本文实例为大家分享了Android实现局部模糊效果展示的具体代码,供大家参考,具体内容如下

要实现模糊或者毛玻璃效果,使用PS自然最方便(模糊的区域就较为固定);
也可在代码里进行动态处理。
因为要模糊的区域并不固定,所以只能琢磨一下后者;

经过一番搜寻研究,得到两种切实可行的方法。

一、使用FastBlur;
二、使用RenderScript。

效果如下:

算法

1.FastBlur

/**
  * 高斯模糊
  *
  * @param srcBitmap
  *   源位图
  * @param radius
  *   模糊半径
  * @return bitmap
  */
 public static Bitmap blurByGauss(Bitmap srcBitmap, int radius) {

  Bitmap bitmap = srcBitmap.copy(srcBitmap.getConfig(), true);

  if (radius < 1) {
   return (null);
  }

  int w = bitmap.getWidth();
  int h = bitmap.getHeight();

  int[] pix = new int[w * h];
  bitmap.getPixels(pix, 0, w, 0, 0, w, h);

  int wm = w - 1;
  int hm = h - 1;
  int wh = w * h;
  int div = radius + radius + 1;

  int r[] = new int[wh];
  int g[] = new int[wh];
  int b[] = new int[wh];
  int rsum, gsum, bsum, x, y, i, p, yp, yi, yw;
  int vmin[] = new int[Math.max(w, h)];

  int divsum = (div + 1) >> 1;
  divsum *= divsum;
  int temp = 256 * divsum;
  int dv[] = new int[temp];
  for (i = 0; i < temp; i++) {
   dv[i] = (i / divsum);
  }

  yw = yi = 0;

  int[][] stack = new int[div][3];
  int stackpointer;
  int stackstart;
  int[] sir;
  int rbs;
  int r1 = radius + 1;
  int routsum, goutsum, boutsum;
  int rinsum, ginsum, binsum;

  for (y = 0; y < h; y++) {
   rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
   for (i = -radius; i <= radius; i++) {
    p = pix[yi + Math.min(wm, Math.max(i, 0))];
    sir = stack[i + radius];
    sir[0] = (p & 0xff0000) >> 16;
    sir[1] = (p & 0x00ff00) >> 8;
    sir[2] = (p & 0x0000ff);
    rbs = r1 - Math.abs(i);
    rsum += sir[0] * rbs;
    gsum += sir[1] * rbs;
    bsum += sir[2] * rbs;
    if (i > 0) {
     rinsum += sir[0];
     ginsum += sir[1];
     binsum += sir[2];
    } else {
     routsum += sir[0];
     goutsum += sir[1];
     boutsum += sir[2];
    }
   }
   stackpointer = radius;

   for (x = 0; x < w; x++) {

    r[yi] = dv[rsum];
    g[yi] = dv[gsum];
    b[yi] = dv[bsum];

    rsum -= routsum;
    gsum -= goutsum;
    bsum -= boutsum;

    stackstart = stackpointer - radius + div;
    sir = stack[stackstart % div];

    routsum -= sir[0];
    goutsum -= sir[1];
    boutsum -= sir[2];

    if (y == 0) {
     vmin[x] = Math.min(x + radius + 1, wm);
    }
    p = pix[yw + vmin[x]];

    sir[0] = (p & 0xff0000) >> 16;
    sir[1] = (p & 0x00ff00) >> 8;
    sir[2] = (p & 0x0000ff);

    rinsum += sir[0];
    ginsum += sir[1];
    binsum += sir[2];

    rsum += rinsum;
    gsum += ginsum;
    bsum += binsum;

    stackpointer = (stackpointer + 1) % div;
    sir = stack[(stackpointer) % div];

    routsum += sir[0];
    goutsum += sir[1];
    boutsum += sir[2];

    rinsum -= sir[0];
    ginsum -= sir[1];
    binsum -= sir[2];

    yi++;
   }
   yw += w;
  }
  for (x = 0; x < w; x++) {
   rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
   yp = -radius * w;
   for (i = -radius; i <= radius; i++) {
    yi = Math.max(0, yp) + x;

    sir = stack[i + radius];

    sir[0] = r[yi];
    sir[1] = g[yi];
    sir[2] = b[yi];

    rbs = r1 - Math.abs(i);

    rsum += r[yi] * rbs;
    gsum += g[yi] * rbs;
    bsum += b[yi] * rbs;

