Revert of Add SkBitmap::readPixels() and reimplement copyTo and SkCanvas::readPixels (https://codereview.chromium.org/388803007/)

Reason for revert:
still failing (randomly?) bench sometimes. need stack dump to diagnose.

Original issue's description:
> Add SkBitmap::readPixels() and reimplement copyTo and SkCanvas::readPixels
> usning it.
>
> Revert "Revert of add readPixels() to SkBitmap (https://codereview.chromium.org/377303002/)"
>
> This reverts commit d08cb905a7cc80d8fb868bbd14fffe1cd68adcce.
>
> TBR=scroggo@google.com
>
> Committed: https://skia.googlesource.com/skia/+/debba5c3d091159149f8a88ab5dcd44dd72e0dc7

R=reed@google.com
TBR=reed@google.com
NOTREECHECKS=true
NOTRY=true

Author: reed@chromium.org

Review URL: https://codereview.chromium.org/382543005

4 files changed, 130 insertions, 219 deletions

diff --git a/src/core/SkBitmap.cpp b/src/core/SkBitmap.cpp
index 9816711225..651152e703 100644
--- a/src/core/SkBitmap.cpp
+++ b/src/core/SkBitmap.cpp
@@ -821,13 +821,11 @@ bool SkBitmap::extractSubset(SkBitmap* result, const SkIRect& subset) const {
 #include "SkPaint.h"
 
 bool SkBitmap::canCopyTo(SkColorType dstColorType) const {
-    const SkColorType srcCT = this->colorType();
-
-    if (srcCT == kUnknown_SkColorType) {
+    if (this->colorType() == kUnknown_SkColorType) {
         return false;
     }
 
-    bool sameConfigs = (srcCT == dstColorType);
+    bool sameConfigs = (this->colorType() == dstColorType);
     switch (dstColorType) {
         case kAlpha_8_SkColorType:
         case kRGB_565_SkColorType:
@@ -840,66 +838,15 @@ bool SkBitmap::canCopyTo(SkColorType dstColorType) const {
             }
             break;
         case kARGB_4444_SkColorType:
-            return sameConfigs || kN32_SkColorType == srcCT || kIndex_8_SkColorType == srcCT;
+            return sameConfigs || kN32_SkColorType == this->colorType();
         default:
             return false;
     }
     return true;
 }
 
-#include "SkConfig8888.h"
-
-bool SkBitmap::readPixels(const SkImageInfo& requestedDstInfo, void* dstPixels, size_t dstRB,
-                          int x, int y) const {
-    if (kUnknown_SkColorType == requestedDstInfo.colorType()) {
-        return false;
-    }
-    if (NULL == dstPixels || dstRB < requestedDstInfo.minRowBytes()) {
-        return false;
-    }
-    if (0 == requestedDstInfo.width() || 0 == requestedDstInfo.height()) {
-        return false;
-    }
-    
-    SkIRect srcR = SkIRect::MakeXYWH(x, y, requestedDstInfo.width(), requestedDstInfo.height());
-    if (!srcR.intersect(0, 0, this->width(), this->height())) {
-        return false;
-    }
-    
-    SkImageInfo dstInfo = requestedDstInfo;
-    // the intersect may have shrunk info's logical size
-    dstInfo.fWidth = srcR.width();
-    dstInfo.fHeight = srcR.height();
-    
-    // if x or y are negative, then we have to adjust pixels
-    if (x > 0) {
-        x = 0;
-    }
-    if (y > 0) {
-        y = 0;
-    }
-    // here x,y are either 0 or negative
-    dstPixels = ((char*)dstPixels - y * dstRB - x * dstInfo.bytesPerPixel());
-
-    //////////////
-    
-    SkAutoLockPixels alp(*this);
-    
-    // since we don't stop creating un-pixeled devices yet, check for no pixels here
-    if (NULL == this->getPixels()) {
-        return false;
-    }
-    
-    SkImageInfo srcInfo = this->info();
-    srcInfo.fWidth = dstInfo.width();
-    srcInfo.fHeight = dstInfo.height();
-    
-    const void* srcPixels = this->getAddr(srcR.x(), srcR.y());
-    return SkPixelInfo::CopyPixels(dstInfo, dstPixels, dstRB, srcInfo, srcPixels, this->rowBytes(),
-                                   this->getColorTable());
-}
-
-bool SkBitmap::copyTo(SkBitmap* dst, SkColorType dstColorType, Allocator* alloc) const {
+bool SkBitmap::copyTo(SkBitmap* dst, SkColorType dstColorType,
+                      Allocator* alloc) const {
     if (!this->canCopyTo(dstColorType)) {
         return false;
     }
@@ -972,21 +919,59 @@ bool SkBitmap::copyTo(SkBitmap* dst, SkColorType dstColorType, Allocator* alloc)
     // returned false.
     SkASSERT(tmpDst.pixelRef() != NULL);
 
