Question

我目前正在构建一个小型罗盘应用程序，我画了南北线使用简单的圆方程：x = a + r Cos（t）和y = b + r Sin（t）其中t =方向或方向（角度）。更多信息在Wiki

到目前为止我已经得到了南北线。这是我的工作

    //canvas.drawLine(startX, startY, stopX, stopY, paint)

    //Drawing North
        canvas.drawLine(cxCompass, cyCompass, 
                (float)(cxCompass + radiusCompass * Math.sin((double)(-direction) * 3.14/180)), 
                (float)(cyCompass - radiusCompass * Math.cos((double)(-direction) * 3.14/180)), 
                paint);

    //Drawing South
        canvas.drawLine(cxCompass, cyCompass, 
                (float)(cxCompass - radiusCompass * Math.sin((double)(-direction) * 3.14/180)), 
                (float)(cyCompass + radiusCompass * Math.cos((double)(-direction) * 3.14/180)), 
                paint);

我的问题：我不知道我们如何获得东西线？

CxCompass，CyCompass：圆心的坐标

Answer 1

通过添加90度修复了该问题。我很乐意分享它

            //Drawing west
        canvas.drawLine(cxCompass, cyCompass, 
                (float)(cxCompass + radiusCompass * Math.sin((double)(-direction-90) * 3.14/180)), 
                (float)(cyCompass - radiusCompass * Math.cos((double)(-direction-90) * 3.14/180)), 
                paint);

        //Drawing east
        canvas.drawLine(cxCompass, cyCompass, 
                (float)(cxCompass - radiusCompass * Math.sin((double)(-direction-90) * 3.14/180)), 
                (float)(cyCompass + radiusCompass * Math.cos((double)(-direction-90) * 3.14/180)), 
                paint);

在圆圈中绘制东西线？

1 个答案: