[英]IOS How to resize image according to actual image ratio and give custom size?
通过检查实际图像比例来调整UIImage
的custom size
以减小图像大小。 我已经试过这个UIImageJPEGRepresentation(Image, 0.8);
但问题是图像质量正在降低。 任何帮助将非常感激。 谢谢
将UIImage
传递给以下方法,该方法使用自定义高度/宽度调整图像大小,您还可以提供图像的压缩值以减小图像大小并检查调整大小前后的图像大小。
这是示例方法-
-(UIImage *)resizeImage:(UIImage *)image
{
NSInteger imageActualSize = UIImageJPEGRepresentation(image,1).length;
NSLog(@"size of IMAGE before resizing: %@ ", [NSByteCountFormatter stringFromByteCount:imageActualSize countStyle:NSByteCountFormatterCountStyleFile]);
float actualHeight = image.size.height;
float actualWidth = image.size.width;
float maxHeight = 400.0; // your custom height
float maxWidth = 350; // your custom width
float imgRatio = actualWidth/actualHeight;
float maxRatio = maxWidth/maxHeight;
float compressionQuality = 0.5;//50 percent compression
if (actualHeight > maxHeight || actualWidth > maxWidth)
{
if(imgRatio < maxRatio)
{
//adjust width according to maxHeight
imgRatio = maxHeight / actualHeight;
actualWidth = imgRatio * actualWidth;
actualHeight = maxHeight;
}
else if(imgRatio > maxRatio)
{
//adjust height according to maxWidth
imgRatio = maxWidth / actualWidth;
actualHeight = imgRatio * actualHeight;
actualWidth = maxWidth;
}
else
{
actualHeight = maxHeight;
actualWidth = maxWidth;
}
}
CGRect rect = CGRectMake(0.0, 0.0, actualWidth, actualHeight);
UIGraphicsBeginImageContext(rect.size);
[image drawInRect:rect];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
NSData *imageData = UIImageJPEGRepresentation(img, compressionQuality);
UIGraphicsEndImageContext();
NSInteger imageReduceSize = imageData.length;
NSLog(@"size of IMAGE after resizing: %@ ",[NSByteCountFormatter stringFromByteCount:imageReduceSize countStyle:NSByteCountFormatterCountStyleFile]);
return [UIImage imageWithData:imageData];
}
这会帮助你..:)
+ (UIImage *)resizeImage:(UIImage *)image toSize:(CGSize)newSize {
UIGraphicsBeginImageContextWithOptions(newSize, NO, 0.0);
[image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
非常简单的方法来做到这一点。
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