Android毛玻璃背景效果
Scofield_Phil 人气:0step1:先进行截屏操作
step2:进行毛玻璃处理
毛玻璃处理的原理为先通过缩小图片,使其丢失一些像素点,接着进行模糊化处理,然后再放大到原来尺寸。由于图片缩小后再进行模糊处理,需要处理的像素点和半径都变小,从而使得模糊处理速度加快。
创建的bitmap为原图的1/8大小,接着,使用fastBlur来进行模糊化处理,最后设置背景,此时,背景图会自动放大到初始大小。注意,由于这里进行了缩放,radius的取值也要比之前小得多(这里将原始取值除以8得到近似值2)。
它相对于renderScript方案来说,节省了拷贝bitmap到Allocation中,处理完后再拷贝回来的时间开销。
activity_main.xml:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/relative" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@drawable/screenshot" > </RelativeLayout>
MainActivity:
package com.scott.blurdemo; import android.annotation.TargetApi; import android.app.Activity; import android.graphics.Bitmap; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Rect; import android.graphics.drawable.BitmapDrawable; import android.os.Build; import android.os.Bundle; import android.support.v7.app.ActionBarActivity; import android.util.Log; import android.view.View; @TargetApi(Build.VERSION_CODES.JELLY_BEAN) public class MainActivity extends ActionBarActivity { private Bitmap bitmap; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } @Override public void onWindowFocusChanged(boolean hasFocus) { super.onWindowFocusChanged(hasFocus); if (null == bitmap) { // 需要在actvity显示出来后 再进行截屏操作。这里进行模糊化图片是个耗时操作,建议在项目中放到非UI线程去做 bitmap = takeScreenShot(MainActivity.this); } if (bitmap != null) { blur(bitmap, findViewById(R.id.relative)); } } /** * 屏幕截图 * * @param activity * @return */ private Bitmap takeScreenShot(Activity activity) { // View是你需要截图的View View view = activity.getWindow().getDecorView(); view.setDrawingCacheEnabled(true); view.buildDrawingCache(); Bitmap b1 = view.getDrawingCache(); // 获取状态栏高度 Rect frame = new Rect(); activity.getWindow().getDecorView().getWindowVisibleDisplayFrame(frame); int statusBarHeight = frame.top; // 获取屏幕长和高 int width = activity.getWindowManager().getDefaultDisplay().getWidth(); int height = activity.getWindowManager().getDefaultDisplay() .getHeight(); // 去掉标题栏 // Bitmap b = Bitmap.createBitmap(b1, 0, 25, 320, 455); Bitmap b = Bitmap.createBitmap(b1, 0, statusBarHeight, width, height - statusBarHeight); view.destroyDrawingCache(); return b; } private void blur(Bitmap bkg, View view) { long startMs = System.currentTimeMillis(); float radius = 2; float scaleFactor = 8; 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); view.setBackground(new BitmapDrawable(getResources(), overlay)); Log.e("Blur", "cost " + (System.currentTimeMillis() - startMs) + "ms"); } }
FastBlur.java:
package com.scott.blurdemo; import android.graphics.Bitmap; 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); } }
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