AuroraMiddleware/skia2
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Fix greenish text rendering on Linux.

Browse Source 
https://codereview.appspot.com/6484048/


git-svn-id: http://skia.googlecode.com/svn/trunk@5280 2bbb7eff-a529-9590-31e7-b0007b416f81
This commit is contained in:
bungeman@google.com 2012-08-24 17:46:11 +00:00
parent 0032407e29
commit fd668cfffe
6 changed files with 72 additions and 18 deletions
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1
gyp/core.gyp
View File

@ -27,7 +27,6 @@
],
'link_settings': {
'libraries': [
'-lfreetype',
'-lpthread',
],
},

17
gyp/ports.gyp
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@ -37,12 +37,23 @@
],
'conditions': [
[ 'skia_os in ["linux", "freebsd", "openbsd", "solaris"]', {
'defines': [
#The font host requires at least FreeType 2.3.0 at runtime.
'SK_FONTHOST_FREETYPE_RUNTIME_VERSION=0x020300',
'SK_CAN_USE_DLOPEN=1',
],
'sources': [
'../src/ports/SkThread_pthread.cpp',
'../src/ports/SkFontHost_FreeType.cpp',
'../src/ports/SkFontHost_FreeType_common.cpp',
'../src/ports/SkFontHost_linux.cpp',
],
'link_settings': {
'libraries': [
'-lfreetype',
'-ldl',
],
},
}],
[ 'skia_os == "mac"', {
'include_dirs': [
@ -100,6 +111,12 @@
],
}],
[ 'skia_os == "android"', {
'defines': [
#Android provides at least FreeType 2.4.0 at runtime.
'SK_FONTHOST_FREETYPE_RUNTIME_VERSION=0x020400',
#Skia should not use dlopen on Android.
'SK_CAN_USE_DLOPEN=0',
],
'sources!': [
'../src/ports/SkDebug_stdio.cpp',
],

9
src/core/SkMaskGamma.cpp
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@ -53,9 +53,12 @@ void SkTMaskGamma_build_correcting_lut(uint8_t table[256], U8CPU srcI, SkScalar
const SkColorSpaceLuminance& dstConvert) {
const float src = (float)srcI / 255.0f;
const float linSrc = srcConvert.toLuma(src);
//Guess at the dst.
const float linDst = 1.0f - linSrc;
const float dst = dstConvert.fromLuma(linDst);
//Guess at the dst. The perceptual inverse provides smaller visual
//discontinuities when slight changes to desaturated colors cause a channel
//to map to a different correcting lut with neighboring srcI.
//See https://code.google.com/p/chromium/issues/detail?id=141425#c59 .
const float dst = 1.0f - src;
const float linDst = dstConvert.toLuma(dst);
//Contrast value tapers off to 0 as the src luminance becomes white
const float adjustedContrast = SkScalarToFloat(contrast) * linDst;

7
src/core/SkPaint.cpp
View File

@ -1706,8 +1706,11 @@ void SkScalerContext::PostMakeRec(const SkPaint& paint, SkScalerContext::Rec* re
SkColor color = rec->getLuminanceColor();
SkAutoMutexAcquire ama(gMaskGammaCacheMutex);
U8CPU lum = cachedPaintLuminance(rec->getPaintGamma())->computeLuminance(color);
// HACK: Prevents green from being pre-blended as white.
lum -= ((255 - lum) * lum) / 255;
//If we are asked to look like LCD, look like LCD.
if (!(rec->fFlags & SkScalerContext::kGenA8FromLCD_Flag)) {
// HACK: Prevents green from being pre-blended as white.
lum -= ((255 - lum) * lum) / 255;
}
// reduce to our finite number of bits
SkMaskGamma* maskGamma = cachedMaskGamma(rec->getContrast(),

5
src/core/SkScalerContext.h
View File

@ -108,8 +108,9 @@ struct SkScalerContextRec {
//The following typedef hides from the rest of the implementation the number of
//most significant bits to consider when creating mask gamma tables. Two bits
//per channel was chosen as a balance between fidelity (more bits) and cache
//sizes (fewer bits).
typedef SkTMaskGamma<2, 2, 2> SkMaskGamma;
//sizes (fewer bits). Three bits per channel was chosen when #303942; (used by
//the Chrome UI) turned out too green.
typedef SkTMaskGamma<3, 3, 3> SkMaskGamma;
class SkScalerContext {
public:

