如何在Apple Watch上绘制自定义图形？

Question

如何在Apple Watch上绘制自定义图形？

如果我理解正确，我们只能在Apple Watch上使用图像和标准控件。 如果是这样，是否可以在内存中的图像上绘制自定义图形，然后将这些图像放在屏幕上？

Answer 1

在watchOS2你可以画WKInterfaceImage使用一些CoreGraphics 。

如需参考，请查看超棒的watchOS2采样器

绘制图像示例：

 // Create a graphics context
    let size = CGSizeMake(100, 100)
    UIGraphicsBeginImageContext(size)
    let context = UIGraphicsGetCurrentContext()

    // Setup for the path appearance
    CGContextSetStrokeColorWithColor(context, UIColor.whiteColor().CGColor)
    CGContextSetLineWidth(context, 4.0)

    // Draw lines
    CGContextBeginPath (context);
    CGContextMoveToPoint(context, 0, 0);
    CGContextAddLineToPoint(context, 100, 100);
    CGContextMoveToPoint(context, 0, 100);
    CGContextAddLineToPoint(context, 100, 0);
    CGContextStrokePath(context);

    // Convert to UIImage
    let cgimage = CGBitmapContextCreateImage(context);
    let uiimage = UIImage(CGImage: cgimage!)

    // End the graphics context
    UIGraphicsEndImageContext()

    image.setImage(uiimage)

使用Bezier路径的示例：

  // Create a graphics context
    let size = CGSizeMake(100, 100)
    UIGraphicsBeginImageContext(size)
    let context = UIGraphicsGetCurrentContext()

    // Setup for the path appearance
    UIColor.greenColor().setStroke()
    UIColor.whiteColor().setFill()

    // Draw an oval
    let rect = CGRectMake(2, 2, 96, 96)
    let path = UIBezierPath(ovalInRect: rect)
    path.lineWidth = 4.0
    path.fill()
    path.stroke()

    // Convert to UIImage
    let cgimage = CGBitmapContextCreateImage(context);
    let uiimage = UIImage(CGImage: cgimage!)

    // End the graphics context
    UIGraphicsEndImageContext()

    image.setImage(uiimage)

最后用PocketSVG显示SVG

  // Create a graphics context
    let size = CGSizeMake(512, 512)
    UIGraphicsBeginImageContext(size)
    let context = UIGraphicsGetCurrentContext()

    // Setup for the path appearance
    UIColor.yellowColor().setFill()

    // Convert SVG -> CGPath -> UIBezierPath
    let pocketSvg = PocketSVG(fromSVGFileNamed: "sample")
    let path = pocketSvg.bezier
    print(path)
    path.fill()

    // Convert to UIImage
    let cgimage = CGBitmapContextCreateImage(context);
    let uiimage = UIImage(CGImage: cgimage!)

    // End the graphics context
    UIGraphicsEndImageContext()

    image.setImage(uiimage)