PathMeasure

来源：互联网发布：淘宝发错货买家不寄回编辑：程序博客网时间：2024/06/05 09:31

转载自：http://www.jianshu.com/p/4bb16cefca23
http://blog.csdn.net/cquwentao/article/details/51436852
http://blog.csdn.net/u013831257/article/details/51565591

1.构造方法

方法名释义 PathMeasure() 创建一个空的测量对象 PathMeasure(Path path, boolean forceClosed) 创建一个与指定路径关联的测量对象

不论 forceClosed 设置为何种状态(true 或者 false)，都不会影响原有Path的状态。
forceClosed为true，该路径将被视为“关闭”（起点终点闭合），即使其轮廓未明确关闭。

2.公共方法

方法名释义 setPath() 关联一个path getLength() 返回当前path的总长度 getPosTan(float distance, float pos[], float tan[]) 获取path路径上distance长度的点，点坐标的值给 pos（二维数组），点的正切值给 tan（二维数组） getMatrix(float distance, Matrix matrix, int flags) 得到path路径上某一长度的位置以及该位置的正切值的矩阵（个人理解不深） getSegment(float startD, float stopD, Path dst, boolean startWithMoveTo) 获取从path路径的startD位置到stopD位置的片段，由dst接收（第四个参数详解见下文） isClosed 用于判断 Path 是否闭合，但是如果你在关联 Path 的时候设置 forceClosed 为 true 的话，这个方法的返回值则一定为true nextContour 用于跳转到下一条曲线的方法，如果跳转成功，则返回 true，如果跳转失败，则返回 false

注意：

getSegment方法中如果 startD、stopD 的数值不在取值范围 [0, getLength] 内，或者 startD ==
stopD 则返回值为 false，不会改变 dst 内容

getSegment的第四个参数startWithMoveTo

若为true，相当于将dst的起点moveTo与pathMesure关联的path起点
若为false，默认moveTo(0,0)，之后怎么画，我没有找到规律，希望大神看到解答
示例如下：白线为原path，黑线为截取的path

path.addRect(200, 200, 400, 400, Path.Direction.CW);

startWithMoveTo为true

        Path dstPath = new Path();        PathMeasure pathMeasure = new PathMeasure(path, false);        pathMeasure.getSegment(0, 300, dstPath, true);        canvas.drawPath(dstPath, dstPaint);        canvas.drawPath(path, this.paint);

startWithMoveTo为true

以下均为：startWithMoveTo为false

 pathMeasure.getSegment(0, 300, dstPath, false);

startWithMoveTo为false

pathMeasure.getSegment(0, 500, dstPath, false);

startWithMoveTo为false

pathMeasure.getSegment(400, 500, dstPath, false);

这里写图片描述

pathMeasure.getSegment(450, 500, dstPath, false);

