Add bitmap utils for Chrome on Android

ui/gfx/android/bitmap_android.cc

Index: ui/gfx/android/bitmap_android.cc
diff --git a/ui/gfx/android/bitmap_android.cc b/ui/gfx/android/bitmap_android.cc
new file mode 100644
index 0000000000000000000000000000000000000000..748533d8ff82322fe5499a551cf2dd3cd5d57f5c
--- /dev/null
+++ b/ui/gfx/android/bitmap_android.cc
@@ -0,0 +1,104 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/gfx/android/bitmap_android.h"
+
+#include <android/bitmap.h>
+
+#include "base/android/jni_android.h"
+#include "base/logging.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "ui/gfx/size.h"
+
+using base::android::AttachCurrentThread;
+using base::android::GetClass;
+using base::android::GetMethodID;
+using base::android::GetStaticFieldID;
+using base::android::GetStaticMethodID;
+using gfx::AutoLockJavaBitmap;

[nilesh, 2012/08/03 04:52:36]

start "namespace gfx" here and move anonymous namespace  above this.
http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml?showone=Constr...

[Jesse Greenwald, 2012/08/03 20:10:06]

Done.

+
+AutoLockJavaBitmap::AutoLockJavaBitmap(jobject bitmap) :

[sky, 2012/08/03 17:15:36]

: on next line.

[Jesse Greenwald, 2012/08/03 20:10:06]

Done.

+    bitmap_(bitmap),

[sky, 2012/08/03 17:15:36]

indentation is off.

[Jesse Greenwald, 2012/08/03 20:10:06]

Done.

+    pixels_(NULL) {
+  int err = AndroidBitmap_lockPixels(AttachCurrentThread(), bitmap_, &pixels_);
+  DCHECK(!err);
+  DCHECK(pixels_);
+}
+
+AutoLockJavaBitmap::~AutoLockJavaBitmap() {
+  // TODO(aelias): Add AndroidBitmap_notifyPixelsChanged() call here

[Yaron, 2012/08/02 18:40:10]

remove comment

[Jesse Greenwald, 2012/08/03 20:10:06]

Done.

+  //               once it's added to the NDK.  Using hardware bitmaps will
+  //               be broken until this is fixed.
+  int err = AndroidBitmap_unlockPixels(AttachCurrentThread(), bitmap_);
+  DCHECK(!err);
+}
+
+gfx::Size AutoLockJavaBitmap::size() const {
+  AndroidBitmapInfo info;
+  int err = AndroidBitmap_getInfo(AttachCurrentThread(), bitmap_, &info);
+  DCHECK(!err);
+  return gfx::Size(info.width, info.height);
+}
+
+int AutoLockJavaBitmap::format() const {
+  AndroidBitmapInfo info;
+  int err = AndroidBitmap_getInfo(AttachCurrentThread(), bitmap_, &info);
+  DCHECK(!err);
+  return info.format;
+}
+
+uint32_t AutoLockJavaBitmap::stride() const {
+  AndroidBitmapInfo info;
+  int err = AndroidBitmap_getInfo(AttachCurrentThread(), bitmap_, &info);

[nilesh, 2012/08/03 04:52:36]

you can skip the variable "err" and directly check the return value.

[Jesse Greenwald, 2012/08/03 20:10:06]

The call to AndroidBitmap_getInfo has side effects on info.  I'm assuming that
if DCHECK's are enabled, the call wouldn't get made?

[nilesh, 2012/08/03 20:41:25]

My bad, thanks for pointing out.

+  DCHECK(!err);
+  return info.stride;
+}
+
+namespace {
+static jclass g_AndroidBitmap_clazz = NULL;
+static jmethodID g_AndroidBitmap_createBitmap_method = NULL;
+static jobject g_BitmapConfig_ARGB8888 = NULL;
+}  // anonymous namespace
+
+namespace gfx {
+
+void RegisterBitmapAndroid(JNIEnv* env) {

[sky, 2012/08/03 17:15:36]

Why is there here and not in the location it's called from?

[Jesse Greenwald, 2012/08/03 20:10:06]

The function is forward declared in gfx_jni_registrar.cc before it's used and
implemented here.  This was done so we don't have to expose this function as
part of the UI API.

We do similar things with the rest of our JNI code.  For example:
content/browser/android/browser_jni_registrar.cc/h.  Our registration functions
are not defined in content/public to avoid exposing them as part of the content
API.

[sky, 2012/08/03 22:33:29]

I don't see any calls to this function here. Can't it be moved entirely to
gfx_jni_registrar.cc  ?

[Jesse Greenwald, 2012/08/03 22:41:51]

This function initializes various g_* globals (see the namespace block above). 
These globals are used in this class (see CreateJavaBitmap below)

+  g_AndroidBitmap_clazz = reinterpret_cast<jclass>(env->NewGlobalRef(
+      base::android::GetUnscopedClass(env, "android/graphics/Bitmap")));
+  ScopedJavaLocalRef<jclass> bitmapConfig_clazz = base::android::GetClass(
+      env, "android/graphics/Bitmap$Config");
+  g_AndroidBitmap_createBitmap_method = GetStaticMethodID(env,
+      g_AndroidBitmap_clazz, "createBitmap",
+      "(IILandroid/graphics/Bitmap$Config;)Landroid/graphics/Bitmap;");
+  jfieldID argb_8888_id = GetStaticFieldID(env, bitmapConfig_clazz, "ARGB_8888",
+      "Landroid/graphics/Bitmap$Config;");
+  g_BitmapConfig_ARGB8888 = reinterpret_cast<jobject>(env->NewGlobalRef(
+      env->GetStaticObjectField(bitmapConfig_clazz.obj(), argb_8888_id)));
+}
+
+ScopedJavaLocalRef<jobject> CreateJavaBitmap(const gfx::Size& size) {
+  DCHECK(g_AndroidBitmap_clazz);
+  JNIEnv* env = AttachCurrentThread();
+  jobject bitmap_object = env->CallStaticObjectMethod(g_AndroidBitmap_clazz,
+        g_AndroidBitmap_createBitmap_method, size.width(), size.height(),
+        g_BitmapConfig_ARGB8888);
+  return ScopedJavaLocalRef<jobject>(env, bitmap_object);
+}
+
+ScopedJavaLocalRef<jobject> ConvertToJavaBitmap(const SkBitmap* skbitmap) {
+  DCHECK(skbitmap);
+  DCHECK_EQ(skbitmap->bytesPerPixel(), 4);
+
+  ScopedJavaLocalRef<jobject> jbitmap =
+      gfx::CreateJavaBitmap(gfx::Size(skbitmap->width(), skbitmap->height()));

[nilesh, 2012/08/03 04:52:36]

You dont need the gfx qualifier as you are in gfx namespace.

[Jesse Greenwald, 2012/08/03 20:10:06]

I removed some of the gfx:: qualifiers.  However, after change the function
"size" to "Size", I still needed the qualifier to avoid ambiguity with the
gfx::Size class.

+  SkAutoLockPixels src_lock(*skbitmap);
+  AutoLockJavaBitmap dst_lock(jbitmap.obj());
+  void* src_pixels = skbitmap->getPixels();
+  void* dst_pixels = dst_lock.pixels();
+  memcpy(dst_pixels, src_pixels, skbitmap->getSize());
+
+  return jbitmap;
+}
+
+}  // gfx namespace

[nilesh, 2012/08/03 04:52:36]

namespace gfx

[Jesse Greenwald, 2012/08/03 20:10:06]

Done.