image manipulation using slider in iphone

Question

Is there a way to apply brightness to uiimages. For example I have a UIImageview and inside that i have a uiimage. I want to manipulate its brightness with a help of UISlider wi

Answer 1

Open Gl to UIImage Create

-(UIImage *) glToUIImage {

NSInteger myDataLength = 320 * 480 * 4;
 // allocate array and read pixels into it.
GLubyte *buffer = (GLubyte *) malloc(myDataLength);
glReadPixels(0, 0, 320, 480, GL_RGBA, GL_UNSIGNED_BYTE, buffer);

// gl renders "upside down" so swap top to bottom into new array.
// there's gotta be a better way, but this works.
GLubyte *buffer2 = (GLubyte *) malloc(myDataLength);
for(int y = 0; y <480; y++)
{
    for(int x = 0; x <320 * 4; x++)
    {
        buffer2[(479 - y) * 320 * 4 + x] = buffer[y * 4 * 320 + x];
    }
}
// make data provider with data.
CGDataProviderRef provider = CGDataProviderCreateWithData(
                                                          NULL, buffer2, myDataLength, NULL);

// prep the ingredients
int bitsPerComponent = 8;
int bitsPerPixel = 32;
int bytesPerRow = 4 * 320;
CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();

CGBitmapInfo bitmapInfo = kCGImageAlphaNone;

CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;

// make the cgimage
CGImageRef imageRef = CGImageCreate(320, 480, bitsPerComponent, bitsPerPixel, bytesPerRow, colorSpaceRef, bitmapInfo, provider, NULL, NO, renderingIntent);

// then make the uiimage from that


UIImage *myImage = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);

//UIImageWriteToSavedPhotosAlbum(myImage,nil,nil,nil);

[[NSUserDefaults standardUserDefaults] setObject:UIImageJPEGRepresentation(myImage,1) forKey:@"image"];    

return myImage;

}