NSWindow+RHPreventCaptureAdditions.m

//
//  NSWindow+RHPreventCaptureAdditions.m
//
//  Created by Richard Heard on 7/03/13.
//  Copyright (c) 2013 Richard Heard. All rights reserved.
//
//  Redistribution and use in source and binary forms, with or without
//  modification, are permitted provided that the following conditions
//  are met:
//  1. Redistributions of source code must retain the above copyright
//  notice, this list of conditions and the following disclaimer.
//  2. Redistributions in binary form must reproduce the above copyright
//  notice, this list of conditions and the following disclaimer in the
//  documentation and/or other materials provided with the distribution.
//  3. The name of the author may not be used to endorse or promote products
//  derived from this software without specific prior written permission.
//
//  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
//  IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
//  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
//  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
//  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
//  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
//  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
//  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
//  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
//  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//

#if defined(INCLUDE_PRIVATE_API) && INCLUDE_PRIVATE_API

#import "NSWindow+RHPreventCaptureAdditions.h"

@implementation NSWindow (RHPreventCaptureAdditions)
-(BOOL)preventWindowFromBeingCaptured{
    return RHPreventWindowCaptureForWindow(self);
}
@end

//define the private CGS methods we need to exclude a window from being captured.
// ------ PRIVATE API ------
typedef int CGSConnectionID;
typedef int CGSWindowID;
typedef CFTypeRef CGSRegionRef;

CG_EXTERN CGSConnectionID CGSMainConnectionID(void);

CG_EXTERN CGError CGSGetWindowBounds(CGSConnectionID cid, CGSWindowID wid, CGRect *rectOut);

CG_EXTERN CGError CGSNewRegionWithRect(const CGRect *rect, CGSRegionRef *regionOut);
CG_EXTERN bool CGSRegionIsEmpty(CGSRegionRef region);
CG_EXTERN CGError CGSReleaseRegion(CGSRegionRef region);

CG_EXTERN CGError CGSSetWindowCaptureExcludeShape(CGSConnectionID cid, CGSWindowID wid, CGSRegionRef region);
// ------ END PRIVATE API ------


//implementation

BOOL RHPreventWindowCaptureForWindow(NSWindow *window){
    CGSConnectionID cid = CGSMainConnectionID();
    CGSWindowID wid = (int)window.windowNumber;
    
    CGRect windowRectOut;
    CGError err = CGSGetWindowBounds(cid, wid, &windowRectOut);
    if (err != kCGErrorSuccess){
        NSLog(@"Error: failed to get windows bounds with error %i", err);
        return NO;
    }
    windowRectOut.origin = CGPointZero;
    
    CGSRegionRef regionOut;
    err = CGSNewRegionWithRect(&windowRectOut, &regionOut);
    if (err != kCGErrorSuccess){
        NSLog(@"Error: failed to get create CGSRegion with error %i", err);
        return NO;
    }
    
    //CFShow(regionOut);
    
    err = CGSSetWindowCaptureExcludeShape(cid, wid, regionOut);
    if (err != kCGErrorSuccess){
        NSLog(@"Error: failed to set capture exclude shape for window with error %i", err);
        CGSReleaseRegion(regionOut);
        return NO;
    }
    
    CGSReleaseRegion(regionOut);
    
    return YES;
}

#endif