electron/atom/common/native_mate_converters/image_converter.cc

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// Copyright (c) 2014 GitHub, Inc.
// Use of this source code is governed by the MIT license that can be
// found in the LICENSE file.
#include "atom/common/native_mate_converters/image_converter.h"
#include <string>
#include <vector>
#include "atom/common/native_mate_converters/file_path_converter.h"
#include "base/file_util.h"
#include "base/strings/string_util.h"
#include "ui/gfx/codec/jpeg_codec.h"
#include "ui/gfx/codec/png_codec.h"
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#include "ui/gfx/image/image.h"
#include "ui/gfx/image/image_skia.h"
#include "ui/base/layout.h"
namespace mate {
namespace {
struct ScaleFactorPair {
const char* name;
float scale;
};
ScaleFactorPair kScaleFactorPairs[] = {
// The "@2x" is put as first one to make scale matching faster.
{ "@2x" , 2.0f },
{ "@3x" , 3.0f },
{ "@1x" , 1.0f },
{ "@1.25x" , 1.25f },
{ "@1.33x" , 1.33f },
{ "@1.4x" , 1.4f },
{ "@1.5x" , 1.5f },
{ "@1.8x" , 1.8f },
{ "@2.5x" , 2.5f },
};
float GetScaleFactorFromPath(const base::FilePath& path) {
std::string filename(path.BaseName().RemoveExtension().AsUTF8Unsafe());
// There is no scale info in the file path.
if (!EndsWith(filename, "x", true))
return 1.0f;
// We don't try to convert string to float here because it is very very
// expensive.
for (unsigned i = 0; i < arraysize(kScaleFactorPairs); ++i) {
if (EndsWith(filename, kScaleFactorPairs[i].name, true))
return kScaleFactorPairs[i].scale;
}
return 1.0f;
}
void AppendIfExists(std::vector<base::FilePath>* paths,
const base::FilePath& path) {
if (base::PathExists(path))
paths->push_back(path);
}
void PopulatePossibleFilePaths(std::vector<base::FilePath>* paths,
const base::FilePath& path) {
AppendIfExists(paths, path);
std::string filename(path.BaseName().RemoveExtension().AsUTF8Unsafe());
if (MatchPattern(filename, "*@*x"))
return;
for (unsigned i = 0; i < arraysize(kScaleFactorPairs); ++i)
AppendIfExists(paths,
path.InsertBeforeExtensionASCII(kScaleFactorPairs[i].name));
}
bool AddImageSkiaRepFromPath(gfx::ImageSkia* image,
const base::FilePath& path) {
std::string file_contents;
if (!base::ReadFileToString(path, &file_contents))
return false;
const unsigned char* data =
reinterpret_cast<const unsigned char*>(file_contents.data());
size_t size = file_contents.size();
scoped_ptr<SkBitmap> decoded(new SkBitmap());
// Try PNG first.
if (!gfx::PNGCodec::Decode(data, size, decoded.get()))
// Try JPEG.
decoded.reset(gfx::JPEGCodec::Decode(data, size));
if (decoded) {
image->AddRepresentation(gfx::ImageSkiaRep(
*decoded.release(), GetScaleFactorFromPath(path)));
return true;
}
return false;
}
} // namespace
bool Converter<gfx::ImageSkia>::FromV8(v8::Isolate* isolate,
v8::Handle<v8::Value> val,
gfx::ImageSkia* out) {
base::FilePath path;
if (Converter<base::FilePath>::FromV8(isolate, val, &path)) {
std::vector<base::FilePath> paths;
PopulatePossibleFilePaths(&paths, path);
if (paths.empty())
return false;
for (size_t i = 0; i < paths.size(); ++i) {
if (!AddImageSkiaRepFromPath(out, paths[i]))
return false;
}
return true;
}
return false;
}
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bool Converter<gfx::Image>::FromV8(v8::Isolate* isolate,
v8::Handle<v8::Value> val,
gfx::Image* out) {
gfx::ImageSkia image;
if (!ConvertFromV8(isolate, val, &image))
return false;
*out = gfx::Image(image);
return true;
}
} // namespace mate