Moonlite <[EMAIL PROTECTED]> wrote:
> I'd like to crop an image, and get another NSImage containing the selected
> rectangle from the source image.
>
> i tried :
>
> - (NSImage *) imageFromRect: (NSRect) rect
> {
> NSImage * canvas = [[NSImage alloc] initWithSize: rect.size];
>
> [ canvas setSize: rect.size ];
> [ canvas lockFocus ];
>
> [self compositeToPoint: NSZeroPoint
> fromRect: rect
> operation: NSCompositeCopy];
>
> [ canvas unlockFocus ];
> return [canvas autorelease];
>
> }
>
> but it didn't work. Can someone tell me how to do it?
Hi,
I was able to crop using NSImageRep (see below). I remember having problems
with [NSImage -compositeToPoint:], but I do not remember the nature of the
problem and
the reason. Here is the code that works for me:
In a category:
@implementation NSImage (PhotoClip)
- (NSImage *) imageFromRect: (NSRect) rect
{
NSAffineTransform * xform = [NSAffineTransform transform];
// translate reference frame to map rectangle 'rect' into first quadrant
[xform translateXBy: -rect.origin.x
yBy: -rect.origin.y];
NSSize canvas_size = [xform transformSize: rect.size];
NSImage * canvas = [[NSImage alloc] initWithSize: canvas_size];
[canvas lockFocus];
[xform concat];
// Get NSImageRep of image
NSImageRep * rep = [self bestRepresentationForDevice: nil];
[rep drawAtPoint: NSZeroPoint];
[canvas unlockFocus];
return [canvas autorelease];
}
@end
I have an unfinished project with a more general method
- (NSImage *) imageFromRect: (NSRect) rect
scaledBy: (float) scale
rotatedBy: (float) degrees
(rotation +/- 90 degrees only) at http://www.vaisburd.net/PhotoClip, you might
want
to look at PHImage.m and PHAffineTransform.m.
Hope that helps,
Tima.
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