效果图

主要代码

 /**
     * 画矩形
     */
    private fun drawRect(canvas: Canvas, isFilled: Boolean = true) {
        setPaintStyle(isFilled)
        canvas.drawRect(0f, 0f, width.toFloat(), height.toFloat(), paint)
    }
/**
     * 画圆形
     */
    private fun drawCircle(canvas: Canvas, isFilled: Boolean = true) {
        setPaintStyle(isFilled)
        canvas.drawCircle(
            width.toFloat() / 2,
            height.toFloat() / 2,
            min(width, height).toFloat() / 2,
            paint
        )
    }
/**
     * 画三角形
     */
    private fun drawTriangle(canvas: Canvas, isFilled: Boolean = true) {
        setPaintStyle(isFilled)
        path.moveTo(width.toFloat() / 2, 0f)
        path.lineTo(width.toFloat(), height.toFloat())
        path.lineTo(0f, height.toFloat())
        path.close()
        canvas.drawPath(path, paint)
    }
 /**
     * 画扇形
     */
    private fun drawSector(canvas: Canvas, isFilled: Boolean = true) {
        setPaintStyle(isFilled)
        val rectF = RectF(0f, 0f, width.toFloat(), height.toFloat())
        canvas.drawArc(rectF, 30f, 120f, true, paint)
    }
/**
     * 画圆弧
     */
    private fun drawArc(canvas: Canvas) {
        setPaintStyle(false)
        val rectF = RectF(0f, 0f, width.toFloat() - strokeWidth, height.toFloat() - strokeWidth)
        canvas.drawArc(rectF, 30f, 120f, false, paint)
    }

完整源代码

https://gitee.com/cxyzy1/my-painter