mac: Make dynamic DPI changes work.

content/browser/renderer_host/render_widget_host_view_mac.mm

 // 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 "content/browser/renderer_host/render_widget_host_view_mac.h"
 
 #include <QuartzCore/QuartzCore.h>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 141 matching lines @@
 + (BOOL)shouldAutohideCursorForEvent:(NSEvent*)event;
 - (id)initWithRenderWidgetHostViewMac:(RenderWidgetHostViewMac*)r;
 - (void)setRWHVDelegate:(NSObject<RenderWidgetHostViewMacDelegate>*)delegate;
 - (void)gotUnhandledWheelEvent;
 - (void)scrollOffsetPinnedToLeft:(BOOL)left toRight:(BOOL)right;
 - (void)setHasHorizontalScrollbar:(BOOL)has_horizontal_scrollbar;
 - (void)keyEvent:(NSEvent*)theEvent wasKeyEquivalent:(BOOL)equiv;
 - (void)cancelChildPopups;
 - (void)windowDidChangeBackingProperties:(NSNotification*)notification;
 - (void)checkForPluginImeCancellation;
+- (void)updateTabBackingStoreScaleFactor;
 @end
 
 // NSEvent subtype for scroll gestures events.
 static const short kIOHIDEventTypeScroll = 6;
 
 // A window subclass that allows the fullscreen window to become main and gain
 // keyboard focus. This is only used for pepper flash. Normal fullscreen is
 // handled by the browser.
 @interface PepperFlashFullscreenWindow : UnderlayOpenGLHostingWindow
 @end
@@ skipping 220 matching lines @@
 }
 
 RenderWidgetHost* RenderWidgetHostViewMac::GetRenderWidgetHost() const {
   return render_widget_host_;
 }
 
 void RenderWidgetHostViewMac::DidBecomeSelected() {
   if (!is_hidden_)
     return;
 
+  // Check if the backing scale factor changed while the tab was in the
+  // background.
+  [cocoa_view_ updateTabBackingStoreScaleFactor];
+
   if (web_contents_switch_paint_time_.is_null())
     web_contents_switch_paint_time_ = base::TimeTicks::Now();
   is_hidden_ = false;
   render_widget_host_->WasRestored();
 
   // We're messing with the window, so do this to ensure no flashes.
   [[cocoa_view_ window] disableScreenUpdatesUntilFlush];
 }
 
 void RenderWidgetHostViewMac::WasHidden() {
@@ skipping 401 matching lines @@
     web_event.type = WebInputEvent::MouseLeave;
   ForwardMouseEvent(web_event);
 }
 
 bool RenderWidgetHostViewMac::IsPopup() const {
   return popup_type_ != WebKit::WebPopupTypeNone;
 }
 
 BackingStore* RenderWidgetHostViewMac::AllocBackingStore(
     const gfx::Size& size) {
-  // TODO(thakis): Register for backing scale factor change events and pass
-  // that on.
   float scale = ScaleFactor(cocoa_view_);
   return new BackingStoreMac(render_widget_host_, size, scale);
 }
 
 void RenderWidgetHostViewMac::CopyFromCompositingSurface(
     const gfx::Size& size,
     skia::PlatformCanvas* output,
     base::Callback<void(bool)> callback) {
   base::ScopedClosureRunner scoped_callback_runner(base::Bind(callback, false));
   if (!compositing_iosurface_.get() ||
@@ skipping 1048 matching lines @@
   }
   if (newWindow) {
     [[NSNotificationCenter defaultCenter]
         addObserver:self
            selector:@selector(windowDidChangeBackingProperties:)
                name:NSWindowDidChangeBackingPropertiesNotification
              object:newWindow];
   }
 }
 
+- (void)updateTabBackingStoreScaleFactor {
+  if (!renderWidgetHostView_->render_widget_host_)
+    return;
+
+  float scaleFactor = ScaleFactor(self);
+  BackingStoreMac* backingStore = static_cast<BackingStoreMac*>(
+      renderWidgetHostView_->render_widget_host_->GetBackingStore(false));
+  if (backingStore)  // NULL in hardware path.
+    backingStore->ScaleFactorChanged(scaleFactor);
+
+  renderWidgetHostView_->render_widget_host_->SetDeviceScaleFactor(
+      scaleFactor);
+}
+
 // http://developer.apple.com/library/mac/#documentation/GraphicsAnimation/Conceptual/HighResolutionOSX/CapturingScreenContents/CapturingScreenContents.html#//apple_ref/doc/uid/TP40012302-CH10-SW4
 - (void)windowDidChangeBackingProperties:(NSNotification*)notification {
   NSWindow* window = (NSWindow*)[notification object];
 
   CGFloat newBackingScaleFactor = [window backingScaleFactor];
   CGFloat oldBackingScaleFactor = [base::mac::ObjCCast<NSNumber>(
       [[notification userInfo] objectForKey:NSBackingPropertyOldScaleFactorKey])
       doubleValue];
   if (newBackingScaleFactor != oldBackingScaleFactor) {
-    // TODO(thakis): Tell backing store about new DPI, schedule repaint.
-    if (renderWidgetHostView_->render_widget_host_) {
-      renderWidgetHostView_->render_widget_host_->SetDeviceScaleFactor(
-          newBackingScaleFactor);
-    }
+    // Background tabs check if their scale factor changed when they become
+    // active, in DidBecomeSelected().

[Avi (use Gerrit), 2012/06/14 04:51:20]

Not for this CL, but we should rename that to DidBecomeActive...

[Nico, 2012/06/14 04:57:45]

There's also a mac-only SetActive(true) call :-) That's for painting controls as
active / inactive (think main window vs bg window), while DidBecomeSelected()
marks the active tab on a window.

+
+    // Allocating a CGLayerRef with the current scale factor immediately from
+    // this handler doesn't work. Schedule the backing store update on the
+    // next runloop cycle, then things are read for CGLayerRef allocations to
+    // work.
+    [self performSelector:@selector(updateTabBackingStoreScaleFactor)
+               withObject:nil
+               afterDelay:0];
   }
 }
 
 - (void)globalFrameDidChange:(NSNotification*)notification {
   if (handlingGlobalFrameDidChange_)
     return;
 
   handlingGlobalFrameDidChange_ = YES;
   if (renderWidgetHostView_->compositing_iosurface_.get())
     renderWidgetHostView_->compositing_iosurface_->GlobalFrameDidChange();
@@ skipping 1120 matching lines @@
   if (!string) return NO;
 
   // If the user is currently using an IME, confirm the IME input,
   // and then insert the text from the service, the same as TextEdit and Safari.
   [self confirmComposition];
   [self insertText:string];
   return YES;
 }
 
 @end