几天来，我一直在向这张脸猛击，尽管我一直觉得自己就在启示的边缘，但我根本无法实现我的目标.
在我的设计概念阶段之前，我认为从iPhone的摄像头或库中抓取一张图片，使用一个相当于UIImageView的Aspect Fill选项的函数(完全在代码中)将其缩小到指定的高度，然后将不适合传递的CGRect的任何东西都放入crop off，这将是一件微不足道的事情.
从相机或图书馆获取原始图像是微不足道的.事实证明，其他两个步骤是多么困难，这让我感到震惊.
附图显示了我正在努力实现的目标.请问有没有人能握着我的手？到目前为止，我发现的每个代码示例似乎都会 destruct 图像、颠倒、看起来像垃圾、超出界限，或者就是不能正常工作.
我需要同样的东西-在我的情况下， Select 合适的尺寸，一旦zoom ，然后裁剪两端，以适应睡觉的宽度.(我工作的是风景，所以可能没有注意到肖像模式的任何不足之处.)这是我的代码-它是UIImage上类别的一部分.我的代码中的目标大小始终设置为设备的全屏大小.
@implementation UIImage (Extras)
#pragma mark -
#pragma mark Scale and crop image
- (UIImage*)imageByScalingAndCroppingForSize:(CGSize)targetSize
{
UIImage *sourceImage = self;
UIImage *newImage = nil;
CGSize imageSize = sourceImage.size;
CGFloat width = imageSize.width;
CGFloat height = imageSize.height;
CGFloat targetWidth = targetSize.width;
CGFloat targetHeight = targetSize.height;
CGFloat scaleFactor = 0.0;
CGFloat scaledWidth = targetWidth;
CGFloat scaledHeight = targetHeight;
CGPoint thumbnailPoint = CGPointMake(0.0,0.0);
if (CGSizeEqualToSize(imageSize, targetSize) == NO)
{
CGFloat widthFactor = targetWidth / width;
CGFloat heightFactor = targetHeight / height;
if (widthFactor > heightFactor)
{
scaleFactor = widthFactor; // scale to fit height
}
else
{
scaleFactor = heightFactor; // scale to fit width
}
scaledWidth = width * scaleFactor;
scaledHeight = height * scaleFactor;
// center the image
if (widthFactor > heightFactor)
{
thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5;
}
else
{
if (widthFactor < heightFactor)
{
thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5;
}
}
}
UIGraphicsBeginImageContext(targetSize); // this will crop
CGRect thumbnailRect = CGRectZero;
thumbnailRect.origin = thumbnailPoint;
thumbnailRect.size.width = scaledWidth;
thumbnailRect.size.height = scaledHeight;
[sourceImage drawInRect:thumbnailRect];
newImage = UIGraphicsGetImageFromCurrentImageContext();
if(newImage == nil)
{
NSLog(@"could not scale image");
}
//pop the context to get back to the default
UIGraphicsEndImageContext();
return newImage;
}