android画布画弧形 在Android中绘制圆弧边缘圆弧 具有浮雕效果

我正在尝试开发一个自定义组件，即圆弧滑块，我完成了弧和拇指，但不能弄清楚如何绘制圆弧边缘弧和其中的浮雕效果。在这一刻，滑块看起来像这样

绘制弧的代码是

private void drawSlider(Canvas canvas) {

float sweepDegrees = (value * arcWidthInAngle)

/ (maximumValue - minimumValue);

// the grey empty part of the circle

drawArc(canvas, startAngle, arcWidthInAngle, mTrackColor);

// the colored "filled" part of the circle

drawArc(canvas, startAngle, sweepDegrees, mFillColor);

// the thumb to drag.

int radius = ((diameter/2) - (mArcThickness/2));

Point thumbPoint = calculatePointOnArc(centerX, centerY, radius, startAngle + sweepDegrees);

thumbPoint.x = thumbPoint.x - (mThumbDiameter/2);

thumbPoint.y = thumbPoint.y - (mThumbDiameter/2);

Bitmap thumbBitmap = BitmapFactory.decodeResource(

mContext.getResources(), R.drawable.circle25);