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fix: overly thin font rendering on mojave
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,179 @@ | ||
| diff --git a/src/ports/SkFontHost_mac.cpp b/src/ports/SkFontHost_mac.cpp | ||
| index 5d8723b95f..c1e64e2351 100644 | ||
| --- a/src/ports/SkFontHost_mac.cpp | ||
| +++ b/src/ports/SkFontHost_mac.cpp | ||
| @@ -200,34 +200,76 @@ static CGAffineTransform MatrixToCGAffineTransform(const SkMatrix& matrix) { | ||
|
|
||
| #define BITMAP_INFO_RGB (kCGImageAlphaNoneSkipFirst | kCGBitmapByteOrder32Host) | ||
|
|
||
| +enum class SmoothBehavior { | ||
| + none, // SmoothFonts produces no effect. | ||
| + some, // SmoothFonts produces some effect, but not subpixel coverage. | ||
| + subpixel, // SmoothFonts produces some effect and provides subpixel coverage. | ||
| +}; | ||
| + | ||
| /** | ||
| * There does not appear to be a publicly accessable API for determining if lcd | ||
| * font smoothing will be applied if we request it. The main issue is that if | ||
| * smoothing is applied a gamma of 2.0 will be used, if not a gamma of 1.0. | ||
| */ | ||
| -static bool supports_LCD() { | ||
| - static bool gSupportsLCD = []{ | ||
| - uint32_t rgb = 0; | ||
| - UniqueCFRef<CGColorSpaceRef> colorspace(CGColorSpaceCreateDeviceRGB()); | ||
| - UniqueCFRef<CGContextRef> cgContext( | ||
| - CGBitmapContextCreate(&rgb, 1, 1, 8, 4, colorspace.get(), BITMAP_INFO_RGB)); | ||
| - UniqueCFRef<CTFontRef> ctFont(CTFontCreateWithName(CFSTR("Helvetica"), 16, nullptr)); | ||
| - CGContextSetShouldSmoothFonts(cgContext.get(), true); | ||
| - CGContextSetShouldAntialias(cgContext.get(), true); | ||
| - CGContextSetTextDrawingMode(cgContext.get(), kCGTextFill); | ||
| - CGContextSetGrayFillColor(cgContext.get(), 1, 1); | ||
| - CGPoint point = CGPointMake(-1, 0); | ||
| - static const UniChar pipeChar = '|'; | ||
| - CGGlyph pipeGlyph; | ||
| - CTFontGetGlyphsForCharacters(ctFont.get(), &pipeChar, &pipeGlyph, 1); | ||
| - CTFontDrawGlyphs(ctFont.get(), &pipeGlyph, &point, 1, cgContext.get()); | ||
| - | ||
| - uint32_t r = (rgb >> 16) & 0xFF; | ||
| - uint32_t g = (rgb >> 8) & 0xFF; | ||
| - uint32_t b = (rgb >> 0) & 0xFF; | ||
| - return (r != g || r != b); | ||
| +static SmoothBehavior smooth_behavior() { | ||
| + static SmoothBehavior gSmoothBehavior = []{ | ||
| + uint32_t noSmoothBitmap[16][16] = {}; | ||
| + uint32_t smoothBitmap[16][16] = {}; | ||
| + | ||
| + SkUniqueCFRef<CGColorSpaceRef> colorspace(CGColorSpaceCreateDeviceRGB()); | ||
| + SkUniqueCFRef<CGContextRef> noSmoothContext( | ||
| + CGBitmapContextCreate(&noSmoothBitmap, 16, 16, 8, 16*4, | ||
| + colorspace.get(), BITMAP_INFO_RGB)); | ||
| + SkUniqueCFRef<CGContextRef> smoothContext( | ||
| + CGBitmapContextCreate(&smoothBitmap, 16, 16, 8, 16*4, | ||
| + colorspace.get(), BITMAP_INFO_RGB)); | ||
| + | ||
| + SkUniqueCFRef<CGDataProviderRef> data( | ||
