28

我正在尝试开发一个自定义组件，即弧形滑块，我完成了弧形和拇指，但无法弄清楚如何绘制圆边弧以及其中的浮雕效果。目前滑块看起来像这样

在此处输入图像描述

绘制圆弧的代码是

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);

    thumbBitmap = getResizedBitmap(thumbBitmap, mThumbDiameter, mThumbDiameter);
    canvas.drawBitmap(thumbBitmap, thumbPoint.x, thumbPoint.y,
            null);  

}

private void drawArc(Canvas canvas, float startAngle, float sweepDegrees,
        Paint paint) {
    if (sweepDegrees <= 0 || sweepDegrees > arcWidthInAngle) {
        return;
    }
    path.reset();
    path.arcTo(outerCircle, startAngle, sweepDegrees);
    path.arcTo(innerCircle, startAngle + sweepDegrees, -sweepDegrees);
    // innerCircle.
    path.close();
    canvas.drawPath(path, paint);
}

我的目标是这样的弧

在此处输入图像描述

4

4 回答 4

48

对于圆形边缘，您可以使用 Paint.setStrokeCap() 方法。此外，默认的油漆帽是 BUTT。您应该改用 Paint.Cap.ROUND 帽。

例如：

Paint mFillColor = new Paint();
mFillColor.setStrokeCap(Paint.Cap.ROUND)
于 2015-07-20T04:41:32.577 回答
14

我设法建立了一些如下所示的弧线

在此处输入图像描述

我所做的是我计算了弧的起点和终点，并在那里绘制直径等于弧厚的圆。

代码是

private void drawSlider(Canvas canvas) {
    float sweepDegrees = (value * arcWidthInAngle)
            / (maximumValue - minimumValue);

    // the grey empty part of the arc       
    drawArc(canvas, startAngle, arcWidthInAngle, mTrackColor);

    // the colored "filled" part of the arc
    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);

    thumbBitmap = getResizedBitmap(thumbBitmap, mThumbDiameter, mThumbDiameter);
    canvas.drawBitmap(thumbBitmap, thumbPoint.x, thumbPoint.y,
            null);

    //drawArc(canvas, startAngle, startAngle + sweepDegrees, white);
}
private void drawArc(Canvas canvas, float startAngle, float sweepDegrees,
        Paint paint) {
    if (sweepDegrees <= 0 || sweepDegrees > arcWidthInAngle) {
        return;
    }
    path.reset();


    int radius = ((diameter/2) - (mArcThickness/2));
    Point startPoint = calculatePointOnArc(centerX, centerY, radius, startAngle);
    Point endPoint = calculatePointOnArc(centerX, centerY, radius, startAngle + sweepDegrees);


    path.arcTo(outerCircle, startAngle, sweepDegrees);
    path.arcTo(innerCircle, startAngle + sweepDegrees, -sweepDegrees);
    // drawing the circle at both the end point of the arc to git it rounded look.
    path.addCircle(startPoint.x, startPoint.y, mArcThickness/2, Path.Direction.CW);
    path.addCircle(endPoint.x, endPoint.y, mArcThickness/2, Path.Direction.CW);

    path.close();            

    canvas.drawPath(path, paint);
}
    // this is to calculate the end points of the arc
private Point calculatePointOnArc(int circleCeX, int circleCeY, int circleRadius, float endAngle) 
    {
    Point point = new Point();
    double endAngleRadian = endAngle * (Math.PI / 180);

    int pointX = (int) Math.round((circleCeX + circleRadius * Math.cos(endAngleRadian)));
    int pointY = (int) Math.round((circleCeY + circleRadius * Math.sin(endAngleRadian)));

    point.x = pointX;
    point.y = pointY;

    return point;
}
// for the emboss effect set maskfilter of the paint to EmbossMaskFilter 
    private Paint mTrackColor = new Paint();
    MaskFilter  mEmboss = new EmbossMaskFilter(new float[] { 0.0f, -1.0f, 0.5f},
            0.8f, 15, 1.0f);
    mTrackColor.setMaskFilter(mEmboss);
于 2012-05-29T10:09:05.877 回答
6

使用 Paint.setStrokeCap() 方法。你需要 Paint.Cap.ROUND。默认值为 Paint.Cap.BUTT。有一个类似的 Path 属性称为路径连接。它确定如何绘制路径的组成部分连接的部分。要设置它，请使用 Path.setPathJoin()。您将来可能需要它。祝你好运。

于 2017-04-30T16:54:22.857 回答
4

您正在使用路径来绘制弧线。用于CornerPathEffect圆角。这里的例子CornerPathEffect example。

这是浮雕效果的示例。我不确定这是否是你想要的。 Embossed effect example

于 2012-05-28T12:07:22.783 回答