将可拉伸的 UIImage 与“正常”图像合并一

Question

我想组合两个 UIImage，一个是可拉伸的，一个是“正常”的。问题是，如果我使用 UIGraphicsImageContext 合并图像，第二个图像也会被拉伸（它应该在第一个图像的顶部，但被拉伸）。有人知道如何避免这种情况吗？

多谢！

来自我的 ViewController 的调用：

UIImage *stretchImage = [[UIImage imageNamed:@"stretchableLeft.png"]   stretchableImageWithLeftCapWidth:0.0 topCapHeight:16.0];
    stretchImage = [self imageWithImage:stretchImage scaledToSize:CGSizeMake(64.0, 64.0)];
    stretchImage = [self mergeImageWithImage:stretchImage secondImage:[UIImage imageNamed:@"topImage.png"]]; // only 40x40 Px

这两种方法是：

- (UIImage*)imageWithImage:(UIImage*)image scaledToSize:(CGSize)newSize  
{
UIGraphicsBeginImageContext( newSize );
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

return newImage;


- (UIImage*)mergeImageWithImage:(UIImage *)image secondImage:(UIImage *)image2 
{
UIGraphicsBeginImageContext(image.size);
[image drawInRect:CGRectMake(0,0,image.size.width,image.size.height)];
[image2 drawInRect:CGRectMake(10,10,image.size.width,image.size.height) blendMode:kCGBlendModeNormal alpha:1.0];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

return newImage;
}

Answer 1

我认为问题在于您要求两个图像都绘制在完整的矩形中。这会导致你的第二张图像拉伸。

合并图像时尝试使用 image2.size。绘制矩形时，您必须使用 x/y 坐标调整位置。

- (UIImage*)mergeImageWithImage:(UIImage *)image secondImage:(UIImage *)image2 
{
UIGraphicsBeginImageContext(image.size);
[image drawInRect:CGRectMake(0,0,image.size.width,image.size.height)];
[image2 drawInRect:CGRectMake(10,10,image2.size.width,image2.size.height) blendMode:kCGBlendModeNormal alpha:1.0];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

return newImage;
}