ios-->截图、生成指定大小图片以及压缩

1、截图

UIImage*snapshot;
CGImageRefcgScreen=UIGetScreenImage();
if(cgScreen){
snapshot=[UIImageimageWithCGImage:cgScreen];
CGImageRelease(cgScreen);
}
CGRectrect=CGRectMake(0,125,640,750);//创建要剪切的矩形框这里你可以自己修改
UIImage*res=[UIImageimageWithCGImage:CGImageCreateWithImageInRect([snapshotCGImage],rect)]
//res就是截图后的UIImage

2、生成指定大小图片

+ (UIImage *)compressImage:(UIImage *)imgSrc
{
CGSize size = {320, 480};
UIGraphicsBeginImageContext(size);
CGRect rect = {{0,0}, size};
[imgSrc drawInRect:rect];
UIImage *compressedImg = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return compressedImg;
}

3、压缩

UIImage *img = [CImageUtil compressImage:[info objectForKey:@"UIImagePickerControllerOriginalImage"]];
NSData *imageData = [[NSData alloc] initWithData:UIImageJPEGRepresentation(img, 0.1)];