Mac: make bookmark bar drag buttons prettier.

(In particular, clip them to their rounded rectangle.)

BUG=28593
TEST=Drag bookmark bar buttons with a wide variety of themes; make sure edges/corners are correctly clipped from drag images.

Review URL: http://codereview.chromium.org/435028

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@32995 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 138 insertions, 26 deletions

diff --git a/chrome/browser/cocoa/bookmark_button.mm b/chrome/browser/cocoa/bookmark_button.mm
index 8ef0682..40a1e0a 100644
--- a/chrome/browser/cocoa/bookmark_button.mm
+++ b/chrome/browser/cocoa/bookmark_button.mm
@@ -2,17 +2,33 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "base/logging.h"
 #import "base/scoped_nsobject.h"
 #import "chrome/browser/cocoa/bookmark_button.h"
+#import "chrome/browser/cocoa/bookmark_button_cell.h"
+#import "third_party/GTM/AppKit/GTMTheme.h"
 
 NSString* kBookmarkButtonDragType = @"ChromiumBookmarkButtonDragType";
 
-// http://codereview.chromium.org/180036/diff/3001/3004
 namespace {
+
+// Code taken from <http://codereview.chromium.org/180036/diff/3001/3004>.
+// TODO(viettrungluu): Do we want common, standard code for drag hysteresis?
 const CGFloat kWebDragStartHysteresisX = 5.0;
 const CGFloat kWebDragStartHysteresisY = 5.0;
+
+// The opacity of the bookmark button drag image.
+const CGFloat kDragImageOpacity = 0.8;
+
 }
 
+@interface BookmarkButton(Private)
+
+// Make a drag image for the button.
+- (NSImage*)dragImage;
+
+@end  // @interface BookmarkButton(Private)
+
 @implementation BookmarkButton
 
 @synthesize draggable = draggable_;
@@ -41,25 +57,13 @@ const CGFloat kWebDragStartHysteresisY = 5.0;
   [pboard setData:[NSData dataWithBytes:&self length:sizeof(self)]
           forType:kBookmarkButtonDragType];
 
-  // This won't work if the source view is clipped.  Fortunately, we
-  // don't display clipped bookmark buttons.
-  [[self superview] lockFocus];
-  scoped_nsobject<NSBitmapImageRep>
-      bitmapImage([[NSBitmapImageRep alloc]
-                    initWithFocusedViewRect:[self frame]]);
-
-  [[self superview] unlockFocus];
-  scoped_nsobject<NSImage> imageDrag([[NSImage alloc]
-                                       initWithSize:[bitmapImage size]]);
-  [imageDrag addRepresentation:bitmapImage];
-
   // At the moment, moving bookmarks causes their buttons (like me!)
   // to be destroyed and rebuilt.  Make sure we don't go away while on
   // the stack.
   [self retain];
 
   CGFloat yAt = [self bounds].size.height;
-  [self dragImage:imageDrag at:NSMakePoint(0, yAt) offset:dragOffset
+  [self dragImage:[self dragImage] at:NSMakePoint(0, yAt) offset:dragOffset
             event:event pasteboard:pboard source:self slideBack:YES];
 
   // And we're done.
@@ -128,3 +132,40 @@ const CGFloat kWebDragStartHysteresisY = 5.0;
 }
 
