Re: NSImage opacity or contrast (brightness)
Re: NSImage opacity or contrast (brightness)
- Subject: Re: NSImage opacity or contrast (brightness)
- From: Jack Nutting <email@hidden>
- Date: Sat, 20 Aug 2005 02:49:27 +0200
On 8/19/05, Michael Marmarou <email@hidden> wrote:
> I have an image I am drawing in an NSRect, but I need it to be much
> lighter (like turning the opactiy down) because it's a background.
> The image file cannot be modified. I see some sample code on the web
> for icons, but it doesn't seem to be working for my NSImage. Also, I
> see there is a dissolveToPoint method which is used, but again I
> cannot get it to work.
>
> - (void)drawBackground:(NSRect)rect
> {
> NSImage *image = [NSImage imageNamed:@"image"];
> .......
>
> [image drawInRect...];
> }
>
> I need that ....... to ligthen my image, or lower opacity, or whatever
> gets that effect.
Actually, forget about the spot where you wrote ...... and instead,
after copying the image with [image drawInRect...], you can
"whitewash" it with something like this:
[[NSColor colorWithCalibratedWhite:0.74 alpha:0.5] set];
NSRectFillUsingOperation([self bounds],NSCompositeSourceOver);
Modify the white value to specify the target color (0.0 is black, 1.0
is white) and the alpha value to specify how "thick" you're laying it
on (0.0 will have no effect, 1.0 will replace your image with the
target color completely).
--
// jack
// http://www.nuthole.com
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