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从相应大小的UIImageView中检索UIImage

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如何从显示的大小（给定内容模式）中检索 imageView 大小的图像，而不是根据本机属性检索图像？

码：

UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, WID, WID)];
imageView.center = CGPointMake(point.x, point.y + Y_OFFSET);
imageView.image = [UIImage imageNamed:@"img"];
imageView.contentMode = UIViewContentModeScaleAspectFit;
ios objective-c uiimageview uiimage

1 回答

  • 0

    您必须再次绘制图像然后保存它 .

    // Image frame size
CGSize size = imageView.bounds.size;
// Grab a new CGContext
UIGraphicsBeginImageContextWithOptions(size, false, 0.0);
// Draw the image
[image drawInRect:CGRectMake(0, 0, size.width, size.height)];
// Grab the new image
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

    上面的代码在框架中绘制图像，拉伸到边界 . 如果你想要绘制它的任何其他模式，你必须自己计算它们并将所需的东西放在“绘制图像”代码行中 .

    例如，对于纵横拟合，请查看此算法：

    - (CGRect) aspectFittedRect:(CGSize)inSize max:(CGRect)maxRect {
    float originalAspectRatio = inSize.width / inSize.height;
    float maxAspectRatio = maxRect.size.width / maxRect.size.height;

    CGRect newRect = maxRect;
    if (originalAspectRatio > maxAspectRatio) { // scale by width
        newRect.size.height = maxRect.size.height * inSize.height / inSize.width;
        newRect.origin.y += (maxRect.size.height - newRect.size.height)/2.0;
    } else {
        newRect.size.width = maxRect.size.height  * inSize.width / inSize.height;
        newRect.origin.x += (maxRect.size.width - newRect.size.width)/2.0;
    }

    return CGRectIntegral(newRect);
}

    只需传入 imageView.image.size 作为 inSize 和 imageView.bounds 作为maxRect .

    资料来源：http://iphonedevsdk.com/forum/iphone-sdk-development-advanced-discussion/15001-aspect-fit-algorithm.html

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