linux: Force full hinting when antialiasing is disabled.

ui/gfx/font_render_params_linux.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gfx/font_render_params.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "ui/gfx/font.h"
 #include "ui/gfx/linux_font_delegate.h"
@@ skipping 110 matching lines @@
   if (family_out)
     family_out->clear();
 
   // Start with the delegate's settings, but let Fontconfig have the final say.
   FontRenderParams params;
   const LinuxFontDelegate* delegate = LinuxFontDelegate::instance();
   if (delegate)
     params = delegate->GetDefaultFontRenderParams();
   QueryFontconfig(query, &params, family_out);
 
-  // Fontconfig doesn't support configuring subpixel positioning; check a flag.
-  params.subpixel_positioning = CommandLine::ForCurrentProcess()->HasSwitch(
-      query.for_web_contents ?
-      switches::kEnableWebkitTextSubpixelPositioning :
-      switches::kEnableBrowserTextSubpixelPositioning);
+  if (!params.antialiasing) {
+    // Cairo forces full hinting when antialiasing is disabled, since anything
+    // less than that looks awful; do the same here. Requesting subpixel
+    // rendering or positioning doesn't make sense either.
+    params.hinting = FontRenderParams::HINTING_FULL;
+    params.subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_NONE;
+    params.subpixel_positioning = false;
+  } else {
+    // Fontconfig doesn't support configuring subpixel positioning; check a
+    // flag.
+    params.subpixel_positioning = CommandLine::ForCurrentProcess()->HasSwitch(
+        query.for_web_contents ?
+        switches::kEnableWebkitTextSubpixelPositioning :
+        switches::kEnableBrowserTextSubpixelPositioning);
 
-  // To enable subpixel positioning, we need to disable hinting.
-  if (params.subpixel_positioning)
-    params.hinting = FontRenderParams::HINTING_NONE;
+    // To enable subpixel positioning, we need to disable hinting.
+    if (params.subpixel_positioning)
+      params.hinting = FontRenderParams::HINTING_NONE;
+  }
 
   // Use the first family from the list if Fontconfig didn't suggest a family.
   if (family_out && family_out->empty() && !query.families.empty())
     *family_out = query.families[0];
 
   return params;
 }
 
 }  // namespace gfx