android图片模糊处理

这里写代码片

现在很多app中使用到了图片的模糊效果，或者背景模糊，看起来感觉还是很不错的，今天介绍下怎么来实现，先给大家看看最终的效果图



模糊的处理，需要用到一个FastBlur，具体大家可以看看android高级模糊技术，本文就直接拿过来FastBlur这个处理类了，具体代码：

package com.fanxl.imagetest;

import android.graphics.Bitmap;

/**
* Created by paveld on 3/6/14.
*/
public class FastBlur {

public static Bitmap doBlur(Bitmap sentBitmap, int radius, boolean canReuseInBitmap) {

// Stack Blur v1.0 from
// http://www.quasimondo.com/StackBlurForCanvas/StackBlurDemo.html //
// Java Author: Mario Klingemann <mario at quasimondo.com>
// http://incubator.quasimondo.com // created Feburary 29, 2004
// Android port : Yahel Bouaziz <yahel at kayenko.com>
// http://www.kayenko.com // ported april 5th, 2012

// This is a compromise between Gaussian Blur and Box blur
// It creates much better looking blurs than Box Blur, but is
// 7x faster than my Gaussian Blur implementation.
//
// I called it Stack Blur because this describes best how this
// filter works internally: it creates a kind of moving stack
// of colors whilst scanning through the image. Thereby it
// just has to add one new block of color to the right side
// of the stack and remove the leftmost color. The remaining
// colors on the topmost layer of the stack are either added on
// or reduced by one, depending on if they are on the right or
// on the left side of the stack.
//
// If you are using this algorithm in your code please add
// the following line:
//
// Stack Blur Algorithm by Mario Klingemann <mario@quasimondo.com>

Bitmap bitmap;
if (canReuseInBitmap) {
bitmap = sentBitmap;
} else {
bitmap = sentBitmap.copy(sentBitmap.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 dv[] = new int[256 * divsum];
for (i = 0; i < 256 * divsum; 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++) {
// Preserve alpha channel: ( 0xff000000 & pix[yi] )
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);
}
}

大家只需要把这个类放入到自己的工具类当中即可。

下面说下布局，Fragment里面放入一个ImageView作为背景，再一个自定义控件作为圆形的图像显示，最后有一个用户名TextView，布局很简单，这里用ImageView做背景是因为要使用到ImageView中的android:scaleType属性，代码如下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">

<ImageView
android:id="@+id/second_bg"
android:layout_width="match_parent"
android:layout_height="200dp"
android:src="@drawable/head"
android:scaleType="centerCrop"/>

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:text="13120752269"
android:layout_marginTop="20dp"
android:textColor="#ffffff"/>

<com.fanxl.imagetest.widget.CircleImageView
android:id="@+id/second_head"
android:layout_width="100dp"
android:layout_height="100dp"
android:src="@drawable/head"
android:layout_gravity="center_horizontal"
android:layout_marginTop="60dp"
app:border_color="@color/background_floating_material_light"
app:border_width="4dp"
android:scaleType="centerCrop"/>

</FrameLayout>

</LinearLayout>

里面有一个CircleImageView的圆形ImageView自定义控件，具体见源码，或者替换成ImageView也可以。

下面就是代码部分了，首先找到背景和图像控件:

second_bg = (ImageView)findViewById(R.id.second_bg);
second_head = (CircleImageView)findViewById(R.id.second_head);

然后给背景控件添加一个测量方法，这个方法在控件绘制完毕之后会进行调用：

second_bg.getViewTreeObserver().addOnPreDrawListener(
new ViewTreeObserver.OnPreDrawListener() {

@Override
public boolean onPreDraw() {

second_bg.getViewTreeObserver().removeOnPreDrawListener(this);
second_bg.buildDrawingCache();

Bitmap bmp = second_bg.getDrawingCache();
blur(bmp, second_bg);
return true;
}
});

调用完毕之后，获取背景的bitmap图像，然后调用blur()方法进行模糊处理，这个方法传入需要模糊的bitmap，以及最终把模糊的图像设置到哪个控件上面。

具体方法代码如下：

@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
private void blur(Bitmap bkg, View view) {
long startMs = System.currentTimeMillis();
float scaleFactor = 8;
float radius = 2;

Bitmap overlay = Bitmap.createBitmap(
(int) (view.getMeasuredWidth() / scaleFactor),
(int) (view.getMeasuredHeight() / scaleFactor),
Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(overlay);
canvas.translate(-view.getLeft() / scaleFactor, -view.getTop()
/ scaleFactor);
canvas.scale(1 / scaleFactor, 1 / scaleFactor);
Paint paint = new Paint();
paint.setFlags(Paint.FILTER_BITMAP_FLAG);
canvas.drawBitmap(bkg, 0, 0, paint);

overlay = FastBlur.doBlur(overlay, (int) radius, true);
if (view instanceof ImageView){
((ImageView)view).setImageBitmap(overlay);
}else {
view.setBackground(new BitmapDrawable(getResources(), overlay));
}
System.out.println(System.currentTimeMillis() - startMs + "ms");
}

到此就处理完毕了demo下载