51
src/ports/SkFontHost_FreeType.cpp
View File

@ -24,6 +24,9 @@
#include "SkTemplates.h"
#include "SkThread.h"
#if defined(SK_CAN_USE_DLOPEN)
#include <dlfcn.h>
#endif
#include <ft2build.h>
#include FT_FREETYPE_H
#include FT_OUTLINE_H
@ -83,23 +86,51 @@ static bool gLCDSupportValid; // true iff |gLCDSupport| has been set.
static bool gLCDSupport; // true iff LCD is supported by the runtime.
static int gLCDExtra; // number of extra pixels for filtering.
// FT_Library_SetLcdFilterWeights was introduced in FreeType 2.4.0.
// The following platforms provide FreeType of at least 2.4.0.
// Ubuntu >= 11.04 (previous deprecated April 2013)
// Debian >= 6.0 (good)
// OpenSuse >= 11.4 (previous deprecated January 2012 / Nov 2013 for Evergreen 11.2)
// Fedora >= 14 (good)
// Android >= Gingerbread (good)
typedef FT_Error (*FT_Library_SetLcdFilterWeightsProc)(FT_Library, unsigned char*);
/////////////////////////////////////////////////////////////////////////
static bool
InitFreetype() {
static bool InitFreetype() {
FT_Error err = FT_Init_FreeType(&gFTLibrary);
if (err) {
return false;
}
// Setup LCD filtering. This reduces colour fringes for LCD rendered
// glyphs.
// Setup LCD filtering. This reduces color fringes for LCD smoothed glyphs.
#ifdef FT_LCD_FILTER_H
err = FT_Library_SetLcdFilter(gFTLibrary, FT_LCD_FILTER_DEFAULT);
// err = FT_Library_SetLcdFilter(gFTLibrary, FT_LCD_FILTER_LIGHT);
gLCDSupport = err == 0;
if (gLCDSupport) {
gLCDExtra = 2; //DEFAULT and LIGHT add one pixel to each side.
//Use light as default, as FT_LCD_FILTER_DEFAULT adds up to 0x110.
err = FT_Library_SetLcdFilter(gFTLibrary, FT_LCD_FILTER_LIGHT);
if (0 == err) {
gLCDSupport = true;
gLCDExtra = 2; //Using a filter adds one full pixel to each side.
static unsigned char gaussianLikeWeights[] = { 0x17, 0x40, 0x52, 0x40, 0x17 };
//static unsigned char triangleLikeWeights[] = { 0x1C, 0x39, 0x56, 0x39, 0x1C };
#if defined(SK_FONTHOST_FREETYPE_RUNTIME_VERSION) && \
SK_FONTHOST_FREETYPE_RUNTIME_VERSION > 0x020400
err = FT_Library_SetLcdFilterWeights(gFTLibrary, gaussianLikeWeights);
#elif defined(SK_CAN_USE_DLOPEN) && SK_CAN_USE_DLOPEN == 1
//The FreeType library is already loaded, so symbols are available in process.
void* self = dlopen(NULL, RTLD_LAZY);
if (NULL != self) {
FT_Library_SetLcdFilterWeightsProc setLcdFilterWeights;
//The following cast is non-standard, but safe for POSIX.
*reinterpret_cast<void**>(&setLcdFilterWeights) = dlsym(self, "FT_Library_SetLcdFilterWeights");
dlclose(self);
if (NULL != setLcdFilterWeights) {
err = setLcdFilterWeights(gFTLibrary, gaussianLikeWeights);
}
}
#endif
}
#else
gLCDSupport = false;
@ -610,7 +641,7 @@ void SkFontHost::FilterRec(SkScalerContext::Rec* rec) {
if (rec->fTextSize > SkIntToScalar(1 << 14)) {
rec->fTextSize = SkIntToScalar(1 << 14);
}
if (!gLCDSupportValid) {
InitFreetype();
FT_Done_FreeType(gFTLibrary);