152}
153
154FontRenderer* LookupGammaFontRenderer::getRenderer(Gamma gamma) {
155    FontRenderer* renderer = mRenderers[gamma];
156    if (!renderer) {
157        renderer = new FontRenderer();
158        mRenderers[gamma] = renderer;
159        renderer->setGammaTable(&mGammaTable[gamma * 256]);
160    }
161    mRenderersUsageCount[gamma]++;
162    return renderer;
163}
164
165FontRenderer& LookupGammaFontRenderer::getFontRenderer(const SkPaint* paint) {
166    if (paint->getShader() == NULL) {
167        uint32_t c = paint->getColor();
168        const int r = (c >> 16) & 0xFF;
169        const int g = (c >>  8) & 0xFF;
170        const int b = (c      ) & 0xFF;
171        const int luminance = (r * 2 + g * 5 + b) >> 3;
172
173        if (luminance <= mBlackThreshold) {
174            return *getRenderer(kGammaBlack);
175        } else if (luminance >= mWhiteThreshold) {
176            return *getRenderer(kGammaWhite);
177        }
178    }
179    return *getRenderer(kGammaDefault);
180}
181
182}; // namespace uirenderer
183}; // namespace android
184