Android实现局部模糊效果

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.createBitmap和Canvas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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以上是 Android实现局部模糊效果 的全部内容, 来源链接: utcz.com/p/240866.html

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