[Linux] Enable subpixel text on high-dpi regardless of hinting

[Linux] Enable subpixel text on high-dpi regardless of hinting

Expose deviceScaleFactor on GraphicsContext and use to selectively
enable subpixel text regardless of the system font hinting settings for
high-dpi systems.

BUG=373441
R=derat@chromium.org, tkent@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=178485

[eae, 2014-07-18 16:43:51]

+ tkent for Source/web OWNERS

[Daniel Erat, 2014-07-18 16:49:57]

https://codereview.chromium.org/407553002/diff/1/Source/platform/fonts/linux/...
File Source/platform/fonts/linux/FontPlatformDataLinuxHarfBuzz.cpp (right):

https://codereview.chromium.org/407553002/diff/1/Source/platform/fonts/linux/...
Source/platform/fonts/linux/FontPlatformDataLinuxHarfBuzz.cpp:89: ||
context->deviceScaleFactor() >= 1.0f);
i think you need > 1.0f here

[eae, 2014-07-18 16:53:29]

On 2014/07/18 16:49:57, Daniel Erat wrote:
>
https://codereview.chromium.org/407553002/diff/1/Source/platform/fonts/linux/...
> File Source/platform/fonts/linux/FontPlatformDataLinuxHarfBuzz.cpp (right):
> 
>
https://codereview.chromium.org/407553002/diff/1/Source/platform/fonts/linux/...
> Source/platform/fonts/linux/FontPlatformDataLinuxHarfBuzz.cpp:89: ||
> context->deviceScaleFactor() >= 1.0f);
> i think you need > 1.0f here

Oh, of course. Good catch!

[Daniel Erat, 2014-07-18 16:54:08]

lgtm other than that. thanks! :-)

[eae, 2014-07-18 16:54:44]

Fixed, thanks derat!

[eae, 2014-07-18 18:29:10]

+adamk for Source/web OWNERS

[adamk, 2014-07-18 18:43:00]

lgtm for Source/web/

[eae, 2014-07-18 18:43:16]

Thanks Adam!

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[eae, 2014-07-18 18:43:27]

The CQ bit was checked by eae@chromium.org

[commit-bot: I haz the power, 2014-07-18 18:43:43]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/eae@chromium.org/407553002/20001

[commit-bot: I haz the power, 2014-07-18 18:43:52]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-07-18 18:43:58]

Failed to apply patch for
Source/platform/fonts/linux/FontPlatformDataLinuxHarfBuzz.cpp:
While running patch -p1 --forward --force --no-backup-if-mismatch;
  can't find file to patch at input line 6
  Perhaps you used the wrong -p or --strip option?
  The text leading up to this was:
  --------------------------
  |Index: Source/platform/fonts/linux/FontPlatformDataLinuxHarfBuzz.cpp
  |diff --git a/Source/platform/fonts/linux/FontPlatformDataLinuxHarfBuzz.cpp
b/Source/platform/fonts/linux/FontPlatformDataLinuxHarfBuzz.cpp
  |index
ab12969ab5dfe270a6343755d1a389a01b5d8611..9be3655e6edac86e32c33e710f57d8553328490b
100644
  |--- a/Source/platform/fonts/linux/FontPlatformDataLinuxHarfBuzz.cpp
  |+++ b/Source/platform/fonts/linux/FontPlatformDataLinuxHarfBuzz.cpp
  --------------------------
  No file to patch.  Skipping patch.
  3 out of 3 hunks ignored

Patch:       Source/platform/fonts/linux/FontPlatformDataLinuxHarfBuzz.cpp
Index: Source/platform/fonts/linux/FontPlatformDataLinuxHarfBuzz.cpp
diff --git a/Source/platform/fonts/linux/FontPlatformDataLinuxHarfBuzz.cpp
b/Source/platform/fonts/linux/FontPlatformDataLinuxHarfBuzz.cpp
index
ab12969ab5dfe270a6343755d1a389a01b5d8611..9be3655e6edac86e32c33e710f57d8553328490b
100644
--- a/Source/platform/fonts/linux/FontPlatformDataLinuxHarfBuzz.cpp
+++ b/Source/platform/fonts/linux/FontPlatformDataLinuxHarfBuzz.cpp
@@ -35,6 +35,7 @@
 #include "platform/LayoutTestSupport.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/fonts/harfbuzz/FontPlatformDataHarfBuzz.h"
+#include "platform/graphics/GraphicsContext.h"
 #include "public/platform/linux/WebFontInfo.h"
 #include "public/platform/linux/WebFontRenderStyle.h"
 #include "public/platform/linux/WebSandboxSupport.h"
@@ -72,7 +73,8 @@ void FontPlatformData::setSubpixelRendering(bool
useSubpixelRendering)
     useSkiaSubpixelRendering = useSubpixelRendering;
 }
 
-void FontPlatformData::setupPaint(SkPaint* paint, GraphicsContext*) const
+void FontPlatformData::setupPaint(SkPaint* paint, GraphicsContext* context)
+    const
 {
     paint->setAntiAlias(m_style.useAntiAlias);
     paint->setHinting(static_cast<SkPaint::Hinting>(m_style.hintStyle));
@@ -81,10 +83,13 @@ void FontPlatformData::setupPaint(SkPaint* paint,
GraphicsContext*) const
     if (m_style.useAntiAlias)
         paint->setLCDRenderText(m_style.useSubpixelRendering);
 
+    // Do not enable subpixel text on low-dpi if full hinting is requested.
+    bool useSubpixelText = RuntimeEnabledFeatures::subpixelFontScalingEnabled()
+        && context && (paint->getHinting() != SkPaint::kFull_Hinting
+            || context->deviceScaleFactor() > 1.0f);
+
     // TestRunner specifically toggles the subpixel positioning flag.
-    if (RuntimeEnabledFeatures::subpixelFontScalingEnabled()
-        && paint->getHinting() != SkPaint::kFull_Hinting
-        && !LayoutTestSupport::isRunningLayoutTest())
+    if (useSubpixelText && !LayoutTestSupport::isRunningLayoutTest())
         paint->setSubpixelText(true);
     else
         paint->setSubpixelText(m_style.useSubpixelPositioning);

[eae, 2014-07-18 18:54:49]

The CQ bit was checked by eae@chromium.org

[commit-bot: I haz the power, 2014-07-18 18:55:58]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/eae@chromium.org/407553002/40001

[commit-bot: I haz the power, 2014-07-18 20:17:04]

Change committed as 178485