Android 高斯模糊效果從319ms到3ms的優化實現
阿新 • • 發佈:2019-01-06
之前做過高斯模糊的的效果,不過依賴一個三方庫,今天看到了一篇文章,一個類檔案就能解決,感覺竊喜,分享給大家。
使用:
Glide.with(getActivity()).load(mUser.avatarUrl).asBitmap().into(new SimpleTarget<Bitmap>() {
@Override
public void onResourceReady(Bitmap resource, GlideAnimation<? super Bitmap> glideAnimation) {
if(resource != null) {
StackBlurManager stackBlurManager = new StackBlurManager(resource);
Bitmap bitmap = stackBlurManager.process(20);
mUserContainer.setBackground(new BitmapDrawable(getResources(),bitmap));
}
}
});
使用簡單方便。
正文開始。
我要做的效果就是自定義image大小,自定義高斯模糊的區域,這樣才算我要的效果。
先上圖分別是優化前和優化後的,大家可想這個優化的作用多麼巨大,我直接把這個效果的顯示耗時在介面繪製出來了,下面圖片中的單位打錯了額,是ms。
3ms VS 209ms
4ms VS 197ms
說下實現吧,那個演算法我就沒有怎麼研究了,直接是個演算法類,直接把要模糊的Bitmap傳進去返回的就是模糊後的。程式碼如下:
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 <[email protected]>
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);
}
}
接下來就是在程式碼中去用了。
先上優化前的方法:因為下面紅字部分那句的程式碼把我坑慘了,原來用了matrix,在新建的時候還是要用matrix前的大小,我也是暈的不要不要的了。。。
還有注意要根據演示區域的大小,縮放bitmap的大小後再剪裁,再模糊。
這裡順便熟悉了canvas,drawBitmap,放大縮小的一些方法
public void test(View v) {
Bitmap srcbitmap = BitmapFactory.decodeResource(getResources(),
R.drawable.meitu);
long t1 = System.currentTimeMillis();
imageView.setBackground(new BitmapDrawable(getResources(), srcbitmap));// 設定大背景
Bitmap backBitmap = Bitmap.createBitmap(textView.getMeasuredWidth(),// 設定需高斯模糊的背景
textView.getMeasuredHeight(), Config.RGB_565);
float f1 = (float) imageView.getMeasuredWidth()
/ (float) srcbitmap.getWidth();
float f2 = (float) imageView.getMeasuredHeight()
/ (float) srcbitmap.getHeight();
Matrix matrix = new Matrix();
matrix.postScale(f1, f2);
Bitmap desBitmap = Bitmap.createBitmap(srcbitmap, 0, 0,
srcbitmap.getWidth(), srcbitmap.getHeight(), matrix, true); //因為作為背景的bmp已經縮放,那麼需要剪裁的bmp也要縮放----------這裡3/4引數是坑
Bitmap lastBitmap = Bitmap.createBitmap(desBitmap, textView.getLeft(),
textView.getTop(), textView.getMeasuredWidth(),
textView.getMeasuredHeight()); // 根據模糊的區域剪裁
Canvas canvas = new Canvas(backBitmap);
canvas.drawBitmap(lastBitmap, 0, 0, new Paint());
backBitmap = FastBlur.doBlur(backBitmap, (int) 20, true);
textView.setBackground(new BitmapDrawable(getResources(), backBitmap));
long t2 = System.currentTimeMillis();
textView.setText((t2 - t1) + "S");// 319S
}
下面是優化後的方法:
其實現原理是反正效果也是模糊的,先把圖片弄小模糊,再把模糊放大,這樣就減少了演算法的複雜度
public void test2(View v) {
int rad = 8;
Bitmap srcbitmap = BitmapFactory.decodeResource(getResources(),
R.drawable.meitu);
long t1 = System.currentTimeMillis();
imageView.setBackground(new BitmapDrawable(getResources(), srcbitmap));// 設定大背景
Bitmap backBitmap = Bitmap.createBitmap(textView.getMeasuredWidth()/rad,// 設定需高斯模糊的背景
textView.getMeasuredHeight()/rad, Config.RGB_565);
float f1 = (float) imageView.getMeasuredWidth()
/ (float) srcbitmap.getWidth();
float f2 = (float) imageView.getMeasuredHeight()
/ (float) srcbitmap.getHeight();
Matrix matrix = new Matrix();
matrix.postScale(f1/8, f2/8);
Bitmap desBitmap = Bitmap.createBitmap(srcbitmap, 0, 0,
srcbitmap.getWidth(), srcbitmap.getHeight(), matrix, true); // 因為作為背景的bmp已經縮放,那麼需要剪裁的bmp也要縮放----------這裡3/4引數是坑
Bitmap lastBitmap = Bitmap.createBitmap(desBitmap, textView.getLeft()/8,
textView.getTop()/8, textView.getMeasuredWidth()/8,
textView.getMeasuredHeight()/8); // 根據模糊的區域剪裁
Canvas canvas = new Canvas(backBitmap);
canvas.drawBitmap(lastBitmap, 0, 0, new Paint());
backBitmap = FastBlur.doBlur(backBitmap, (int) 2, true);
canvas.scale(1/rad, 1/rad);
textView.setBackground(new BitmapDrawable(getResources(), backBitmap));
long t2 = System.currentTimeMillis();
textView.setText((t2 - t1) + "S");// 2S
}