使用stretchableImageWithLeftCapWidth调整图像大小 [英] Resizing an image with stretchableImageWithLeftCapWidth

问题描述

我试图使用stretchableImageWithLeftCapWidth调整图片大小：它在模拟器上工作，但在设备上，显示垂直的绿色条。

使用imageNamed，imageWithContentOfFile和imageWithData加载图片，但不更改。

  UIImage * bottomImage = [[UIImage imageWithData：
 [NSData dataWithContentsOfFile：
 [NSString stringWithFormat：@％@ / bottom_part.png，
 [[NSBundle mainBundle] resourcePath]]]] 
 stretchableImageWithLeftCapWidth：27 topCapHeight：9]; 
 
 UIImageView * bottomView = [[UIImageView alloc] initWithFrame：CGRectMake（10，200 + 73，100，73）]; 
 [self.view addSubview：bottomView]; 
 UIGraphicsBeginImageContext（CGSizeMake（100，73））; 
 [bottomImage drawInRect：CGRectMake（0，0，100，73）]; 
 UIImage * bottomResizedImage = UIGraphicsGetImageFromCurrentImageContext（）; 
 UIGraphicsEndImageContext（）; 
 bottomView.image = bottomResizedImage 
  

查看结果：绿色条不应该出现在模拟器上。 / p>

$ b

似乎这可能是一个与UIGraphicsGetImageFromCurrentImageContext有关的错误。如果我画一个有透明度的图像，我会得到红色/绿色的假象。这些只出现在设备上（不在sim）。此外，如果我从图像中移除透明度，则工件会消失。

更新：有些更奇怪。我之前使用的是PNG，所以我试着使用透明的gif。使用GIF，在模拟器上显示工件问题。

胜利！找到解决方案：

在您的项目的构建设置中关闭压缩PNG文件。停用此选项后，PNG透明度将无任何工件。

I'm trying to resize an image using stretchableImageWithLeftCapWidth: it works on the simulator, but on the device, vertical green bars appears.

I've tried to use imageNamed, imageWithContentOfFile and imageWithData lo load the image, it doesnt change.

UIImage *bottomImage = [[UIImage imageWithData:
     [NSData dataWithContentsOfFile:
    [NSString stringWithFormat:@"%@/bottom_part.png", 
     [[NSBundle mainBundle] resourcePath]]]] 
       stretchableImageWithLeftCapWidth:27 topCapHeight:9];

UIImageView *bottomView = [[UIImageView alloc] initWithFrame:CGRectMake(10, 200+73, 100, 73)];
[self.view addSubview:bottomView];
UIGraphicsBeginImageContext(CGSizeMake(100, 73));
[bottomImage drawInRect:CGRectMake(0, 0, 100, 73)];
UIImage *bottomResizedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
bottomView.image = bottomResizedImage;

See the result: the green bars shouldn't be there, they dont appear on the simulator.

解决方案

Did you figure this out?

Seems like it might be a bug with UIGraphicsGetImageFromCurrentImageContext. If I draw an image that has transparency I get red/green artifacts. These only appear on the device (not in the sim). Also, if I remove transparency from the image, the artifacts go away.

Update: Some more weirdness. I was using PNGs before, so I tried using a transparent gif instead. Using a GIF, shows the artifact problem on the sim.

Victory! Found a solution:

Turn off 'Compress PNG Files' in the build settings for your project. Disabling this makes the PNG transparency work without any artifacts.

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