Add a new method for text gamma correction
To select the gamma correction method, adb shell setprop hwui.text_gamma_correction
with one of the following values:
lookup3
lookup
shader3
shader
See Properties.h for more information about these different methods.
You can also control gamma correction using the following properties:
hwui.text_gamma
hwui.text_gamma.black_threshold
hwui.text_gamma.white_threshold
Change-Id: I47970b804d2c590c37d3da5008db094241579e25
diff --git a/libs/hwui/GammaFontRenderer.cpp b/libs/hwui/GammaFontRenderer.cpp
index 226f4bc..fe532ab 100644
--- a/libs/hwui/GammaFontRenderer.cpp
+++ b/libs/hwui/GammaFontRenderer.cpp
@@ -43,16 +43,16 @@
// Choose the best renderer
char property[PROPERTY_VALUE_MAX];
if (property_get(PROPERTY_TEXT_GAMMA_SHADER, property, DEFAULT_TEXT_GAMMA_SHADER) > 0) {
- if (!strcasecmp(property, "true")) {
- return new ShaderGammaFontRenderer();
+ if (!strcasecmp(property, "shader")) {
+ return new ShaderGammaFontRenderer(false);
+ } else if (!strcasecmp(property, "shader3")) {
+ return new ShaderGammaFontRenderer(true);
+ } else if (!strcasecmp(property, "lookup")) {
+ return new LookupGammaFontRenderer();
}
}
-#if DEBUG_FONT_RENDERER_FORCE_SHADER_GAMMA
- return new ShaderGammaFontRenderer();
-#else
- return new LookupGammaFontRenderer();
-#endif
+ return new Lookup3GammaFontRenderer();
}
GammaFontRenderer::GammaFontRenderer() {
@@ -96,20 +96,26 @@
// Shader-based renderer
///////////////////////////////////////////////////////////////////////////////
-ShaderGammaFontRenderer::ShaderGammaFontRenderer(): GammaFontRenderer() {
+ShaderGammaFontRenderer::ShaderGammaFontRenderer(bool multiGamma): GammaFontRenderer() {
INIT_LOGD("Creating shader gamma font renderer");
mRenderer = NULL;
+ mMultiGamma = multiGamma;
}
void ShaderGammaFontRenderer::describe(ProgramDescription& description,
const SkPaint* paint) const {
if (paint->getShader() == NULL) {
- const int l = luminance(paint);
+ if (mMultiGamma) {
+ const int l = luminance(paint);
- if (l <= mBlackThreshold) {
- description.hasGammaCorrection = true;
- description.gamma = mGamma;
- } else if (l >= mWhiteThreshold) {
+ if (l <= mBlackThreshold) {
+ description.hasGammaCorrection = true;
+ description.gamma = mGamma;
+ } else if (l >= mWhiteThreshold) {
+ description.hasGammaCorrection = true;
+ description.gamma = 1.0f / mGamma;
+ }
+ } else {
description.hasGammaCorrection = true;
description.gamma = 1.0f / mGamma;
}
@@ -131,16 +137,32 @@
INIT_LOGD("Creating lookup gamma font renderer");
// Compute the gamma tables
+ const float gamma = 1.0f / mGamma;
+
+ for (uint32_t i = 0; i <= 255; i++) {
+ mGammaTable[i] = uint8_t((float)::floor(pow(i / 255.0f, gamma) * 255.0f + 0.5f));
+ }
+
+ mRenderer = NULL;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// Lookup-based renderer, using 3 different correction tables
+///////////////////////////////////////////////////////////////////////////////
+
+Lookup3GammaFontRenderer::Lookup3GammaFontRenderer(): GammaFontRenderer() {
+ INIT_LOGD("Creating lookup3 gamma font renderer");
+
+ // Compute the gamma tables
const float blackGamma = mGamma;
const float whiteGamma = 1.0f / mGamma;
for (uint32_t i = 0; i <= 255; i++) {
- mGammaTable[i] = i;
-
const float v = i / 255.0f;
const float black = pow(v, blackGamma);
const float white = pow(v, whiteGamma);
+ mGammaTable[i] = i;
mGammaTable[256 + i] = uint8_t((float)::floor(black * 255.0f + 0.5f));
mGammaTable[512 + i] = uint8_t((float)::floor(white * 255.0f + 0.5f));
}
@@ -149,20 +171,20 @@
memset(mRenderersUsageCount, 0, sizeof(uint32_t) * kGammaCount);
}
-LookupGammaFontRenderer::~LookupGammaFontRenderer() {
+Lookup3GammaFontRenderer::~Lookup3GammaFontRenderer() {
for (int i = 0; i < kGammaCount; i++) {
delete mRenderers[i];
}
}
-void LookupGammaFontRenderer::clear() {
+void Lookup3GammaFontRenderer::clear() {
for (int i = 0; i < kGammaCount; i++) {
delete mRenderers[i];
mRenderers[i] = NULL;
}
}
-void LookupGammaFontRenderer::flush() {
+void Lookup3GammaFontRenderer::flush() {
int count = 0;
int min = -1;
uint32_t minCount = UINT_MAX;
@@ -190,7 +212,7 @@
}
}
-FontRenderer* LookupGammaFontRenderer::getRenderer(Gamma gamma) {
+FontRenderer* Lookup3GammaFontRenderer::getRenderer(Gamma gamma) {
FontRenderer* renderer = mRenderers[gamma];
if (!renderer) {
renderer = new FontRenderer();
@@ -201,7 +223,7 @@
return renderer;
}
-FontRenderer& LookupGammaFontRenderer::getFontRenderer(const SkPaint* paint) {
+FontRenderer& Lookup3GammaFontRenderer::getFontRenderer(const SkPaint* paint) {
if (paint->getShader() == NULL) {
const int l = luminance(paint);