config: allow to bind multiple keys to the same action

Allows for both Space and Enter to save the selection, for example.

dulcepan.cfg

@@ -33,12 +33,14 @@ animation-duration = 0
 # or when a whole output is selected with a mouse button.
 quick-select = false
 
-# If true, dulcepan will remember selection between runs
+# If true, dulcepan will remember selection between runs.
+# The state is stored at $XDG_CACHE_HOME/dulcepan.
 persistence = true
 
 # PNG (zlib) compression level, 0-9
 png-compression = 6
 
-# Key bindings
+# Key bindings. Each binding is a comma-separated list of key names; empty names
+# are ignored. A binding may be empty.
 quit-key = Escape
-save-key = Space
+save-key = Space,Enter

meson.build

@@ -1,7 +1,7 @@
 project(
   'dulcepan',
   'c',
-  version: '1.0.0',
+  version: '1.0.2',
   license: 'GPL-3.0-only',
   default_options: [
     'c_std=c11',

src/config.c

@@ -15,7 +15,22 @@ static inline void bytes_to_color(uint8_t bytes[static 4], float out[static 4])
 	}
 }
 
-static void load_color(const char *value, int line_idx, float out[static 4]) {
+static void keybinding_init(struct dp_keybinding *kb, xkb_keysym_t *syms, size_t n_syms) {
+	*kb = (struct dp_keybinding){
+		.syms = dp_zalloc(sizeof(*kb->syms) * n_syms),
+		.n_syms = n_syms,
+	};
+	for (size_t i = 0; i < n_syms; i++) {
+		xkb_keysym_t sym = syms[i];
+		kb->syms[i] = sym;
+	}
+}
+
+static void keybinding_finish(struct dp_keybinding *kb) {
+	free(kb->syms);
+}
+
+static void load_color(char *value, int line_idx, float out[static 4]) {
 	size_t len = strlen(value);
 
 	uint8_t bytes[4] = {0, 0, 0, 0};
@@ -46,7 +61,7 @@ bad:
 	dp_log_fatal("Config: invalid color %s on line %d", value, line_idx);
 }
 
-static void load_int(const char *value, int line_idx, int min, int max, int *out) {
+static void load_int(char *value, int line_idx, int min, int max, int *out) {
 	const char *p = value;
 	int mul = 1;
 	if (*p == '-') {
@@ -68,7 +83,7 @@ static void load_int(const char *value, int line_idx, int min, int max, int *out
 	}
 }
 
-static void load_bool(const char *value, int line_idx, bool *out) {
+static void load_bool(char *value, int line_idx, bool *out) {
 	if (strcmp(value, "true") == 0) {
 		*out = true;
 	} else if (strcmp(value, "false") == 0) {
@@ -78,19 +93,31 @@ static void load_bool(const char *value, int line_idx, bool *out) {
 	}
 }
 
-static void load_key(const char *value, int line_idx, xkb_keysym_t *out) {
-	*out = xkb_keysym_from_name(value, XKB_KEYSYM_CASE_INSENSITIVE);
-	if (*out == XKB_KEY_NoSymbol) {
-		dp_log_fatal("Config: unknown key %s on line %d", value, line_idx);
+static void load_key(char *value, int line_idx, struct dp_keybinding *out) {
+	size_t n_syms = 0;
+	xkb_keysym_t syms[32];
+
+	char *save_ptr = NULL;
+	for (char *name; (name = strtok_r(value, ",", &save_ptr)) != NULL; value = NULL) {
+		if (n_syms == sizeof(syms) / sizeof(*syms)) {
+			// chill out
+			dp_log_fatal("Config: too many keys on line %d", line_idx);
+		}
+		xkb_keysym_t sym = xkb_keysym_from_name(name, XKB_KEYSYM_CASE_INSENSITIVE);
+		if (sym == XKB_KEY_NoSymbol) {
+			dp_log_fatal("Config: unknown key \"%s\" on line %d", name, line_idx);
+		}
+		syms[n_syms++] = sym;
 	}
+
+	keybinding_finish(out);
+	keybinding_init(out, syms, n_syms);
 }
 
 void dp_config_load(struct dp_state *state, const char *user_path) {
 	struct dp_config *config = &state->config;
 