这里写图片描述

光能使者阵：

public class PathView extends View {    private Paint paint;    private Path innerCircle;//内圆路径    private Path outerCircle;//外圆路径    private Path triangle1;//第一个三角形路径    private Path triangle2;//第二个三角形路径    private Path drawPath;//截取的路径    private PathMeasure pathMeasure;    private Handler mHandler;    private State mCurrentState = State.CIRCLE_STATE;    private ValueAnimator.AnimatorUpdateListener animatorUpdateListener;    private Animator.AnimatorListener animatorListener;    private float distance;//当前动画执行的百分比取值为0-1    private ValueAnimator valueAnimator;    private long duration = 3000;    private float mViewWidth;    private float mViewHeight;    //三个阶段的枚举    private enum State {        CIRCLE_STATE,//圆形阶段        TRANGLE_STATE,//截取阶段        FINISH_STATE//完成阶段    }    public PathView(Context context) {        this(context, null);    }    public PathView(Context context, AttributeSet attrs) {        this(context, attrs, 0);    }    public PathView(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        init();    }    @Override    protected void onSizeChanged(int w, int h, int oldw, int oldh) {        super.onSizeChanged(w, h, oldw, oldh);        mViewWidth = w;        mViewHeight = h;    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        canvas.drawColor(ContextCompat.getColor(getContext(), R.color.colorPrimary));        canvas.save();        canvas.translate(mViewWidth / 2, mViewHeight / 2);        switch (mCurrentState) {            case CIRCLE_STATE:                //画内圆                drawPath.reset();                pathMeasure.setPath(innerCircle, false);                pathMeasure.getSegment(0, distance * pathMeasure.getLength(), drawPath, true);                canvas.drawPath(drawPath, paint);                //画外圆                drawPath.reset();                pathMeasure.setPath(outerCircle, false);                pathMeasure.getSegment(0, distance * pathMeasure.getLength(), drawPath, true);                canvas.drawPath(drawPath, paint);                break;            case TRANGLE_STATE:                canvas.drawPath(innerCircle, paint);                canvas.drawPath(outerCircle, paint);                drawPath.reset();                pathMeasure.setPath(triangle1, false);                //结束点在path上从起点到终点移动                float stopD = distance * pathMeasure.getLength();                //开始点为结束点减去一段距离（先增后减）                float startD = stopD - (0.5f - Math.abs(0.5f - distance)) * 200;                pathMeasure.getSegment(startD, stopD, drawPath, true);                canvas.drawPath(drawPath, paint);                drawPath.reset();                pathMeasure.setPath(triangle2, false);                pathMeasure.getSegment(startD, stopD, drawPath, true);                canvas.drawPath(drawPath, paint);                break;            case FINISH_STATE:                canvas.drawPath(innerCircle, paint);                canvas.drawPath(outerCircle, paint);                drawPath.reset();                pathMeasure.setPath(triangle1, false);                pathMeasure.getSegment(0, distance * pathMeasure.getLength(), drawPath, true);                canvas.drawPath(drawPath, paint);                drawPath.reset();                pathMeasure.setPath(triangle2, false);                pathMeasure.getSegment(0, distance * pathMeasure.getLength(), drawPath, true);                canvas.drawPath(drawPath, paint);                break;        }        canvas.restore();    }    private void init() {        initPaint();        initPath();        initHandler();        initAnimatorListener();        initAnimator();        mCurrentState = State.CIRCLE_STATE;        valueAnimator.start();    }    private void initAnimator() {        valueAnimator = ValueAnimator.ofFloat(0, 1).setDuration(duration);        valueAnimator.addUpdateListener(animatorUpdateListener);        valueAnimator.addListener(animatorListener);    }    private void initAnimatorListener() {        animatorUpdateListener = new ValueAnimator.AnimatorUpdateListener() {            @Override            public void onAnimationUpdate(ValueAnimator animation) {                distance = (float) animation.getAnimatedValue();                invalidate();            }        };        animatorListener = new Animator.AnimatorListener() {            @Override            public void onAnimationStart(Animator animation) {            }            @Override            public void onAnimationEnd(Animator animation) {                mHandler.sendEmptyMessage(0);            }            @Override            public void onAnimationCancel(Animator animation) {            }            @Override            public void onAnimationRepeat(Animator animation) {            }        };    }    private void initHandler() {        mHandler = new Handler() {            @Override            public void handleMessage(Message msg) {                switch (mCurrentState) {                    case CIRCLE_STATE:                        mCurrentState = State.TRANGLE_STATE;                        valueAnimator.start();                        break;                    case TRANGLE_STATE:                        mCurrentState = State.FINISH_STATE;                        valueAnimator.start();                        break;                }            }        };    }    private void initPath() {        innerCircle = new Path();        outerCircle = new Path();        triangle1 = new Path();        triangle2 = new Path();        drawPath = new Path();        innerCircle.addArc(-220, -220, 220, 220, 150, -359.9F);        outerCircle.addArc(-280, -280, 280, 280, 60, -359.9F);        pathMeasure = new PathMeasure();        pathMeasure.setPath(innerCircle, false);        float[] pos = new float[2];        //获取path路径上distance长度的 point 值给 pos，point 点的正切值给 tan。        pathMeasure.getPosTan(0, pos, null);        triangle1.moveTo(pos[0], pos[1]);//三角形1的起点为内圆的终点        pathMeasure.getPosTan((1f / 3f) * pathMeasure.getLength(), pos, null);        triangle1.lineTo(pos[0], pos[1]);//从内圆起点到内圆1/3的点画线        pathMeasure.getPosTan((2f / 3f) * pathMeasure.getLength(), pos, null);        triangle1.lineTo(pos[0], pos[1]);//从内圆1/3到内圆2/3的点画线        triangle1.close();//从内圆2/3的点到内圆终点画线        pathMeasure.getPosTan((2f / 3f) * pathMeasure.getLength(), pos, null);        Matrix matrix = new Matrix();        matrix.postRotate(-180);        triangle1.transform(matrix, triangle2);//triangle2的路径为triangle1的路径旋转180度    }    //初始化画笔    private void initPaint() {        paint = new Paint(Paint.ANTI_ALIAS_FLAG);        paint.setColor(Color.WHITE);        paint.setStyle(Paint.Style.STROKE);        paint.setStrokeWidth(5);        paint.setStrokeCap(Paint.Cap.ROUND);//圆头线条        paint.setStrokeJoin(Paint.Join.BEVEL);//拐角为平角        paint.setShadowLayer(10, 0, 0,ContextCompat.getColor(getContext(),R.color.colorAccent));//绘制内容下加一层阴影    }}

这里写图片描述
自己仿做的：

阅读全文

0 0