Add a tool to convert PNG file to PBGRA32 BMP

Currently the logo image on the candidate window footer is rendered by
AlphaBlend GDI API, which implicitly assumes that the specified bitmap
is a PBGRA (pre-multiplied alpha) Device Independent Bitmap (DIB) when
AC_SRC_ALPHA parameter is specified.

This tool is designed for doing such a required conversion in build time
as follow.
  gen_pbgra32_bitmap.exe --src=src.png --dest=dest.bmp

Ideally candidate_window.cc should be able to handle PNG file directly,
but doing that requires some non-trivial code changes that need to run
in end user environment.

This CL has no impact on production binaries. Hence no user-visible
behavior change is intended.

BUG=
TEST=
REF_BUG=25634278
REF_CL=110514591

src/mozc_version_template.txt

@@ -1,6 +1,6 @@
 MAJOR=2
 MINOR=17
-BUILD=2403
+BUILD=2404
 REVISION=102
 # NACL_DICTIONARY_VERSION is the target version of the system dictionary to be
 # downloaded by NaCl Mozc.

src/renderer/renderer.gyp

@@ -362,6 +362,25 @@
             'renderer_style_handler',
           ],
         },
+        {
+          'target_name': 'gen_pbgra32_bitmap',
+          'type': 'executable',
+          'sources': [
+            'win32/gen_pbgra32_bitmap.cc',
+          ],
+          'dependencies': [
+            '../base/base.gyp:base_core',
+            '../base/base.gyp:scoped_handle',
+          ],
+          'msvs_settings': {
+            'VCLinkerTool': {
+              'AdditionalDependencies': [
+                'gdiplus.lib',  # used in 'gen_pbgra32_bitmap.cc'
+              ],
+              'SubSystem': '1',  # 1 == subSystemConsole
+            },
+          },
+        },
         {
           'target_name': 'mozc_renderer',
           'product_name': '<(renderer_product_name_win)',

src/renderer/win32/gen_pbgra32_bitmap.cc

@@ -0,0 +1,164 @@
+// Copyright 2010-2016, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <Windows.h>
+#include <objbase.h>
+
+#include <algorithm>
+#include <memory>
+
+#include "base/file_stream.h"
+#include "base/flags.h"
+#include "base/init_mozc.h"
+#include "base/logging.h"
+#include "base/port.h"
+#include "base/util.h"
+
+DEFINE_string(src, "", "path to the input PNG file");
+DEFINE_string(dest, "", "path to the output BMP file");
+
+using ::std::min;
+using ::std::max;
+
+// gdiplus.h must be placed here because it internally depends on
+// global min/max functions.
+// TODO(yukawa): Use WIC (Windows Imaging Component) instead of GDI+.
+#include <gdiplus.h>  // NOLINT
+
+namespace {
+
+const int kErrorLevelSuccess = 0;
+const int kErrorLevelFail = 1;
+
+const uint32 kMaxBitmapWidth = 16384;
+const uint32 kMaxBitmapHeight = 16384;
+
+bool ConvertMain() {
+  wstring wide_src;
+  mozc::Util::UTF8ToWide(FLAGS_src, &wide_src);
+  std::unique_ptr<Gdiplus::Bitmap> image(
+      Gdiplus::Bitmap::FromFile(wide_src.c_str()));
+
+  const uint32 width_original = image->GetWidth();
+  if (width_original > kMaxBitmapWidth) {
+    LOG(ERROR) << "Too long width: " << width_original;
+    return false;
+  }
+  const int32 width = static_cast<int32>(width_original);
+
+  const uint32 height_original = image->GetHeight();
+  if (height_original > kMaxBitmapHeight) {
+    LOG(ERROR) << "Too long height: " << height_original;
+    return false;
+  }
+  const int32 height = static_cast<int32>(height_original);
+
+  const uint32 num_pixels = static_cast<uint32>(width * height);
+  const uint32 pixel_data_bytes = num_pixels * 4;
+
+  // Use <pshpack2.h> header to match the actual file BMP file format,
+  // which uses 2 byte packing.  Include <poppack.h> to restore the
+  // current packing mode.
+  // c.f. https://msdn.microsoft.com/en-us/library/2e70t5y1.aspx
+#include <pshpack2.h>    // NOLINT
+  struct PBGR32Bitmap {
+    uint16   file_signature;
+    uint32   file_size;
+    uint16   reserved1;
+    uint16   reserved2;
+    uint32   pixel_data_offset;
+    uint32   header_size;
+    int32    width;
+    int32    height;
+    uint16   num_planes;
+    uint16   bit_count;
+    uint32   compression;
+    uint32   pixel_data_size;
+    int32    pixel_per_meter_x;
+    int32    pixel_per_meter_y;
+    uint32   num_pallete;
+    uint32   important_color;
+  };
+#include <poppack.h>  // NOLINT
+
+  PBGR32Bitmap header = {};
+  header.file_signature = 0x4d42;  // 'BM'
+  header.file_size = sizeof(header) + pixel_data_bytes;
+  header.pixel_data_offset = sizeof(header);
+  header.header_size = sizeof(header) - offsetof(PBGR32Bitmap, header_size);
+  header.width = width;
+  header.height = height;
+  header.num_planes = 1;
+  header.bit_count = 32;
+  header.pixel_data_size = pixel_data_bytes;
+
+  mozc::OutputFileStream output_file(
+      FLAGS_dest.c_str(), std::ios::out | std::ios::binary | std::ios::trunc);
+  if (!output_file.good()) {
+    return false;
+  }
+
+  output_file.write(reinterpret_cast<const char *>(&header), sizeof(header));
+  for (size_t y = 0; y < height; ++y) {
+    for (size_t x = 0; x < width; ++x) {
+      Gdiplus::Color color;
+      image->GetPixel(x, height - y - 1, &color);
+      const size_t index = (y * width + x) * 4;
+      output_file << static_cast<uint8>(color.GetB() / 255.0 * color.GetA());
+      output_file << static_cast<uint8>(color.GetG() / 255.0 * color.GetA());
+      output_file << static_cast<uint8>(color.GetR() / 255.0 * color.GetA());
+      output_file << color.GetA();
+    }
+  }
+  return true;
+}
+
+}  // namespace
+
+int main(int argc, char **argv) {
+  mozc::InitMozc(argv[0], &argc, &argv, false);
+
+  if (FLAGS_src.empty()) {
+    std::cout << "Specify --src option";
+    return kErrorLevelFail;
+  }
+  if (FLAGS_dest.empty()) {
+    std::cout << "Specify --dest option";
+    return kErrorLevelFail;
+  }
+
+  ULONG_PTR gdiplus_token;
+  Gdiplus::GdiplusStartupInput input;
+  Gdiplus::GdiplusStartup(&gdiplus_token, &input, nullptr);
+
+  const bool result = ConvertMain();
+
+  Gdiplus::GdiplusShutdown(gdiplus_token);
+  return result ? kErrorLevelSuccess : kErrorLevelFail;
+}