 	*config = (struct dp_config){
-		.quit_key = XKB_KEY_Escape,
-		.save_key = XKB_KEY_space,
 		.border_size = 2,
 		.border_gradient = DP_BORDER_GRADIENT_NONE,
 		.gradient_angle = 45,
@@ -100,11 +127,15 @@ void dp_config_load(struct dp_state *state, const char *user_path) {
 		.quick_select = false,
 		.persistence = true,
 	};
+
 	bytes_to_color((uint8_t[]){0xff, 0xff, 0xff, 0x40}, config->unselected_color);
 	bytes_to_color((uint8_t[]){0x00, 0x00, 0x00, 0x00}, config->selected_color);
 	bytes_to_color((uint8_t[]){0xff, 0xff, 0xff, 0xff}, config->border_color);
 	bytes_to_color((uint8_t[]){0x00, 0x00, 0x00, 0xff}, config->border_secondary_color);
 
+	keybinding_init(&config->quit_kb, (xkb_keysym_t[]){XKB_KEY_Escape}, 1);
+	keybinding_init(&config->save_kb, (xkb_keysym_t[]){XKB_KEY_space, XKB_KEY_Return}, 2);
+
 	FILE *fp = NULL;
 	if (user_path != NULL) {
 		fp = fopen(user_path, "r");
@@ -215,9 +246,9 @@ void dp_config_load(struct dp_state *state, const char *user_path) {
 		} else if (strcmp(key, "persistence") == 0) {
 			load_bool(value, line_idx, &config->persistence);
 		} else if (strcmp(key, "quit-key") == 0) {
-			load_key(value, line_idx, &config->quit_key);
+			load_key(value, line_idx, &config->quit_kb);
 		} else if (strcmp(key, "save-key") == 0) {
-			load_key(value, line_idx, &config->save_key);
+			load_key(value, line_idx, &config->save_kb);
 		} else {
 			dp_log_error("Config: unknown key %s on line %d", key, line_idx);
 		}
@@ -226,3 +257,10 @@ void dp_config_load(struct dp_state *state, const char *user_path) {
 
 	fclose(fp);
 }
+
+void dp_config_finish(struct dp_state *state) {
+	struct dp_config *config = &state->config;
+
+	keybinding_finish(&config->quit_kb);
+	keybinding_finish(&config->save_kb);
+}

src/dulcepan.h

@@ -71,6 +71,7 @@ struct dp_output {
 	void *frame_data;
 	size_t frame_size;
 
+	// wl_buffer is NULL if uninitialized
 	struct dp_buffer swapchain[DP_SWAPCHAIN_LEN];
 
 	struct wl_list link;
@@ -88,6 +89,7 @@ struct dp_seat {
 	struct xkb_keymap *xkb_keymap;
 	struct xkb_state *xkb_state;
 
+	uint32_t pointer_serial;
 	struct wp_cursor_shape_device_v1 *cursor_shape_device;
 
 	// The output the pointer is on
@@ -139,6 +141,11 @@ enum dp_border_gradient {
 	DP_BORDER_GRADIENT_LOOP,
 };
 
+struct dp_keybinding {
+	xkb_keysym_t *syms;
+	size_t n_syms;
+};
+
 struct dp_config {
 	// RGBA, not premultiplied
 	float unselected_color[4];
@@ -146,8 +153,8 @@ struct dp_config {
 	float border_color[4];
 	float border_secondary_color[4];
 
-	xkb_keysym_t quit_key;
-	xkb_keysym_t save_key;
+	struct dp_keybinding quit_kb;
+	struct dp_keybinding save_kb;
 
 	int border_size; // 0 if disabled
 	enum dp_border_gradient border_gradient;
@@ -172,6 +179,8 @@ struct dp_state {
 	struct wl_shm *shm;
 	struct zwlr_layer_shell_v1 *layer_shell;
 	struct zwlr_screencopy_manager_v1 *screencopy_manager;
+
+	// Optional
 	struct wp_cursor_shape_manager_v1 *cursor_shape_manager;
 
 	bool initialized;
@@ -200,6 +209,7 @@ struct dp_state {
 };
 
 void dp_config_load(struct dp_state *state, const char *user_path);
+void dp_config_finish(struct dp_state *state);
 
