Line data    Source code

       1             : /*
       2             :  * Copyright 2011 Google Inc.
       3             :  *
       4             :  * Use of this source code is governed by a BSD-style license that can be
       5             :  * found in the LICENSE file.
       6             :  */
       7             : #include "SkUnPreMultiply.h"
       8             : #include "SkColorPriv.h"
       9             : 
      10           0 : SkColor SkUnPreMultiply::PMColorToColor(SkPMColor c) {
      11           0 :     const unsigned a = SkGetPackedA32(c);
      12           0 :     const Scale scale = GetScale(a);
      13           0 :     return SkColorSetARGB(a,
      14             :                           ApplyScale(scale, SkGetPackedR32(c)),
      15             :                           ApplyScale(scale, SkGetPackedG32(c)),
      16             :                           ApplyScale(scale, SkGetPackedB32(c)));
      17             : }
      18             : 
      19           0 : uint32_t SkUnPreMultiply::UnPreMultiplyPreservingByteOrder(SkPMColor c) {
      20           0 :     const U8CPU a = SkGetPackedA32(c);
      21           0 :     const Scale scale = GetScale(a);
      22           0 :     return SkPackARGB32NoCheck(a,
      23           0 :                                ApplyScale(scale, SkGetPackedR32(c)),
      24           0 :                                ApplyScale(scale, SkGetPackedG32(c)),
      25           0 :                                ApplyScale(scale, SkGetPackedB32(c)));
      26             : }
      27             : 
      28             : const uint32_t SkUnPreMultiply::gTable[] = {
      29             :     0x00000000, 0xFF000000, 0x7F800000, 0x55000000, 0x3FC00000, 0x33000000, 0x2A800000, 0x246DB6DB,
      30             :     0x1FE00000, 0x1C555555, 0x19800000, 0x172E8BA3, 0x15400000, 0x139D89D9, 0x1236DB6E, 0x11000000,
      31             :     0x0FF00000, 0x0F000000, 0x0E2AAAAB, 0x0D6BCA1B, 0x0CC00000, 0x0C249249, 0x0B9745D1, 0x0B1642C8,
      32             :     0x0AA00000, 0x0A333333, 0x09CEC4EC, 0x0971C71C, 0x091B6DB7, 0x08CB08D4, 0x08800000, 0x0839CE74,
      33             :     0x07F80000, 0x07BA2E8C, 0x07800000, 0x07492492, 0x07155555, 0x06E45307, 0x06B5E50D, 0x0689D89E,
      34             :     0x06600000, 0x063831F4, 0x06124925, 0x05EE23B9, 0x05CBA2E9, 0x05AAAAAB, 0x058B2164, 0x056CEFA9,
      35             :     0x05500000, 0x05343EB2, 0x0519999A, 0x05000000, 0x04E76276, 0x04CFB2B8, 0x04B8E38E, 0x04A2E8BA,
      36             :     0x048DB6DB, 0x0479435E, 0x0465846A, 0x045270D0, 0x04400000, 0x042E29F8, 0x041CE73A, 0x040C30C3,
      37             :     0x03FC0000, 0x03EC4EC5, 0x03DD1746, 0x03CE540F, 0x03C00000, 0x03B21643, 0x03A49249, 0x03976FC6,
      38             :     0x038AAAAB, 0x037E3F20, 0x03722983, 0x03666666, 0x035AF287, 0x034FCACE, 0x0344EC4F, 0x033A5441,
      39             :     0x03300000, 0x0325ED09, 0x031C18FA, 0x0312818B, 0x03092492, 0x03000000, 0x02F711DC, 0x02EE5847,
      40             :     0x02E5D174, 0x02DD7BAF, 0x02D55555, 0x02CD5CD6, 0x02C590B2, 0x02BDEF7C, 0x02B677D4, 0x02AF286C,
      41             :     0x02A80000, 0x02A0FD5C, 0x029A1F59, 0x029364D9, 0x028CCCCD, 0x0286562E, 0x02800000, 0x0279C952,
      42             :     0x0273B13B, 0x026DB6DB, 0x0267D95C, 0x026217ED, 0x025C71C7, 0x0256E62A, 0x0251745D, 0x024C1BAD,
