Revert "remove unused TableMaskFilter"

This reverts commit d72b55b32cf6b3bf7b8d7b4c08045597652285cf.

Reason for revert: used by android

Original change's description:
> remove unused TableMaskFilter
> 
> will revert if its needed in android
> 
> Bug: skia:
> Change-Id: I2ef777d31de4bbed6556d013054083ff6ff2cb8c
> Reviewed-on: https://skia-review.googlesource.com/20206
> Reviewed-by: Mike Reed <reed@google.com>
> Commit-Queue: Mike Reed <reed@google.com>

TBR=djsollen@google.com,reed@google.com,stani@google.com

Change-Id: I8ea36a912496e12c9fbfb73587d11e002252e8b8
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:
Reviewed-on: https://skia-review.googlesource.com/20212
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>

3 files changed, 213 insertions, 0 deletions

diff --git a/gn/effects.gni b/gn/effects.gni
index 3c8ef914ca..9418e12dd0 100644
--- a/gn/effects.gni
+++ b/gn/effects.gni
@@ -55,6 +55,7 @@ skia_effects_sources = [
   "$_src/effects/SkPictureImageFilter.cpp",
   "$_src/effects/SkRRectsGaussianEdgeMaskFilter.cpp",
   "$_src/effects/SkTableColorFilter.cpp",
+  "$_src/effects/SkTableMaskFilter.cpp",
   "$_src/effects/SkTileImageFilter.cpp",
   "$_src/effects/SkXfermodeImageFilter.cpp",
 
@@ -110,6 +111,7 @@ skia_effects_sources = [
   "$_include/effects/SkPerlinNoiseShader.h",
   "$_include/effects/SkRRectsGaussianEdgeMaskFilter.h",
   "$_include/effects/SkTableColorFilter.h",
+  "$_include/effects/SkTableMaskFilter.h",
   "$_include/effects/SkTileImageFilter.h",
   "$_include/effects/SkXfermodeImageFilter.h",
 ]
diff --git a/include/effects/SkTableMaskFilter.h b/include/effects/SkTableMaskFilter.h
new file mode 100644
index 0000000000..f226dd1760
--- /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:
+    ~SkTableMaskFilter() override;
+
+    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