-    if (!src->readPixels(tmpDst.info(), tmpDst.getPixels(), tmpDst.rowBytes(), 0, 0)) {
-        return false;
-    }
+    /* do memcpy for the same configs cases, else use drawing
+    */
+    if (src->colorType() == dstColorType) {
+        if (tmpDst.getSize() == src->getSize()) {
+            memcpy(tmpDst.getPixels(), src->getPixels(), src->getSafeSize());
 
-    //  (for BitmapHeap) Clone the pixelref genID even though we have a new pixelref.
-    //  The old copyTo impl did this, so we continue it for now.
-    //
-    //  TODO: should we ignore rowbytes (i.e. getSize)? Then it could just be
-    //      if (src_pixelref->info == dst_pixelref->info)
-    //
-    if (src->colorType() == dstColorType && tmpDst.getSize() == src->getSize()) {
-        SkPixelRef* dstPixelRef = tmpDst.pixelRef();
-        if (dstPixelRef->info() == fPixelRef->info()) {
-            dstPixelRef->cloneGenID(*fPixelRef);
+            SkPixelRef* dstPixelRef = tmpDst.pixelRef();
+            if (dstPixelRef->info() == fPixelRef->info()) {
+                dstPixelRef->cloneGenID(*fPixelRef);
+            }
+        } else {
+            const char* srcP = reinterpret_cast<const char*>(src->getPixels());
+            char* dstP = reinterpret_cast<char*>(tmpDst.getPixels());
+            // to be sure we don't read too much, only copy our logical pixels
+            size_t bytesToCopy = tmpDst.width() * tmpDst.bytesPerPixel();
+            for (int y = 0; y < tmpDst.height(); y++) {
+                memcpy(dstP, srcP, bytesToCopy);
+                srcP += src->rowBytes();
+                dstP += tmpDst.rowBytes();
+            }
         }
+    } else if (kARGB_4444_SkColorType == dstColorType
+               && kN32_SkColorType == src->colorType()) {
+        if (src->alphaType() == kUnpremul_SkAlphaType) {
+            // Our method for converting to 4444 assumes premultiplied.
+            return false;
+        }
+        SkASSERT(src->height() == tmpDst.height());
+        SkASSERT(src->width() == tmpDst.width());
+        for (int y = 0; y < src->height(); ++y) {
+            SkPMColor16* SK_RESTRICT dstRow = (SkPMColor16*) tmpDst.getAddr16(0, y);
+            SkPMColor* SK_RESTRICT srcRow = (SkPMColor*) src->getAddr32(0, y);
+            DITHER_4444_SCAN(y);
+            for (int x = 0; x < src->width(); ++x) {
+                dstRow[x] = SkDitherARGB32To4444(srcRow[x],
+                                                 DITHER_VALUE(x));
+            }
+        }
+    } else {
+        if (tmpDst.alphaType() == kUnpremul_SkAlphaType) {
+            // We do not support drawing to unpremultiplied bitmaps.
+            return false;
+        }
+
+        // Always clear the dest in case one of the blitters accesses it
+        // TODO: switch the allocation of tmpDst to call sk_calloc_throw
+        tmpDst.eraseColor(SK_ColorTRANSPARENT);
+
+        SkCanvas canvas(tmpDst);
+        SkPaint  paint;
+
+        paint.setDither(true);
+        canvas.drawBitmap(*src, 0, 0, &paint);
     }
 
