open

.gitignore

@@ -1 +1,3 @@
-.vscode/
+.vscode/
+.DS_Store
+*.dSYM/

imgtool.cpp

@@ -17,6 +17,7 @@ struct Options {
 	int resize_w = 0;
 	int resize_h = 0;
 	enum class ResizeAlg { NEAREST, BILINEAR } resize_alg = ResizeAlg::BILINEAR;
+    bool open_window = false;
 };
 struct OptionDef {
 	string name;
@@ -75,6 +76,9 @@ vector<OptionDef> register_options() {
 		{"--decode", "", "Decode a compressed image", 0,
 			[](Options& opt, const vector<string>&){ opt.decode_compressed = true; },
 			[](const Options& opt){ return opt.decode_compressed; }},
+        {"--open", "", "Open resulting .ppm in an external OpenCV viewer (non-blocking)", 0,
+            [](Options& opt, const vector<string>&){ opt.open_window = true; },
+            [](const Options& opt){ return opt.open_window; }},
 		{"-h", "", "Show help message", 0,
 			[](Options& opt, const vector<string>&){ opt.show_help = true; },
 			[](const Options& opt){ return opt.show_help; }},
@@ -204,6 +208,15 @@ int main(int argc, char* argv[]) {
 			}
 		}
 		cout << "Done: output saved to " << opt.output << "\n";
+		// If requested, launch the viewer in background so the window remains
+		// but does not block this process. We rely on the `viewer` executable
+		// being present in the current working directory.
+		if (opt.open_window) {
+			string cmd = "./viewer \"" + opt.output + "\" &";
+			cerr << "Launching viewer: " << cmd << "\n";
+			// Use system to spawn the viewer process; appending '&' sends it to background
+			int rc = system(cmd.c_str()); (void)rc;
+		}
 	}
 	catch (const exception& e) {
 		cerr << "Fatal error: " << e.what() << "\n";

viewer.cpp

@@ -0,0 +1,22 @@
+// Simple OpenCV viewer for .ppm files
+#include <opencv2/opencv.hpp>
+#include <iostream>
+
+int main(int argc, char* argv[]) {
+    if (argc < 2) {
+        std::cerr << "Usage: viewer <file.ppm>\n";
+        return 1;
+    }
+    std::string path = argv[1];
+    cv::Mat img = cv::imread(path, cv::IMREAD_UNCHANGED);
+    if (img.empty()) {
+        std::cerr << "Failed to open image: " << path << "\n";
+        return 2;
+    }
+    const std::string win = "viewer - " + path;
+    cv::namedWindow(win, cv::WINDOW_AUTOSIZE);
+    cv::imshow(win, img);
+    // Wait until user presses a key or closes the window
+    cv::waitKey(0);
+    return 0;
+}