Mac: Use high-quality interpolation to draw tabpose thumbnails.

chrome/browser/ui/cocoa/tabpose_window.mm

 // Copyright (c) 2010 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.
 
 #import "chrome/browser/ui/cocoa/tabpose_window.h"
 
 #import <QuartzCore/QuartzCore.h>
 
 #include "app/resource_bundle.h"
 #include "base/mac_util.h"
 #include "base/mac/scoped_cftyperef.h"
 #include "base/scoped_callback_factory.h"
 #include "base/sys_string_conversions.h"
 #include "chrome/app/chrome_command_ids.h"
 #include "chrome/browser/browser_process.h"
 #import "chrome/browser/debugger/devtools_window.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/renderer_host/backing_store_mac.h"
 #include "chrome/browser/renderer_host/render_view_host.h"
 #include "chrome/browser/renderer_host/render_widget_host_view_mac.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/browser/tab_contents/thumbnail_generator.h"
 #import "chrome/browser/ui/cocoa/bookmarks/bookmark_bar_constants.h"
 #import "chrome/browser/ui/cocoa/browser_window_controller.h"
 #import "chrome/browser/ui/cocoa/tab_strip_controller.h"
 #import "chrome/browser/ui/cocoa/tab_strip_model_observer_bridge.h"
 #include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
 #include "chrome/common/pref_names.h"
+#include "gfx/scoped_cg_context_state_mac.h"
 #include "grit/app_resources.h"
 #include "skia/ext/skia_utils_mac.h"
 #include "third_party/skia/include/utils/mac/SkCGUtils.h"
 
 const int kTopGradientHeight  = 15;
 
 NSString* const kAnimationIdKey = @"AnimationId";
 NSString* const kAnimationIdFadeIn = @"FadeIn";
 NSString* const kAnimationIdFadeOut = @"FadeOut";
 
@@ skipping 176 matching lines @@
   }
   return bottomOffset;
 }
 
 - (void)drawBackingStore:(BackingStoreMac*)backing_store
                   inRect:(CGRect)destRect
                  context:(CGContextRef)context {
   // TODO(thakis): Add a sublayer for each accelerated surface in the rwhv.
   // Until then, accelerated layers (CoreAnimation NPAPI plugins, compositor)
   // won't show up in tabpose.
+  gfx::ScopedCGContextSaveGState CGContextSaveGState(context);
+  CGContextSetInterpolationQuality(context, kCGInterpolationHigh);
   if (backing_store->cg_layer()) {
     CGContextDrawLayerInRect(context, destRect, backing_store->cg_layer());
   } else {
     base::mac::ScopedCFTypeRef<CGImageRef> image(
         CGBitmapContextCreateImage(backing_store->cg_bitmap()));
     CGContextDrawImage(context, destRect, image);
   }
 }
 
 - (void)drawInContext:(CGContextRef)context {
@@ skipping 53 matching lines @@
 
     // Fill with bg color.
     [super drawInContext:context];
   }
 
   if (draw_backing_store) {
     // Backing store 'cache' hit!
     [self drawBackingStore:backing_store inRect:destRect context:context];
   } else if (thumbnail_) {
     // No cache hit, but the renderer returned a thumbnail to us.
+    gfx::ScopedCGContextSaveGState CGContextSaveGState(context);
+    CGContextSetInterpolationQuality(context, kCGInterpolationHigh);
     CGContextDrawImage(context, destRect, thumbnail_.get());
   }
 }
 
 @end
 
 namespace {
 
 class ScopedCAActionDisabler {
  public:
@@ skipping 1119 matching lines @@
   tile.set_tab_contents(contents->tab_contents());
   ThumbnailLayer* thumbLayer = [allThumbnailLayers_ objectAtIndex:index];
   [thumbLayer setTabContents:contents->tab_contents()];
 }
 
 - (void)tabStripModelDeleted {
   [self close];
 }
 
 @end