 // When done, data must be unmapped
 struct wl_buffer *dp_buffer_create(struct dp_state *state, int32_t width, int32_t height,

src/main.c

@@ -1,6 +1,7 @@
 #include <getopt.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 #include <wayland-client-core.h>
 #include <wayland-client-protocol.h>
 #include <xkbcommon/xkbcommon.h>
@@ -89,8 +90,6 @@ static void run(struct dp_state *state) {
 		dp_log_fatal("The compositor has no zwlr_layer_shell_v1");
 	} else if (state->screencopy_manager == NULL) {
 		dp_log_fatal("The compositor has no zwlr_screencopy_manager_v1");
-	} else if (state->cursor_shape_manager == NULL) {
-		dp_log_fatal("The compositor has no wp_cursor_shape_manager_v1");
 	}
 
 	if (wl_list_empty(&state->outputs)) {
@@ -150,7 +149,10 @@ static void run(struct dp_state *state) {
 	wl_shm_destroy(state->shm);
 	zwlr_layer_shell_v1_destroy(state->layer_shell);
 	zwlr_screencopy_manager_v1_destroy(state->screencopy_manager);
-	wp_cursor_shape_manager_v1_destroy(state->cursor_shape_manager);
+
+	if (state->cursor_shape_manager) {
+		wp_cursor_shape_manager_v1_destroy(state->cursor_shape_manager);
+	}
 
 	wl_registry_destroy(registry);
 }
@@ -165,12 +167,16 @@ static void help(const char *prog) {
 			"  -f <format>  Specify the output file format.\n"
 			"  -o <path>    Specify the output file path.\n"
 			"\n"
-			"If the output file path is not specified, the resuling image will be printed\n"
-			"to the standard output. If the output file format is not specified, it is\n"
-			"guessed from the output file path if it's specified, and assumed to be PNG\n"
-			"otherwise.\n"
+			"If the output file path is not specified, the resuling image will be printed to\n"
+			"the standard output, which is expected to not be a terminal. If the output file\n"
+			"format is not specified, it is guessed from the output file path if it's\n"
+			"specified, and assumed to be PNG otherwise.\n"
 			"\n"
-			"Supported formats: png, ppm.\n",
+			"Supported formats: png, ppm.\n"
+			"\n"
+			"Use the left or right mouse button to select a part of the output. A selection\n"
+			"can also be moved and resized with the left mouse button. Clicking the middle\n"
+			"mouse button selects the entire output.\n",
 			prog);
 }
 
@@ -206,9 +212,13 @@ int main(int argc, char **argv) {
 		}
 	}
 
-	state.basedir_ctx = sfdo_basedir_ctx_create();
-
-	dp_config_load(&state, config_path);
+	if (state.output_path == NULL && isatty(STDOUT_FILENO)) {
+		fprintf(stderr,
+				"Refusing to run as the standard output is a terminal and there's no output file\n"
+				"path specified.\n\n");
+		help(argv[0]);
+		exit(1);
+	}
 
 	if (state.output_format == DP_FILE_UNKNOWN) {
 		if (state.output_path != NULL) {
@@ -223,6 +233,10 @@ int main(int argc, char **argv) {
 		}
 	}
 
+	state.basedir_ctx = sfdo_basedir_ctx_create();
+
+	dp_config_load(&state, config_path);
+
 	wl_list_init(&state.outputs);
 	wl_list_init(&state.seats);
 
@@ -264,6 +278,8 @@ int main(int argc, char **argv) {
 
 	run(&state);
 
+	dp_config_finish(&state);
+
 	cairo_pattern_destroy(state.border_pattern);
 
 	xkb_context_unref(state.xkb_context);

src/output.c

@@ -79,6 +79,12 @@ static void frame_handle_buffer(void *data, struct zwlr_screencopy_frame_v1 *fra
 		wl_buffer_destroy(output->frame_buffer);
 	}
 
+	if ((int32_t)width != output->width || (int32_t)height != output->height) {
+		dp_log_fatal("Output/buffer size mismatch: mode=%" PRIi32 "x%" PRIi32 ", buffer=%" PRIu32
+					 "x%" PRIu32,
+				output->width, output->height, width, height);
+	}
+
 	output->frame_format = format;
 	output->frame_stride = (int)stride;
 	output->frame_buffer = dp_buffer_create(output->state, output->width, output->height,
@@ -126,6 +132,19 @@ static const struct wl_buffer_listener buffer_listener = {
 	.release = buffer_handle_release,
 };
 
