convince/swaybg/main.c

#include "wayland-desktop-shell-client-protocol.h"
#include <stdio.h>
#include <stdlib.h>
#include <wayland-client.h>
#include <time.h>
#include "client/window.h"
#include "client/registry.h"
#include "log.h"
#include "list.h"

list_t *surfaces;

struct registry *registry;

enum scaling_mode_t {
	SCALING_MODE_STRETCH,
	SCALING_MODE_FILL,
	SCALING_MODE_CENTER,
};

void sway_terminate(void) {
	int i;
	for (i = 0; i < surfaces->length; ++i) {
		struct window *window = surfaces->items[i];
		window_teardown(window);
	}
	list_free(surfaces);
	registry_teardown(registry);
	exit(1);
}

int main(int argc, const char **argv) {
	init_log(L_INFO);
	surfaces = create_list();
	registry = registry_poll();

	if (argc != 4) {
		sway_abort("Do not run this program manually. See man 5 sway and look for output options.");
	}

	if (!registry->desktop_shell) {
		sway_abort("swaybg requires the compositor to support the desktop-shell extension.");
	}

	int desired_output = atoi(argv[1]);
	sway_log(L_INFO, "Using output %d of %d", desired_output, registry->outputs->length);
	int i;
	struct output_state *output = registry->outputs->items[desired_output];
	struct window *window = window_setup(registry, 100, 100, false);
	if (!window) {
		sway_abort("Failed to create surfaces.");
	}
	window->width = output->width;
	window->height = output->height;
	desktop_shell_set_background(registry->desktop_shell, output->output, window->surface);
	list_add(surfaces, window);

	cairo_surface_t *image = cairo_image_surface_create_from_png(argv[2]);
	double width = cairo_image_surface_get_width(image);
	double height = cairo_image_surface_get_height(image);

	const char *scaling_mode_str = argv[3];
	enum scaling_mode_t scaling_mode;
	if (strcmp(scaling_mode_str, "stretch") == 0) {
		scaling_mode = SCALING_MODE_STRETCH;
	} else if (strcmp(scaling_mode_str, "fill") == 0) {
		scaling_mode = SCALING_MODE_FILL;
	} else if (strcmp(scaling_mode_str, "center") == 0) {
		scaling_mode = SCALING_MODE_CENTER;
	} else {
		sway_abort("Unsupported scaling mode: %s", scaling_mode_str);
	}

	for (i = 0; i < surfaces->length; ++i) {
		struct window *window = surfaces->items[i];
		if (window_prerender(window) && window->cairo) {

			switch (scaling_mode) {
				case SCALING_MODE_STRETCH:
					cairo_scale(window->cairo,
							(double) window->width / width,
							(double) window->height / height);
					cairo_set_source_surface(window->cairo, image, 0, 0);
					break;
				case SCALING_MODE_FILL:
					{
						double window_ratio = (double) window->width / window->height;
						double bg_ratio = width / height;

						if (window_ratio > bg_ratio) {
							double scale = (double) window->width / width;
							cairo_scale(window->cairo, scale, scale);
							cairo_set_source_surface(window->cairo, image,
									0,
									(double) window->height/2 / scale - height/2);
						} else {
							double scale = (double) window->height / height;
							cairo_scale(window->cairo, scale, scale);
							cairo_set_source_surface(window->cairo, image,
									(double) window->width/2 / scale - width/2,
									0);
						}
					}
					break;
				case SCALING_MODE_CENTER:
					cairo_set_source_surface(window->cairo, image,
							(double) window->width/2 - width/2,
							(double) window->height/2 - height/2);
					break;
				default:
					sway_abort("Scaling mode '%s' not implemented yet!", scaling_mode_str);
			}

			cairo_paint(window->cairo);

			window_render(window);
		}
	}

	while (wl_display_dispatch(registry->display) != -1);

	for (i = 0; i < surfaces->length; ++i) {
		struct window *window = surfaces->items[i];
		window_teardown(window);
	}
	list_free(surfaces);
	registry_teardown(registry);
	return 0;
}