android 实现拖动水纹效果

package cn.vaga.waterwave; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.os.Handler; import android.os.Message; import android.util.AttributeSet; import android.util.Log; import android.view.MotionEvent; import android.view.SurfaceHolder; import android.view.SurfaceView; import android.view.View; public class WaterWaveView extends SurfaceView implements SurfaceHolder.Callback{ private int backWidth; private int backHeight; /** * buf1 和 buf2是波能缓冲区，分别代表了每个点的前一时刻和后一时刻的波幅数据 */ private short[] buf1; private short[] buf2; private int[] bitmap1; private int[] bitmap2; private Bitmap bgImage = null; private boolean firstLoad = false; WavingThread wavingThread = new WavingThread(); SurfaceHolder mSurfaceHolder = null; private int doubleWidth; private int fiveWidth; private int loopTime; private int bitmapLen; public WaterWaveView(Context context) { super(context); mSurfaceHolder = getHolder(); mSurfaceHolder.addCallback(this); } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { if (!firstLoad) { bgImage = BitmapFactory.decodeResource(this.getResources(), R.drawable.bg); bgImage = Bitmap.createScaledBitmap(bgImage, w, h, false);// 缩放而已 backWidth = bgImage.getWidth(); backHeight = bgImage.getHeight(); buf2 = new short[backWidth * backHeight]; buf1 = new short[backWidth * backHeight]; bitmap2 = new int[backWidth * backHeight]; bitmap1 = new int[backWidth * backHeight]; // 将bgImage的像素拷贝到bitmap1数组中，用于渲染。。。 bgImage.getPixels(bitmap1, 0, backWidth, 0, 0, backWidth, backHeight); bgImage.getPixels(bitmap2, 0, backWidth, 0, 0, backWidth, backHeight); for (int i = 0; i < backWidth * backHeight; ++i) { buf2[i] = 0; buf1[i] = 0; } doubleWidth = backWidth << 1; fiveWidth = 5 * backWidth; loopTime = ((backHeight - 4) * backWidth) >> 1; bitmapLen = backWidth * backHeight - 1; firstLoad = true; } } class WavingThread extends Thread { boolean running = true; public void setRunning(boolean running) { this.running = running; } @Override public void run() { Canvas c = null; while (running) { c = mSurfaceHolder.lockCanvas(); makeRipple(); doDraw(c); mSurfaceHolder.unlockCanvasAndPost(c); } } } /******************************************************* *计算波能数据缓冲区 *******************************************************/ private void makeRipple() { int k = fiveWidth; int xoff = 0, yoff = 0; int cp = 0; int tarClr = 0; int i = fiveWidth; while(i < loopTime){ // 波能扩散 buf2[k] = (short) (((buf1[k - 2] + buf1[k + 2] + buf1[k - doubleWidth] + buf1[k + doubleWidth]) >> 1) - buf2[k]); // 波能衰减 buf2[k] = (short)(buf2[k] - (buf2[k] >> 5)); // 求出该点的左上的那个点xoff,yoff cp = k - doubleWidth - 2; xoff = buf2[cp - 2] - buf2[cp + 2]; yoff = buf2[cp - doubleWidth] - buf2[k - 2]; tarClr = k + yoff * doubleWidth + xoff; if(tarClr > bitmapLen || tarClr < 0){ k += 2; continue; } // 复制象素 bitmap2[k] = bitmap1[tarClr]; k += 2; ++i; } short[] tmpBuf = buf2; buf2 = buf1; buf1 = tmpBuf; } /***************************************************** * 增加波源 x坐标 y坐标 波源半径 波源能量 *****************************************************/ private void touchWater(int x, int y, int stonesize, int stoneweight) { // 判断坐标是否在屏幕范围内 if (x + stonesize > backWidth) { return; } if (y + stonesize > backHeight) { return; } if (x - stonesize < 0) { return; } if (y - stonesize < 0) { return; } // 产生波源，填充前导波能缓冲池 int endStoneX = x + stonesize; int endStoneY = y + stonesize; int squaSize = stonesize * stonesize; int posy = y - stonesize; int posx = x - stonesize; for (posy = y - stonesize; posy < endStoneY; ++posy) { for (posx = x - stonesize; posx < endStoneX; ++posx) { if ((posx - x) * (posx - x) + (posy - y) * (posy - y) < squaSize) { buf1[backWidth * posy + posx] = (short) -stoneweight; } } } } /***************************************************** * 增加波源 x坐标 y坐标 波源半径 波源能量 *****************************************************/ private void trickWater(int x, int y, int stonesize, int stoneweight) { // 判断坐标是否在屏幕范围内 if (x + stonesize > backWidth) { return; } if (y + stonesize > backHeight) { return; } if (x - stonesize < 0) { return; } if (y - stonesize < 0) { return; } // 产生波源，填充前导波能缓冲池 int endStoneX = x + stonesize; int endStoneY = y + stonesize; int posy = y - stonesize; int posx = x - stonesize; for (posy = y - stonesize; posy < endStoneY; ++posy) { for (posx = x - stonesize; posx < endStoneX; ++posx) { if (posy >= 0 && posy < backHeight && posx >= 0 && posx < backWidth) { buf1[backWidth * posy + posx] = (short) -stoneweight; } } } } @Override public boolean onTouchEvent(MotionEvent event) { if (event.getAction() == MotionEvent.ACTION_DOWN) { touchWater((int) event.getX(), (int) event.getY(), 4, 160); } else if (event.getAction() == MotionEvent.ACTION_MOVE) { trickWater((int) event.getX(), (int) event.getY(), 2, 64); } return true; } protected void doDraw(Canvas canvas) { canvas.drawBitmap(bitmap2, 0, backWidth, 0, 0, backWidth, backHeight, false, null); } @Override public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) { } @Override public void surfaceCreated(SurfaceHolder holder) { wavingThread.setRunning(true); wavingThread.start(); } @Override public void surfaceDestroyed(SurfaceHolder holder) { boolean retry = true; wavingThread.setRunning(false); // 非暴力关闭线程，直到此次该线程运行结束之前，主线程停止运行，以防止Surface被重新激活 while (retry) { try { wavingThread.join(); //阻塞current Thread(当前执行线程)直到被调用线程(thread)完成。 retry = false; } catch (InterruptedException e) { } } } }