change offset to xy for pixelref subsetting

src/core/SkBitmap.cpp

 
 /*
  * Copyright 2008 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.
  */
 
 
 #include "SkBitmap.h"
@@ skipping 111 matching lines @@
         }
     }
 
     SkDEBUGCODE(this->validate();)
     return *this;
 }
 
 void SkBitmap::swap(SkBitmap& other) {
     SkTSwap(fColorTable, other.fColorTable);
     SkTSwap(fPixelRef, other.fPixelRef);
-    SkTSwap(fPixelRefOffset, other.fPixelRefOffset);
+    SkTSwap(fPixelRefOrigin, other.fPixelRefOrigin);
     SkTSwap(fPixelLockCount, other.fPixelLockCount);
     SkTSwap(fMipMap, other.fMipMap);
     SkTSwap(fPixels, other.fPixels);
     SkTSwap(fRowBytes, other.fRowBytes);
     SkTSwap(fWidth, other.fWidth);
     SkTSwap(fHeight, other.fHeight);
     SkTSwap(fConfig, other.fConfig);
     SkTSwap(fAlphaType, other.fAlphaType);
     SkTSwap(fFlags, other.fFlags);
     SkTSwap(fBytesPerPixel, other.fBytesPerPixel);
@@ skipping 190 matching lines @@
     return true;
 }
 
 void SkBitmap::updatePixelsFromRef() const {
     if (NULL != fPixelRef) {
         if (fPixelLockCount > 0) {
             SkASSERT(fPixelRef->isLocked());
 
             void* p = fPixelRef->pixels();
             if (NULL != p) {
-                p = (char*)p + fPixelRefOffset;
+                p = (char*)p
+                    + fPixelRef->rowBytes() * fPixelRefOrigin.fY
+                    + fPixelRefOrigin.fX * fBytesPerPixel;
             }
             fPixels = p;
             SkRefCnt_SafeAssign(fColorTable, fPixelRef->colorTable());
         } else {
             SkASSERT(0 == fPixelLockCount);
             fPixels = NULL;
             if (fColorTable) {
                 fColorTable->unref();
                 fColorTable = NULL;
             }
@@ skipping 36 matching lines @@
     }
     if (info) {
         info->fWidth = fWidth;
         info->fHeight = fHeight;
         info->fAlphaType = this->alphaType();
         info->fColorType = ct;
     }
     return true;
 }
 
-SkPixelRef* SkBitmap::setPixelRef(SkPixelRef* pr, size_t offset) {
-    // do this first, we that we never have a non-zero offset with a null ref
-    if (NULL == pr) {
-        offset = 0;
-    }
+SkPixelRef* SkBitmap::setPixelRef(SkPixelRef* pr, int dx, int dy) {
 #ifdef SK_DEBUG
-    else {
+    if (pr) {
         SkImageInfo info;
         if (this->asImageInfo(&info)) {
             const SkImageInfo& prInfo = pr->info();
             SkASSERT(info.fWidth <= prInfo.fWidth);
             SkASSERT(info.fHeight <= prInfo.fHeight);
             SkASSERT(info.fColorType == prInfo.fColorType);
             switch (prInfo.fAlphaType) {
                 case kIgnore_SkAlphaType:
                     SkASSERT(fAlphaType == kIgnore_SkAlphaType);
                     break;
                 case kOpaque_SkAlphaType:
                 case kPremul_SkAlphaType:
                     SkASSERT(info.fAlphaType == kOpaque_SkAlphaType ||
                              info.fAlphaType == kPremul_SkAlphaType);
                     break;
                 case kUnpremul_SkAlphaType:
                     SkASSERT(info.fAlphaType == kOpaque_SkAlphaType ||
                              info.fAlphaType == kUnpremul_SkAlphaType);
                     break;
             }
         }
     }
 #endif
 
-    if (fPixelRef != pr || fPixelRefOffset != offset) {
+    if (pr) {
+        const SkImageInfo& info = pr->info();
+        fPixelRefOrigin.set(SkPin32(dx, 0, info.fWidth),
+                            SkPin32(dy, 0, info.fHeight));
+    } else {
+        // ignore dx,dy if there is no pixelref
+        fPixelRefOrigin.setZero();
+    }
+
+    if (fPixelRef != pr) {
         if (fPixelRef != pr) {
             this->freePixels();
             SkASSERT(NULL == fPixelRef);
 
             SkSafeRef(pr);
             fPixelRef = pr;
         }
-        fPixelRefOffset = offset;
         this->updatePixelsFromRef();
     }
 
