Canvas画图设置渐变色

来源：互联网发布：百度大数据交响乐编辑：程序博客网时间：2024/05/01 08:58

1、线形图设置填充色为渐变色方法：

/** * Draws the provided path in filled mode with the provided drawable. * * @param c * @param filledPath * @param drawable */protected void drawFilledPath(Canvas c, Path filledPath, Drawable drawable) {    if (clipPathSupported()) {        c.save();        c.clipPath(filledPath);        drawable.setBounds((int) mViewPortHandler.contentLeft(),                (int) mViewPortHandler.contentTop(),                (int) mViewPortHandler.contentRight(),                (int) mViewPortHandler.contentBottom());        drawable.draw(c);        c.restore();//在canvas上设置渐变色图片    } else {        throw new RuntimeException("Fill-drawables not (yet) supported below API level 18, " +                "this code was run on API level " + Utils.getSDKInt() + ".");    }}

渐变色图片：

最终效果:

具体代码参见：MPChartLibrary开源项目中的LineRadarRenderer.class类

2、为canvas背景设置渐变色

 final Drawable drawable = dataSet.getFillDrawable();            c.save();            drawable.setBounds((int) mViewPortHandler.contentLeft(),                    (int) mViewPortHandler.contentTop(),                    (int) mViewPortHandler.contentRight(),                    (int) mViewPortHandler.contentBottom());            drawable.draw(c);//            mRenderPaint.setColor(dataSet.getColor());            for (int j = 0; j < buffer.size(); j += 4) {                if (!mViewPortHandler.isInBoundsLeft(buffer.buffer[j + 2]))                    continue;                if (!mViewPortHandler.isInBoundsRight(buffer.buffer[j]))                    break;                c.drawRect(buffer.buffer[j], buffer.buffer[j + 1], buffer.buffer[j + 2],                        buffer.buffer[j + 3], mRenderPaint);                if (drawBorder) {                    c.drawRect(buffer.buffer[j], buffer.buffer[j + 1], buffer.buffer[j + 2],                            buffer.buffer[j + 3], mBarBorderPaint);                }            }            c.restore();

效果图：看后面背景

代码初步是在BarChartRenderer.class中做了修改。并且在

BaseDataSet.class中添加了两个接口

public Drawable getFillDrawable() {    return mFillDrawable;}/** * Sets the drawable to be used to fill the area below the line. * * @param drawable */@TargetApi(18)public void setFillDrawable(Drawable drawable) {    this.mFillDrawable = drawable;}

大致是这样的修改的。具体可再优化。

3、为柱状图每个元素设置渐变色

for (int j = 0; j < buffer.size(); j += 4) {                if (!mViewPortHandler.isInBoundsLeft(buffer.buffer[j + 2]))                    continue;                if (!mViewPortHandler.isInBoundsRight(buffer.buffer[j]))                    break;                //设置柱状图的颜色为渐变色                LinearGradient linearGradient = new LinearGradient(0, 0, 0, 2000,Color.GREEN, Color.WHITE, Shader.TileMode.CLAMP);                mRenderPaint.setShader(linearGradient);//目标Paint即为绘制柱的Paint                c.drawRect(buffer.buffer[j], buffer.buffer[j + 1], buffer.buffer[j + 2],                        buffer.buffer[j + 3], mRenderPaint);                if (drawBorder) {                    c.drawRect(buffer.buffer[j], buffer.buffer[j + 1], buffer.buffer[j + 2],                            buffer.buffer[j + 3], mBarBorderPaint);                }            }

效果图：

代码初步是在BarChartRenderer.class中做了修改。

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