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      1 
      2 /*
      3  * Copyright 2011 Google Inc.
      4  *
      5  * Use of this source code is governed by a BSD-style license that can be
      6  * found in the LICENSE file.
      7  */
      8 
      9 
     10 #include "SkTableMaskFilter.h"
     11 #include "SkReadBuffer.h"
     12 #include "SkWriteBuffer.h"
     13 #include "SkString.h"
     14 
     15 SkTableMaskFilter::SkTableMaskFilter() {
     16     for (int i = 0; i < 256; i++) {
     17         fTable[i] = i;
     18     }
     19 }
     20 
     21 SkTableMaskFilter::SkTableMaskFilter(const uint8_t table[256]) {
     22     memcpy(fTable, table, sizeof(fTable));
     23 }
     24 
     25 SkTableMaskFilter::~SkTableMaskFilter() {}
     26 
     27 bool SkTableMaskFilter::filterMask(SkMask* dst, const SkMask& src,
     28                                  const SkMatrix&, SkIPoint* margin) const {
     29     if (src.fFormat != SkMask::kA8_Format) {
     30         return false;
     31     }
     32 
     33     dst->fBounds = src.fBounds;
     34     dst->fRowBytes = SkAlign4(dst->fBounds.width());
     35     dst->fFormat = SkMask::kA8_Format;
     36     dst->fImage = NULL;
     37 
     38     if (src.fImage) {
     39         dst->fImage = SkMask::AllocImage(dst->computeImageSize());
     40 
     41         const uint8_t* srcP = src.fImage;
     42         uint8_t* dstP = dst->fImage;
     43         const uint8_t* table = fTable;
     44         int dstWidth = dst->fBounds.width();
     45         int extraZeros = dst->fRowBytes - dstWidth;
     46 
     47         for (int y = dst->fBounds.height() - 1; y >= 0; --y) {
     48             for (int x = dstWidth - 1; x >= 0; --x) {
     49                 dstP[x] = table[srcP[x]];
     50             }
     51             srcP += src.fRowBytes;
     52             // we can't just inc dstP by rowbytes, because if it has any
     53             // padding between its width and its rowbytes, we need to zero those
     54             // so that the bitters can read those safely if that is faster for
     55             // them
     56             dstP += dstWidth;
     57             for (int i = extraZeros - 1; i >= 0; --i) {
     58                 *dstP++ = 0;
     59             }
     60         }
     61     }
     62 
     63     if (margin) {
     64         margin->set(0, 0);
     65     }
     66     return true;
     67 }
     68 
     69 SkMask::Format SkTableMaskFilter::getFormat() const {
     70     return SkMask::kA8_Format;
     71 }
     72 
     73 void SkTableMaskFilter::flatten(SkWriteBuffer& wb) const {
     74     this->INHERITED::flatten(wb);
     75     wb.writeByteArray(fTable, 256);
     76 }
     77 
     78 SkTableMaskFilter::SkTableMaskFilter(SkReadBuffer& rb)
     79         : INHERITED(rb) {
     80     SkASSERT(256 == rb.getArrayCount());
     81     rb.readByteArray(fTable, 256);
     82 }
     83 
     84 ///////////////////////////////////////////////////////////////////////////////
     85 
     86 void SkTableMaskFilter::MakeGammaTable(uint8_t table[256], SkScalar gamma) {
     87     const float dx = 1 / 255.0f;
     88     const float g = SkScalarToFloat(gamma);
     89 
     90     float x = 0;
     91     for (int i = 0; i < 256; i++) {
     92      // float ee = powf(x, g) * 255;
     93         table[i] = SkPin32(sk_float_round2int(powf(x, g) * 255), 0, 255);
     94         x += dx;
     95     }
     96 }
     97 
     98 void SkTableMaskFilter::MakeClipTable(uint8_t table[256], uint8_t min,
     99                                       uint8_t max) {
    100     if (0 == max) {
    101         max = 1;
    102     }
    103     if (min >= max) {
    104         min = max - 1;
    105     }
    106     SkASSERT(min < max);
    107 
    108     SkFixed scale = (1 << 16) * 255 / (max - min);
    109     memset(table, 0, min + 1);
    110     for (int i = min + 1; i < max; i++) {
    111         int value = SkFixedRoundToInt(scale * (i - min));
    112         SkASSERT(value <= 255);
    113         table[i] = value;
    114     }
    115     memset(table + max, 255, 256 - max);
    116 
    117 #if 0
    118     int j;
    119     for (j = 0; j < 256; j++) {
    120         if (table[j]) {
    121             break;
    122         }
    123     }
    124     SkDebugf("%d %d start [%d]", min, max, j);
    125     for (; j < 256; j++) {
    126         SkDebugf(" %d", table[j]);
    127     }
    128     SkDebugf("\n\n");
    129 #endif
    130 }
    131 
    132 #ifndef SK_IGNORE_TO_STRING
    133 void SkTableMaskFilter::toString(SkString* str) const {
    134     str->append("SkTableMaskFilter: (");
    135 
    136     str->append("table: ");
    137     for (int i = 0; i < 255; ++i) {
    138         str->appendf("%d, ", fTable[i]);
    139     }
    140     str->appendf("%d", fTable[255]);
    141 
    142     str->append(")");
    143 }
    144 #endif
    145