     SkDEBUGCODE(this->validate();)
     return pr;
 }
 
 void SkBitmap::lockPixels() const {
     if (NULL != fPixelRef && 0 == sk_atomic_inc(&fPixelLockCount)) {
         fPixelRef->lockPixels();
@@ skipping 11 matching lines @@
     }
     SkDEBUGCODE(this->validate();)
 }
 
 bool SkBitmap::lockPixelsAreWritable() const {
     return (fPixelRef) ? fPixelRef->lockPixelsAreWritable() : false;
 }
 
 void SkBitmap::setPixels(void* p, SkColorTable* ctable) {
     if (NULL == p) {
-        this->setPixelRef(NULL, 0);
+        this->setPixelRef(NULL);
         return;
     }
 
     SkImageInfo info;
     if (!this->asImageInfo(&info)) {
-        this->setPixelRef(NULL, 0);
+        this->setPixelRef(NULL);
         return;
     }
 
     SkPixelRef* pr = SkMallocPixelRef::NewDirect(info, p, fRowBytes, ctable);
     if (NULL == pr) {
-        this->setPixelRef(NULL, 0);
+        this->setPixelRef(NULL);
         return;
     }
 
     this->setPixelRef(pr)->unref();
 
     // since we're already allocated, we lockPixels right away
     this->lockPixels();
     SkDEBUGCODE(this->validate();)
 }
 
@@ skipping 14 matching lines @@
         fColorTable->unref();
         fColorTable = NULL;
     }
 
     if (NULL != fPixelRef) {
         if (fPixelLockCount > 0) {
             fPixelRef->unlockPixels();
         }
         fPixelRef->unref();
         fPixelRef = NULL;
-        fPixelRefOffset = 0;
+        fPixelRefOrigin.setZero();
     }
     fPixelLockCount = 0;
     fPixels = NULL;
 }
 
 void SkBitmap::freeMipMap() {
     if (fMipMap) {
         fMipMap->unref();
         fMipMap = NULL;
     }
@@ skipping 26 matching lines @@
 //        SkDebugf("unsupported config for info %d\n", dst->config());
         return false;
     }
 
     SkPixelRef* pr = SkMallocPixelRef::NewAllocate(info, dst->rowBytes(),
                                                    ctable);
     if (NULL == pr) {
         return false;
     }
 
-    dst->setPixelRef(pr, 0)->unref();
+    dst->setPixelRef(pr)->unref();
     // since we're already allocated, we lockPixels right away
     dst->lockPixels();
     return true;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 size_t SkBitmap::getSafeSize() const {
     // This is intended to be a size_t version of ComputeSafeSize64(), just
     // faster. The computation is meant to be identical.
@@ skipping 304 matching lines @@
     SkIRect area = { 0, 0, this->width(), this->height() };
     if (area.intersect(rect)) {
         this->internalErase(area, SkColorGetA(c), SkColorGetR(c),
                             SkColorGetG(c), SkColorGetB(c));
     }
 }
 
 //////////////////////////////////////////////////////////////////////////////////////
 //////////////////////////////////////////////////////////////////////////////////////
 
-#define SUB_OFFSET_FAILURE  ((size_t)-1)
-
-/**
- *  Based on the Config and rowBytes() of bm, return the offset into an SkPixelRef of the pixel at
- *  (x, y).
- *  Note that the SkPixelRef does not need to be set yet. deepCopyTo takes advantage of this fact.
- *  Also note that (x, y) may be outside the range of (0 - width(), 0 - height()), so long as it is
- *  within the bounds of the SkPixelRef being used.
- */
-static size_t get_sub_offset(const SkBitmap& bm, int x, int y) {
-    switch (bm.config()) {
-        case SkBitmap::kA8_Config:
-        case SkBitmap:: kIndex8_Config:
-            // x is fine as is for the calculation
-            break;
-
-        case SkBitmap::kRGB_565_Config:
-        case SkBitmap::kARGB_4444_Config:
-            x <<= 1;
-            break;
-
-        case SkBitmap::kARGB_8888_Config:
-            x <<= 2;
-            break;
-
-        case SkBitmap::kNo_Config:
-        default:
-            return SUB_OFFSET_FAILURE;
-    }
-    return y * bm.rowBytes() + x;
-}
-
-/**
- *  Using the pixelRefOffset(), rowBytes(), and Config of bm, determine the (x, y) coordinate of the
- *  upper left corner of bm relative to its SkPixelRef.
- *  x and y must be non-NULL.
- */
-bool get_upper_left_from_offset(SkBitmap::Config config, size_t offset, size_t rowBytes,
-                                   int32_t* x, int32_t* y);
-bool get_upper_left_from_offset(SkBitmap::Config config, size_t offset, size_t rowBytes,
-                                   int32_t* x, int32_t* y) {
-    SkASSERT(x != NULL && y != NULL);
-    if (0 == offset) {
-        *x = *y = 0;
-        return true;
-    }
-    // Use integer division to find the correct y position.
-    // The remainder will be the x position, after we reverse get_sub_offset.
-    SkTDivMod(offset, rowBytes, y, x);
-    switch (config) {
-        case SkBitmap::kA8_Config:
-            // Fall through.
-        case SkBitmap::kIndex8_Config:
-            // x is unmodified
-            break;
-
-        case SkBitmap::kRGB_565_Config:
-            // Fall through.
-        case SkBitmap::kARGB_4444_Config:
-            *x >>= 1;
-            break;
-
-        case SkBitmap::kARGB_8888_Config:
-            *x >>= 2;
-            break;
-
-        case SkBitmap::kNo_Config:
-            // Fall through.
-        default:
-            return false;
-    }
-    return true;
-}
-
-static bool get_upper_left_from_offset(const SkBitmap& bm, int32_t* x, int32_t* y) {
-    return get_upper_left_from_offset(bm.config(), bm.pixelRefOffset(), bm.rowBytes(), x, y);
-}
-
 bool SkBitmap::extractSubset(SkBitmap* result, const SkIRect& subset) const {
     SkDEBUGCODE(this->validate();)
 
