Move NSImage-to-CGImageRef conversion code into a common helper function in base/mac_util.h.

base/mac_util.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.
 
 #include "base/mac_util.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/file_path.h"
 #include "base/logging.h"
@@ skipping 461 matching lines @@
   // Constant used by WebKit; what exactly it means is unknown.
   const int magic_session_constant = -2;
   OSErr err =
       ls_set_application_information_item_func(magic_session_constant, asn,
                                                ls_display_name_key,
                                                process_name,
                                                NULL /* optional out param */);
   LOG_IF(ERROR, err) << "Call to set process name failed, err " << err;
 }
 
+// Converts a NSImage to a CGImageRef.  Normally, the system frameworks can do
+// this fine, especially on 10.6.  On 10.5, however, CGImage cannot handle
+// converting a PDF-backed NSImage into a CGImageRef.  This function will
+// rasterize the PDF into a bitmap CGImage.  The caller is responsible for
+// releasing the return value.
+CGImageRef CopyNSImageToCGImage(NSImage* image) {
+  // This is based loosely on http://www.cocoadev.com/index.pl?CGImageRef .
+  NSSize size = [image size];
+  scoped_cftyperef<CGContextRef> context(
+      CGBitmapContextCreate(NULL,  // Allow CG to allocate memory.
+                            size.width,
+                            size.height,
+                            8,  // bitsPerComponent
+                            0,  // bytesPerRow - CG will calculate by default.
+                            [[NSColorSpace genericRGBColorSpace] CGColorSpace],
+                            kCGBitmapByteOrder32Host |
+                                kCGImageAlphaPremultipliedFirst));
+  if (!context.get())
+    return NULL;
+
+  [NSGraphicsContext saveGraphicsState];
+  [NSGraphicsContext setCurrentContext:
+      [NSGraphicsContext graphicsContextWithGraphicsPort:context.get()
+                                                 flipped:NO]];
+  [image drawInRect:NSMakeRect(0,0, size.width, size.height)
+           fromRect:NSZeroRect
+          operation:NSCompositeCopy
+           fraction:1.0];
+  [NSGraphicsContext restoreGraphicsState];
+
+  return CGBitmapContextCreateImage(context);
+}
+
 }  // namespace mac_util