为实现一些玻璃蒙版的效果，需要用到高斯算法对图片进行模糊处理，基础算法代码如下
1 public static Bitmap fastblur(Context context, Bitmap sentBitmap, int radius) { 2 3 if (VERSION.SDK_INT > 20) { 4 Bitmap bitmap = sentBitmap.copy(sentBitmap.getConfig(), true); 5 6 final RenderScript rs = RenderScript.create(context); 7 final Allocation input = Allocation.createFromBitmap(rs, sentBitmap, 8 Allocation.MipmapControl.MIPMAP_NONE, Allocation.USAGE_SCRIPT); 9 final Allocation output = Allocation.createTyped(rs, input.getType()); 10 final ScriptIntrinsicBlur script = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs)); 11 script.setRadius(radius /* e.g. 3.f */); 12 script.setInput(input); 13 script.forEach(output); 14 output.copyTo(bitmap); 15 return bitmap; 16 } 17 18 Bitmap bitmap = sentBitmap.copy(sentBitmap.getConfig(), true); 19 20 if (radius < 1) { 21 return (null); 22 } 23 24 int w = bitmap.getWidth(); 25 int h = bitmap.getHeight(); 26 27 int[] pix = new int[w * h]; 28 Log.e("pix", w + " " + h + " " + pix.length); 29 bitmap.getPixels(pix, 0, w, 0, 0, w, h); 30 31 int wm = w - 1; 32 int hm = h - 1; 33 int wh = w * h; 34 int div = radius + radius + 1; 35 36 int r[] = new int[wh]; 37 int g[] = new int[wh]; 38 int b[] = new int[wh]; 39 int rsum, gsum, bsum, x, y, i, p, yp, yi, yw; 40 int vmin[] = new int[Math.max(w, h)]; 41 42 int divsum = (div + 1) >> 1; 43 divsum *= divsum; 44 int dv[] = new int[256 * divsum]; 45 for (i = 0; i < 256 * divsum; i++) { 46 dv[i] = (i / divsum); 47 } 48 49 yw = yi = 0; 50 51 int[][] stack = new int[div][3]; 52 int stackpointer; 53 int stackstart; 54 int[] sir; 55 int rbs; 56 int r1 = radius + 1; 57 int routsum, goutsum, boutsum; 58 int rinsum, ginsum, binsum; 59 60 for (y = 0; y < h; y++) { 61 rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0; 62 for (i = -radius; i <= radius; i++) { 63 p = pix[yi + Math.min(wm, Math.max(i, 0))]; 64 sir = stack[i + radius]; 65 sir[0] = (p & 0xff0000) >> 16; 66 sir[1] = (p & 0x00ff00) >> 8; 67 sir[2] = (p & 0x0000ff); 68 rbs = r1 - Math.abs(i); 69 rsum += sir[0] * rbs; 70 gsum += sir[1] * rbs; 71 bsum += sir[2] * rbs; 72 if (i > 0) { 73 rinsum += sir[0]; 74 ginsum += sir[1]; 75 binsum += sir[2]; 76 } else { 77 routsum += sir[0]; 78 goutsum += sir[1]; 79 boutsum += sir[2]; 80 } 81 } 82 stackpointer = radius; 83 84 for (x = 0; x < w; x++) { 85 86 r[yi] = dv[rsum]; 87 g[yi] = dv[gsum]; 88 b[yi] = dv[bsum]; 89 90 rsum -= routsum; 91 gsum -= goutsum; 92 bsum -= boutsum; 93 94 stackstart = stackpointer - radius + div; 95 sir = stack[stackstart % div]; 96 97 routsum -= sir[0]; 98 goutsum -= sir[1]; 99 boutsum -= sir[2]; 100 101 if (y == 0) { 102 vmin[x] = Math.min(x + radius + 1, wm); 103 } 104 p = pix[yw + vmin[x]]; 105 106 sir[0] = (p & 0xff0000) >> 16; 107 sir[1] = (p & 0x00ff00) >> 8; 108 sir[2] = (p & 0x0000ff); 109 110 rinsum += sir[0]; 111 ginsum += sir[1]; 112 binsum += sir[2]; 113 114 rsum += rinsum; 115 gsum += ginsum; 116 bsum += binsum; 117 118 stackpointer = (stackpointer + 1) % div; 119 sir = stack[(stackpointer) % div]; 120 121 routsum += sir[0]; 122 goutsum += sir[1]; 123 boutsum += sir[2]; 124 125 rinsum -= sir[0]; 126 ginsum -= sir[1]; 127 binsum -= sir[2]; 128 129 yi++; 130 } 131 yw += w; 132 } 133 for (x = 0; x < w; x++) { 134 rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0; 135 yp = -radius * w; 136 for (i = -radius; i <= radius; i++) { 137 yi = Math.max(0, yp) + x; 138 139 sir = stack[i + radius]; 140 141 sir[0] = r[yi]; 142 sir[1] = g[yi]; 143 sir[2] = b[yi]; 144 145 rbs = r1 - Math.abs(i); 146 147 rsum += r[yi] * rbs; 148 gsum += g[yi] * rbs; 149 bsum += b[yi] * rbs; 150 151 if (i > 0) { 152 rinsum += sir[0]; 153 ginsum += sir[1]; 154 binsum += sir[2]; 155 } else { 156 routsum += sir[0]; 157 goutsum += sir[1]; 158 boutsum += sir[2]; 159 } 160 161 if (i < hm) { 162 yp += w; 163 } 164 } 165 yi = x; 166 stackpointer = radius; 167 for (y = 0; y < h; y++) { 168 // Preserve alpha channel: ( 0xff000000 & pix[yi] ) 169 pix[yi] = (0xff000000 & pix[yi]) | (dv[rsum] << 16) | (dv[gsum] << 8) | dv[bsum]; 170 171 rsum -= routsum; 172 gsum -= goutsum; 173 bsum -= boutsum; 174 175 stackstart = stackpointer - radius + div; 176 sir = stack[stackstart % div]; 177 178 routsum -= sir[0]; 179 goutsum -= sir[1]; 180 boutsum -= sir[2]; 181 182 if (x == 0) { 183 vmin[y] = Math.min(y + r1, hm) * w; 184 } 185 p = x + vmin[y]; 186 187 sir[0] = r[p]; 188 sir[1] = g[p]; 189 sir[2] = b[p]; 190 191 rinsum += sir[0]; 192 ginsum += sir[1]; 193 binsum += sir[2]; 194 195 rsum += rinsum; 196 gsum += ginsum; 197 bsum += binsum; 198 199 stackpointer = (stackpointer + 1) % div; 200 sir = stack[stackpointer]; 201 202 routsum += sir[0]; 203 goutsum += sir[1]; 204 boutsum += sir[2]; 205 206 rinsum -= sir[0]; 207 ginsum -= sir[1]; 208 binsum -= sir[2]; 209 210 yi += w; 211 } 212 } 213 214 Log.e("pix", w + " " + h + " " + pix.length); 215 bitmap.setPixels(pix, 0, w, 0, 0, w, h); 216 return (bitmap); 217 }
但是此类实现模糊效果效率是个很大的问题，所以我们需要把原图先处理一下，再进行模糊操作。
1 private static Bitmap small(Bitmap bitmap) { 2 Matrix matrix = new Matrix(); 3 matrix.postScale(0.08f, 0.08f); // 长和宽放大缩小的比例 4 Bitmap resizeBmp = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, 5 true); 6 return resizeBmp; 7 }
在使用模糊图的地方可以再添加一些透明蒙版来实现高亮偏暗的效果。