Add image export roundtrip automation

tools/pano_cli/main.cpp

@@ -55,6 +55,12 @@ struct ImportImageArgs {
     std::uint32_t y = 0;
 };
 
+struct ExportImageArgs {
+    std::string path;
+    std::uint32_t width = 2;
+    std::uint32_t height = 2;
+};
+
 struct ParseLayoutArgs {
     std::string path;
 };
@@ -173,6 +179,7 @@ void print_help()
     std::cout
         << "pano_cli commands:\n"
         << "  create-document --width N --height N [--layers N] [--frames N] [--frame-duration-ms N]\n"
+        << "  export-image --path FILE [--width N] [--height N]\n"
         << "  inspect-image --path FILE\n"
         << "  import-image --path FILE [--document-width N] [--document-height N] [--face N] [--x N] [--y N]\n"
         << "  inspect-project --path FILE\n"
@@ -623,6 +630,102 @@ int import_image(int argc, char** argv)
     return 0;
 }
 
+pp::foundation::Status parse_export_image_args(int argc, char** argv, ExportImageArgs& args)
+{
+    for (int i = 2; i < argc; ++i) {
+        const std::string_view key(argv[i]);
+        if (key == "--path") {
+            if (i + 1 >= argc) {
+                return pp::foundation::Status::invalid_argument("missing value for option");
+            }
+
+            args.path = argv[++i];
+        } else if (key == "--width" || key == "--height") {
+            if (i + 1 >= argc) {
+                return pp::foundation::Status::invalid_argument("missing value for option");
+            }
+
+            const auto value = pp::foundation::parse_u32(argv[++i]);
+            if (!value) {
+                return value.status();
+            }
+
+            if (key == "--width") {
+                args.width = value.value();
+            } else {
+                args.height = value.value();
+            }
+        } else {
+            return pp::foundation::Status::invalid_argument("unknown option");
+        }
+    }
+
+    if (args.path.empty()) {
+        return pp::foundation::Status::invalid_argument("path must not be empty");
+    }
+
+    if (args.width == 0 || args.height == 0) {
+        return pp::foundation::Status::invalid_argument("width and height must be greater than zero");
+    }
+
+    constexpr std::uint64_t max_cli_export_bytes = 64ULL * 1024ULL * 1024ULL;
+    if (static_cast<std::uint64_t>(args.width) > max_cli_export_bytes / 4ULL / static_cast<std::uint64_t>(args.height)) {
+        return pp::foundation::Status::out_of_range("export image exceeds the CLI automation size limit");
+    }
+
+    return pp::foundation::Status::success();
+}
+
+int export_image(int argc, char** argv)
+{
+    ExportImageArgs args;
+    const auto status = parse_export_image_args(argc, argv, args);
+    if (!status.ok()) {
+        print_error("export-image", status.message);
+        return 2;
+    }
+
+    std::vector<std::uint8_t> pixels(
+        static_cast<std::size_t>(args.width) * static_cast<std::size_t>(args.height) * 4U);
+    for (std::uint32_t y = 0; y < args.height; ++y) {
+        for (std::uint32_t x = 0; x < args.width; ++x) {
+            const auto offset = (static_cast<std::size_t>(y) * args.width + x) * 4U;
+            pixels[offset + 0U] = static_cast<std::uint8_t>((x * 37U) & 0xffU);
+            pixels[offset + 1U] = static_cast<std::uint8_t>((y * 53U) & 0xffU);
+            pixels[offset + 2U] = static_cast<std::uint8_t>(((x + y) * 29U) & 0xffU);
+            pixels[offset + 3U] = 255U;
+        }
+    }
+
+    const auto encoded = pp::assets::encode_png_rgba8(args.width, args.height, pixels);
+    if (!encoded) {
+        print_error("export-image", encoded.status().message);
+        return 2;
+    }
+
+    std::ofstream stream(args.path, std::ios::binary);
+    if (!stream) {
+        print_error("export-image", "image file could not be opened for writing");
+        return 2;
+    }
+
+    const auto& bytes = encoded.value();
+    stream.write(reinterpret_cast<const char*>(bytes.data()), static_cast<std::streamsize>(bytes.size()));
+    if (!stream) {
+        print_error("export-image", "image file could not be written");
+        return 2;
+    }
+
+    std::cout << "{\"ok\":true,\"command\":\"export-image\""
+              << ",\"path\":\"" << json_escape(args.path) << "\""
+              << ",\"image\":{\"format\":\"png\",\"width\":" << args.width
+              << ",\"height\":" << args.height
+              << ",\"bytes\":" << pixels.size()
+              << "},\"file\":{\"bytes\":" << bytes.size()
+              << "}}\n";
+    return 0;
+}
+
 pp::foundation::Status parse_inspect_project_args(int argc, char** argv, InspectProjectArgs& args)
 {
     for (int i = 2; i < argc; ++i) {
@@ -1554,6 +1657,10 @@ int main(int argc, char** argv)
         return inspect_image(argc, argv);
     }
 
+    if (command == "export-image") {
+        return export_image(argc, argv);
+    }
+
     if (command == "import-image") {
         return import_image(argc, argv);
     }