核心方法

    CGImageCreateWithImageInRect(CGImageRef image, CGRect rect)

實(shí)現(xiàn)

    UIImage *toCropImage = [image fixOrientation];

    CGImageRef cgImage = CGImageCreateWithImageInRect(toCropImage.CGImage, croprect);

    UIImage *cropped = [UIImage imageWithCGImage:cgImage];

    CGImageRelease(cgImage);

     return cropped;

這樣做會發(fā)現(xiàn)，明明給了個正方形區(qū)域，但是寬高總有一邊多一個像素點(diǎn)。如果是裁剪大圖還好，要是裁剪一個10X10的正方形，裁出來11X10，就很明顯。

解決辦法：

查看官方API （ https://developer.apple.com/documentation/coregraphics/1454683-cgimagecreatewithimageinrect?language=objc）發(fā)現(xiàn)，CGImageCreateWithImageInRect要傳 CGRectIntegral類型。

所以，區(qū)域需要都是整數(shù)，如下處理一下就好了

CGRect croprect = CGRectMake(floor(x), floor(y), round(width), round(height));

貼上完整方法

- (UIImage *)cropImage:(UIImage *)image toRect:(CGRect)rect {

    CGFloat x = rect.origin.x;

    CGFloat y = rect.origin.y;

    CGFloat width = rect.size.width;

    CGFloat height = rect.size.height;

    CGRect croprect = CGRectMake(floor(x), floor(y), round(width), round(height));

    UIImage *toCropImage = [image fixOrientation];// 糾正方向

    CGImageRef cgImage = CGImageCreateWithImageInRect(toCropImage.CGImage, croprect);

    UIImage *cropped = [UIImage imageWithCGImage:cgImage];

    CGImageRelease(cgImage);

    return cropped;

}