[Mac RTL] Correctly position icons and fade text for RTL.

chrome/browser/ui/cocoa/drag_util.mm

 // Copyright (c) 2011 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/drag_util.h"
 
 #include <cmath>
 
 #include "base/files/file_path.h"
+#include "base/i18n/rtl.h"
 #include "base/mac/scoped_nsobject.h"
 #include "base/strings/sys_string_conversions.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/cocoa/l10n_util.h"
 #include "components/mime_util/mime_util.h"
 #include "content/public/browser/plugin_service.h"
 #include "content/public/common/webplugininfo.h"
 #include "ipc/ipc_message.h"
 #include "net/base/filename_util.h"
 #include "net/base/mime_util.h"
 #import "third_party/mozilla/NSPasteboard+Utils.h"
 #import "ui/base/dragdrop/cocoa_dnd_util.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/scoped_ns_graphics_context_save_gstate_mac.h"
@@ skipping 29 matching lines @@
   return PluginService::GetInstance()->GetPluginInfo(
       -1,                // process ID
       MSG_ROUTING_NONE,  // routing ID
       profile->GetResourceContext(), url, url::Origin(), mime_type,
       allow_wildcard, NULL, &plugin, NULL);
 }
 
 // Draws string |title| within box |frame|, positioning it at the origin.
 // Truncates text with fading if it is too long to fit horizontally.
 // Based on code from GradientButtonCell but simplified where possible.
-void DrawTruncatedTitle(NSAttributedString* title, NSRect frame) {
+void DrawTruncatedTitle(const base::string16& title16,

[erikchen, 2017/02/18 01:56:25]

I was a little bit confused about why you needed both title16 and title. Pehraps
you could just pass in base::i18n::GetFirstStrongCharacterDirection(title16)?

[Avi (use Gerrit), 2017/02/18 02:17:00]

Done.

+                        NSAttributedString* title,
+                        NSRect frame) {
   NSSize size = [title size];
   if (std::floor(size.width) <= NSWidth(frame)) {
     [title drawAtPoint:frame.origin];
     return;
   }
 
-  // Gradient is about twice our line height long.
+  // The gradient is about twice the line height long.
+  NSRectEdge gradient_edge;
+  bool is_title_rtl = base::i18n::GetFirstStrongCharacterDirection(title16) ==
+                      base::i18n::RIGHT_TO_LEFT;
+  if (is_title_rtl)
+    gradient_edge = NSMinXEdge;
+  else
+    gradient_edge = NSMaxXEdge;
+
   CGFloat gradient_width = std::min(size.height * 2, NSWidth(frame) / 4);
   NSRect solid_part, gradient_part;
-  NSDivideRect(frame, &gradient_part, &solid_part, gradient_width, NSMaxXEdge);
+  NSDivideRect(frame, &gradient_part, &solid_part, gradient_width,
+               gradient_edge);
   CGContextRef context = static_cast<CGContextRef>(
       [[NSGraphicsContext currentContext] graphicsPort]);
   CGContextBeginTransparencyLayerWithRect(context, NSRectToCGRect(frame), 0);
   { // Draw text clipped to frame.
     gfx::ScopedNSGraphicsContextSaveGState scoped_state;
     [NSBezierPath clipRect:frame];
-    [title drawAtPoint:frame.origin];
+    [title drawInRect:frame];
   }
 
   NSColor* color = [NSColor blackColor];
   NSColor* alpha_color = [color colorWithAlphaComponent:0.0];
   base::scoped_nsobject<NSGradient> mask(
       [[NSGradient alloc] initWithStartingColor:color endingColor:alpha_color]);
   // Draw the gradient mask.
   CGContextSetBlendMode(context, kCGBlendModeDestinationIn);
-  [mask drawFromPoint:NSMakePoint(NSMaxX(frame) - gradient_width,
-                                  NSMinY(frame))
-              toPoint:NSMakePoint(NSMaxX(frame),
-                                  NSMinY(frame))
+  CGFloat gradient_x_start, gradient_x_end;
+  if (is_title_rtl) {
+    gradient_x_start = NSMaxX(gradient_part);
+    gradient_x_end = NSMinX(gradient_part);
+  } else {
+    gradient_x_start = NSMinX(gradient_part);
+    gradient_x_end = NSMaxX(gradient_part);
+  }
+  [mask drawFromPoint:NSMakePoint(gradient_x_start, NSMinY(frame))
+              toPoint:NSMakePoint(gradient_x_end, NSMinY(frame))
               options:NSGradientDrawsBeforeStartingLocation];
   CGContextEndTransparencyLayer(context);
 }
 
