src/chrome/browser/ui/cocoa/bookmarks/bookmark_drag_drop_cocoa.mm

   1 // Copyright 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/browser/ui/cocoa/bookmarks/bookmark_drag_drop_cocoa.h"
   6
   7 #import <Cocoa/Cocoa.h>
   8
   9 #include <cmath>
  10
  11 #include "base/logging.h"
  12 #include "base/mac/scoped_nsobject.h"
  13 #include "base/message_loop/message_loop.h"
  14 #include "base/strings/string16.h"
  15 #include "base/strings/sys_string_conversions.h"
  16 #include "chrome/browser/bookmarks/bookmark_model.h"
  17 #include "chrome/browser/bookmarks/bookmark_model_factory.h"
  18 #include "chrome/browser/bookmarks/bookmark_node_data.h"
  19 #include "chrome/browser/profiles/profile.h"
  20 #include "chrome/browser/ui/bookmarks/bookmark_drag_drop.h"
  21 #import "chrome/browser/ui/cocoa/bookmarks/bookmark_bar_controller.h"
  22 #include "grit/ui_resources.h"
  23 #include "ui/base/dragdrop/drag_drop_types.h"
  24 #include "ui/base/resource/resource_bundle.h"
  25 #include "ui/gfx/scoped_ns_graphics_context_save_gstate_mac.h"
  26
  27 namespace chrome {
  28
  29 namespace {
  30
  31 // Make a drag image from the drop data.
  32 NSImage* MakeDragImage(BookmarkModel* model,
  33                        const std::vector<const BookmarkNode*>& nodes) {
  34   if (nodes.size() == 1) {
  35     const BookmarkNode* node = nodes[0];
  36     const gfx::Image& favicon = model->GetFavicon(node);
  37     return DragImageForBookmark(
  38         favicon.IsEmpty() ? nil : favicon.ToNSImage(), node->GetTitle());
  39   } else {
  40     // TODO(feldstein): Do something better than this. Should have badging
  41     // and a single drag image.
  42     // http://crbug.com/37264
  43     return [NSImage imageNamed:NSImageNameMultipleDocuments];
  44   }
  45 }
  46
  47 // Draws string |title| within box |frame|, positioning it at the origin.
  48 // Truncates text with fading if it is too long to fit horizontally.
  49 // Based on code from GradientButtonCell but simplified where possible.
  50 void DrawTruncatedTitle(NSAttributedString* title, NSRect frame) {
  51   NSSize size = [title size];
  52   if (std::floor(size.width) <= NSWidth(frame)) {
  53     [title drawAtPoint:frame.origin];
  54     return;
  55   }
  56
  57   // Gradient is about twice our line height long.
  58   CGFloat gradient_width = std::min(size.height * 2, NSWidth(frame) / 4);
  59   NSRect solid_part, gradient_part;
  60   NSDivideRect(frame, &gradient_part, &solid_part, gradient_width, NSMaxXEdge);
  61   CGContextRef context = static_cast<CGContextRef>(
  62       [[NSGraphicsContext currentContext] graphicsPort]);
  63   CGContextBeginTransparencyLayerWithRect(context, NSRectToCGRect(frame), 0);
  64   { // Draw text clipped to frame.
  65     gfx::ScopedNSGraphicsContextSaveGState scoped_state;
  66     [NSBezierPath clipRect:frame];
  67     [title drawAtPoint:frame.origin];
  68   }
  69
  70   NSColor* color = [NSColor blackColor];
  71   NSColor* alpha_color = [color colorWithAlphaComponent:0.0];
  72   base::scoped_nsobject<NSGradient> mask(
  73       [[NSGradient alloc] initWithStartingColor:color endingColor:alpha_color]);
  74   // Draw the gradient mask.
  75   CGContextSetBlendMode(context, kCGBlendModeDestinationIn);
  76   [mask drawFromPoint:NSMakePoint(NSMaxX(frame) - gradient_width,
  77                                   NSMinY(frame))
  78               toPoint:NSMakePoint(NSMaxX(frame),
  79                                   NSMinY(frame))
  80               options:NSGradientDrawsBeforeStartingLocation];
  81   CGContextEndTransparencyLayer(context);
  82 }
  83
  84 }  // namespace
  85
  86 NSImage* DragImageForBookmark(NSImage* favicon, const base::string16& title) {
  87   // If no favicon, use a default.
