add SkPixmap and external locking to bitmaps

include/core/SkPixmap.h

Index: include/core/SkPixmap.h
diff --git a/include/core/SkPixmap.h b/include/core/SkPixmap.h
new file mode 100644
index 0000000000000000000000000000000000000000..5f4d70438203978020eb63c9e89453e329b4b382
--- /dev/null
+++ b/include/core/SkPixmap.h
@@ -0,0 +1,100 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkPixmap_DEFINED
+#define SkPixmap_DEFINED
+
+#include "SkImageInfo.h"
+
+class SkColorTable;
+
+class SkPixmap {

[scroggo, 2015/05/19 20:11:42]

Comments?

It looks like this is designed to be a short-lived object whose members (fPixels
and fCTable) are unowned.

Shouldn't this be SkNoncopyable, so no one tries to copy it and use it after the
associated pixel ref is unlocked?

[reed1, 2015/05/21 20:59:35]

Done.

+public:
+    SkPixmap()
+        : fPixels(NULL), fCTable(NULL), fRowBytes(0), fInfo(SkImageInfo::MakeUnknown(0, 0))
+    {}
+
+    SkPixmap(const SkImageInfo& info, const void* addr, size_t rowBytes,
+             SkColorTable* ctable = NULL)
+        : fPixels(addr), fCTable(ctable), fRowBytes(rowBytes), fInfo(info)
+    {
+        if (kIndex_8_SkColorType == info.colorType()) {
+            SkASSERT(ctable);
+        } else {
+            SkASSERT(NULL == ctable);
+        }
+    }
+
+    const SkImageInfo& info() const { return fInfo; }
+    size_t rowBytes() const { return fRowBytes; }
+    const void* addr() const { return fPixels; }
+    SkColorTable* ctable() const { return fCTable; }
+
+    int width() const { return fInfo.width(); }
+    int height() const { return fInfo.height(); }
+    SkColorType colorType() const { return fInfo.colorType(); }
+    SkAlphaType alphaType() const { return fInfo.alphaType(); }
+    bool isOpaque() const { return fInfo.isOpaque(); }
+
+    int64_t getSafeSize64() const { return fInfo.getSafeSize64(fRowBytes); }
+    size_t getSafeSize() const { return fInfo.getSafeSize(fRowBytes); }
+
+    const uint32_t* addr32() const {
+        SkASSERT(4 == SkColorTypeBytesPerPixel(fInfo.colorType()));
+        return reinterpret_cast<const uint32_t*>(fPixels);
+    }
+
+    const uint16_t* addr16() const {
+        SkASSERT(2 == SkColorTypeBytesPerPixel(fInfo.colorType()));
+        return reinterpret_cast<const uint16_t*>(fPixels);
+    }
+
+    const uint8_t* addr8() const {
+        SkASSERT(1 == SkColorTypeBytesPerPixel(fInfo.colorType()));
+        return reinterpret_cast<const uint8_t*>(fPixels);
+    }
+
+    const uint32_t* addr32(int x, int y) const {
+        SkASSERT((unsigned)x < (unsigned)fInfo.width());
+        SkASSERT((unsigned)y < (unsigned)fInfo.height());
+        return (const uint32_t*)((const char*)this->addr32() + y * fRowBytes + (x << 2));
+    }
+    const uint16_t* addr16(int x, int y) const {
+        SkASSERT((unsigned)x < (unsigned)fInfo.width());
+        SkASSERT((unsigned)y < (unsigned)fInfo.height());
+        return (const uint16_t*)((const char*)this->addr16() + y * fRowBytes + (x << 1));
+    }
+    const uint8_t* addr8(int x, int y) const {
+        SkASSERT((unsigned)x < (unsigned)fInfo.width());
+        SkASSERT((unsigned)y < (unsigned)fInfo.height());
+        return (const uint8_t*)((const char*)this->addr8() + y * fRowBytes + (x << 0));
+    }
+    const void* addr(int x, int y) const {
+        return (const char*)fPixels + fInfo.computeOffset(x, y, fRowBytes);
+    }
+
+    // Writable versions
+
+    void* writable_addr() const { return const_cast<void*>(fPixels); }
+    uint32_t* writable_addr32(int x, int y) const {
+        return const_cast<uint32_t*>(this->addr32(x, y));
+    }
+    uint16_t* writable_addr16(int x, int y) const {
+        return const_cast<uint16_t*>(this->addr16(x, y));
+    }
+    uint8_t* writable_addr8(int x, int y) const {
+        return const_cast<uint8_t*>(this->addr8(x, y));
+    }
+
+private:
+    const void*     fPixels;
+    SkColorTable*   fCTable;
+    size_t          fRowBytes;
+    SkImageInfo     fInfo;
+};
+
+#endif