     dst->swap(tmpDst);
diff --git a/src/core/SkBitmapDevice.cpp b/src/core/SkBitmapDevice.cpp
index 09b3b605f8..86c5702f03 100644
--- a/src/core/SkBitmapDevice.cpp
+++ b/src/core/SkBitmapDevice.cpp
@@ -141,8 +141,59 @@ void* SkBitmapDevice::onAccessPixels(SkImageInfo* info, size_t* rowBytes) {
     return NULL;
 }
 
+static void rect_memcpy(void* dst, size_t dstRB, const void* src, size_t srcRB, size_t bytesPerRow,
+                        int rowCount) {
+    SkASSERT(bytesPerRow <= srcRB);
+    SkASSERT(bytesPerRow <= dstRB);
+    for (int i = 0; i < rowCount; ++i) {
+        memcpy(dst, src, bytesPerRow);
+        dst = (char*)dst + dstRB;
+        src = (const char*)src + srcRB;
+    }
+}
+
 #include "SkConfig8888.h"
 
+static bool copy_pixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes,
+                        const SkImageInfo& srcInfo, const void* srcPixels, size_t srcRowBytes) {
+    if (srcInfo.dimensions() != dstInfo.dimensions()) {
+        return false;
+    }
+    if (4 == srcInfo.bytesPerPixel() && 4 == dstInfo.bytesPerPixel()) {
+        SkDstPixelInfo dstPI;
+        dstPI.fColorType = dstInfo.colorType();
+        dstPI.fAlphaType = dstInfo.alphaType();
+        dstPI.fPixels = dstPixels;
+        dstPI.fRowBytes = dstRowBytes;
+
+        SkSrcPixelInfo srcPI;
+        srcPI.fColorType = srcInfo.colorType();
+        srcPI.fAlphaType = srcInfo.alphaType();
+        srcPI.fPixels = srcPixels;
+        srcPI.fRowBytes = srcRowBytes;
+
+        return srcPI.convertPixelsTo(&dstPI, srcInfo.width(), srcInfo.height());
+    }
+    if (srcInfo.colorType() == dstInfo.colorType()) {
+        switch (srcInfo.colorType()) {
+            case kRGB_565_SkColorType:
+            case kAlpha_8_SkColorType:
+                break;
+            case kARGB_4444_SkColorType:
+                if (srcInfo.alphaType() != dstInfo.alphaType()) {
+                    return false;
+                }
+                break;
+            default:
+                return false;
+        }
+        rect_memcpy(dstPixels, dstRowBytes, srcPixels, srcRowBytes,
+                    srcInfo.width() * srcInfo.bytesPerPixel(), srcInfo.height());
+    }
+    // TODO: add support for more conversions as needed
+    return false;
+}
+
 bool SkBitmapDevice::onWritePixels(const SkImageInfo& srcInfo, const void* srcPixels,
                                    size_t srcRowBytes, int x, int y) {
     // since we don't stop creating un-pixeled devices yet, check for no pixels here
@@ -157,7 +208,7 @@ bool SkBitmapDevice::onWritePixels(const SkImageInfo& srcInfo, const void* srcPi
     void* dstPixels = fBitmap.getAddr(x, y);
     size_t dstRowBytes = fBitmap.rowBytes();
 