  88   if (!favicon) {
  89     ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
  90     favicon = rb.GetNativeImageNamed(IDR_DEFAULT_FAVICON).ToNSImage();
  91   }
  92
  93   // If no title, just use icon.
  94   if (title.empty())
  95     return favicon;
  96   NSString* ns_title = base::SysUTF16ToNSString(title);
  97
  98   // Set the look of the title.
  99   NSDictionary* attrs =
 100       [NSDictionary dictionaryWithObject:[NSFont systemFontOfSize:
 101                                            [NSFont smallSystemFontSize]]
 102                                   forKey:NSFontAttributeName];
 103   base::scoped_nsobject<NSAttributedString> rich_title(
 104       [[NSAttributedString alloc] initWithString:ns_title attributes:attrs]);
 105
 106   // Set up sizes and locations for rendering.
 107   const CGFloat kIconMargin = 2.0;  // Gap between icon and text.
 108   CGFloat text_left = [favicon size].width + kIconMargin;
 109   NSSize drag_image_size = [favicon size];
 110   NSSize text_size = [rich_title size];
 111   CGFloat max_text_width = bookmarks::kDefaultBookmarkWidth - text_left;
 112   text_size.width = std::min(text_size.width, max_text_width);
 113   drag_image_size.width = text_left + text_size.width;
 114
 115   // Render the drag image.
 116   NSImage* drag_image =
 117       [[[NSImage alloc] initWithSize:drag_image_size] autorelease];
 118   [drag_image lockFocus];
 119   [favicon drawAtPoint:NSZeroPoint
 120               fromRect:NSZeroRect
 121              operation:NSCompositeSourceOver
 122               fraction:0.7];
 123   NSRect target_text_rect = NSMakeRect(text_left, 0,
 124                                        text_size.width, drag_image_size.height);
 125   DrawTruncatedTitle(rich_title, target_text_rect);
 126   [drag_image unlockFocus];
 127
 128   return drag_image;
 129 }
 130
 131 void DragBookmarks(Profile* profile,
 132                    const std::vector<const BookmarkNode*>& nodes,
 133                    gfx::NativeView view,
 134                    ui::DragDropTypes::DragEventSource source) {
 135   DCHECK(!nodes.empty());
 136
 137   // Allow nested message loop so we get DnD events as we drag this around.
 138   bool was_nested = base::MessageLoop::current()->IsNested();
 139   base::MessageLoop::current()->SetNestableTasksAllowed(true);
 140
 141   BookmarkNodeData drag_data(nodes);
 142   drag_data.SetOriginatingProfile(profile);
 143   drag_data.WriteToClipboard(ui::CLIPBOARD_TYPE_DRAG);
 144
 145   // Synthesize an event for dragging, since we can't be sure that
 146   // [NSApp currentEvent] will return a valid dragging event.
 147   NSWindow* window = [view window];
 148   NSPoint position = [window mouseLocationOutsideOfEventStream];
 149   NSTimeInterval event_time = [[NSApp currentEvent] timestamp];
 150   NSEvent* drag_event = [NSEvent mouseEventWithType:NSLeftMouseDragged
 151                                            location:position
 152                                       modifierFlags:NSLeftMouseDraggedMask
 153                                           timestamp:event_time
 154                                        windowNumber:[window windowNumber]
 155                                             context:nil
 156                                         eventNumber:0
 157                                          clickCount:1
 158                                            pressure:1.0];
 159
 160   // TODO(avi): Do better than this offset.
 161   NSImage* drag_image = chrome::MakeDragImage(
 162       BookmarkModelFactory::GetForProfile(profile), nodes);
 163   NSSize image_size = [drag_image size];
 164   position.x -= std::floor(image_size.width / 2);
 165   position.y -= std::floor(image_size.height / 5);
 166   [window dragImage:drag_image
 167                  at:position
 168              offset:NSZeroSize
 169               event:drag_event
 170          pasteboard:[NSPasteboard pasteboardWithName:NSDragPboard]
 171              source:nil
 172           slideBack:YES];
 173
 174   base::MessageLoop::current()->SetNestableTasksAllowed(was_nested);
 175 }
 176
 177 }  // namespace chrome