ios - 调整图像大小以适合背景

Question

我已经使用此方法来调整图像大小

extension UIColor {
    static func imageWithBackgroundColor(image: UIImage, bgColor: UIColor) -> UIColor {
        let size = CGSize(width: 70, height: 70)

        UIGraphicsBeginImageContextWithOptions(size, false, 0)
        let context = UIGraphicsGetCurrentContext()


        let rectangle = CGRect(x: 0, y: 0, width: size.width, height: size.height)

        CGContextSetFillColorWithColor(context, bgColor.CGColor)
        CGContextAddRect(context, rectangle)
        CGContextDrawPath(context, .Fill)

        CGContextDrawImage(context, rectangle, image.CGImage)

        let img = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return UIColor(patternImage: img)
    }
}

func tableView(tableView: UITableView, editActionsForRowAtIndexPath indexPath: NSIndexPath) -> [UITableViewRowAction]? {
     let delete = UITableViewRowAction(style: .Default, title: "Delete") { (action, indexPath) in

     // do some action
     // 
     if let buttonImage = UIImage(named: "myImage") { 
         delete.backgroundColor = UIColor.imageWithBackgroundColor(image: buttonImage, bgColor: UIColor.blueColor()) 
     }
     return [delete]
}

但是，此方法的图像是颠倒的。有什么想法吗？任何人都可以帮忙修改它或建议任何其他方法来调整图像大小，使其完全适合背景。

Answer 1

- (UIImage *)resizeImage:(UIImage *)image
    withMaxDimension:(CGFloat)maxDimension
{
if (fmax(image.size.width, image.size.height) <= maxDimension) {
    return image;
}

CGFloat aspect = image.size.width / image.size.height;
CGSize newSize;

if (image.size.width > image.size.height) {
    newSize = CGSizeMake(maxDimension, maxDimension / aspect);
} else {
    newSize = CGSizeMake(maxDimension * aspect, maxDimension);
}

UIGraphicsBeginImageContextWithOptions(newSize,NO,0);
CGRect newImageRect = CGRectMake(0.0, 0.0, newSize.width, newSize.height);
[image drawInRect:newImageRect];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

return newImage;
}

   /////// OR ////

- (UIImage *)image:(UIImage*)originalImage scaledToSize:(CGSize)size
 {
   //avoid redundant drawing
if (CGSizeEqualToSize(originalImage.size, size))
{
    return originalImage;
}

//create drawing context
UIGraphicsBeginImageContextWithOptions(size, NO, 0.0f);

//draw
[originalImage drawInRect:CGRectMake(0.0f, 0.0f, size.width, size.height)];

//capture resultant image
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

//return image
return image;
 }