1 // Copyright (c) 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 #import <Cocoa/Cocoa.h> 6 7 // CustomFrameView is a class whose methods we swizzle into NSGrayFrame 8 // on 10.7 and below, or NSThemeFrame on 10.8 and above, so that we can 9 // support custom frame drawing. This is used with a textured window so that 10 // AppKit does not draw a title bar. 11 // This class is never to be instantiated on its own. 12 // We explored a variety of ways to support custom frame drawing and custom 13 // window widgets. 14 // Our requirements were: 15 // a) that we could fall back on standard system drawing at any time for the 16 // "default theme" 17 // b) We needed to be able to draw both a background pattern, and an overlay 18 // graphic, and we need to be able to set the pattern phase of our background 19 // window. 20 // c) We had to be able to support "transparent" themes, so that you could see 21 // through to the underlying windows in places without the system theme 22 // getting in the way. 23 // 24 // Since we want "A" we couldn't just do a transparent borderless window. At 25 // least I couldn't find the right combination of HITheme calls to make it draw 26 // nicely, and I don't trust that the HITheme calls are going to exist in future 27 // system versions. 28 // "C" precluded us from inserting a view between the system frame and the 29 // the content frame in Z order. To get the transparency we actually need to 30 // replace the drawing of the system frame. 31 // "B" precluded us from just setting a background color on the window. 32 // 33 // Originally we tried overriding the private API +frameViewForStyleMask: to 34 // add our own subclass of NSGrayView to our window. Turns out that if you 35 // subclass NSGrayView it does not draw correctly when you call NSGrayView's 36 // drawRect. It appears that NSGrayView's drawRect: method (and that of its 37 // superclasses) do lots of "isMemberOfClass/isKindOfClass" calls, and if your 38 // class is NOT an instance of NSGrayView (as opposed to a subclass of 39 // NSGrayView) then the system drawing will not work correctly. 40 // 41 // Given all of the above, we found swizzling drawRect in _load to be the 42 // easiest and safest method of achieving our goals. We do the best we can to 43 // check that everything is safe, and attempt to fallback gracefully if it is 44 // not. 45 46 @interface NSWindow (CustomFrameView) 47 48 // To define custom window drawing behaviour, override this method on an 49 // NSWindow subclass. Call the default method (on super) to draw the 50 // default frame. 51 // NOTE: Always call the default implementation (even if you just immediately 52 // draw over it), otherwise the top-left and top-right corners of the window 53 // won't be drawn correctly. 54 - (void)drawCustomFrameRect:(NSRect)rect forView:(NSView*)view; 55 56 @end 57