 @end
+
+@implementation BookmarkButton(Private)
+
+- (NSImage*)dragImage {
+  NSRect bounds = [self bounds];
+
+  // Grab the image from the screen and put it in an |NSImage|. We can't use
+  // this directly since we need to clip it and set its opacity. This won't work
+  // if the source view is clipped. Fortunately, we don't display clipped
+  // bookmark buttons.
+  [self lockFocus];
+  scoped_nsobject<NSBitmapImageRep>
+      bitmap([[NSBitmapImageRep alloc] initWithFocusedViewRect:bounds]);
+  [self unlockFocus];
+  scoped_nsobject<NSImage> image([[NSImage alloc] initWithSize:[bitmap size]]);
+  [image addRepresentation:bitmap];
+
+  // Make an autoreleased |NSImage|, which will be returned, and draw into it.
+  // By default, the |NSImage| will be completely transparent.
+  NSImage* dragImage =
+      [[[NSImage alloc] initWithSize:[bitmap size]] autorelease];
+  [dragImage lockFocus];
+
+  // Draw the image with the appropriate opacity, clipping it tightly.
+  GradientButtonCell* cell = static_cast<GradientButtonCell*>([self cell]);
+  DCHECK([cell isKindOfClass:[GradientButtonCell class]]);
+  [[cell clipPathForFrame:bounds inView:self] setClip];
+  [image drawAtPoint:NSMakePoint(0, 0)
+            fromRect:NSMakeRect(0, 0, NSWidth(bounds), NSHeight(bounds))
+           operation:NSCompositeSourceOver
+            fraction:kDragImageOpacity];
+
+  [dragImage unlockFocus];
+  return dragImage;
+}
+
+@end  // @implementation BookmarkButton(Private)
diff --git a/chrome/browser/cocoa/gradient_button_cell.h b/chrome/browser/cocoa/gradient_button_cell.h
index 23dc5d1..e9d09bd 100644
--- a/chrome/browser/cocoa/gradient_button_cell.h
+++ b/chrome/browser/cocoa/gradient_button_cell.h
@@ -62,6 +62,12 @@ typedef NSInteger ButtonType;
 // the current hoverAlpha_ based on these events.
 - (void)setMouseInside:(BOOL)flag animate:(BOOL)animate;
 
+// Gets the path which tightly bounds the outside of the button. This is needed
+// to produce images of clear buttons which only include the area inside, since
+// the background of the button is drawn by someone else.
+- (NSBezierPath*)clipPathForFrame:(NSRect)cellFrame
+                           inView:(NSView*)controlView;
+
 @property(assign, nonatomic)CGFloat hoverAlpha;
 @end
 
diff --git a/chrome/browser/cocoa/gradient_button_cell.mm b/chrome/browser/cocoa/gradient_button_cell.mm
index d0aaed9..838397c8 100644
--- a/chrome/browser/cocoa/gradient_button_cell.mm
+++ b/chrome/browser/cocoa/gradient_button_cell.mm
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "base/logging.h"
 #import "base/scoped_nsobject.h"
 #include "chrome/browser/cocoa/gradient_button_cell.h"
 #import "third_party/GTM/AppKit/GTMTheme.h"
@@ -11,6 +12,20 @@
 - (void)sharedInit;
 - (void)drawUnderlayImageWithFrame:(NSRect)cellFrame
                             inView:(NSView*)controlView;
+
+// Get drawing parameters for a given cell frame in a given view. The inner
+// frame is the one required by |-drawInteriorWithFrame:inView:|. The inner and
+// outer paths are the ones required by |-drawBorderAndFillForTheme:...|. The
+// outer path also gives the area in which to clip. Any of the |return...|
+// arguments may be NULL (in which case the given parameter won't be returned).
+// If |returnInnerPath| or |returnOuterPath|, |*returnInnerPath| or
+// |*returnOuterPath| should be nil, respectively.
+- (void)getDrawParamsForFrame:(NSRect)cellFrame
+                       inView:(NSView*)controlView
+                   innerFrame:(NSRect*)returnInnerFrame
+                    innerPath:(NSBezierPath**)returnInnerPath
+                    outerPath:(NSBezierPath**)returnOuterPath
+                     clipPath:(NSBezierPath**)returnClipPath;
 @end
 
 static const NSTimeInterval kAnimationShowDuration = 0.2;
@@ -258,11 +273,20 @@ static const NSTimeInterval kAnimationHideDuration = 0.4;
   [innerPath stroke];
 }
 