| + CGDataProviderCreateWithData(nullptr, kSpiderSymbol_ttf, | ||
| + SK_ARRAY_COUNT(kSpiderSymbol_ttf), nullptr)); | ||
| + SkUniqueCFRef<CGFontRef> cgFont(CGFontCreateWithDataProvider(data.get())); | ||
| + SkASSERT(cgFont); | ||
| + SkUniqueCFRef<CTFontRef> ctFont( | ||
| + CTFontCreateWithGraphicsFont(cgFont.get(), 16, nullptr, nullptr)); | ||
| + SkASSERT(ctFont); | ||
| + | ||
| + CGContextSetShouldSmoothFonts(noSmoothContext.get(), false); | ||
| + CGContextSetShouldAntialias(noSmoothContext.get(), true); | ||
| + CGContextSetTextDrawingMode(noSmoothContext.get(), kCGTextFill); | ||
| + CGContextSetGrayFillColor(noSmoothContext.get(), 1, 1); | ||
| + | ||
| + CGContextSetShouldSmoothFonts(smoothContext.get(), true); | ||
| + CGContextSetShouldAntialias(smoothContext.get(), true); | ||
| + CGContextSetTextDrawingMode(smoothContext.get(), kCGTextFill); | ||
| + CGContextSetGrayFillColor(smoothContext.get(), 1, 1); | ||
| + | ||
| + CGPoint point = CGPointMake(0, 3); | ||
| + CGGlyph spiderGlyph = 3; | ||
| + CTFontDrawGlyphs(ctFont.get(), &spiderGlyph, &point, 1, noSmoothContext.get()); | ||
| + CTFontDrawGlyphs(ctFont.get(), &spiderGlyph, &point, 1, smoothContext.get()); | ||
| + | ||
| + // For debugging. | ||
| + //SkUniqueCFRef<CGImageRef> image(CGBitmapContextCreateImage(noSmoothContext())); | ||
| + //SkUniqueCFRef<CGImageRef> image(CGBitmapContextCreateImage(smoothContext())); | ||
| + | ||
| + SmoothBehavior smoothBehavior = SmoothBehavior::none; | ||
| + for (int x = 0; x < 16; ++x) { | ||
| + for (int y = 0; y < 16; ++y) { | ||
| + uint32_t smoothPixel = smoothBitmap[x][y]; | ||
| + uint32_t r = (smoothPixel >> 16) & 0xFF; | ||
| + uint32_t g = (smoothPixel >> 8) & 0xFF; | ||
| + uint32_t b = (smoothPixel >> 0) & 0xFF; | ||
| + if (r != g || r != b) { | ||
| + return SmoothBehavior::subpixel; | ||
| + } | ||
| + if (noSmoothBitmap[x][y] != smoothPixel) { | ||
| + smoothBehavior = SmoothBehavior::some; | ||
| + } | ||
| + } | ||
| + } | ||
| + return smoothBehavior; | ||
| }(); | ||
| - return gSupportsLCD; | ||
| + return gSmoothBehavior; | ||
| } | ||
|
|
||
| class Offscreen { | ||
| @@ -809,7 +851,7 @@ CGRGBPixel* Offscreen::getCG(const SkScalerContext_Mac& context, const SkGlyph& | ||
| if (!fRGBSpace) { | ||
| //It doesn't appear to matter what color space is specified. | ||
| //Regular blends and antialiased text are always (s*a + d*(1-a)) | ||
| - //and smoothed text is always g=2.0. | ||
| + //and subpixel antialiased text is always g=2.0. | ||
| fRGBSpace.reset(CGColorSpaceCreateDeviceRGB()); | ||
| } | ||
|
|
||
| @@ -1064,7 +1106,7 @@ static constexpr uint8_t sk_pow2_table(size_t i) { | ||
| * This will invert the gamma applied by CoreGraphics, so we can get linear | ||
| * values. | ||
| * | ||
| - * CoreGraphics obscurely defaults to 2.0 as the smoothing gamma value. | ||
