178 lines
8.1 KiB
Diff
178 lines
8.1 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Shelley Vohr <shelley.vohr@gmail.com>
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Date: Mon, 22 Oct 2018 10:45:53 -0700
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Subject: fix_font_thickness.patch
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Backports https://skia-review.googlesource.com/c/157566/ to
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fix an issue whereby font rendering weight was too thin compared
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to other fonts present on MacOS Mojave.
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diff --git a/src/ports/SkFontHost_mac.cpp b/src/ports/SkFontHost_mac.cpp
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index 18d09b4ec06a23f8c046d4f08a51296b77e37d8b..fc3902156b65b5875d231ff52101764d7b068f91 100644
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--- a/src/ports/SkFontHost_mac.cpp
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+++ b/src/ports/SkFontHost_mac.cpp
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@@ -380,17 +380,28 @@ static constexpr const uint8_t kSpiderSymbol_ttf[] = {
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0x00, 0x02, 0x00, 0x00
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};
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+enum class SmoothBehavior {
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+ none, // SmoothFonts produces no effect.
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+ some, // SmoothFonts produces some effect, but not subpixel coverage.
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+ subpixel, // SmoothFonts produces some effect and provides subpixel coverage.
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+};
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+
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/**
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* There does not appear to be a publicly accessable API for determining if lcd
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* font smoothing will be applied if we request it. The main issue is that if
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* smoothing is applied a gamma of 2.0 will be used, if not a gamma of 1.0.
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*/
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-static bool supports_LCD() {
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- static bool gSupportsLCD = []{
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- uint32_t bitmap[16][16] = {};
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+static SmoothBehavior smooth_behavior() {
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+ static SmoothBehavior gSmoothBehavior = []{
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+ uint32_t noSmoothBitmap[16][16] = {};
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+ uint32_t smoothBitmap[16][16] = {};
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UniqueCFRef<CGColorSpaceRef> colorspace(CGColorSpaceCreateDeviceRGB());
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- UniqueCFRef<CGContextRef> cgContext(
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- CGBitmapContextCreate(&bitmap, 16, 16, 8, 16*4, colorspace.get(), BITMAP_INFO_RGB));
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+ UniqueCFRef<CGContextRef> noSmoothContext(
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+ CGBitmapContextCreate(&noSmoothBitmap, 16, 16, 8, 16*4,
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+ colorspace.get(), BITMAP_INFO_RGB));
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+ UniqueCFRef<CGContextRef> smoothContext(
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+ CGBitmapContextCreate(&smoothBitmap, 16, 16, 8, 16*4,
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+ colorspace.get(), BITMAP_INFO_RGB));
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UniqueCFRef<CGDataProviderRef> data(
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CGDataProviderCreateWithData(nullptr, kSpiderSymbol_ttf,
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@@ -401,31 +412,39 @@ static bool supports_LCD() {
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CTFontCreateWithGraphicsFont(cgFont.get(), 16, nullptr, nullptr));
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SkASSERT(ctFont);
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- CGContextSetShouldSmoothFonts(cgContext.get(), true);
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- CGContextSetShouldAntialias(cgContext.get(), true);
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- CGContextSetTextDrawingMode(cgContext.get(), kCGTextFill);
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- CGContextSetGrayFillColor(cgContext.get(), 1, 1);
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+ CGContextSetShouldSmoothFonts(noSmoothContext.get(), false);
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+ CGContextSetShouldAntialias(noSmoothContext.get(), true);
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+ CGContextSetTextDrawingMode(noSmoothContext.get(), kCGTextFill);
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+ CGContextSetGrayFillColor(noSmoothContext.get(), 1, 1);
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+
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+ CGContextSetShouldSmoothFonts(smoothContext.get(), true);
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+ CGContextSetShouldAntialias(smoothContext.get(), true);
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+ CGContextSetTextDrawingMode(smoothContext.get(), kCGTextFill);
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+ CGContextSetGrayFillColor(smoothContext.get(), 1, 1);
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CGPoint point = CGPointMake(0, 3);
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CGGlyph spiderGlyph = 3;
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- CTFontDrawGlyphs(ctFont.get(), &spiderGlyph, &point, 1, cgContext.get());
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+ CTFontDrawGlyphs(ctFont.get(), &spiderGlyph, &point, 1, noSmoothContext.get());
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+ CTFontDrawGlyphs(ctFont.get(), &spiderGlyph, &point, 1, smoothContext.get());
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// For debugging.