    if (i > 0) {
     rinsum += sir[0];
     ginsum += sir[1];
     binsum += sir[2];
    } else {
     routsum += sir[0];
     goutsum += sir[1];
     boutsum += sir[2];
    }

    if (i < hm) {
     yp += w;
    }
   }
   yi = x;
   stackpointer = radius;
   for (y = 0; y < h; y++) {
    pix[yi] = (0xff000000 & pix[yi]) | (dv[rsum] << 16) | (dv[gsum] << 8) | dv[bsum];

    rsum -= routsum;
    gsum -= goutsum;
    bsum -= boutsum;

    stackstart = stackpointer - radius + div;
    sir = stack[stackstart % div];

    routsum -= sir[0];
    goutsum -= sir[1];
    boutsum -= sir[2];

    if (x == 0) {
     vmin[y] = Math.min(y + r1, hm) * w;
    }
    p = x + vmin[y];

    sir[0] = r[p];
    sir[1] = g[p];
    sir[2] = b[p];

    rinsum += sir[0];
    ginsum += sir[1];
    binsum += sir[2];

    rsum += rinsum;
    gsum += ginsum;
    bsum += binsum;

    stackpointer = (stackpointer + 1) % div;
    sir = stack[stackpointer];

    routsum += sir[0];
    goutsum += sir[1];
    boutsum += sir[2];

    rinsum -= sir[0];
    ginsum -= sir[1];
    binsum -= sir[2];

    yi += w;
   }
  }

  bitmap.setPixels(pix, 0, w, 0, 0, w, h);
  return bitmap;
 }

这种算法是直接对像素进行处理,使用java写会慢一些,懂jni的话可以用C/C++写下,效率高一些。

2. RenderScript

/**
  * RenderScript模糊
  *
  * @param context
  *   上下文
  * @param bitmap
  *   源位图
  * @param radius
  *   模糊半径
  * @return bitmap
  */
 @SuppressLint("NewApi")
 public static Bitmap blurBitmapByRender(Context context, Bitmap bitmap, float radius) {
  Bitmap outBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Config.ARGB_8888);
  RenderScript rs = RenderScript.create(context);
  ScriptIntrinsicBlur blurScript = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs));
  Allocation allIn = Allocation.createFromBitmap(rs, bitmap);
  Allocation allOut = Allocation.createFromBitmap(rs, outBitmap);
  blurScript.setRadius(radius);
  blurScript.setInput(allIn);
  blurScript.forEach(allOut);
  allOut.copyTo(outBitmap);

  bitmap.recycle();
  rs.destroy();

  return outBitmap;
 }

实现

整个例子就两个步骤:

一、为整体布局LayoutA设置背景图A;
二、为局部布局LayoutB设置经过模糊处理的背景图B。

需要注意的是,背景图B是从背景图A中截取出来的,并且经过模糊处理。

细分下来有以下几个步骤:

1.搭建整体布局,在xml中设置整体布局的背景图;

布局如下:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:id="@+id/rl_bg_layout"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:background="@drawable/bg"
 tools:context="${relativePackage}.${activityClass}" >

 <LinearLayout
  android:id="@+id/ll_blur_layout"
  android:layout_width="match_parent"
  android:layout_height="150dp"
  android:layout_alignParentBottom="true"
  android:orientation="horizontal" >
 </LinearLayout>

</RelativeLayout>

2.实例化布局控件,获取整体布局的显示内容;

要点一:这里要用到ViewTreeObserver, 是因为在onCreate方法中直接获取某控件的属性内容是得不到正确结果的(尚未完成绘制),所以采用ViewTreeObserver来进行监听;
要点二:获取一个控件的显示内容要用到getDrawingCache() ,使用BitmapFactory.decodeResource(getResources(), R.drawable.bg)得到是原图,并不是控件中显示的内容,控件中显示的内容是已经经过缩放适配了的;
代码如下:

public class BlurActivity extends Activity {

 /**
  * 整体布局
  */
 private RelativeLayout rlBgLayout;
 /**
  * 局部布局
  */
 private LinearLayout llBlurLayout;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_blur);
  initView();
 }

 protected void initView() {
  rlBgLayout = (RelativeLayout) findViewById(R.id.rl_bg_layout);
  llBlurLayout = (LinearLayout) findViewById(R.id.ll_blur_layout);
  setBlur();
 }

 protected void setBlur() {
  ViewTreeObserver vto = rlBgLayout.getViewTreeObserver();
  vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {

