目前在android上很少见到毛玻璃效果，我认为很重要的原因是性能问题，虚化一张图片所需要的时间会因设备而异，如果为了虚化使得用户需要刻意等待，那么就是弊大于利。另外，Google官方提供的renderScript一般只是做一些小幅度的虚化，很难达到毛玻璃这类深度虚化效果。
建议对静态的内容做高斯模糊，不要在滑动或者定时地进行计算刷新
package com.demo.utils;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.LinearGradient;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Shader;
import android.graphics.drawable.Drawable;
import android.os.Build;
import android.util.DisplayMetrics;
import android.view.WindowManager;
/**
* 高斯模糊工具类
*/
public class BlurUtil {
public static DisplayMetrics getDisplayMetrics(Context context) {
DisplayMetrics displaymetrics = new DisplayMetrics();
((WindowManager) context.getSystemService(
Context.WINDOW_SERVICE)).getDefaultDisplay().getMetrics(
displaymetrics);
return displaymetrics;
}
/**
* 根据图片绘制高斯模糊背景
*
* @param srcBitmap 源图片
* @param radius 圆角
* @param canReuseInBitmap 重用资源
* @return 高斯模糊后的资源
*/
public static Bitmap doBlur(Context context,Bitmap srcBitmap, int radius, boolean canReuseInBitmap) {
Bitmap bitmap;
if (canReuseInBitmap) {
bitmap = srcBitmap;
} else {
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 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);
drawForeground(context,bitmap, w, h);
return (bitmap);
}
/**
* 绘制前景
*
* @param context
* @param bitmap
* @param w
* @param h
*/
private static void drawForeground(Context context, Bitmap bitmap, int w, int h) {
Canvas canvas = new Canvas(bitmap);
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setStyle(Paint.Style.FILL);
Shader shader = new LinearGradient(0, (int) (h / 2.0), w, (int) (h / 2.0), Color.parseColor("#A6100700"), Color.parseColor("#BF311C00"), Shader.TileMode.MIRROR);
paint.setShader(shader);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
int dp10 = (int) dpToPixel(context, 10);
canvas.drawRoundRect(0, 0, w, h, dp10, dp10, paint);
} else {
canvas.drawRect(0, 0, w, h, paint);
}
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
}
private static float dpToPixel(Context context, float dp) {
return dp * (getDisplayMetrics(context).densityDpi / 160F);
}
public static Bitmap drawableToBitmap(Drawable drawable) {
int intrinsicWidth = drawable.getIntrinsicWidth();
int intrinsicHeight = drawable.getIntrinsicHeight();
Bitmap bitmap = Bitmap.createBitmap(intrinsicWidth, intrinsicHeight,
drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565);
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, intrinsicWidth, intrinsicHeight);
drawable.draw(canvas);
return bitmap;
}
}