Cocoa Touch - 使用叠加视图添加纹理 [英] Cocoa Touch - Adding texture with overlay view

问题描述

我有一组瓷砖作为UIViews具有可编程的背景颜色，每个
可以是不同的颜色。我想添加纹理，像侧面照明的斜面，每个。可以使用重叠视图或其他方法吗？

I have a set of tiles as UIViews that have a programmable background color, and each one can be a different color. I want to add texture, like a side-lit bevel, to each one. Can this be done with an overlay view or by some other method?

我正在寻找不需要每个案例的自定义图像文件的建议。

I'm looking for suggestions that don't require a custom image file for each case.

推荐答案

这可能有助于某人，虽然这是从SO的其他主题拼凑而成。
要为正常和视网膜显示创建任意颜色的斜角平铺图像，我在photoshop中创建了一个斜面图像，并将饱和度设置为零，使得一个灰度图像称为 tileBevel.png

This may help someone, although this was pieced together from other topics on SO. To create a beveled tile image with an arbitrary color for normal and for retina display, I made a beveled image in photoshop and set the saturation to zero, making a grayscale image called tileBevel.png

我还为视网膜显示器创建了一个（ [e-mail] ）

I also created one for the retina display ([e-mail])

这里是代码：

+ (UIImage*) createTileWithColor:(UIColor*)tileColor {

    int pixelsHigh = 44;
    int pixelsWide = 46;
    UIImage *bottomImage;

    if([UIScreen respondsToSelector:@selector(scale)] && [[UIScreen mainScreen] scale] == 2.0) {
        pixelsHigh *= 2;
        pixelsWide *= 2;
        bottomImage = [UIImage imageNamed:@"[e-mail]"];        
    }
    else {
        bottomImage = [UIImage imageNamed:@"tileBevel.png"];
    }

    CGImageRef theCGImage = NULL;
    CGContextRef tileBitmapContext = NULL;

    CGRect rectangle = CGRectMake(0,0,pixelsWide,pixelsHigh);

    UIGraphicsBeginImageContext(rectangle.size);

    [bottomImage drawInRect:rectangle];

    tileBitmapContext = UIGraphicsGetCurrentContext();

    CGContextSetBlendMode(tileBitmapContext, kCGBlendModeOverlay);

    CGContextSetFillColorWithColor(tileBitmapContext, tileColor.CGColor);        
    CGContextFillRect(tileBitmapContext, rectangle);

    theCGImage=CGBitmapContextCreateImage(tileBitmapContext);

    UIGraphicsEndImageContext();

    return [UIImage imageWithCGImage:theCGImage];

}

这会检查视网膜显示器是否使用，尺寸矩形绘制，选择适当的灰度基本图像，设置混合模式为叠加，然后在底部图像的顶部绘制一个矩形。所有这些都是在由BeginImageContext和EndImageContext调用包围的图形上下文中完成的。这些设置UIImage drawRect：方法所需的当前上下文。核心图形函数需要上下文作为参数，通过调用获得当前上下文。

This checks to see if the retina display is used, sizes the rectangle to draw in, picks the appropriate grayscale base image, set the blending mode to overlay, then draws a rectangle on top of the bottom image. All of this is done inside a graphics context bracketed by the BeginImageContext and EndImageContext calls. These set the current context needed by the UIImage drawRect: method. The Core Graphics functions need the context as a parameter, which is obtained by a call to get the current context.

结果如下所示：

>

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