ios - Swift - 为 CGrect 添加颜色

Question

我目前正在向图像添加一个矩形，以防它不是正方形“填充”剩余空间，使其成为正方形。这个想法是，这是一种廉价的方法(就“强制”图像进行平方所需的时间而言)。

如您在附图中所见，我生成的正方形没有颜色，这可能会使用户感到困惑。这就是为什么我想为我生成的 CGRect 添加颜色。问题是我还没有找到任何方法来做到这一点。任何有关如何为生成的正方形着色的建议，将不胜感激。

我必须执行此操作的当前代码如下:

func forceSquaredImage(image: UIImage) -> UIImage{
    let maxDimension = max(image.size.height, image.size.width)

    var newImage : UIImage = image

    if(image.size.height > image.size.width){

        UIGraphicsBeginImageContextWithOptions(CGSize(width: maxDimension, height: maxDimension), false, 0.0);

        image.drawInRect(CGRectMake(image.size.height/2-image.size.width/2, 0, image.size.width, image.size.height))
        newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

    }else if(image.size.height < image.size.width){

        UIGraphicsBeginImageContextWithOptions(CGSize(width: maxDimension, height: maxDimension), false, 0.0);
        image.drawInRect(CGRectMake(0, image.size.width/2-image.size.height/2, image.size.width, image.size.height))
        newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return newImage

    }

    return newImage

}

期望的结果应该是这样的(在这种情况下，红色只是一个例子):

Answer 1

在绘制图像之前填充背景颜色:

func forceSquaredImage(image: UIImage) -> UIImage{
    let maxDimension = max(image.size.height, image.size.width)

    var newImage : UIImage = image
    UIGraphicsBeginImageContextWithOptions(CGSize(width: maxDimension, height: maxDimension), false, 0.0);
    UIColor.redColor().set()
    UIBezierPath(rect: CGRect(x:0, y: 0, width:maxDimension, height:maxDimension)).fill()
    if(image.size.height > image.size.width) {
        image.drawInRect(CGRectMake(image.size.height/2-image.size.width/2, 0, image.size.width, image.size.height))
        }
    else if (image.size.height < image.size.width) {
        image.drawInRect(CGRectMake(0, image.size.width/2-image.size.height/2, image.size.width, image.size.height))
        }
        newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return newImage
}