如何将大精灵 png 切成较小的 UIImages？

Question

例如，png文件是1200（h）x 50（w）像素，我如何剪切 png并在6个UIImage中加载，每个200（h） x 50（宽）。谢谢！

编辑 - 感谢 Michal 的回答，最终代码：

 CGImageRef imageToSplit = [UIImage imageNamed:@"huge.png"].CGImage;
 CGImageRef partOfImageAsCG = CGImageCreateWithImageInRect(imageToSplit, CGRectMake(0, 0, 50, 50));

 UIImage *partOfImage = [UIImage imageWithCGImage:partOfImageAsCG]; 
 // ...

 CGImageRelease(partOfImageAsCG);

Answer 1

看一下 CGImageCreateWithImageInRect 函数。它与 CGImage 一起使用，但在 CGImage 和 UIImage 之间进行转换很容易。

这是一个示例（凭记忆输入，可能无法编译）：

CGImageRef imageToSplit = [UIImage imageNamed:@"huge.png"].CGImage;
CGImageRef partOfImageAsCG = CGImageCreateWithImageInRect(imageToSplit, CGRectMake(0, 0, 200, 50));
CGRelease(imageToSplit);
UIImage *partOfImage = [UIImage imageWithCGImage:partOfImageAsCG];
CGImageRelease(partOfImageAsCG);

Answer 2

可重用的方法：

-(UIImage*)ExtractImageOn:(CGPoint)pointExtractedImg ofSize:(CGSize)sizeExtractedImg FromSpriteSheet:(UIImage*)imgSpriteSheet
{
    UIImage *ExtractedImage;

    CGRect rectExtractedImage;

    rectExtractedImage=CGRectMake(pointExtractedImg.x,pointExtractedImg.y,sizeExtractedImg.width,sizeExtractedImg.height);

    CGImageRef imgRefSpriteSheet=imgSpriteSheet.CGImage;

    CGImageRef imgRefExtracted=CGImageCreateWithImageInRect(imgRefSpriteSheet,rectExtractedImage);

    ExtractedImage=[UIImage imageWithCGImage:imgRefExtracted];

    CGImageRelease(imgRefExtracted);

    //CGImageRelease(imgRefSpriteSheet); I have commented it because
    // we should not release the object that we don't own.
    // So why do we release imgRefExtracted alone? because it has 
    // name create in its method so the ownership comes to us so we
    // have to release it.

    return ExtractedImage;

}

仅供参考：

尽管它已经得到了明确的回答，但我认为将其作为简单的可重用“复制粘贴”代码片段会给程序员带来很大的帮助，我将答案归因于 michal