在iOS中将图像叠加在另一个图像上

Question

我正在iOS应用中显示来自youtube的缩略图.点击后,将转到youtube.

我需要一种将播放按钮覆盖到这些图像上的方法.这可能是最直接的方式吗？

此外,图像被远程加载到桌子上,因此性能是一个重要的考虑因素

Answer 1

如果您关心表格滚动性能,请检索缩略图并在其上绘制播放按钮.

+(UIImage*) drawImage:(UIImage*) fgImage
              inImage:(UIImage*) bgImage
              atPoint:(CGPoint)  point
{
    UIGraphicsBeginImageContextWithOptions(bgImage.size, FALSE, 0.0);
    [bgImage drawInRect:CGRectMake( 0, 0, bgImage.size.width, bgImage.size.height)];
    [fgImage drawInRect:CGRectMake( point.x, point.y, fgImage.size.width, fgImage.size.height)];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return newImage;
}

Answer 2

Swift 2.2版本

  static func drawImage(image foreGroundImage:UIImage, inImage backgroundImage:UIImage, atPoint point:CGPoint) -> UIImage{
    UIGraphicsBeginImageContextWithOptions(backgroundImage.size, false, 0.0)
    backgroundImage.drawInRect(CGRectMake(0, 0, backgroundImage.size.width, backgroundImage.size.height))
    foreGroundImage .drawInRect(CGRectMake(point.x, point.y, foreGroundImage.size.width, foreGroundImage.size.height))
    let newImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return newImage
  }