Android－贝赛尔曲线源码

package com.qpath; import java.util.Random; import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.Paint.Style; import android.graphics.Path; import android.view.KeyEvent; import android.view.MotionEvent; import android.view.SurfaceHolder; import android.view.SurfaceHolder.Callback; import android.view.SurfaceView; /** * 赛贝尔曲线 * @author Himi * */ public class MySurfaceView extends SurfaceView implements Callback, Runnable { private SurfaceHolder sfh; private Paint paint; private Thread th; private boolean flag; private Canvas canvas; public static int screenW, screenH; // -----------以上是SurfaceView游戏框架 // 贝赛尔曲线成员变量(起始点，控制（操作点），终止点，3点坐标) private int startX, startY, controlX, controlY, endX, endY; // Path private Path path; // 为了不影响主画笔，这里绘制贝赛尔曲线单独用一个新画笔 private Paint paintQ; // 随机库（让贝赛尔曲线更明显） private Random random; /** * SurfaceView初始化函数 */ public MySurfaceView(Context context) { super(context); sfh = this.getHolder(); sfh.addCallback(this); paint = new Paint(); paint.setColor(Color.WHITE); paint.setAntiAlias(true); setFocusable(true); // -----------以上是SurfaceView游戏框架 //贝赛尔曲线相关初始化 path = new Path(); paintQ = new Paint(); paintQ.setAntiAlias(true); paintQ.setStyle(Style.STROKE); paintQ.setStrokeWidth(5); paintQ.setColor(Color.WHITE); random = new Random(); } /** * SurfaceView视图创建，响应此函数 */ public void surfaceCreated(SurfaceHolder holder) { screenW = this.getWidth(); screenH = this.getHeight(); flag = true; // 实例线程 th = new Thread(this); // 启动线程 th.start(); // -----------以上是SurfaceView游戏框架 } /** * 游戏绘图 */ public void myDraw() { try { canvas = sfh.lockCanvas(); if (canvas != null) { canvas.drawColor(Color.BLACK); // -----------以上是SurfaceView游戏框架 drawQpath(canvas); } } catch (Exception e) { // TODO: handle exception } finally { if (canvas != null) sfh.unlockCanvasAndPost(canvas); } } /** * 绘制贝赛尔曲线 * * @param canvas 主画布 */ public void drawQpath(Canvas canvas) { path.reset();// 重置path // 贝赛尔曲线的起始点 path.moveTo(startX, startY); // 设置贝赛尔曲线的操作点以及终止点 path.quadTo(controlX, controlY, endX, endY); // 绘制贝赛尔曲线（Path） canvas.drawPath(path, paintQ); } /** * 触屏事件监听 */ @Override public boolean onTouchEvent(MotionEvent event) { endX = (int) event.getX(); endY = (int) event.getY(); return true; } /** * 游戏逻辑 */ private void logic() { if (endX != 0 && endY != 0) { // 设置操作点为线段x/y的一半 controlX = random.nextInt((endX - startX) / 2); controlY = random.nextInt((endY - startY) / 2); } } /** * 按键事件监听 */ @Override public boolean onKeyDown(int keyCode, KeyEvent event) { return super.onKeyDown(keyCode, event); } public void run() { while (flag) { long start = System.currentTimeMillis(); myDraw(); logic(); long end = System.currentTimeMillis(); try { if (end - start < 50) { Thread.sleep(50 - (end - start)); } } catch (InterruptedException e) { e.printStackTrace(); } } } /** * SurfaceView视图状态发生改变，响应此函数 */ public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) { } /** * SurfaceView视图消亡时，响应此函数 */ public void surfaceDestroyed(SurfaceHolder holder) { flag = false; } }