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      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 
      8 
      9 #include "SkFixed.h"
     10 #include "SkReadBuffer.h"
     11 #include "SkString.h"
     12 #include "SkTableMaskFilter.h"
     13 #include "SkWriteBuffer.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 = nullptr;
     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     wb.writeByteArray(fTable, 256);
     75 }
     76 
     77 sk_sp<SkFlattenable> SkTableMaskFilter::CreateProc(SkReadBuffer& buffer) {
     78     uint8_t table[256];
     79     if (!buffer.readByteArray(table, 256)) {
     80         return nullptr;
     81     }
     82     return sk_sp<SkFlattenable>(Create(table));
     83 }
     84 
     85 ///////////////////////////////////////////////////////////////////////////////
     86 
     87 void SkTableMaskFilter::MakeGammaTable(uint8_t table[256], SkScalar gamma) {
     88     const float dx = 1 / 255.0f;
     89     const float g = SkScalarToFloat(gamma);
     90 
     91     float x = 0;
     92     for (int i = 0; i < 256; i++) {
     93      // float ee = powf(x, g) * 255;
     94         table[i] = SkTPin(sk_float_round2int(powf(x, g) * 255), 0, 255);
     95         x += dx;
     96     }
     97 }
     98 
     99 void SkTableMaskFilter::MakeClipTable(uint8_t table[256], uint8_t min,
    100                                       uint8_t max) {
    101     if (0 == max) {
    102         max = 1;
    103     }
    104     if (min >= max) {
    105         min = max - 1;
    106     }
    107     SkASSERT(min < max);
    108 
    109     SkFixed scale = (1 << 16) * 255 / (max - min);
    110     memset(table, 0, min + 1);
    111     for (int i = min + 1; i < max; i++) {
    112         int value = SkFixedRoundToInt(scale * (i - min));
    113         SkASSERT(value <= 255);
    114         table[i] = value;
    115     }
    116     memset(table + max, 255, 256 - max);
    117 
    118 #if 0
    119     int j;
    120     for (j = 0; j < 256; j++) {
    121         if (table[j]) {
    122             break;
    123         }
    124     }
    125     SkDebugf("%d %d start [%d]", min, max, j);
    126     for (; j < 256; j++) {
    127         SkDebugf(" %d", table[j]);
    128     }
    129     SkDebugf("\n\n");
    130 #endif
    131 }
    132 
    133 #ifndef SK_IGNORE_TO_STRING
    134 void SkTableMaskFilter::toString(SkString* str) const {
    135     str->append("SkTableMaskFilter: (");
    136 
    137     str->append("table: ");
    138     for (int i = 0; i < 255; ++i) {
    139         str->appendf("%d, ", fTable[i]);
    140     }
    141     str->appendf("%d", fTable[255]);
    142 
    143     str->append(")");
    144 }
    145 #endif
    146