screencast: add option to select cropping region

include/config.h

@@ -12,6 +12,8 @@ struct config_screencast {
 	char *chooser_cmd;
 	enum xdpw_chooser_types chooser_type;
 	bool force_mod_linear;
+	enum xdpw_cropmode cropmode;
+	struct xdpw_frame_crop region;
 };
 
 struct xdpw_config {

include/screencast_common.h

@@ -210,4 +210,5 @@ enum spa_video_format xdpw_format_pw_strip_alpha(enum spa_video_format format);
 
 enum xdpw_chooser_types get_chooser_type(const char *chooser_type);
 const char *chooser_type_str(enum xdpw_chooser_types chooser_type);
+const char *cropmode_str(enum xdpw_cropmode cropmode);
 #endif /* SCREENCAST_COMMON_H */

src/core/config.c

@@ -17,6 +17,11 @@ void print_config(enum LOGLEVEL loglevel, struct xdpw_config *config) {
 	logprint(loglevel, "config: chooser_cmd: %s", config->screencast_conf.chooser_cmd);
 	logprint(loglevel, "config: chooser_type: %s", chooser_type_str(config->screencast_conf.chooser_type));
 	logprint(loglevel, "config: force_mod_linear: %d", config->screencast_conf.force_mod_linear);
+	logprint(loglevel, "config: cropmode: %s", cropmode_str(config->screencast_conf.cropmode));
+	logprint(loglevel, "config: cropping_region x: %u", config->screencast_conf.region.x);
+	logprint(loglevel, "config: cropping_region y: %u", config->screencast_conf.region.y);
+	logprint(loglevel, "config: cropping_region width: %u", config->screencast_conf.region.width);
+	logprint(loglevel, "config: cropping_region height: %u", config->screencast_conf.region.height);
 }
 
 // NOTE: calling finish_config won't prepare the config to be read again from config file
@@ -60,6 +65,28 @@ static void parse_bool(bool *dest, const char* value) {
 	}
 }
 
+static void parse_region(struct xdpw_frame_crop *dest, const char* value) {
+	if (value == NULL || *value == '\0') {
+		logprint(TRACE, "config: skipping empty value in config file");
+		return;
+	}
+	sscanf(value, "%u,%u:%ux%u", &dest->x, &dest->y, &dest->width, &dest->height);
+}
+
+static void parse_cropmode(enum xdpw_cropmode *dest, const char* value) {
+	if (value == NULL || *value == '\0') {
+		logprint(TRACE, "config: skipping empty value in config file");
+		return;
+	}
+	if (strcmp(value, "none") == 0) {
+		*dest = XDPW_CROP_NONE;
+	} else if (strcmp(value, "wlroots") == 0) {
+		*dest = XDPW_CROP_WLROOTS;
+	} else if (strcmp(value, "pipewire") == 0) {
+		*dest = XDPW_CROP_PIPEWIRE;
+	}
+}
+
 static int handle_ini_screencast(struct config_screencast *screencast_conf, const char *key, const char *value) {
 	if (strcmp(key, "output_name") == 0) {
 		parse_string(&screencast_conf->output_name, value);
@@ -78,6 +105,10 @@ static int handle_ini_screencast(struct config_screencast *screencast_conf, cons
 		free(chooser_type);
 	} else if (strcmp(key, "force_mod_linear") == 0) {
 		parse_bool(&screencast_conf->force_mod_linear, value);
+	} else if (strcmp(key, "cropmode") == 0) {
+		parse_cropmode(&screencast_conf->cropmode, value);
+	} else if (strcmp(key, "region") == 0) {
+		parse_region(&screencast_conf->region, value);
 	} else {
 		logprint(TRACE, "config: skipping invalid key in config file");
 		return 0;
@@ -100,6 +131,11 @@ static int handle_ini_config(void *data, const char* section, const char *key, c
 static void default_config(struct xdpw_config *config) {
 	config->screencast_conf.max_fps = 0;
 	config->screencast_conf.chooser_type = XDPW_CHOOSER_DEFAULT;
+	config->screencast_conf.cropmode = XDPW_CROP_NONE;
+	config->screencast_conf.region.x = 0;
+	config->screencast_conf.region.y = 0;
+	config->screencast_conf.region.width = 0;
+	config->screencast_conf.region.height = 0;
 }
 
 static bool file_exists(const char *path) {

src/screencast/screencast.c

@@ -73,6 +73,16 @@ void xdpw_screencast_instance_init(struct xdpw_screencast_context *ctx,
 	cast->avoid_dmabufs = false;
 	cast->teardown = false;
 	wl_list_init(&cast->buffer_list);
+	if (ctx->state->config->screencast_conf.chooser_type == XDPW_CHOOSER_NONE &&
+			ctx->state->config->screencast_conf.cropmode != XDPW_CROP_NONE &&
+			ctx->state->config->screencast_conf.region.width != 0 &&
+			ctx->state->config->screencast_conf.region.height != 0) {
+		cast->cropmode = ctx->state->config->screencast_conf.cropmode;
+		cast->current_frame.crop.x = ctx->state->config->screencast_conf.region.x;
+		cast->current_frame.crop.y = ctx->state->config->screencast_conf.region.y;
+		cast->current_frame.crop.width = ctx->state->config->screencast_conf.region.width;
+		cast->current_frame.crop.height = ctx->state->config->screencast_conf.region.height;
+	}
 	logprint(INFO, "xdpw: screencast instance %p has %d references", cast, cast->refcount);
 	wl_list_insert(&ctx->screencast_instances, &cast->link);
 	logprint(INFO, "xdpw: %d active screencast instances",

src/screencast/screencast_common.c

@@ -404,3 +404,16 @@ const char *chooser_type_str(enum xdpw_chooser_types chooser_type) {
 	fprintf(stderr, "Could not find chooser type %d\n", chooser_type);
 	abort();
 }
+
+const char *cropmode_str(enum xdpw_cropmode cropmode) {
+	switch (cropmode) {
+	case XDPW_CROP_NONE:
+		return "none";
+	case XDPW_CROP_WLROOTS:
+		return "wlroots";
+	case XDPW_CROP_PIPEWIRE:
+		return "pipewire";
+	}
+	fprintf(stderr, "Could not find chooser type %d\n", cropmode);
+	abort();
+}

xdg-desktop-portal-wlr.5.scd

@@ -80,6 +80,17 @@ These options need to be placed under the **[screencast]** section.
 
 	This option is experimental and can be removed or replaced in future versions.
 
+**cropmode** = _type_
+	Specifies the mode to crop the output to the defined region.
+
+	The supported types are:
+	- none: No cropping, ignore region.
+	- wlroots: Crop inside the compositor. Better performance.
+	- pipewire: Send cropping information via PipeWire.
+
+**region** = _offset_x_,_offset_y_:_width_x_height_
+	Specifies the region the output is cropped to. Only works with **chooser_type** = none.
+
 ## OUTPUT CHOOSER
 
 The chooser can be any program or script with the following behaviour: