对图片进行高斯模糊处理的办法

高斯模糊一词简单理解为图片看上去有点朦胧美的感觉。此文是结合sean_帅恩博主写的一篇博文。

首先最重要的高斯模糊帮助类：

package com.example.lianshou_test.utils;

import android.annotation.TargetApi;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.drawable.BitmapDrawable;
import android.os.Build;
import android.view.View;

/**
 * 设置高斯模糊的工具类
 * 
 */
public class GaussianBlurUtils {

    /**
     * 设置高斯模糊
     *
     * ps:
     * 设置高斯模糊是依靠scaleFactor和radius配合使用的，比如这里默认设置是：scaleFactor = 8;radius = 2; 模糊效果和scaleFactor = 1;radius = 20;是一样的，而且效率高
     * @param fromView 从某个View获取截图
     * @param toView 高斯模糊设置到某个View上
     * @param radius 模糊度
     * @param scaleFactor 缩放比例
     */
    @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
    public static void blur(View fromView, View toView,float radius,float scaleFactor) {

        //获取View的截图
        fromView.buildDrawingCache();
        Bitmap bkg = fromView.getDrawingCache();

        if (radius<1||radius>26) {
            scaleFactor = 8;
            radius = 2;
        }

        Bitmap overlay = Bitmap.createBitmap((int) (toView.getMeasuredWidth()/scaleFactor),
                (int) (toView.getMeasuredHeight()/scaleFactor), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(overlay);
        canvas.translate(-toView.getLeft()/scaleFactor, -toView.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 = GaussianBlurUtils.doBlur(overlay, (int) radius, true);
        toView.setBackground(new BitmapDrawable(overlay));

    }

    /**
     * 高斯模糊操作
     * @param sentBitmap
     * @param radius
     * @param canReuseInBitmap
     * @return
     */
    public static Bitmap doBlur(Bitmap sentBitmap, int radius, boolean canReuseInBitmap) {

        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);
    }
}

调用方式：

GaussianBlurUtils.blur(image, text, 2, 8);

xml布局，仅作参考：

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

    <ImageView
        android:id="@+id/picture"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scaleType="centerCrop"
        android:src="@drawable/test" />

    <TextView
        android:id="@+id/text"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="bottom|center"
        android:text="Hello World"
        android:textColor="@android:color/white"
        android:textSize="48sp"
        android:textStyle="bold" />

    <LinearLayout
        android:id="@+id/controls"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#000000"
        android:orientation="vertical" >
        <CheckBox
            android:id="@+id/main_cb_fastblur"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="是否进行高斯模糊"
            android:textColor="@android:color/white"
            android:padding="20dp"/>

    </LinearLayout>
</FrameLayout>

下面就来说下注意事项了：

1：fromview和toview传参时别搞反了，formview是从某个view获取的截图在做处理最后设置到toview背景上。

2：模糊度和缩放比例范围是1到25之间，默认是2,8   大家也可以根据需求做不同调整

3：formview和toview的宽高必须是大于0.

附上效果图：

上面显示出了处理高斯模糊的时间，相比还是比较快的。。。。完结！！！