http://blog.csdn.net/pkukevin/article/details/6681217
http://www.cocoachina.com/bbs/read.php?tid=36896
0,關於初始化
使用ImageNamed方法,類方法,系統有緩存
autorealease
使NSData的話,系統不會有緩存,這樣作者可以很好的控制系統內存
1.等比率縮放
- (UIImage *)scaleImage:(UIImage *)image toScale:(float)scaleSize
{
UIGraphicsBeginImageContext(CGSizeMake(image.size.width * scaleSize, image.size.height * scaleSize);
[image drawInRect:CGRectMake(0, 0, image.size.width * scaleSize, image.size.height * scaleSize)];
UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return scaledImage;
}
2.自定長寬
- (UIImage *)reSizeImage:(UIImage *)image toSize:(CGSize)reSize
{
UIGraphicsBeginImageContext(CGSizeMake(reSize.width, reSize.height));
[image drawInRect:CGRectMake(0, 0, reSize.width, reSize.height)];
UIImage *reSizeImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return reSizeImage;
}
3.處理某個特定View
只要是繼承UIView的object 都可以處理
必須先import QuzrtzCore.framework
-(UIImage*)captureView:(UIView *)theView
{
CGRect rect = theView.frame;
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
[theView.layer renderInContext:context];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return img;
}
4.儲存圖片
儲存圖片這里分成儲存到app的文件里, 儲存到手機的圖片庫里
1) 儲存到app的文件里
NSString *path = [[NSHomeDirectory()stringByAppendingPathComponent:@"Documents"]stringByAppendingPathComponent:@"image.png"];
[UIImagePNGRepresentation(image) writeToFile:pathatomically:YES];
這樣就把你要處理的圖片, 以image.png這個檔名存到app home底下的Documents目錄裡
2)儲存到手機的圖片庫里
CGImageRef screen = UIGetScreenImage();
UIImage* image = [UIImage imageWithCGImage:screen];
CGImageRelease(screen);
UIImageWriteToSavedPhotosAlbum(image, self, nil, nil);
UIGetScreenImage()原本是private(私有)api, 用來截取整個畫麵
不過SDK 4.0後apple就開放了
另外儲存到手機的圖片庫裡, 必須在實機使用, 模擬器無法使用