我完全被这个问题困扰了,它应该是如此简单以至于让我疯狂.
我正在使用这个苹果反射教程.
它们具有从上到下显示的图像渐变.
>如何从左到右制作渐变
>如何水平翻转图像.在他们的例子中,他们垂直翻转图像.
任何帮助？
//The gradient code is here but I don't know what should be the gradient start / end points
CGImageRef CreateGradientImage(int pixelsWide,int pixelsHigh)
{
.....
gradientStartPoint = CGPointZero;
gradientEndPoint = CGPointMake(0,pixelsHigh);
}
//similarly I know the image flip happens here but for life of me I cannot make it flip horizontally
- (UIImage *)reflectedImage:(UIImageView *)fromImage withHeight:(NSUInteger)height
{
.....
CGContextTranslateCTM(mainViewContentContext,0.0,height);
CGContextScaleCTM(mainViewContentContext,1.0,-1.0);
}
解决方法
试试这个：
//horizontal gradient
CGImageRef CreateGradientImage(int pixelsWide,int pixelsHigh)
{
.....
gradientStartPoint = CGPointZero;
gradientEndPoint = CGPointMake(pixelsWide,0);
}
//horizontal flip
- (UIImage *)reflectedImage:(UIImageView *)fromImage withWidth:(NSUInteger)width
{
.....
CGContextTranslateCTM(mainViewContentContext,width,0);
CGContextScaleCTM(mainViewContentContext,-1.0,1.0);
}
对于水平翻转,您应该添加一个新方法,因为您必须指定宽度,而不是高度.
祝好运！
编辑1：
为了获得渐变,您应该为reflectImage添加另一个修改：withWidth.
- (UIImage *)reflectedImage:(UIImageView *)fromImage withWidth:(NSUInteger)width
{
.....
CGImageRef gradientMaskImage = CreateGradientImage(width,1);
.....
}