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我们有透明度的问题。使用渐变将图像写入上下文时,透明度(这是不需要的)正在得到应用。我们不确定为什么这已被应用。我们需要上下文是“ONLY”与渐变,但不与“透明度”。问题与透明度
附加的代码片段供大家参考。
- (UIImage *)ReflectImage:(CGFloat)refFract {
int reflectionHeight = self.size.height * refFract;
CGImageRef gradientMaskImage = NULL;
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray();
CGContextRef gradientBitmapContext = CGBitmapContextCreate(nil, 1, reflectionHeight,
8, 0, colorSpace, kCGImageAlphaNone);
CGFloat colors[] = {0.0, 1.0, 1.0, 1.0};
CGGradientRef grayScaleGradient = CGGradientCreateWithColorComponents(colorSpace, colors, NULL, 2);
CGColorSpaceRelease(colorSpace);
CGPoint gradientStartPoint = CGPointMake(0, reflectionHeight);
CGPoint gradientEndPoint = CGPointZero;
CGContextDrawLinearGradient(gradientBitmapContext, grayScaleGradient, gradientStartPoint,
gradientEndPoint, kCGGradientDrawsAfterEndLocation);
CGGradientRelease(grayScaleGradient);
CGContextSetGrayFillColor(gradientBitmapContext, 0.0, 0.5);
CGContextFillRect(gradientBitmapContext, CGRectMake(0, 0, 1, reflectionHeight));
gradientMaskImage = CGBitmapContextCreateImage(gradientBitmapContext);
CGContextRelease(gradientBitmapContext);
CGImageRef reflectionImage = CGImageCreateWithMask(self.CGImage, gradientMaskImage);
CGImageRelease(gradientMaskImage);
CGSize size = CGSizeMake(self.size.width, self.size.height + reflectionHeight);
UIGraphicsBeginImageContext(size);
[self drawAtPoint:CGPointZero];
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextDrawImage(context, CGRectMake(0, self.size.height, self.size.width, reflectionHeight), reflectionImage);
UIImage* result = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGImageRelease(reflectionImage);
return result;
}
因此,有人可以请让我知道为什么会是这样?如果这个问题得到解决,这将非常有帮助。
谢谢!