gistfile1.txt

    - (void)drawInRect:(NSRect)dstRect fromRect:(NSRect)srcRect operation:(NSCompositingOperation)op fraction:(CGFloat)alpha {
    	[self drawInRect:dstRect fromRect:srcRect operation:op fraction:alpha respectFlipped:YES hints:nil];
    }
    
    - (void)drawInRect:(NSRect)dstRect fromRect:(NSRect)srcRect operation:(NSCompositingOperation)op fraction:(CGFloat)alpha respectFlipped:(BOOL)respectFlipped hints:(NSDictionary *)hints {
    	CGImageRef image = [self CGImageForProposedRect:&dstRect context:[NSGraphicsContext currentContext] hints:hints];
    	if (image == NULL) {
    		NSLog(@"*** Could not get CGImage of %@", self);
    		return;
    	}
    
    	CGSize size = CGSizeMake(CGImageGetWidth(image), CGImageGetHeight(image));
    	TUIEdgeInsets insets = self.capInsets;
    
        BOOL retina =   roundf(size.width)  == roundf(self.size.width   * 2) &&
                        roundf(size.height) == roundf(self.size.height  * 2);
        if (retina) {
            insets.top      *= 2.0;
            insets.left     *= 2.0;
            insets.bottom   *= 2.0;
            insets.right    *= 2.0;
        }
    
    	// TODO: Cache the nine-part images for this common case of wanting to draw
    	// the whole source image.
    	if (CGRectIsEmpty(srcRect)) {
    		// Match the image creation that occurs in the 'else' clause.
    		CGImageRetain(image);
    	} else {
    		image = CGImageCreateWithImageInRect(image, srcRect);
    		if (!image) return;
    
    		// Reduce insets to account for taking only part of the original image.
    		insets.left = fmax(0, insets.left - CGRectGetMinX(srcRect));
    		insets.top = fmax(0, insets.top - CGRectGetMinY(srcRect));
    
    		CGFloat srcRightInset = size.width - CGRectGetMaxX(srcRect);
    		insets.right = fmax(0, insets.right - srcRightInset);
    
    		CGFloat srcTopInset = size.height - CGRectGetMaxY(srcRect);
    		insets.bottom = fmax(0, insets.bottom - srcTopInset);
    	}
    
    	NSImage *topLeft = nil, *topEdge = nil, *topRight = nil;
    	NSImage *leftEdge = nil, *center = nil, *rightEdge = nil;
    	NSImage *bottomLeft = nil, *bottomEdge = nil, *bottomRight = nil;
    
    	// Length of sides that run vertically.
    	CGFloat verticalEdgeLength = fmax(0, size.height - insets.bottom - insets.top);
    
    	// Length of sides that run horizontally.
    	CGFloat horizontalEdgeLength = fmax(0, size.width - insets.left - insets.right);
    
    	NSImage *(^imageWithRect)(CGRect) = ^ id (CGRect rect){
    		CGImageRef part = CGImageCreateWithImageInRect(image, rect);
    		if (part == NULL) return nil;
    
            if (retina) {
                rect.size.width     /= 2.0;
                rect.size.height    /= 2.0;
            }
    
    		NSImage *image = [[NSImage alloc] initWithCGImage:part size:rect.size];
    		CGImageRelease(part);
    
    		return image;
    	};
    
    	if (verticalEdgeLength > 0) {
    		if (insets.left > 0) {
    			CGRect partRect = CGRectMake(0, insets.top, insets.left, verticalEdgeLength);
    			leftEdge = imageWithRect(partRect);
    		}
    
    		if (insets.right > 0) {
    			CGRect partRect = CGRectMake(size.width - insets.right, insets.top, insets.right, verticalEdgeLength);
    			rightEdge = imageWithRect(partRect);
    		}
    	}
    
    	if (horizontalEdgeLength > 0) {
    		if (insets.top > 0) {
    			CGRect partRect = CGRectMake(insets.left, 0, horizontalEdgeLength, insets.top);
    			topEdge = imageWithRect(partRect);
    		}
    
    		if (insets.bottom > 0) {
    			CGRect partRect = CGRectMake(insets.left, size.height - insets.bottom, horizontalEdgeLength, insets.bottom);
    			bottomEdge = imageWithRect(partRect);
    		}
    	}
    
    	if (insets.left > 0 && insets.bottom > 0) {
    		CGRect partRect = CGRectMake(0, size.height - insets.bottom, insets.left, insets.bottom);
    		bottomLeft = imageWithRect(partRect);
    	}
    
    	if (insets.left > 0 && insets.top > 0) {
    		CGRect partRect = CGRectMake(0, 0, insets.left, insets.top);
    		topLeft = imageWithRect(partRect);
    	}
    
    	if (insets.right > 0 && insets.bottom > 0) {
    		CGRect partRect = CGRectMake(size.width - insets.right, size.height - insets.bottom, insets.right, insets.bottom);
    		bottomRight = imageWithRect(partRect);
    	}
    
    	if (insets.right > 0 && insets.top > 0) {
    		CGRect partRect = CGRectMake(size.width - insets.right, 0, insets.right, insets.top);
    		topRight = imageWithRect(partRect);
    	}
    
    	CGRect centerRect = TUIEdgeInsetsInsetRect(CGRectMake(0, 0, size.width, size.height), insets);
    	if (centerRect.size.width > 0 && centerRect.size.height > 0) {
    		center = imageWithRect(centerRect);
    	}
    
    	CGImageRelease(image);
    
    	BOOL flipped = NO;
    	if (respectFlipped) {
    		flipped = [[NSGraphicsContext currentContext] isFlipped];
    	}
    
    	if (bottomLeft != nil || topRight != nil) {
    		NSDrawNinePartImage(dstRect, topLeft, topEdge, topRight, leftEdge, center, rightEdge, bottomLeft, bottomEdge, bottomRight, op, alpha, flipped);
    	} else if (leftEdge != nil) {
    		// Horizontal three-part image.
    		NSDrawThreePartImage(dstRect, leftEdge, center, rightEdge, NO, op, alpha, flipped);
    	} else {
    		// Vertical three-part image.
    		NSDrawThreePartImage(dstRect, topEdge, center, bottomEdge, YES, op, alpha, flipped);
    	}
    }