-    if (SkPixelInfo::CopyPixels(dstInfo, dstPixels, dstRowBytes, srcInfo, srcPixels, srcRowBytes)) {
+    if (copy_pixels(dstInfo, dstPixels, dstRowBytes, srcInfo, srcPixels, srcRowBytes)) {
         fBitmap.notifyPixelsChanged();
         return true;
     }
@@ -166,7 +217,28 @@ bool SkBitmapDevice::onWritePixels(const SkImageInfo& srcInfo, const void* srcPi
 
 bool SkBitmapDevice::onReadPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes,
                                   int x, int y) {
-    return fBitmap.readPixels(dstInfo, dstPixels, dstRowBytes, x, y);
+    // since we don't stop creating un-pixeled devices yet, check for no pixels here
+    if (NULL == fBitmap.getPixels()) {
+        return false;
+    }
+
+    SkImageInfo srcInfo = fBitmap.info();
+
+    // perhaps can relax these in the future
+    if (4 != dstInfo.bytesPerPixel()) {
+        return false;
+    }
+    if (4 != srcInfo.bytesPerPixel()) {
+        return false;
+    }
+
+    srcInfo.fWidth = dstInfo.width();
+    srcInfo.fHeight = dstInfo.height();
+
+    const void* srcPixels = fBitmap.getAddr(x, y);
+    const size_t srcRowBytes = fBitmap.rowBytes();
+
+    return copy_pixels(dstInfo, dstPixels, dstRowBytes, srcInfo, srcPixels, srcRowBytes);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
diff --git a/src/core/SkConfig8888.cpp b/src/core/SkConfig8888.cpp
index b0572c0544..189309dae6 100644
--- a/src/core/SkConfig8888.cpp
+++ b/src/core/SkConfig8888.cpp
@@ -1,15 +1,5 @@
-/*
- * Copyright 2014 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#include "SkBitmap.h"
-#include "SkCanvas.h"
 #include "SkConfig8888.h"
 #include "SkColorPriv.h"
-#include "SkDither.h"
 #include "SkMathPriv.h"
 #include "SkUnPreMultiply.h"
 
