iphone - 如何从 UILabel 创建图像？

Question

我目前正在 iPhone 上开发一个简单的类似 Photoshop 的应用程序。当我想要展平图层时，标签位于良好的位置，但字体大小不佳。这是我要展平的代码:

UIGraphicsBeginImageContext(CGSizeMake(widthDocument,widthDocument));

for (UILabel *label in arrayLabel) {
    [label drawTextInRect:label.frame];
}

UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

有人可以帮助我吗？

Answer 1

来自:pulling an UIImage from a UITextView or UILabel gives white image .

//iOS

- (UIImage *)grabImage {
    // Create a "canvas" (image context) to draw in.
    UIGraphicsBeginImageContextWithOptions(self.bounds.size, self.opaque, 0.0);  // high res
    // Make the CALayer to draw in our "canvas".
    [[self layer] renderInContext: UIGraphicsGetCurrentContext()];

    // Fetch an UIImage of our "canvas".
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    // Stop the "canvas" from accepting any input.
    UIGraphicsEndImageContext();

    // Return the image.
    return image;
}

//带有用法的 Swift 扩展。在下面的评论中注明@Heberti Almeida

extension UIImage {
    class func imageWithLabel(label: UILabel) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(label.bounds.size, false, 0.0)
        label.layer.renderInContext(UIGraphicsGetCurrentContext()!)
        let img = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return img
    }
}

用法:

let label = UILabel(frame: CGRect(x: 0, y: 0, width: 30, height: 22))
label.text = bulletString
let image = UIImage.imageWithLabel(label)