改變UIImage的大小

 1 lazytable 例子
 2 
 3 // Set appIcon and clear temporary data/image
 4     UIImage *image = [[UIImage alloc] initWithData:self.activeDownload];
 5     
 6     if (image.size.width != kAppIconHeight && image.size.height != kAppIconHeight)
 7     {
 8         CGSize itemSize = CGSizeMake(kAppIconHeight, kAppIconHeight);
 9         UIGraphicsBeginImageContext(itemSize);
10         CGRect imageRect = CGRectMake(0.0, 0.0, itemSize.width, itemSize.height);
11         [image drawInRect:imageRect];
12         self.appRecord.appIcon = UIGraphicsGetImageFromCurrentImageContext();
13         UIGraphicsEndImageContext();
14     }
15     else
16     {
17         self.appRecord.appIcon = image;
18     }
19     
20     self.activeDownload = nil;
21     [image release];
22    
23 
24 圖片縮放到指定大小尺寸
25 
26 - (UIImage *)scaleToSize:(UIImage *)img size:(CGSize)size{  
27     // 創建一個bitmap的context  
28 // 並把它設置成為當前正在使用的context  
29     UIGraphicsBeginImageContext(size);  
30     // 繪制改變大小的圖片  
31     [img drawInRect:CGRectMake(0, 0, size.width, size.height)];  
32     // 從當前context中創建一個改變大小后的圖片  
33     UIImage* scaledImage = UIGraphicsGetImageFromCurrentImageContext();  
34     // 使當前的context出堆棧  
35     UIGraphicsEndImageContext();  
36     // 返回新的改變大小后的圖片  
37     return scaledImage;  
38 }