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我有一個UISlider,它隨着UIImage的值增加而增加亮度。但是,當我想降低亮度並將UISlider恢復爲保留原始圖像的值時,圖像的亮度不會降低,並且與UISlider的最後一個值保持不變。使用UISlider將UIImage更改回原始圖像的問題
的代碼如下
Slider1 = [[UISlider alloc]initWithFrame:CGRectMake(100, 350, 100, 100)];
[Slider1 addTarget:self action:@selector(Slider1Action:) forControlEvents:UIControlEventValueChanged];
Slider1.minimumValue = 0.0;
//slider.maximumValue = 50.0;
Slider1.continuous = YES;
[self.view addSubview:Slider1];
-(void)Slider1Action:(id)sender{
CGImageRef inImage = imageCollage.image.CGImage;
CFDataRef ref = CGDataProviderCopyData(CGImageGetDataProvider(inImage));
UInt8 * buf = (UInt8 *) CFDataGetBytePtr(ref);
int length = CFDataGetLength(ref);
float value2 = (1+Slider1.value);
for(int i=0; i<length; i+=4)
{
int r = i;
int g = i+1;
int b = i+2;
int red = buf[r];
int green = buf[g];
int blue = buf[b];
buf[r] = SAFECOLOR(red*value2);
buf[g] = SAFECOLOR(green*value2);
buf[b] = SAFECOLOR(blue*value2);
}
CGContextRef ctx = CGBitmapContextCreate(buf,
CGImageGetWidth(inImage),
CGImageGetHeight(inImage),
CGImageGetBitsPerComponent(inImage),
CGImageGetBytesPerRow(inImage),
CGImageGetColorSpace(inImage),
CGImageGetAlphaInfo(inImage));
CGImageRef img = CGBitmapContextCreateImage(ctx);
[imageCollage setImage:[UIImage imageWithCGImage:img]];
CFRelease(ref);
CGContextRelease(ctx);
CGImageRelease(img);}
我怎樣才能減少UIImage的亮度與UISlider這樣我就可以再次獲得原始圖像? 非常感謝您的幫助。 P.S.-我不想爲此使用Apple的OpenGL。
我認爲,但我不能重建像素 ? – IronManGill 2012-07-26 05:04:50