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- //UniqueCFRef<CGImageRef> image(CGBitmapContextCreateImage(cgContext.get()));
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+ //UniqueCFRef<CGImageRef> image(CGBitmapContextCreateImage(noSmoothContext()));
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+ //UniqueCFRef<CGImageRef> image(CGBitmapContextCreateImage(smoothContext()));
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+ SmoothBehavior smoothBehavior = SmoothBehavior::none;
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for (int x = 0; x < 16; ++x) {
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for (int y = 0; y < 16; ++y) {
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- uint32_t pixel = bitmap[x][y];
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- uint32_t r = (pixel >> 16) & 0xFF;
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- uint32_t g = (pixel >> 8) & 0xFF;
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- uint32_t b = (pixel >> 0) & 0xFF;
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+ uint32_t smoothPixel = smoothBitmap[x][y];
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+ uint32_t r = (smoothPixel >> 16) & 0xFF;
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+ uint32_t g = (smoothPixel >> 8) & 0xFF;
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+ uint32_t b = (smoothPixel >> 0) & 0xFF;
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if (r != g || r != b) {
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- return true;
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+ return SmoothBehavior::subpixel;
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}
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}
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}
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- return false;
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+ return smoothBehavior;
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}();
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- return gSupportsLCD;
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+ return gSmoothBehavior;
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}
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class Offscreen {
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@@ -1008,7 +1027,7 @@ CGRGBPixel* Offscreen::getCG(const SkScalerContext_Mac& context, const SkGlyph&
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if (!fRGBSpace) {
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//It doesn't appear to matter what color space is specified.
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//Regular blends and antialiased text are always (s*a + d*(1-a))
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- //and smoothed text is always g=2.0.
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+ //and subpixel antialiased text is always g=2.0.
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fRGBSpace.reset(CGColorSpaceCreateDeviceRGB());
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}
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@@ -1264,7 +1283,7 @@ static constexpr uint8_t sk_pow2_table(size_t i) {
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* This will invert the gamma applied by CoreGraphics, so we can get linear
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* values.
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*
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- * CoreGraphics obscurely defaults to 2.0 as the smoothing gamma value.
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+ * CoreGraphics obscurely defaults to 2.0 as the subpixel coverage gamma value.
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* The color space used does not appear to affect this choice.
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*/
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static constexpr auto gLinearCoverageFromCGLCDValue = SkMakeArray<256>(sk_pow2_table);
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@@ -1354,18 +1373,20 @@ void SkScalerContext_Mac::generateImage(const SkGlyph& glyph) {
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CGGlyph cgGlyph = SkTo<CGGlyph>(glyph.getGlyphID());
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// FIXME: lcd smoothed un-hinted rasterization unsupported.
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- bool generateA8FromLCD = fRec.getHinting() != SkPaint::kNo_Hinting;
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+ bool requestSmooth = fRec.getHinting() != SkPaint::kNo_Hinting;
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// Draw the glyph
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size_t cgRowBytes;
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- CGRGBPixel* cgPixels = fOffscreen.getCG(*this, glyph, cgGlyph, &cgRowBytes, generateA8FromLCD);
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+ CGRGBPixel* cgPixels = fOffscreen.getCG(*this, glyph, cgGlyph, &cgRowBytes, requestSmooth);
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if (cgPixels == nullptr) {
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return;
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}
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// Fix the glyph
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if ((glyph.fMaskFormat == SkMask::kLCD16_Format) ||
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- (glyph.fMaskFormat == SkMask::kA8_Format && supports_LCD() && generateA8FromLCD))
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+ (glyph.fMaskFormat == SkMask::kA8_Format
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+ && requestSmooth
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+ && smooth_behavior() == SmoothBehavior::subpixel))
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{
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const uint8_t* linear = gLinearCoverageFromCGLCDValue.data();
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@@ -2261,14 +2282,14 @@ void SkTypeface_Mac::onFilterRec(SkScalerContextRec* rec) const {
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rec->fFlags &= ~flagsWeDontSupport;
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- bool lcdSupport = supports_LCD();
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+ SmoothBehavior smoothBehavior = smooth_behavior();
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// Only two levels of hinting are supported.
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// kNo_Hinting means avoid CoreGraphics outline dilation.
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// kNormal_Hinting means CoreGraphics outline dilation is allowed.
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// If there is no lcd support, hinting (dilation) cannot be supported.
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SkPaint::Hinting hinting = rec->getHinting();
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- if (SkPaint::kSlight_Hinting == hinting || !lcdSupport) {
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+ if (SkPaint::kSlight_Hinting == hinting || smoothBehavior == SmoothBehavior::none) {
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hinting = SkPaint::kNo_Hinting;
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} else if (SkPaint::kFull_Hinting == hinting) {
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hinting = SkPaint::kNormal_Hinting;
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@@ -2295,12 +2316,15 @@ void SkTypeface_Mac::onFilterRec(SkScalerContextRec* rec) const {
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// [LCD][yes-hint]: generate LCD using CoreGraphic's LCD output.
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if (rec->fMaskFormat == SkMask::kLCD16_Format) {
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- if (lcdSupport) {
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+ if (smoothBehavior == SmoothBehavior::subpixel) {
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//CoreGraphics creates 555 masks for smoothed text anyway.
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rec->fMaskFormat = SkMask::kLCD16_Format;
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rec->setHinting(SkPaint::kNormal_Hinting);
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} else {
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rec->fMaskFormat = SkMask::kA8_Format;
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+ if (smoothBehavior == SmoothBehavior::some) {
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+ rec->setHinting(SkPaint::kNormal_Hinting);
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+ }
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}
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}
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--
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2.17.0
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