iOS图片翻转处理

最新推荐文章于 2022-08-05 13:26:59 发布

Richar_D_Tyson

最新推荐文章于 2022-08-05 13:26:59 发布

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分类专栏： iOS开发文章标签： ios 图片 uiimage

本文链接：https://blog.youkuaiyun.com/Richar_D_Tyson/article/details/52943471

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本文主要讨论了iOS开发中遇到的图片翻转问题，特别是在用户选择或拍摄照片后出现90度或-90度翻转的情况。文章提供了解决这种问题的方法和技巧。

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在处理图片的过程中发现一个有意思的事情，就是有得图片选择后是呈90度翻转或者-90度翻转的情况。有得时候确实也莫名其妙。尤其是手机拍照做裁切之后，就会莫名其妙翻转。找到了解决办法在这里分享一下：

- (UIImage *)cropImage:(UIImage*)image toRect:(CGRect)rect {
    CGFloat (^rad)(CGFloat) = ^CGFloat(CGFloat deg) {
        return deg / 180.0f * (CGFloat) M_PI;
    };

    // determine the orientation of the image and apply a transformation to the crop rectangle to shift it to the correct position
    CGAffineTransform rectTransform;
    switch (image.imageOrientation) {
        case UIImageOrientationLeft:
            rectTransform = CGAffineTransformTranslate(CGAffineTransformMakeRotation(rad(90)), 0, -image.size.height);
            break;
        case UIImageOrientationRight:
            rectTransform = CGAffineTransformTranslate(CGAffineTransformMakeRotation(rad(-90)), -image.size.width, 0);
            break;
        case UIImageOrientationDown:
            rectTransform = CGAffineTransformTranslate(CGAffineTransformMakeRotation(rad(-180)), -image.size.width, -image.size.height);
            break;
        default:
            rectTransform = CGAffineTransformIdentity;
    };

    // adjust the transformation scale based on the image scale
    rectTransform = CGAffineTransformScale(rectTransform, image.scale, image.scale);

    // apply the transformation to the rect to create a new, shifted rect
    CGRect transformedCropSquare = CGRectApplyAffineTransform(rect, rectTransform);
    // use the rect to crop the image
    CGImageRef imageRef = CGImageCreateWithImageInRect(image.CGImage, transformedCropSquare);
    // create a new UIImage and set the scale and orientation appropriately
    UIImage *result = [UIImage imageWithCGImage:imageRef scale:image.scale orientation:image.imageOrientation];
    // memory cleanup
    CGImageRelease(imageRef);

    return result;
}