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/Debug.h b/libs/hwui/Debug.h
index 7d150bb..6795ac3 100644
--- a/libs/hwui/Debug.h
+++ b/libs/hwui/Debug.h
@@ -65,9 +65,6 @@
// Turn on to enable additional debugging in the font renderers
#define DEBUG_FONT_RENDERER 0
-// Force gamma correction in shaders
-#define DEBUG_FONT_RENDERER_FORCE_SHADER_GAMMA 0
-
// Turn on to dump display list state
#define DEBUG_DISPLAY_LIST 0
diff --git a/libs/hwui/GammaFontRenderer.cpp b/libs/hwui/GammaFontRenderer.cpp
index 226f4bc..fe532abc 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);
diff --git a/libs/hwui/GammaFontRenderer.h b/libs/hwui/GammaFontRenderer.h
index 8e1db78..9180778 100644
--- a/libs/hwui/GammaFontRenderer.h
+++ b/libs/hwui/GammaFontRenderer.h
@@ -79,23 +79,71 @@
}
uint32_t getFontRendererSize(uint32_t fontRenderer) const {
- return mRenderer->getCacheSize();
+ return mRenderer ? mRenderer->getCacheSize() : 0;
}
void describe(ProgramDescription& description, const SkPaint* paint) const;
void setupProgram(ProgramDescription& description, Program* program) const;
private:
- ShaderGammaFontRenderer();
+ ShaderGammaFontRenderer(bool multiGamma);
FontRenderer* mRenderer;
+ bool mMultiGamma;
friend class GammaFontRenderer;
};
class LookupGammaFontRenderer: public GammaFontRenderer {
public:
- ~LookupGammaFontRenderer();
+ ~LookupGammaFontRenderer() {
+ delete mRenderer;
+ }
+
+ void clear() {
+ delete mRenderer;
+ }
+
+ void flush() {
+ if (mRenderer) {
+ mRenderer->flushLargeCaches();
+ }
+ }
+
+ FontRenderer& getFontRenderer(const SkPaint* paint) {
+ if (!mRenderer) {
+ mRenderer = new FontRenderer;
+ mRenderer->setGammaTable(&mGammaTable[0]);
+ }
+ return *mRenderer;
+ }
+
+ uint32_t getFontRendererCount() const {
+ return 1;
+ }
+
+ uint32_t getFontRendererSize(uint32_t fontRenderer) const {
+ return mRenderer ? mRenderer->getCacheSize() : 0;
+ }
+
+ void describe(ProgramDescription& description, const SkPaint* paint) const {
+ }
+
+ void setupProgram(ProgramDescription& description, Program* program) const {
+ }
+
+private:
+ LookupGammaFontRenderer();
+
+ FontRenderer* mRenderer;
+ uint8_t mGammaTable[256];
+
+ friend class GammaFontRenderer;
+};
+
+class Lookup3GammaFontRenderer: public GammaFontRenderer {
+public:
+ ~Lookup3GammaFontRenderer();
void clear();
void flush();
@@ -122,7 +170,7 @@
}
private:
- LookupGammaFontRenderer();
+ Lookup3GammaFontRenderer();
enum Gamma {
kGammaDefault = 0,
diff --git a/libs/hwui/Properties.h b/libs/hwui/Properties.h
index 4a12e39..447b1d0 100644
--- a/libs/hwui/Properties.h
+++ b/libs/hwui/Properties.h
@@ -74,13 +74,28 @@
#define PROPERTY_TEXT_CACHE_HEIGHT "ro.hwui.text_cache_height"
// Indicates whether gamma correction should be applied in the shaders
-// or in lookup tables. Accepted values: true, false
-#define PROPERTY_TEXT_GAMMA_SHADER "ro.hwui.text_gamma_shader"
+// or in lookup tables. Accepted values:
+//
+// - "lookup3", correction based on lookup tables. Gamma correction
+// is different for black and white text (see thresholds below)
+//
+// - "lookup", correction based on a single lookup table
+//
+// - "shader3", correction applied by a GLSL shader. Gamma correction
+// is different for black and white text (see thresholds below)
+//
+// - "shader", correction applied by a GLSL shader
+//
+// See PROPERTY_TEXT_GAMMA, PROPERTY_TEXT_BLACK_GAMMA_THRESHOLD and
+// PROPERTY_TEXT_WHITE_GAMMA_THRESHOLD for more control.
+#define PROPERTY_TEXT_GAMMA_SHADER "hwui.text_gamma_correction"
// Gamma (>= 1.0, <= 10.0)
-#define PROPERTY_TEXT_GAMMA "ro.text_gamma"
-#define PROPERTY_TEXT_BLACK_GAMMA_THRESHOLD "ro.text_gamma.black_threshold"
-#define PROPERTY_TEXT_WHITE_GAMMA_THRESHOLD "ro.text_gamma.white_threshold"
+#define PROPERTY_TEXT_GAMMA "hwui.text_gamma"
+// Luminance threshold below which black gamma correction is applied. Range: [0..255]
+#define PROPERTY_TEXT_BLACK_GAMMA_THRESHOLD "hwui.text_gamma.black_threshold"
+// Lumincance threshold above which white gamma correction is applied. Range: [0..255]
+#define PROPERTY_TEXT_WHITE_GAMMA_THRESHOLD "hwui.text_gamma.white_threshold"
// Converts a number of mega-bytes into bytes
#define MB(s) s * 1024 * 1024