     if (NULL == result || NULL == fPixelRef) {
         return false;   // no src pixels
     }
 
     SkIRect srcRect, r;
     srcRect.set(0, 0, this->width(), this->height());
     if (!r.intersect(srcRect, subset)) {
@@ skipping 13 matching lines @@
             result->swap(dst);
             return true;
         }
     }
 
     // If the upper left of the rectangle was outside the bounds of this SkBitmap, we should have
     // exited above.
     SkASSERT(static_cast<unsigned>(r.fLeft) < static_cast<unsigned>(this->width()));
     SkASSERT(static_cast<unsigned>(r.fTop) < static_cast<unsigned>(this->height()));
 
-    size_t offset = get_sub_offset(*this, r.fLeft, r.fTop);
-    if (SUB_OFFSET_FAILURE == offset) {
-        return false;   // config not supported
-    }
-
     SkBitmap dst;
     dst.setConfig(this->config(), r.width(), r.height(), this->rowBytes(),
                   this->alphaType());
     dst.setIsVolatile(this->isVolatile());
 
     if (fPixelRef) {
+        SkIPoint origin = fPixelRefOrigin;
+        origin.fX += r.fLeft;
+        origin.fY += r.fTop;
         // share the pixelref with a custom offset
-        dst.setPixelRef(fPixelRef, fPixelRefOffset + offset);
+        dst.setPixelRef(fPixelRef, origin);
     }
     SkDEBUGCODE(dst.validate();)
 
     // we know we're good, so commit to result
     result->swap(dst);
     return true;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
@@ skipping 28 matching lines @@
     if (!this->canCopyTo(dstConfig)) {
         return false;
     }
 
     // if we have a texture, first get those pixels
     SkBitmap tmpSrc;
     const SkBitmap* src = this;
 
     if (fPixelRef) {
         SkIRect subset;
-        if (get_upper_left_from_offset(*this, &subset.fLeft, &subset.fTop)) {
-            subset.fRight = subset.fLeft + fWidth;
-            subset.fBottom = subset.fTop + fHeight;
-            if (fPixelRef->readPixels(&tmpSrc, &subset)) {
-                SkASSERT(tmpSrc.width() == this->width());
-                SkASSERT(tmpSrc.height() == this->height());
+        subset.setXYWH(fPixelRefOrigin.fX, fPixelRefOrigin.fY, fWidth, fHeight);
+        if (fPixelRef->readPixels(&tmpSrc, &subset)) {
+            SkASSERT(tmpSrc.width() == this->width());
+            SkASSERT(tmpSrc.height() == this->height());
 
-                // did we get lucky and we can just return tmpSrc?
-                if (tmpSrc.config() == dstConfig && NULL == alloc) {
-                    dst->swap(tmpSrc);
-                    if (dst->pixelRef() && this->config() == dstConfig) {
-                        // TODO(scroggo): fix issue 1742
-                        dst->pixelRef()->cloneGenID(*fPixelRef);
-                    }
-                    return true;
+            // did we get lucky and we can just return tmpSrc?
+            if (tmpSrc.config() == dstConfig && NULL == alloc) {
+                dst->swap(tmpSrc);
+                if (dst->pixelRef() && this->config() == dstConfig) {
+                    // TODO(scroggo): fix issue 1742
+                    dst->pixelRef()->cloneGenID(*fPixelRef);
                 }
+                return true;
+            }
 
