ios - 像android九补丁一样拉伸图像？

Question

UIImage方法 ：

- (UIImage *)stretchableImageWithLeftCapWidth:(NSInteger)leftCapWidth topCapHeight:(NSInteger)topCapHeight.

在这里，可拉伸区域被强制为单个像素高/宽。

我无法设置可拉伸区域，所以我想知道：是否有 UIImage 类别可以做到这一点？

谷歌搜索后，我找到了一个库。

问： iPhone 有九个补丁加载器吗？

公告： http ://blog.tortuga22.com/2010/05/31/announcing-tortuga-22-ninepatch/

这是源图片，我想拉伸内部灰色矩形。

提前致谢。

Answer 1

实现此目的的一种方法是使用以下方法，

UIImage * backgroundImg = [UIImage imageNamed:@"bg.png"];

backgroundImg = [backgroundImg resizableImageWithCapInsets:UIEdgeInsetsMake(2,2, 2, 2)];

[imgView setImage: backgroundImg];

UIEdgeInsetsMake(2,2, 2, 2) 是您希望不可拉伸的像素数量。

Answer 2

Tortuga22软件可以实现九个补丁

你可以在这里找到这个 GitHub 的源代码

像这样使用它

[btnSubmit setImage: [TUNinePatchCache imageOfSize:[btnSubmit bounds].size 
                                forNinePatchNamed:@"imgNormalBackground"]
                       forControlState:UIControlStateNormal];

Answer 3

从 iOS5 开始，您可以使用resizableImageWithCapInsets:来实现这一点。

Answer 4

I didn't want to load so much code for the simple 9 patch images we had. So anyway, here's a simple solution to the problem for those interested. It's somewhat hard coded to our 3 pixel stretch regions but you could easily adjust those to your needs or find those in the image with some basic code and use that instead of my hard-coded inset parameters.

+ (UIImage *) makeNinePatchImage:(UIImage *)image;
{
    //Clear the black 9patch regions
    CGRect imageRect = CGRectMake(0.0, 0.0, image.size.width, image.size.height);
    UIGraphicsBeginImageContextWithOptions(image.size, NO, [UIScreen mainScreen].scale);
    [image drawInRect:imageRect];

    CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextClearRect(context, CGRectMake(0, 0, image.size.width, 1));
    CGContextClearRect(context, CGRectMake(0, 0, 1, image.size.height));

    image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    UIEdgeInsets insets;

    //hard coded for now, could easily read the black regions if necessary
    insets.left = insets.right = image.size.width / 2 - 1;
    insets.top = insets.bottom = image.size.height / 2 - 1;

    UIImage *nineImage = [image resizableImageWithCapInsets:insets     
                          resizingMode:UIImageResizingModeStretch];

    return nineImage;

}

Then to use it in say, a button's background, just call it like this:

[self.dummyButton setBackgroundImage:[EVUtility makeNinePatchImage:learnMoreImage] forState:UIControlStateNormal];

Done.

Answer 5

如果我理解正确，您希望矩形的长度和高度增加。虽然可能有更有效的解决方案，但我可以建议将边界分解为一个基本单元。一个接一个地重复添加此图像，以形成所需长度和高度的边框矩形。然后用灰色绘制内部矩形。