+static void init_buffer(struct dp_output *output, struct dp_buffer *buffer) {
+	int stride = output->transformed_width * 4;
+
+	buffer->wl_buffer =
+			dp_buffer_create(output->state, output->transformed_width, output->transformed_height,
+					stride, WL_SHM_FORMAT_ARGB8888, &buffer->data, &buffer->size);
+	buffer->cairo_surface = cairo_image_surface_create_for_data(buffer->data, CAIRO_FORMAT_ARGB32,
+			output->transformed_width, output->transformed_height, stride);
+	buffer->cairo = cairo_create(buffer->cairo_surface);
+
+	wl_buffer_add_listener(buffer->wl_buffer, &buffer_listener, buffer);
+}
+
 static void output_handle_geometry(void *data, struct wl_output *wl_output, int32_t x, int32_t y,
 		int32_t phys_width, int32_t phys_height, int32_t subpixel, const char *make,
 		const char *model, int32_t transform) {
@@ -143,6 +162,10 @@ static void output_handle_geometry(void *data, struct wl_output *wl_output, int3
 
 static void output_handle_mode(void *data, struct wl_output *wl_output, uint32_t flags,
 		int32_t width, int32_t height, int32_t refresh) {
+	if ((flags & WL_OUTPUT_MODE_CURRENT) == 0) {
+		return;
+	}
+
 	struct dp_output *output = data;
 
 	if (output->has_geom) {
@@ -165,6 +188,7 @@ static void output_handle_done(void *data, struct wl_output *wl_output) {
 
 	assert(output->name != NULL);
 
+	assert(output->width > 0 && output->height > 0);
 	if ((output->transform & WL_OUTPUT_TRANSFORM_90) != 0) {
 		output->transformed_width = output->height;
 		output->transformed_height = output->width;
@@ -208,19 +232,6 @@ static void output_handle_done(void *data, struct wl_output *wl_output) {
 	wl_subsurface_set_desync(output->select_subsurface);
 
 	wl_surface_set_user_data(output->select_surface, output);
-
-	for (size_t i = 0; i < DP_SWAPCHAIN_LEN; i++) {
-		struct dp_buffer *buffer = &output->swapchain[i];
-		int stride = output->transformed_width * 4;
-		buffer->wl_buffer =
-				dp_buffer_create(state, output->transformed_width, output->transformed_height,
-						stride, WL_SHM_FORMAT_ARGB8888, &buffer->data, &buffer->size);
-		buffer->cairo_surface = cairo_image_surface_create_for_data(buffer->data,
-				CAIRO_FORMAT_ARGB32, output->transformed_width, output->transformed_height, stride);
-		buffer->cairo = cairo_create(buffer->cairo_surface);
-
-		wl_buffer_add_listener(buffer->wl_buffer, &buffer_listener, buffer);
-	}
 }
 
 static void output_handle_scale(void *data, struct wl_output *wl_output, int32_t scale) {
@@ -330,6 +341,8 @@ static void redraw(struct dp_output *output) {
 	if (buffer == NULL) {
 		dp_log_error("Output %s: no free buffers in a swapchain\n", output->name);
 		return;
+	} else if (buffer->wl_buffer == NULL) {
+		init_buffer(output, buffer);
 	}
 	buffer->used = true;
 
@@ -371,15 +384,22 @@ static void redraw(struct dp_output *output) {
 			}
 
 			cairo_stroke(buffer->cairo);
+
+			if (config->border_gradient != DP_BORDER_GRADIENT_NONE &&
+					config->animation_duration != 0) {
+				bool whole = selection->x == 0 && selection->y == 0 &&
+						selection->width == output->effective_width &&
+						selection->height == output->effective_height;
+				if (!whole) {
+					// The border is animated and visible
+					output->needs_redraw = true;
+				}
+			}
 		}
 
 		cairo_rectangle(buffer->cairo, x, y, width, height);
 		set_cairo_color(buffer->cairo, config->selected_color);
 		cairo_fill(buffer->cairo);
-
-		if (config->border_gradient != DP_BORDER_GRADIENT_NONE && config->animation_duration != 0) {
-			output->needs_redraw = true;
-		}
 	}
 
 	wl_surface_attach(output->select_surface, buffer->wl_buffer, 0, 0);
@@ -431,10 +451,12 @@ void dp_output_destroy(struct dp_output *output) {
 
 	for (size_t i = 0; i < DP_SWAPCHAIN_LEN; i++) {
 		struct dp_buffer *buffer = &output->swapchain[i];
-		wl_buffer_destroy(buffer->wl_buffer);
-		cairo_destroy(buffer->cairo);
-		cairo_surface_destroy(buffer->cairo_surface);
-		munmap(buffer->data, buffer->size);
+		if (buffer->wl_buffer != NULL) {
+			wl_buffer_destroy(buffer->wl_buffer);
+			cairo_destroy(buffer->cairo);
+			cairo_surface_destroy(buffer->cairo_surface);
+			munmap(buffer->data, buffer->size);
+		}
 	}
 
