java - 如何改变 Android Canvas.drawTextOnPath() 的输出

Question

我是 Android 新手，我编写了以下示例代码。

public class Circle extends View {
    Paint paint = new Paint();
    Path path = new Path();
    private static final String s = "Hello world example";

    public Circle(Context context) {
      super(context);
      paint.setColor(Color.BLACK);
      paint.setStyle(Style.STROKE);
      paint.setStrokeWidth(2);
      paint.setAntiAlias(true);
      paint.setTextSize(30);
    }

    public void onDraw(Canvas c) {    
      path.addCircle(getWidth()/2, getHeight()/2, 180, Direction.CW);
      c.drawTextOnPath(s, path, 0, 10, paint);
      setLayerType(View.LAYER_TYPE_SOFTWARE, null);
    } 

  }

Canvas.drawTextOnPath() 显示从右侧开始的文本(我的意思是正 X 轴)。我想从顶部顺时针显示文本。我想更改文本的起始位置。我对 Android Canvas.translate() 和 Canvas.scale() 感到困惑。或者我应该使用 Canvas.rotate()？我粘贴了下面的输出以便清楚地理解我的问题。

我想以这种形式显示输出。

Answer 1

我终于解决了我的 Canvas 问题，方法是在应用之前在我的代码中添加 Canvas.rotate(float degrees, float px, float py) 和 Canvas 方法。下面是代码。

public class Circle extends View {
    Paint paint = new Paint();
    Path path = new Path();
    private static final String s = "Hello world example";

    public Circle(Context context) {
      super(context);
      paint.setColor(Color.BLACK);
      paint.setStyle(Style.STROKE);
      paint.setStrokeWidth(2);
      paint.setAntiAlias(true);
      paint.setTextSize(30);
    }

    public void onDraw(Canvas c) {   
      c.rotate(-90, getWidth()/2, getHeight()/2);
      path.addCircle(getWidth()/2, getHeight()/2, 180, Direction.CW);
      c.drawTextOnPath(s, path, 0, 10, paint);
      setLayerType(View.LAYER_TYPE_SOFTWARE, null);
    } 
}

我之前尝试过 Canvas.rotate(float degrees) 但没有成功。但是，Canvas.rotate(float degrees, float px, float py) 起作用了!