在没有MKMapView的情况下生成MKPolyline的小缩略图？

Our app contains several MKPolyline boundaries that all create a closed in polygon. These are primarily to display as an MKOverlay on a MKMapView but I'm looking for a solution to display these polygons as small thumbnails to be visible not on the MKMapView but instead as a standard UIImage or UIImageView.

我们的应用程序包含几个MKPolyline边界,这些边界都创建一个封闭的多边形。这些主要是在MKMapView上显示为MKOverlay,但我正在寻找一种解决方案,将这些多边形显示为小缩略图,不在MKMapView上可见,而是作为标准UIImage或UIImageView显示。

Just to be clear, I'm wanting these small thumbnails would just be displayed as small shapes that have a stroke color and a fill color but without any map background.

为了清楚起见,我希望这些小缩略图只显示为具有笔触颜色和填充颜色但没有任何地图背景的小形状。

Could anyone help me with this?

任何人都可以帮我这个吗?

1 个解决方案

#1

Here you go.

干得好。

+ (UIImage *)imageNamed:(NSString *)name withColor:(UIColor *)color{
    // load the image
    UIImage *img = [UIImage imageNamed:name];

    // begin a new image context, to draw our colored image onto
    UIGraphicsBeginImageContext(img.size);

    // get a reference to that context we created
    CGContextRef context = UIGraphicsGetCurrentContext();

    // set the fill color
    [color setFill];

    // translate/flip the graphics context (for transforming from CG* coords to UI* coords
    CGContextTranslateCTM(context, 0, img.size.height);
    CGContextScaleCTM(context, 1.0, -1.0);

    // set the blend mode to color burn, and the original image
    CGContextSetBlendMode(context, kCGBlendModeColorBurn);
    CGRect rect = CGRectMake(0, 0, img.size.width, img.size.height);
    CGContextDrawImage(context, rect, img.CGImage);

    // set a mask that matches the shape of the image, then draw (color burn) a colored rectangle
    CGContextClipToMask(context, rect, img.CGImage);
    CGContextAddRect(context, rect);
    CGContextDrawPath(context,kCGPathFill);

    // generate a new UIImage from the graphics context we drew onto
    UIImage *coloredImg = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    //return the color-burned image
    return coloredImg;
}

Please check this original post for detail description.

有关详细说明,请查看此原始帖子。

#1