| + * CoreGraphics obscurely defaults to 2.0 as the subpixel coverage gamma value. | ||
| * The color space used does not appear to affect this choice. | ||
| */ | ||
| static constexpr auto gLinearCoverageFromCGLCDValue = SkMakeArray<256>(sk_pow2_table); | ||
| @@ -1154,18 +1196,20 @@ void SkScalerContext_Mac::generateImage(const SkGlyph& glyph) { | ||
| CGGlyph cgGlyph = SkTo<CGGlyph>(glyph.getGlyphID()); | ||
|
|
||
| // FIXME: lcd smoothed un-hinted rasterization unsupported. | ||
| - bool generateA8FromLCD = fRec.getHinting() != SkPaint::kNo_Hinting; | ||
| + bool requestSmooth = fRec.getHinting() != SkPaint::kNo_Hinting; | ||
|
|
||
| // Draw the glyph | ||
| size_t cgRowBytes; | ||
| - CGRGBPixel* cgPixels = fOffscreen.getCG(*this, glyph, cgGlyph, &cgRowBytes, generateA8FromLCD); | ||
| + CGRGBPixel* cgPixels = fOffscreen.getCG(*this, glyph, cgGlyph, &cgRowBytes, requestSmooth); | ||
| if (cgPixels == nullptr) { | ||
| return; | ||
| } | ||
|
|
||
| // Fix the glyph | ||
| if ((glyph.fMaskFormat == SkMask::kLCD16_Format) || | ||
| - (glyph.fMaskFormat == SkMask::kA8_Format && supports_LCD() && generateA8FromLCD)) | ||
| + (glyph.fMaskFormat == SkMask::kA8_Format | ||
| + && requestSmooth | ||
| + && smooth_behavior() == SmoothBehavior::subpixel)) | ||
| { | ||
| const uint8_t* linear = gLinearCoverageFromCGLCDValue.data(); | ||
|
|
||
| @@ -2042,14 +2086,14 @@ void SkTypeface_Mac::onFilterRec(SkScalerContextRec* rec) const { | ||
|
|
||
| rec->fFlags &= ~flagsWeDontSupport; | ||
|
|
||
| - bool lcdSupport = supports_LCD(); | ||
| + SmoothBehavior smoothBehavior = smooth_behavior(); | ||
|
|
||
| // Only two levels of hinting are supported. | ||
| // kNo_Hinting means avoid CoreGraphics outline dilation. | ||
| // kNormal_Hinting means CoreGraphics outline dilation is allowed. | ||
| // If there is no lcd support, hinting (dilation) cannot be supported. | ||
| SkPaint::Hinting hinting = rec->getHinting(); | ||
| - if (SkPaint::kSlight_Hinting == hinting || !lcdSupport) { | ||
| + if (SkPaint::kSlight_Hinting == hinting || smoothBehavior == SmoothBehavior::none) { | ||
| hinting = SkPaint::kNo_Hinting; | ||
| } else if (SkPaint::kFull_Hinting == hinting) { | ||
| hinting = SkPaint::kNormal_Hinting; | ||
| @@ -2076,12 +2120,15 @@ void SkTypeface_Mac::onFilterRec(SkScalerContextRec* rec) const { | ||
| // [LCD][yes-hint]: generate LCD using CoreGraphic's LCD output. | ||
|
|
||
| if (rec->fMaskFormat == SkMask::kLCD16_Format) { | ||
| - if (lcdSupport) { | ||
| + if (smoothBehavior == SmoothBehavior::subpixel) { | ||
| //CoreGraphics creates 555 masks for smoothed text anyway. | ||
| rec->fMaskFormat = SkMask::kLCD16_Format; | ||
| rec->setHinting(SkPaint::kNormal_Hinting); | ||
| } else { | ||
| rec->fMaskFormat = SkMask::kA8_Format; | ||
| + if (smoothBehavior == SmoothBehavior::some) { | ||
| + rec->setHinting(SkPaint::kNormal_Hinting); | ||
| + } | ||
| } | ||
| } | ||
|
|