-- (void)drawWithFrame:(NSRect)cellFrame inView:(NSView*)controlView {
+// TODO(viettrungluu): clean this up.
+// (Private)
+- (void)getDrawParamsForFrame:(NSRect)cellFrame
+                       inView:(NSView*)controlView
+                   innerFrame:(NSRect*)returnInnerFrame
+                    innerPath:(NSBezierPath**)returnInnerPath
+                    outerPath:(NSBezierPath**)returnOuterPath
+                     clipPath:(NSBezierPath**)returnClipPath {
   // Constants from Cole.  Will kConstant them once the feedback loop
   // is complete.
   NSRect drawFrame = NSInsetRect(cellFrame, 1.5, 1.5);
   NSRect innerFrame = NSInsetRect(cellFrame, 2, 1);
+  const CGFloat radius = 3.5;
+
   ButtonType type = [[(NSControl*)controlView cell] tag];
   switch (type) {
     case kMiddleButtonType:
@@ -280,23 +304,52 @@ static const NSTimeInterval kAnimationHideDuration = 0.4;
     default:
       break;
   }
+  if (type == kLeftButtonWithShadowType)
+    innerFrame.size.width -= 1.0;
+
+  // Return results if |return...| not null.
+  if (returnInnerFrame)
+    *returnInnerFrame = innerFrame;
+  if (returnInnerPath) {
+    DCHECK(*returnInnerPath == nil);
+    *returnInnerPath = [NSBezierPath bezierPathWithRoundedRect:drawFrame
+                                                       xRadius:radius
+                                                       yRadius:radius];
+  }
+  if (returnOuterPath) {
+    DCHECK(*returnOuterPath == nil);
+    NSRect outerPathRect = NSInsetRect(drawFrame, -1, -1);
+    *returnOuterPath = [NSBezierPath bezierPathWithRoundedRect:outerPathRect
+                                                       xRadius:radius + 1
+                                                       yRadius:radius + 1];
+  }
+  if (returnClipPath) {
+    DCHECK(*returnClipPath == nil);
+    NSRect clipPathRect = NSInsetRect(drawFrame, -0.5, -0.5);
+    *returnClipPath = [NSBezierPath bezierPathWithRoundedRect:clipPathRect
+                                                      xRadius:radius + 0.5
+                                                      yRadius:radius + 0.5];
+  }
+}
+
+// TODO(viettrungluu): clean this up.
+- (void)drawWithFrame:(NSRect)cellFrame inView:(NSView*)controlView {
+  NSRect innerFrame;
+  NSBezierPath* innerPath = nil;
+  NSBezierPath* outerPath = nil;
+  [self getDrawParamsForFrame:cellFrame
+                       inView:controlView
+                   innerFrame:&innerFrame
+                    innerPath:&innerPath
+                    outerPath:&outerPath
+                     clipPath:NULL];
 
-  const float radius = 3.5;
   BOOL pressed = [self isHighlighted];
   NSWindow* window = [controlView window];
   BOOL active = [window isKeyWindow] || [window isMainWindow];
 
   GTMTheme* theme = [controlView gtm_theme];
 
-  NSBezierPath* innerPath =
-      [NSBezierPath bezierPathWithRoundedRect:drawFrame
-                                      xRadius:radius
-                                      yRadius:radius];
-  NSBezierPath* outerPath =
-      [NSBezierPath bezierPathWithRoundedRect:NSInsetRect(drawFrame, -1, -1)
-                                      xRadius:radius + 1
-                                      yRadius:radius + 1];
-
   // Stroke the borders and appropriate fill gradient. If we're borderless,
   // the only time we want to draw the inner gradient is if we're highlighted.
   if (([self isBordered] && ![self showsBorderOnlyWhileMouseInside]) ||
@@ -316,6 +369,7 @@ static const NSTimeInterval kAnimationHideDuration = 0.4;
   }
 
   // If this is the left side of a segmented button, draw a slight shadow.
+  ButtonType type = [[(NSControl*)controlView cell] tag];
   if (type == kLeftButtonWithShadowType) {
     NSRect borderRect, contentRect;
     NSDivideRect(cellFrame, &borderRect, &contentRect, 1.0, NSMaxXEdge);
@@ -324,7 +378,6 @@ static const NSTimeInterval kAnimationHideDuration = 0.4;
     [[stroke colorWithAlphaComponent:0.2] set];
     NSRectFillUsingOperation(NSInsetRect(borderRect, 0, 2),
                              NSCompositeSourceOver);
-    innerFrame.size.width -= 1.0;
   }
   [self drawInteriorWithFrame:innerFrame inView:controlView];
 }
@@ -396,4 +449,16 @@ static const NSTimeInterval kAnimationHideDuration = 0.4;
   }
 }
 
+- (NSBezierPath*)clipPathForFrame:(NSRect)cellFrame
+                           inView:(NSView*)controlView {
+  NSBezierPath* boundingPath = nil;
+  [self getDrawParamsForFrame:cellFrame
+                       inView:controlView
+                   innerFrame:NULL
+                    innerPath:NULL
+                    outerPath:NULL
+                     clipPath:&boundingPath];
+  return boundingPath;
+}
+
 @end