-                // fall through to the raster case
-                src = &tmpSrc;
-            }
+            // fall through to the raster case
+            src = &tmpSrc;
         }
     }
 
     // we lock this now, since we may need its colortable
     SkAutoLockPixels srclock(*src);
     if (!src->readyToDraw()) {
         return false;
     }
 
     SkBitmap tmpDst;
@@ skipping 77 matching lines @@
             if (dstConfig == fConfig) {
                 // TODO(scroggo): fix issue 1742
                 pixelRef->cloneGenID(*fPixelRef);
                 // Use the same rowBytes as the original.
                 rowBytes = fRowBytes;
             } else {
                 // With the new config, an appropriate fRowBytes will be computed by setConfig.
                 rowBytes = 0;
             }
             dst->setConfig(dstConfig, fWidth, fHeight, rowBytes);
-
-            size_t pixelRefOffset;
-            if (0 == fPixelRefOffset || dstConfig == fConfig) {
-                // Use the same offset as the original.
-                pixelRefOffset = fPixelRefOffset;
-            } else {
-                // Find the correct offset in the new config. This needs to be done after calling
-                // setConfig so dst's fConfig and fRowBytes have been set properly.
-                int32_t x, y;
-                if (!get_upper_left_from_offset(*this, &x, &y)) {
-                    return false;
-                }
-                pixelRefOffset = get_sub_offset(*dst, x, y);
-                if (SUB_OFFSET_FAILURE == pixelRefOffset) {
-                    return false;
-                }
-            }
-            dst->setPixelRef(pixelRef, pixelRefOffset)->unref();
+            dst->setPixelRef(pixelRef, fPixelRefOrigin)->unref();
             return true;
         }
     }
 
     if (this->getTexture()) {
         return false;
     } else {
         return this->copyTo(dst, dstConfig, NULL);
     }
 }
@@ skipping 390 matching lines @@
 void SkBitmap::flatten(SkFlattenableWriteBuffer& buffer) const {
     buffer.writeInt(fWidth);
     buffer.writeInt(fHeight);
     buffer.writeInt(fRowBytes);
     buffer.writeInt(fConfig);
     buffer.writeInt(fAlphaType);
 
     if (fPixelRef) {
         if (fPixelRef->getFactory()) {
             buffer.writeInt(SERIALIZE_PIXELTYPE_REF_DATA);
-            buffer.writeUInt(SkToU32(fPixelRefOffset));
+            buffer.writeInt(fPixelRefOrigin.fX);
+            buffer.writeInt(fPixelRefOrigin.fY);
             buffer.writeFlattenable(fPixelRef);
             return;
         }
         // if we get here, we can't record the pixels
         buffer.writeInt(SERIALIZE_PIXELTYPE_NONE);
     } else {
         buffer.writeInt(SERIALIZE_PIXELTYPE_NONE);
     }
 }
 
@@ skipping 12 matching lines @@
     // Note : Using (fRowBytes >= (fWidth * fBytesPerPixel)) in the following test can create false
     //        positives if the multiplication causes an integer overflow. Use the division instead.
     buffer.validate(configIsValid && (fBytesPerPixel > 0) &&
                     ((fRowBytes / fBytesPerPixel) >= fWidth));
 
     int reftype = buffer.readInt();
     if (buffer.validate((SERIALIZE_PIXELTYPE_REF_DATA == reftype) ||
                         (SERIALIZE_PIXELTYPE_NONE == reftype))) {
         switch (reftype) {
             case SERIALIZE_PIXELTYPE_REF_DATA: {
-                size_t offset = buffer.readUInt();
+                SkIPoint origin;
+                origin.fX = buffer.readInt();
+                origin.fY = buffer.readInt();
+                size_t offset = origin.fY * rowBytes + origin.fX * fBytesPerPixel;
                 SkPixelRef* pr = buffer.readPixelRef();
                 if (!buffer.validate((NULL == pr) ||
                        (pr->getAllocatedSizeInBytes() >= (offset + this->getSafeSize())))) {
-                    offset = 0;
+                    origin.setZero();
                 }
-                SkSafeUnref(this->setPixelRef(pr, offset));
+                SkSafeUnref(this->setPixelRef(pr, origin));
                 break;
             }
             case SERIALIZE_PIXELTYPE_NONE:
                 break;
             default:
                 SkDEBUGFAIL("unrecognized pixeltype in serialized data");
                 sk_throw();
         }
     }
 }
@@ skipping 69 matching lines @@
         if (NULL != uri) {
             str->appendf(" uri:\"%s\"", uri);
         } else {
             str->appendf(" pixelref:%p", pr);
         }
     }
 
     str->append(")");
 }
 #endif