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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 {
+
+char byte0(uint32_t word) {
+  return static_cast<char>(word);
+}
+
+char byte1(uint32_t word) {
+  return static_cast<char>(word >> 8);
+}
+
+char byte2(uint32_t word) {
+  return static_cast<char>(word >> 16);
+}
+
+}  // namespace
+
+std::pair<amber::Result, std::string> ConvertToPPM(
+    uint32_t width,
+    uint32_t height,
+    const std::vector<amber::Value>& values) {
+  assert(values.size() == width * height);
+
+  // Write PPM header
+  const uint32_t maximum_color_value = 255;
+  std::string image = "P6\n";
+  image += std::to_string(width) + " " + std::to_string(height) + "\n";
+  image += std::to_string(maximum_color_value) + "\n";
+
+  // Write PPM data
+  for (amber::Value value : values) {
+    const uint32_t pixel = value.AsUint32();
+    // We assume R8G8B8A8_UINT here:
+    image.push_back(byte0(pixel));  // R
+    image.push_back(byte1(pixel));  // G
+    image.push_back(byte2(pixel));  // B
+    // PPM does not support alpha channel
+  }
+
+  return std::make_pair(amber::Result(), image);
+}
+
+}  // namespace ppm