   @Override
   public void onGlobalLayout() {
    // 保证只调用一次
    rlBgLayout.getViewTreeObserver().removeOnGlobalLayoutListener(this);
    // 组件生成cache(组件显示内容)
    rlBgLayout.buildDrawingCache();
    // 得到组件显示内容
    Bitmap bitmap = rlBgLayout.getDrawingCache();
    // 局部模糊处理
    BitmapUtils.blur(getApplicationContext(), bitmap, llBlurLayout, 5);
   }
  });
 }
}

3.根据整体布局与局部布局的大小获取要进行模糊处理的内容;

要点一:结合Bitmap.createBitmapCanvas来获取正确的坐标和大小;
要点二:这里只需要知道局部布局的位置与大小即可,整体布局的背景图作为bitmap,局部布局作为view,可得到局部布局所在坐标为:(x,y)=(view.getLeft(),view.getLeft()),其大小为(w,h)=(view.getMeasuredWidth(),view.getMeasuredHeight())。再根据Canvas的位移函数translate与绘图函数drawBitmap即可从整体布局的背景图中截取到被局部布局覆盖的位图;

/**
  * 得到待处理的位图
  *
  * @param bitmap
  *   模糊位图
  * @param view
  *   模糊区域
  * @return bitmap
  */
 public static Bitmap getDstArea(Bitmap bitmap, View view) {
  Bitmap dstArea = Bitmap.createBitmap((int) (view.getMeasuredWidth()), (int) (view.getMeasuredHeight()),
    Bitmap.Config.ARGB_8888);
  Canvas canvas = new Canvas(dstArea);
  canvas.translate(-view.getLeft(), -view.getTop());
  canvas.drawBitmap(bitmap, 0, 0, null);
  return dstArea;
 }

4.进行模糊处理,为局部布局设置背景图;

要点一:有两种方法,即上文说的两种算法,一种直接高斯计算像素FastBlur,一种利用RenderScript;
要点二:FastBlur相对慢一些,不过兼容性较好,支持所有版本;RenderScript则只支持17以上的SDK;
要点三:为了减少处理时间、提高处理效率,可以先将位图进行一定的压缩,然后再作模糊处理;

/**
  * 高斯局部模糊
  *
  * @param context
  *   上下文
  * @param bitmap
  *   模糊位图
  * @param view
  *   模糊区域
  * @param radius
  *   模糊半径
  */
 public static void blurByGauss(Context context, Bitmap bitmap, View view, float radius) {
  // 得到要处理的区域
  Bitmap dstArea = getDstArea(bitmap, view);

  // 作模糊处理
  dstArea = blurByGauss(zoomImage(dstArea, 0.8f), (int) radius);

  // 设置背景
  view.setBackground(new BitmapDrawable(context.getResources(), dstArea));

  bitmap.recycle();
 }

 /**
  * RenderScript局部模糊
  *
  * @param context
  *   上下文
  * @param bitmap
  *   模糊位图
  * @param view
  *   模糊区域
  * @param radius
  *   模糊半径
  */
 @SuppressLint("NewApi")
 public static void blurByRender(Context context, Bitmap bitmap, View view, float radius) {
  // 得到要处理的区域
  Bitmap dstArea = getDstArea(bitmap, view);
  dstArea = zoomImage(dstArea, 0.8f);

  // 作模糊处理
  RenderScript rs = RenderScript.create(context);
  Allocation overlayAlloc = Allocation.createFromBitmap(rs, dstArea);
  ScriptIntrinsicBlur blur = ScriptIntrinsicBlur.create(rs, overlayAlloc.getElement());
  blur.setInput(overlayAlloc);
  blur.setRadius(radius);
  blur.forEach(overlayAlloc);
  overlayAlloc.copyTo(dstArea);

  // 设置背景
  view.setBackground(new BitmapDrawable(context.getResources(), dstArea));

  bitmap.recycle();
  rs.destroy();
 }
/**
  * 缩放图片
  *
  * @param srcBitmap
  *   源图
  * @param newWidth
  *   新宽
  * @param newHeight
  *   新高
  * @return bitmap
  */
 public static Bitmap zoomImage(Bitmap srcBitmap, float scale) {
  // 获取这个图片的宽和高
  float width = srcBitmap.getWidth();
  float height = srcBitmap.getHeight();
  // 创建操作图片用的matrix对象
  Matrix matrix = new Matrix();
  // 缩放图片动作
  matrix.postScale(scale, scale);
  Bitmap bitmap = Bitmap.createBitmap(srcBitmap, 0, 0, (int) width, (int) height, matrix, true);
  return bitmap;
 }

源码地址:Android局部模糊

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