// Copyright (c) 2012 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 <Cocoa/Cocoa.h> // CustomFrameView is a class whose methods we swizzle into NSGrayFrame // on 10.7 and below, or NSThemeFrame on 10.8 and above, so that we can // support custom frame drawing. This is used with a textured window so that // AppKit does not draw a title bar. // This class is never to be instantiated on its own. // We explored a variety of ways to support custom frame drawing and custom // window widgets. // Our requirements were: // a) that we could fall back on standard system drawing at any time for the // "default theme" // b) We needed to be able to draw both a background pattern, and an overlay // graphic, and we need to be able to set the pattern phase of our background // window. // c) We had to be able to support "transparent" themes, so that you could see // through to the underlying windows in places without the system theme // getting in the way. // // Since we want "A" we couldn't just do a transparent borderless window. At // least I couldn't find the right combination of HITheme calls to make it draw // nicely, and I don't trust that the HITheme calls are going to exist in future // system versions. // "C" precluded us from inserting a view between the system frame and the // the content frame in Z order. To get the transparency we actually need to // replace the drawing of the system frame. // "B" precluded us from just setting a background color on the window. // // Originally we tried overriding the private API +frameViewForStyleMask: to // add our own subclass of NSGrayView to our window. Turns out that if you // subclass NSGrayView it does not draw correctly when you call NSGrayView's // drawRect. It appears that NSGrayView's drawRect: method (and that of its // superclasses) do lots of "isMemberOfClass/isKindOfClass" calls, and if your // class is NOT an instance of NSGrayView (as opposed to a subclass of // NSGrayView) then the system drawing will not work correctly. // // Given all of the above, we found swizzling drawRect in _load to be the // easiest and safest method of achieving our goals. We do the best we can to // check that everything is safe, and attempt to fallback gracefully if it is // not. @interface NSWindow (CustomFrameView) // To define custom window drawing behaviour, override this method on an // NSWindow subclass. Call the default method (on super) to draw the // default frame. // NOTE: Always call the default implementation (even if you just immediately // draw over it), otherwise the top-left and top-right corners of the window // won't be drawn correctly. - (void)drawCustomFrameRect:(NSRect)rect forView:(NSView*)view; @end