@@ -125,135 +115,3 @@ bool SkSrcPixelInfo::convertPixelsTo(SkDstPixelInfo* dst, int width, int height)
     }
     return true;
 }
-
-static void rect_memcpy(void* dst, size_t dstRB, const void* src, size_t srcRB, size_t bytesPerRow,
-                        int rowCount) {
-    SkASSERT(bytesPerRow <= srcRB);
-    SkASSERT(bytesPerRow <= dstRB);
-    for (int i = 0; i < rowCount; ++i) {
-        memcpy(dst, src, bytesPerRow);
-        dst = (char*)dst + dstRB;
-        src = (const char*)src + srcRB;
-    }
-}
-
-bool SkPixelInfo::CopyPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRB,
-                             const SkImageInfo& srcInfo, const void* srcPixels, size_t srcRB,
-                             SkColorTable* ctable) {
-    if (srcInfo.dimensions() != dstInfo.dimensions()) {
-        return false;
-    }
-
-    const int width = srcInfo.width();
-    const int height = srcInfo.height();
-
-    // Handle fancy alpha swizzling if both are ARGB32
-    if (4 == srcInfo.bytesPerPixel() && 4 == dstInfo.bytesPerPixel()) {
-        SkDstPixelInfo dstPI;
-        dstPI.fColorType = dstInfo.colorType();
-        dstPI.fAlphaType = dstInfo.alphaType();
-        dstPI.fPixels = dstPixels;
-        dstPI.fRowBytes = dstRB;
-        
-        SkSrcPixelInfo srcPI;
-        srcPI.fColorType = srcInfo.colorType();
-        srcPI.fAlphaType = srcInfo.alphaType();
-        srcPI.fPixels = srcPixels;
-        srcPI.fRowBytes = srcRB;
-        
-        return srcPI.convertPixelsTo(&dstPI, width, height);
-    }
-
-    // If they agree on colorType and the alphaTypes are compatible, then we just memcpy.
-    // Note: we've already taken care of 32bit colortypes above.
-    if (srcInfo.colorType() == dstInfo.colorType()) {
-        switch (srcInfo.colorType()) {
-            case kRGB_565_SkColorType:
-            case kAlpha_8_SkColorType:
-                break;
-            case kIndex_8_SkColorType:
-            case kARGB_4444_SkColorType:
-                if (srcInfo.alphaType() != dstInfo.alphaType()) {
-                    return false;
-                }
-                break;
-            default:
-                return false;
-        }
-        rect_memcpy(dstPixels, dstRB, srcPixels, srcRB, width * srcInfo.bytesPerPixel(), height);
-        return true;
-    }
-
-    /*
-     *  Begin section where we try to change colorTypes along the way. Not all combinations
-     *  are supported.
-     */
-
-    // Can no longer draw directly into 4444, but we can manually whack it for a few combinations
-    if (kARGB_4444_SkColorType == dstInfo.colorType() &&
-        (kN32_SkColorType == srcInfo.colorType() || kIndex_8_SkColorType == srcInfo.colorType())) {
-        if (srcInfo.alphaType() == kUnpremul_SkAlphaType) {
-            // Our method for converting to 4444 assumes premultiplied.
-            return false;
-        }
-        
-        const SkPMColor* table = NULL;
-        if (kIndex_8_SkColorType == srcInfo.colorType()) {
-            if (NULL == ctable) {
-                return false;
-            }
-            table = ctable->lockColors();
-        }
-
-        for (int y = 0; y < height; ++y) {
-            DITHER_4444_SCAN(y);
-            SkPMColor16* SK_RESTRICT dstRow = (SkPMColor16*)dstPixels;
-            if (table) {
-                const uint8_t* SK_RESTRICT srcRow = (const uint8_t*)srcPixels;
-                for (int x = 0; x < width; ++x) {
-                    dstRow[x] = SkDitherARGB32To4444(table[srcRow[x]], DITHER_VALUE(x));
-                }
-            } else {
-                const SkPMColor* SK_RESTRICT srcRow = (const SkPMColor*)srcPixels;
-                for (int x = 0; x < width; ++x) {
-                    dstRow[x] = SkDitherARGB32To4444(srcRow[x], DITHER_VALUE(x));
-                }
-            }
-            dstPixels = (char*)dstPixels + dstRB;
-            srcPixels = (const char*)srcPixels + srcRB;
-        }
-        
-        if (table) {
-            ctable->unlockColors();
-        }
-        return true;
-    }
-
-    if (dstInfo.alphaType() == kUnpremul_SkAlphaType) {
-        // We do not support drawing to unpremultiplied bitmaps.
-        return false;
-    }
-
-    // Final fall-back, draw with a canvas
-    //
-    // Always clear the dest in case one of the blitters accesses it
-    // TODO: switch the allocation of tmpDst to call sk_calloc_throw
-    {
-        SkBitmap bm;
-        if (!bm.installPixels(srcInfo, const_cast<void*>(srcPixels), srcRB, ctable, NULL, NULL)) {
-            return false;
-        }
-        SkAutoTUnref<SkCanvas> canvas(SkCanvas::NewRasterDirect(dstInfo, dstPixels, dstRB));
-        if (NULL == canvas.get()) {
-            return false;
-        }
-
-        SkPaint  paint;
-        paint.setDither(true);
-
-        canvas->clear(0);
-        canvas->drawBitmap(bm, 0, 0, &paint);
-        return true;
-    }
-}
-
diff --git a/src/core/SkConfig8888.h b/src/core/SkConfig8888.h
index da0cbc6688..97a3433ad2 100644
--- a/src/core/SkConfig8888.h
+++ b/src/core/SkConfig8888.h
@@ -14,10 +14,6 @@ struct SkPixelInfo {
     SkColorType fColorType;
     SkAlphaType fAlphaType;
     size_t      fRowBytes;
-
-    static bool CopyPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes,
-                           const SkImageInfo& srcInfo, const void* srcPixels, size_t srcRowBytes,
-                           SkColorTable* srcCTable = NULL);
 };
 
 struct SkDstPixelInfo : SkPixelInfo {