libcamera: qcam: Allow specifying sizes on command line

Add a '-s|--size' option to qcam to allow selecting the stream
resolution using a command line option.

If the sizes are not supported by the camera, they get automatically
adjusted and the user notified via an output message.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

src/qcam/main.cpp

@@ -25,12 +25,20 @@ void signalHandler(int signal)
 
 OptionsParser::Options parseOptions(int argc, char *argv[])
 {
+	KeyValueParser sizeParser;
+	sizeParser.addOption("width", OptionInteger, "Width in pixels",
+			     ArgumentRequired);
+	sizeParser.addOption("height", OptionInteger, "Height in pixels",
+			     ArgumentRequired);
+
 	OptionsParser parser;
 	parser.addOption(OptCamera, OptionString,
 			 "Specify which camera to operate on", "camera",
 			 ArgumentRequired, "camera");
 	parser.addOption(OptHelp, OptionNone, "Display this help message",
 			 "help");
+	parser.addOption(OptSize, &sizeParser, "Set the stream size",
+			 "size", true);
 
 	OptionsParser::Options options = parser.parse(argc, argv);
 	if (options.isSet(OptHelp))

src/qcam/main_window.cpp

@@ -116,13 +116,41 @@ int MainWindow::startCapture()
 	int ret;
 
 	config_ = camera_->generateConfiguration({ StreamRole::VideoRecording });
+
+	StreamConfiguration &cfg = config_->at(0);
+	if (options_.isSet(OptSize)) {
+		const std::vector<OptionValue> &sizeOptions =
+			options_[OptSize].toArray();
+
+		/* Set desired stream size if requested. */
+		for (const auto &value : sizeOptions) {
+			KeyValueParser::Options opt = value.toKeyValues();
+
+			if (opt.isSet("width"))
+				cfg.size.width = opt["width"];
+
+			if (opt.isSet("height"))
+				cfg.size.height = opt["height"];
+		}
+	}
+
+	CameraConfiguration::Status validation = config_->validate();
+	if (validation == CameraConfiguration::Invalid) {
+		std::cerr << "Failed to create valid camera configuration";
+		return -EINVAL;
+	}
+
+	if (validation == CameraConfiguration::Adjusted) {
+		std::cout << "Stream size adjusted to "
+			  << cfg.size.toString() << std::endl;
+	}
+
 	ret = camera_->configure(config_.get());
 	if (ret < 0) {
 		std::cout << "Failed to configure camera" << std::endl;
 		return ret;
 	}
 
-	const StreamConfiguration &cfg = config_->at(0);
 	Stream *stream = cfg.stream();
 	ret = viewfinder_->setFormat(cfg.pixelFormat, cfg.size.width,
 				     cfg.size.height);

src/qcam/main_window.h

@@ -27,6 +27,7 @@ class ViewFinder;
 enum {
 	OptCamera = 'c',
 	OptHelp = 'h',
+	OptSize = 's',
 };
 
 class MainWindow : public QMainWindow