 	wl_subsurface_destroy(output->select_subsurface);

src/seat.c

@@ -50,6 +50,15 @@ static void keyboard_handle_leave(
 	// Ignored
 }
 
+static bool match_keybinding(struct dp_keybinding *kb, uint32_t sym) {
+	for (size_t i = 0; i < kb->n_syms; i++) {
+		if (sym == kb->syms[i]) {
+			return true;
+		}
+	}
+	return false;
+}
+
 static void keyboard_handle_key(void *data, struct wl_keyboard *wl_keyboard, uint32_t serial,
 		uint32_t time_msec, uint32_t keycode, enum wl_keyboard_key_state key_state) {
 	struct dp_seat *seat = data;
@@ -62,9 +71,9 @@ static void keyboard_handle_key(void *data, struct wl_keyboard *wl_keyboard, uin
 	struct dp_state *state = seat->state;
 	struct dp_config *config = &state->config;
 
-	if (keysym == config->quit_key) {
+	if (match_keybinding(&config->quit_kb, keysym)) {
 		state->status = DP_STATUS_QUIT;
-	} else if (keysym == config->save_key) {
+	} else if (match_keybinding(&config->save_kb, keysym)) {
 		state->status = DP_STATUS_SAVED;
 	}
 }
@@ -86,10 +95,10 @@ static const struct wl_keyboard_listener keyboard_listener = {
 static enum wp_cursor_shape_device_v1_shape get_cursor_shape(struct dp_selection *selection) {
 	switch (selection->action) {
 	case DP_SELECTION_ACTION_NONE:
-		return WP_CURSOR_SHAPE_DEVICE_V1_SHAPE_CROSSHAIR;
+		break;
 	case DP_SELECTION_ACTION_RESIZING:
 		if (selection->width == 0 || selection->height == 0) {
-			return WP_CURSOR_SHAPE_DEVICE_V1_SHAPE_CROSSHAIR;
+			break;
 		}
 		switch (selection->resize_edges) {
 		case DP_EDGE_TOP:
@@ -116,24 +125,27 @@ static enum wp_cursor_shape_device_v1_shape get_cursor_shape(struct dp_selection
 				selection->width == selection->output->effective_width &&
 				selection->height == selection->output->effective_height) {
 			// Moving is impossible
-			return WP_CURSOR_SHAPE_DEVICE_V1_SHAPE_DEFAULT;
+			break;
 		}
 		return WP_CURSOR_SHAPE_DEVICE_V1_SHAPE_MOVE;
 	}
-	abort(); // Unreachable
+	// The default cursor
+	return WP_CURSOR_SHAPE_DEVICE_V1_SHAPE_CROSSHAIR;
 }
 
-static void update_cursor(struct dp_seat *seat, uint32_t serial) {
-	wp_cursor_shape_device_v1_set_shape(
-			seat->cursor_shape_device, serial, get_cursor_shape(&seat->state->selection));
+static void update_cursor(struct dp_seat *seat) {
+	if (seat->cursor_shape_device != NULL) {
+		wp_cursor_shape_device_v1_set_shape(seat->cursor_shape_device, seat->pointer_serial,
+				get_cursor_shape(&seat->state->selection));
+	}
 }
 
-static void process_position(struct dp_seat *seat, wl_fixed_t x, wl_fixed_t y, uint32_t serial) {
+static void process_position(struct dp_seat *seat, wl_fixed_t x, wl_fixed_t y) {
 	struct dp_output *output = seat->ptr_output;
 	seat->ptr_x = wl_fixed_to_double(x);
 	seat->ptr_y = wl_fixed_to_double(y);
 	dp_select_notify_pointer_position(&seat->state->selection, output, seat->ptr_x, seat->ptr_y);
-	update_cursor(seat, serial);
+	update_cursor(seat);
 }
 
 static void pointer_handle_enter(void *data, struct wl_pointer *wl_pointer, uint32_t serial,
@@ -141,22 +153,24 @@ static void pointer_handle_enter(void *data, struct wl_pointer *wl_pointer, uint
 	struct dp_seat *seat = data;
 	seat->ptr_output = wl_surface_get_user_data(surface);
 	assert(seat->ptr_output != NULL);
-	process_position(seat, sx, sy, serial);
+	seat->pointer_serial = serial;
+	process_position(seat, sx, sy);
 }
 
 static void pointer_handle_leave(
 		void *data, struct wl_pointer *wl_pointer, uint32_t serial, struct wl_surface *surface) {
 	struct dp_seat *seat = data;
 	seat->ptr_output = NULL;
+	seat->pointer_serial = serial;
 }
 
