The first thing I notice is that none of the CGContext* calls after UIGraphicsBeginImageContext is referring to that image context so they are having no effect on it. You should move the UIGraphicsGetCurrentContext down after the [drawImage...] call.
If you are still not able to get the desired result with any of the Quartz blend modes, you'll need to create a bitmap context and tweak the pixels in the pixel buffer directly. On Jul 11, 2011, at 8:48 AM, Development wrote: > Sorry I figured since it was only a sudo change anyway it wouldn't matter. > > UIImage * drawImage = rotatingView.image; > CGContextRef context = UIGraphicsGetCurrentContext(); > CGRect newRect = CGRectMake(0.0, 0.0, rotatingView.frame.size.width, > rotatingView.frame.size.height); > > UIGraphicsBeginImageContext(newRect.size); > [drawImage drawInRect:newRect]; > CGContextTranslateCTM(context, 0.0, rotatingView.frame.size.height); > CGContextScaleCTM(context, 1.0, -1.0); > CGContextClipToMask(context, newRect, drawImage.CGImage); > CGContextSetBlendMode(context, kCGBlendModeHue); > CGContextSetRGBFillColor(context, self.color.r ,self.color.g , > self.color.b, 1.0); > CGContextFillRect(context, newRect); > UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext(); > UIGraphicsEndImageContext(); > > This applies a colored rectangle applied over the image and clipped to > it as a mask. Which is not what I want. But even it if was the problem is > that when I get the png rep so I can save it with transparency to the > document, the applied color is lost. An easy way around this is to sable the > color values and reapply because when the document is "flattened" and save as > a png the color appears correctly. > But again that's effort in the wrong direction anyway. > A side note the alpha is 1.0 right now, but in the finished product I thought > I'd use a slider to adjust that as intensity or something. Anyway it doesn't > matter it's just a colored rectangle over top of the image. > > > On Jul 11, 2011, at 5:16 AM, Mike Abdullah wrote: > >> Giving us a link to the example code would be a big help in understanding >> what you're trying. >> >> On 11 Jul 2011, at 02:06, Development wrote: >> >>> Im having a problem with adjusting the color values of a UIImage. >>> >>> How does one adjust levels and color values of a UIImage. >>> The example code I found only overlays a rectangle clipped to an image >>> mask. It looks like color value adjustment until you realize 2 things. >>> a) I absolutely cannot render the image view with the color adjustment into >>> a graphic context with the adjustment in tact, because what I always get >>> back is the original, unadjusted image. >>> a b) it's not really adjusting the levels. And since it isn't it also means >>> I cannot actually adjust the brightness, contrast or anything else either. >>> >>> >>> Is adjusting UIImage color levels even possible? _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
