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// Copyright 2019 The Amber Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "samples/ppm.h"
#include <cassert>
#include "amber/result.h"
#include "amber/value.h"
namespace ppm {
namespace {
const uint32_t kMaximumColorValue = 255;
uint8_t byte0(uint32_t word) {
return static_cast<uint8_t>(word & 0xff);
}
uint8_t byte1(uint32_t word) {
return static_cast<uint8_t>((word >> 8) & 0xff);
}
uint8_t byte2(uint32_t word) {
return static_cast<uint8_t>((word >> 16) & 0xff);
}
} // namespace
amber::Result ConvertToPPM(uint32_t width,
uint32_t height,
const std::vector<amber::Value>& values,
std::vector<uint8_t>* buffer) {
assert(values.size() == (width * height) &&
"Buffer values != width * height");
assert(!values.empty() && "Buffer empty");
// Write PPM header
std::string image = "P6\n";
image += std::to_string(width) + " " + std::to_string(height) + "\n";
image += std::to_string(kMaximumColorValue) + "\n";
for (char ch : image)
buffer->push_back(static_cast<uint8_t>(ch));
// Write PPM data
for (amber::Value value : values) {
const uint32_t pixel = value.AsUint32();
// We assume B8G8R8A8_UNORM here:
buffer->push_back(byte2(pixel)); // R
buffer->push_back(byte1(pixel)); // G
buffer->push_back(byte0(pixel)); // B
// PPM does not support alpha channel
}
return {};
}
} // namespace ppm