Revert of remove unused TableMaskFilter (patchset #1 id:1 of https://codereview.chromium.org/2156463002/ )

Reason for revert:
Needed for Android:

frameworks/base/core/jni/android/graphics/MaskFilter.cpp:5:10: fatal error: 'SkTableMaskFilter.h' file not found

Original issue's description:
> remove unused TableMaskFilter
>
> BUG=skia:
> GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2156463002
>
> TBR=
>
> Committed: https://skia.googlesource.com/skia/+/59779ae8ce316bf8b8082ec2df1683ccd38161f1

TBR=reed@google.com
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=skia:

Review-Url: https://codereview.chromium.org/2156183002

3 files changed, 213 insertions, 0 deletions

diff --git a/gyp/effects.gypi b/gyp/effects.gypi
index 149d9bfc2e..33c8c13d41 100644
--- a/gyp/effects.gypi
+++ b/gyp/effects.gypi
@@ -61,6 +61,7 @@
     '<(skia_src_path)/effects/SkPerlinNoiseShader.cpp',
     '<(skia_src_path)/effects/SkPictureImageFilter.cpp',
     '<(skia_src_path)/effects/SkTableColorFilter.cpp',
+    '<(skia_src_path)/effects/SkTableMaskFilter.cpp',
     '<(skia_src_path)/effects/SkTileImageFilter.cpp',
     '<(skia_src_path)/effects/SkXfermodeImageFilter.cpp',
 
