GSK Demo

gsk-demo.c

// compile with: cc -g `pkg-config --libs --cflags gtk4` -o gsk-demo gsk-demo.c

#include <stdio.h>
#include <gdk/gdk.h>
#include <gsk/gsk.h>

void gtk_init(void);

static const char node[] = "container {\
  color {\
    color: #d4d0c8;\
  }\
  border {\
    outline: 5 5 40 40;\
    colors: #808080 #ffffff #ffffff #808080;\
  }\
  border {\
    outline: 6 6 38 38;\
    colors: #ffffff #808080 #808080 #ffffff;\
  }\
}";

static gboolean surface_event(GdkSurface *surface, GdkEvent *event, GMainLoop *loop) {
	(void) surface;

	GdkEventType event_type = gdk_event_get_event_type(event);
	if (event_type == GDK_DELETE) {
		g_main_loop_quit(loop);
		return TRUE;
	}
	return FALSE;
}

static gboolean surface_render(GdkSurface *surface, cairo_region_t *region, GskRenderer *renderer) {
	(void) surface;

	GBytes *bytes = g_bytes_new_static(node, sizeof(node));
	GskRenderNode *root = gsk_render_node_deserialize(bytes, 0, 0);
	gsk_renderer_render(renderer, root, region);
	gsk_render_node_unref(root);
	return TRUE;
}

static void toplevel_compute_size(GdkToplevel *toplevel, GdkToplevelSize *size, void *userdata) {
	(void) toplevel;
	(void) userdata;

	gdk_toplevel_size_set_size(size, 50, 50);
}

int main(int argc, char const *argv[]) {
	(void) argc;
	(void) argv;

	gtk_init(); // needed to call gdk_event_init_types
	GMainLoop *loop = g_main_loop_new(NULL, FALSE);

	GdkDisplay *display = gdk_display_open(0);
	GdkSurface *surface = gdk_surface_new_toplevel(display);
	GskRenderer *renderer = gsk_renderer_new_for_surface(surface);
	g_signal_connect(surface, "event", G_CALLBACK (surface_event), /*userdata=*/loop);
	g_signal_connect(surface, "render", G_CALLBACK (surface_render), /*userdata=*/renderer);
	g_signal_connect(surface, "compute-size", G_CALLBACK (toplevel_compute_size), /*userdata=*/0);
	GdkToplevelLayout *layout = gdk_toplevel_layout_new();
	gdk_toplevel_layout_set_resizable(layout, FALSE);
	gdk_toplevel_present(GDK_TOPLEVEL(surface), layout);

	g_main_loop_run(loop);
	g_main_loop_unref(loop);
	return 0;
}