ios – 制作UIImage的正方形裁剪图像以拉伸图像

概述当尝试执行UI Image的中心裁剪时,我得到以下结果(左边是640 * 1136处的原始图像,右边是适合320 * 320的正方形UIImageView的裁剪图像)：  转向： 我对比率元素进行了相当多的修改,以便能够正确地检测要修剪的数量：使用图像的较短边,构建基于short_side / width_of_desired_rect的比率,但在这种情况下似乎不起作用.帮助赞赏！ - (UIIm 当尝试执行UI Image的中心裁剪时,我得到以下结果(左边是640 * 1136处的原始图像,右边是适合320 * 320的正方形UIImageVIEw的裁剪图像)：

转向：@H_403_3@

我对比率元素进行了相当多的修改,以便能够正确地检测要修剪的数量：使用图像的较短边,构建基于short_sIDe / wIDth_of_desired_rect的比率,但在这种情况下似乎不起作用.帮助赞赏！@H_403_3@

- (UIImage *)squareImageWithImage:(UIImage *)image scaledToSize:(CGSize)newSize {    double ratio;    double delta;    CGPoint offset;    //make a new square size,that is the resized imaged wIDth    CGSize sz = CGSizeMake(newSize.wIDth,newSize.wIDth);    //figure out if the picture is landscape or portrait,then    //calculate scale factor and offset    if (image.size.wIDth > image.size.height) {        ratio = newSize.wIDth / image.size.wIDth;        delta = (ratio*image.size.wIDth - ratio*image.size.height);        offset = CGPointMake(delta/2,0);    } else {        ratio = newSize.wIDth / image.size.height;        delta = (ratio*image.size.height - ratio*image.size.wIDth);        offset = CGPointMake(0,delta/2);    }    //make the final clipPing rect based on the calculated values    CGRect clipRect = CGRectMake(-offset.x,-offset.y,(ratio * image.size.wIDth) + delta,(ratio * image.size.height) + delta);    //for retina consIDeration    if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)]) {        UIGraphicsBeginImageContextWithOptions(sz,YES,0.0);    } else {        UIGraphicsBeginImageContext(sz);    }    UIRectClip(clipRect);    [image drawInRect:clipRect];    UIImage *newImage = UIGraphicsGetimageFromCurrentimageContext();    UIGraphicsEndImageContext();    return newImage;}

解决方法 试试这个：

- (UIImage *)squareImageFromImage:(UIImage *)image scaledToSize:(CGfloat)newSize {    CGAffinetransform scaletransform;    CGPoint origin;    if (image.size.wIDth > image.size.height) {        CGfloat scaleRatio = newSize / image.size.height;        scaletransform = CGAffinetransformMakeScale(scaleRatio,scaleRatio);        origin = CGPointMake(-(image.size.wIDth - image.size.height) / 2.0f,0);    } else {        CGfloat scaleRatio = newSize / image.size.wIDth;        scaletransform = CGAffinetransformMakeScale(scaleRatio,scaleRatio);        origin = CGPointMake(0,-(image.size.height - image.size.wIDth) / 2.0f);    }    CGSize size = CGSizeMake(newSize,newSize);    if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)]) {        UIGraphicsBeginImageContextWithOptions(size,0);    } else {        UIGraphicsBeginImageContext(size);    }    CGContextRef context = UIGraphicsGetCurrentContext();    CGContextConcatCTM(context,scaletransform);    [image drawAtPoint:origin];    image = UIGraphicsGetimageFromCurrentimageContext();    UIGraphicsEndImageContext();    return image;}

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