      43             :     0x0246DB6E, 0x0241B2F9, 0x023CA1AF, 0x0237A6F5, 0x0232C235, 0x022DF2DF, 0x02293868, 0x02249249,
      44             :     0x02200000, 0x021B810F, 0x021714FC, 0x0212BB51, 0x020E739D, 0x020A3D71, 0x02061862, 0x02020408,
      45             :     0x01FE0000, 0x01FA0BE8, 0x01F62762, 0x01F25214, 0x01EE8BA3, 0x01EAD3BB, 0x01E72A08, 0x01E38E39,
      46             :     0x01E00000, 0x01DC7F11, 0x01D90B21, 0x01D5A3EA, 0x01D24925, 0x01CEFA8E, 0x01CBB7E3, 0x01C880E5,
      47             :     0x01C55555, 0x01C234F7, 0x01BF1F90, 0x01BC14E6, 0x01B914C2, 0x01B61EED, 0x01B33333, 0x01B05161,
      48             :     0x01AD7943, 0x01AAAAAB, 0x01A7E567, 0x01A5294A, 0x01A27627, 0x019FCBD2, 0x019D2A20, 0x019A90E8,
      49             :     0x01980000, 0x01957741, 0x0192F685, 0x01907DA5, 0x018E0C7D, 0x018BA2E9, 0x018940C5, 0x0186E5F1,
      50             :     0x01849249, 0x018245AE, 0x01800000, 0x017DC11F, 0x017B88EE, 0x0179574E, 0x01772C23, 0x01750750,
      51             :     0x0172E8BA, 0x0170D045, 0x016EBDD8, 0x016CB157, 0x016AAAAB, 0x0168A9B9, 0x0166AE6B, 0x0164B8A8,
      52             :     0x0162C859, 0x0160DD68, 0x015EF7BE, 0x015D1746, 0x015B3BEA, 0x01596596, 0x01579436, 0x0155C7B5,
      53             :     0x01540000, 0x01523D04, 0x01507EAE, 0x014EC4EC, 0x014D0FAC, 0x014B5EDD, 0x0149B26D, 0x01480A4B,
      54             :     0x01466666, 0x0144C6B0, 0x01432B17, 0x0141938C, 0x01400000, 0x013E7064, 0x013CE4A9, 0x013B5CC1,
      55             :     0x0139D89E, 0x01385831, 0x0136DB6E, 0x01356246, 0x0133ECAE, 0x01327A97, 0x01310BF6, 0x012FA0BF,
      56             :     0x012E38E4, 0x012CD45A, 0x012B7315, 0x012A150B, 0x0128BA2F, 0x01276276, 0x01260DD6, 0x0124BC45,
      57             :     0x01236DB7, 0x01222222, 0x0120D97D, 0x011F93BC, 0x011E50D8, 0x011D10C5, 0x011BD37A, 0x011A98EF,
      58             :     0x0119611A, 0x01182BF3, 0x0116F970, 0x0115C988, 0x01149C34, 0x0113716B, 0x01124925, 0x01112359,
      59             :     0x01100000, 0x010EDF12, 0x010DC087, 0x010CA458, 0x010B8A7E, 0x010A72F0, 0x01095DA9, 0x01084AA0,
      60             :     0x010739CE, 0x01062B2E, 0x01051EB8, 0x01041466, 0x01030C31, 0x01020612, 0x01010204, 0x01000000
      61             : };
      62             : 
      63             : #ifdef BUILD_DIVIDE_TABLE
      64             : void SkUnPreMultiply_BuildTable() {
      65             :     for (unsigned i = 0; i <= 255; i++) {
      66             :         uint32_t scale;
      67             : 
      68             :         if (0 == i) {
      69             :             scale = 0;
      70             :         } else {
      71             :             scale = ((255 << 24) + (i >> 1)) / i;
      72             :         }
      73             : 
      74             :         SkDebugf(" 0x%08X,", scale);
      75             :         if ((i & 7) == 7) {
      76             :             SkDebugf("\n");
      77             :         }
      78             : 
      79             :         // test the result
      80             :         for (int j = 1; j <= i; j++) {
      81             :             uint32_t test = (j * scale + (1 << 23)) >> 24;
      82             :             uint32_t div = roundf(j * 255.0f / i);
      83             :             int diff = SkAbs32(test - div);
      84             :             SkASSERT(diff <= 1 && test <= 255);
      85             :         }
      86             :     }
      87             : }
      88             : #endif