 }  // namespace
 
 GURL GetFileURLFromDropData(id<NSDraggingInfo> info) {
   if ([[info draggingPasteboard] containsURLDataConvertingTextToURL:YES]) {
     GURL url;
     ui::PopulateURLAndTitleFromPasteboard(&url,
@@ skipping 12 matching lines @@
   if (!url.is_empty()) {
     // If dragging a file, only allow dropping supported file types (that the
     // web view can display).
     return !IsSupportedFileURL(profile, url);
   }
   return NO;
 }
 
 NSImage* DragImageForBookmark(NSImage* favicon,
                               const base::string16& title,
-                              CGFloat title_width) {
+                              CGFloat drag_image_width) {
   // If no favicon, use a default.
   if (!favicon) {
     ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
     favicon = rb.GetNativeImageNamed(IDR_DEFAULT_FAVICON).ToNSImage();
   }
 
   // If no title, just use icon.
   if (title.empty())
     return favicon;
   NSString* ns_title = base::SysUTF16ToNSString(title);
 
   // Set the look of the title.
   NSDictionary* attrs =
       [NSDictionary dictionaryWithObject:[NSFont systemFontOfSize:
                                            [NSFont smallSystemFontSize]]
                                   forKey:NSFontAttributeName];
   base::scoped_nsobject<NSAttributedString> rich_title(
       [[NSAttributedString alloc] initWithString:ns_title attributes:attrs]);
 
   // Set up sizes and locations for rendering.
-  const CGFloat kIconMargin = 2.0;  // Gap between icon and text.
-  CGFloat text_left = [favicon size].width + kIconMargin;
-  NSSize drag_image_size = [favicon size];
-  NSSize text_size = [rich_title size];
-  CGFloat max_text_width = title_width - text_left;
-  text_size.width = std::min(text_size.width, max_text_width);
-  drag_image_size.width = text_left + text_size.width;
+  const CGFloat kIconPadding = 2.0;  // Gap between icon and text.
+  NSRect favicon_rect = {NSZeroPoint, [favicon size]};
+  CGFloat icon_plus_padding_width = NSWidth(favicon_rect) + kIconPadding;
+  CGFloat full_text_width = [rich_title size].width;
+  CGFloat allowed_text_width = drag_image_width - icon_plus_padding_width;
+  CGFloat used_text_width = std::min(full_text_width, allowed_text_width);
+  NSRect full_drag_image_rect = NSMakeRect(
+      0, 0, icon_plus_padding_width + used_text_width, NSHeight(favicon_rect));
+
+  NSRectEdge icon_edge;
+  if (cocoa_l10n_util::ShouldDoExperimentalRTLLayout())
+    icon_edge = NSMaxXEdge;
+  else
+    icon_edge = NSMinXEdge;
+
+  NSRect icon_rect;
+  NSRect text_plus_padding_rect;
+  NSRect padding_rect;
+  NSRect text_rect;
+
+  // Slice off the icon.
+  NSDivideRect(full_drag_image_rect, &icon_rect, &text_plus_padding_rect,
+               NSWidth(favicon_rect), icon_edge);
+
+  // Slice off the padding.
+  NSDivideRect(text_plus_padding_rect, &padding_rect, &text_rect, kIconPadding,
+               icon_edge);
 
   // Render the drag image.
   NSImage* drag_image =
-      [[[NSImage alloc] initWithSize:drag_image_size] autorelease];
+      [[[NSImage alloc] initWithSize:full_drag_image_rect.size] autorelease];
   [drag_image lockFocus];
-  [favicon drawAtPoint:NSZeroPoint
+  [favicon drawAtPoint:icon_rect.origin
               fromRect:NSZeroRect
              operation:NSCompositeSourceOver
               fraction:0.7];
-  NSRect target_text_rect = NSMakeRect(text_left, 0,
-                                       text_size.width, drag_image_size.height);
-  DrawTruncatedTitle(rich_title, target_text_rect);
+
+  DrawTruncatedTitle(title, rich_title, text_rect);
   [drag_image unlockFocus];
 
   return drag_image;
 }
 
 }  // namespace drag_util