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fix: overly thin font rendering on mojave (#15007)

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* fix: overly thin font rendering on mojave

* SkUniqueCFRef => UniqueCFRef
This commit is contained in:
Shelley Vohr 2018-10-09 07:52:11 -07:00 committed by John Kleinschmidt
parent e9a5b19223
commit 532ee2dadf
2 changed files with 175 additions and 0 deletions
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7
patches/common/skia/.patches.yaml
View file

@ -4,3 +4,10 @@ patches:
author: Ales Pergl <alpergl@microsoft.com>
file: dcheck.patch
description: null
-
author: Shelley Vohr <shelley.vohr@gmail.com>
file: fix_font_thickness.patch
description: |
Backports https://skia-review.googlesource.com/c/157566/ to
fix an issue whereby font rendering weight was too thin compared
to other fonts present on MacOS Mojave.

168
patches/common/skia/fix_font_thickness.patch Normal file
View file

@ -0,0 +1,168 @@
diff --git a/src/ports/SkFontHost_mac.cpp b/src/ports/SkFontHost_mac.cpp
index 3cc51d43f6..c0b606c004 100644
--- a/src/ports/SkFontHost_mac.cpp
+++ b/src/ports/SkFontHost_mac.cpp
@@ -377,17 +377,28 @@ static constexpr const uint8_t kSpiderSymbol_ttf[] = {
0x00, 0x02, 0x00, 0x00
};
+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 bitmap[16][16] = {};
+static SmoothBehavior smooth_behavior() {
+ static SmoothBehavior gSmoothBehavior = []{
+ uint32_t noSmoothBitmap[16][16] = {};
+ uint32_t smoothBitmap[16][16] = {};
UniqueCFRef<CGColorSpaceRef> colorspace(CGColorSpaceCreateDeviceRGB());
- UniqueCFRef<CGContextRef> cgContext(
- CGBitmapContextCreate(&bitmap, 16, 16, 8, 16*4, colorspace.get(), BITMAP_INFO_RGB));
+ UniqueCFRef<CGContextRef> noSmoothContext(
+ CGBitmapContextCreate(&noSmoothBitmap, 16, 16, 8, 16*4,
+ colorspace.get(), BITMAP_INFO_RGB));
+ UniqueCFRef<CGContextRef> smoothContext(
+ CGBitmapContextCreate(&smoothBitmap, 16, 16, 8, 16*4,
+ colorspace.get(), BITMAP_INFO_RGB));
UniqueCFRef<CGDataProviderRef> data(
CGDataProviderCreateWithData(nullptr, kSpiderSymbol_ttf,
@@ -398,31 +409,39 @@ static bool supports_LCD() {
CTFontCreateWithGraphicsFont(cgFont.get(), 16, nullptr, nullptr));
SkASSERT(ctFont);
- CGContextSetShouldSmoothFonts(cgContext.get(), true);
- CGContextSetShouldAntialias(cgContext.get(), true);
- CGContextSetTextDrawingMode(cgContext.get(), kCGTextFill);
- CGContextSetGrayFillColor(cgContext.get(), 1, 1);
+ 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, cgContext.get());
+ CTFontDrawGlyphs(ctFont.get(), &spiderGlyph, &point, 1, noSmoothContext.get());
+ CTFontDrawGlyphs(ctFont.get(), &spiderGlyph, &point, 1, smoothContext.get());
// For debugging.
- //UniqueCFRef<CGImageRef> image(CGBitmapContextCreateImage(cgContext.get()));
-
+ //UniqueCFRef<CGImageRef> image(CGBitmapContextCreateImage(noSmoothContext()));
+ //UniqueCFRef<CGImageRef> image(CGBitmapContextCreateImage(smoothContext()));
+
+ SmoothBehavior smoothBehavior = SmoothBehavior::none;
for (int x = 0; x < 16; ++x) {
for (int y = 0; y < 16; ++y) {
- uint32_t pixel = bitmap[x][y];
- uint32_t r = (pixel >> 16) & 0xFF;
- uint32_t g = (pixel >> 8) & 0xFF;
- uint32_t b = (pixel >> 0) & 0xFF;
+ 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 true;
+ return SmoothBehavior::subpixel;
}
}
}
- return false;
+ return smoothBehavior;
}();
- return gSupportsLCD;
+ return gSmoothBehavior;
}
class Offscreen {
@@ -1005,7 +1024,7 @@ 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());
}
@@ -1260,7 +1279,7 @@ 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);
@@ -1350,18 +1369,20 @@ 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();
@@ -2257,14 +2278,14 @@ 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;
@@ -2291,12 +2312,15 @@ 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);
+ }
}
}