-static void pointer_handle_motion(
-		void *data, struct wl_pointer *wl_pointer, uint32_t serial, wl_fixed_t sx, wl_fixed_t sy) {
+static void pointer_handle_motion(void *data, struct wl_pointer *wl_pointer, uint32_t time_msec,
+		wl_fixed_t sx, wl_fixed_t sy) {
 	struct dp_seat *seat = data;
 	if (seat->ptr_output == NULL) {
 		return; // Shouldn't happen
 	}
-	process_position(seat, sx, sy, serial);
+	process_position(seat, sx, sy);
 }
 
 static void pointer_handle_button(void *data, struct wl_pointer *wl_pointer, uint32_t serial,
@@ -164,6 +178,8 @@ static void pointer_handle_button(void *data, struct wl_pointer *wl_pointer, uin
 	struct dp_seat *seat = data;
 	struct dp_state *state = seat->state;
 
+	seat->pointer_serial = serial;
+
 	struct dp_selection *selection = &state->selection;
 	if (button_state != WL_POINTER_BUTTON_STATE_PRESSED) {
 		if (selection->width > 0 && selection->height > 0 && state->config.quick_select) {
@@ -182,14 +198,14 @@ static void pointer_handle_button(void *data, struct wl_pointer *wl_pointer, uin
 	case BTN_RIGHT:
 		dp_select_start_interactive(
 				selection, seat->ptr_output, seat->ptr_x, seat->ptr_y, button == BTN_LEFT);
-		update_cursor(seat, serial);
+		update_cursor(seat);
 		break;
 	case BTN_MIDDLE:
 		dp_select_whole(selection, seat->ptr_output);
 
 		// dp_select_whole() doesn't invalidate the interactive state, so do it manually
 		dp_select_notify_pointer_position(selection, seat->ptr_output, seat->ptr_x, seat->ptr_y);
-		update_cursor(seat, serial);
+		update_cursor(seat);
 
 		if (state->config.quick_select) {
 			state->status = DP_STATUS_SAVED;
@@ -220,8 +236,11 @@ static void seat_handle_capabilities(void *data, struct wl_seat *wl_seat, uint32
 	if ((caps & WL_SEAT_CAPABILITY_POINTER) != 0 && seat->pointer == NULL) {
 		seat->pointer = wl_seat_get_pointer(wl_seat);
 		wl_pointer_add_listener(seat->pointer, &pointer_listener, seat);
-		seat->cursor_shape_device = wp_cursor_shape_manager_v1_get_pointer(
-				seat->state->cursor_shape_manager, seat->pointer);
+
+		if (seat->state->cursor_shape_manager != NULL) {
+			seat->cursor_shape_device = wp_cursor_shape_manager_v1_get_pointer(
+					seat->state->cursor_shape_manager, seat->pointer);
+		}
 	}
 }
 
@@ -256,6 +275,8 @@ void dp_seat_destroy(struct dp_seat *seat) {
 	}
 	if (seat->pointer != NULL) {
 		wl_pointer_release(seat->pointer);
+	}
+	if (seat->cursor_shape_device != NULL) {
 		wp_cursor_shape_device_v1_destroy(seat->cursor_shape_device);
 	}
 

src/select.c

@@ -187,6 +187,8 @@ void dp_select_start_interactive(struct dp_selection *selection, struct dp_outpu
 	selection->resize_edges = DP_EDGE_BOTTOM | DP_EDGE_RIGHT;
 
 	init_resize(selection, x, y);
+
+	dp_output_redraw(output);
 }
 
 void dp_select_stop_interactive(struct dp_selection *selection) {

src/util.c

@@ -28,6 +28,10 @@ void dp_log_fatal(const char *fmt, ...) {
 }
 
 void *dp_zalloc(size_t size) {
+	if (size == 0) {
+		return NULL;
+	}
+
 	void *ptr = calloc(1, size);
 	if (ptr == NULL) {
 		dp_log_fatal("Failed to allocate %zu bytes", size);