@@ -116,6 +117,7 @@
     '<(skia_include_path)/effects/SkPaintImageFilter.h',
     '<(skia_include_path)/effects/SkPerlinNoiseShader.h',
     '<(skia_include_path)/effects/SkTableColorFilter.h',
+    '<(skia_include_path)/effects/SkTableMaskFilter.h',
     '<(skia_include_path)/effects/SkTileImageFilter.h',
     '<(skia_include_path)/effects/SkXfermodeImageFilter.h',
   ],
diff --git a/include/effects/SkTableMaskFilter.h b/include/effects/SkTableMaskFilter.h
new file mode 100644
index 0000000000..757ddf2084
--- /dev/null
+++ b/include/effects/SkTableMaskFilter.h
@@ -0,0 +1,66 @@
+/*
+ * Copyright 2006 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkTableMaskFilter_DEFINED
+#define SkTableMaskFilter_DEFINED
+
+#include "SkMaskFilter.h"
+#include "SkScalar.h"
+
+/** \class SkTableMaskFilter
+
+    Applies a table lookup on each of the alpha values in the mask.
+    Helper methods create some common tables (e.g. gamma, clipping)
+ */
+class SK_API SkTableMaskFilter : public SkMaskFilter {
+public:
+    /** Utility that sets the gamma table
+     */
+    static void MakeGammaTable(uint8_t table[256], SkScalar gamma);
+
+    /** Utility that creates a clipping table: clamps values below min to 0
+        and above max to 255, and rescales the remaining into 0..255
+     */
+    static void MakeClipTable(uint8_t table[256], uint8_t min, uint8_t max);
+
+    static SkMaskFilter* Create(const uint8_t table[256]) {
+        return new SkTableMaskFilter(table);
+    }
+
+    static SkMaskFilter* CreateGamma(SkScalar gamma) {
+        uint8_t table[256];
+        MakeGammaTable(table, gamma);
+        return new SkTableMaskFilter(table);
+    }
+
+    static SkMaskFilter* CreateClip(uint8_t min, uint8_t max) {
+        uint8_t table[256];
+        MakeClipTable(table, min, max);
+        return new SkTableMaskFilter(table);
+    }
+
+    SkMask::Format getFormat() const override;
+    bool filterMask(SkMask*, const SkMask&, const SkMatrix&, SkIPoint*) const override;
+
+    SK_TO_STRING_OVERRIDE()
+    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkTableMaskFilter)
+
+protected:
+    virtual ~SkTableMaskFilter();
+
+    void flatten(SkWriteBuffer&) const override;
+
+private:
+    SkTableMaskFilter();
+    explicit SkTableMaskFilter(const uint8_t table[256]);
+
+    uint8_t fTable[256];
+
+    typedef SkMaskFilter INHERITED;
+};
+
+#endif
diff --git a/src/effects/SkTableMaskFilter.cpp b/src/effects/SkTableMaskFilter.cpp
new file mode 100644
index 0000000000..a3b4038a2f
--- /dev/null
+++ b/src/effects/SkTableMaskFilter.cpp
@@ -0,0 +1,145 @@
+/*
+ * Copyright 2011 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+
+#include "SkFixed.h"
+#include "SkReadBuffer.h"
+#include "SkString.h"
+#include "SkTableMaskFilter.h"
+#include "SkWriteBuffer.h"
+
+SkTableMaskFilter::SkTableMaskFilter() {
+    for (int i = 0; i < 256; i++) {
+        fTable[i] = i;
+    }
+}
+
+SkTableMaskFilter::SkTableMaskFilter(const uint8_t table[256]) {
+    memcpy(fTable, table, sizeof(fTable));
+}
+
+SkTableMaskFilter::~SkTableMaskFilter() {}
+
+bool SkTableMaskFilter::filterMask(SkMask* dst, const SkMask& src,
+                                 const SkMatrix&, SkIPoint* margin) const {
+    if (src.fFormat != SkMask::kA8_Format) {
+        return false;
+    }
+
+    dst->fBounds = src.fBounds;
+    dst->fRowBytes = SkAlign4(dst->fBounds.width());
+    dst->fFormat = SkMask::kA8_Format;
+    dst->fImage = nullptr;
+
+    if (src.fImage) {
+        dst->fImage = SkMask::AllocImage(dst->computeImageSize());
+
+        const uint8_t* srcP = src.fImage;
+        uint8_t* dstP = dst->fImage;
+        const uint8_t* table = fTable;
+        int dstWidth = dst->fBounds.width();
+        int extraZeros = dst->fRowBytes - dstWidth;
+
+        for (int y = dst->fBounds.height() - 1; y >= 0; --y) {
+            for (int x = dstWidth - 1; x >= 0; --x) {
+                dstP[x] = table[srcP[x]];
+            }
+            srcP += src.fRowBytes;
+            // we can't just inc dstP by rowbytes, because if it has any
+            // padding between its width and its rowbytes, we need to zero those
+            // so that the bitters can read those safely if that is faster for
+            // them
+            dstP += dstWidth;
+            for (int i = extraZeros - 1; i >= 0; --i) {
+                *dstP++ = 0;
+            }
+        }
+    }
+
+    if (margin) {
+        margin->set(0, 0);
+    }
+    return true;
+}
+
+SkMask::Format SkTableMaskFilter::getFormat() const {
+    return SkMask::kA8_Format;
+}
+
+void SkTableMaskFilter::flatten(SkWriteBuffer& wb) const {
+    wb.writeByteArray(fTable, 256);
+}
+
+sk_sp<SkFlattenable> SkTableMaskFilter::CreateProc(SkReadBuffer& buffer) {
+    uint8_t table[256];
+    if (!buffer.readByteArray(table, 256)) {
+        return nullptr;
+    }
+    return sk_sp<SkFlattenable>(Create(table));
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+void SkTableMaskFilter::MakeGammaTable(uint8_t table[256], SkScalar gamma) {
+    const float dx = 1 / 255.0f;
+    const float g = SkScalarToFloat(gamma);
+
+    float x = 0;
+    for (int i = 0; i < 256; i++) {
+     // float ee = powf(x, g) * 255;
+        table[i] = SkTPin(sk_float_round2int(powf(x, g) * 255), 0, 255);
+        x += dx;
+    }
+}
+
+void SkTableMaskFilter::MakeClipTable(uint8_t table[256], uint8_t min,
+                                      uint8_t max) {
+    if (0 == max) {
+        max = 1;
+    }
+    if (min >= max) {
+        min = max - 1;
+    }
+    SkASSERT(min < max);
+
+    SkFixed scale = (1 << 16) * 255 / (max - min);
+    memset(table, 0, min + 1);
+    for (int i = min + 1; i < max; i++) {
+        int value = SkFixedRoundToInt(scale * (i - min));
+        SkASSERT(value <= 255);
+        table[i] = value;
+    }
+    memset(table + max, 255, 256 - max);
+
+#if 0
+    int j;
+    for (j = 0; j < 256; j++) {
+        if (table[j]) {
+            break;
+        }
+    }
+    SkDebugf("%d %d start [%d]", min, max, j);
+    for (; j < 256; j++) {
+        SkDebugf(" %d", table[j]);
+    }
+    SkDebugf("\n\n");
+#endif
+}
+
+#ifndef SK_IGNORE_TO_STRING
+void SkTableMaskFilter::toString(SkString* str) const {
+    str->append("SkTableMaskFilter: (");
+
+    str->append("table: ");
+    for (int i = 0; i < 255; ++i) {
+        str->appendf("%d, ", fTable[i]);
+    }
+    str->appendf("%d", fTable[255]);
+
+    str->append(")");
+}
+#endif