Minimal GLFW+Cairo+Xlib example

glfw-cairo-xlib.c

//gcc $(pkg-config --cflags --libs glfw3 cairo) glfw-cairo-xlib.c

#include <math.h>
#include <stdio.h>

#include <cairo/cairo.h>
#include <cairo/cairo-xlib.h>

#include <GLFW/glfw3.h>
#define GLFW_EXPOSE_NATIVE_X11
#include <GLFW/glfw3native.h>


int main(int argc, char * argv[]) {
	/* Initialize the library */
	if (!glfwInit())
		return -1;

	glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API);
	GLFWwindow * window = glfwCreateWindow(800, 600, "Test", NULL, NULL);
	if (!window) {
		glfwTerminate();
		return -1;
	}

	glfwSwapInterval(1);

	int fb_w, fb_h;
	glfwGetFramebufferSize(window, &fb_w, &fb_h);
	Display * x11_display = glfwGetX11Display();
	Window x11_window = glfwGetX11Window(window);
	Visual * vis = DefaultVisual(x11_display, DefaultScreen(x11_display));
	cairo_surface_t * surface = cairo_xlib_surface_create(x11_display, x11_window, vis, fb_w, fb_h);
	cairo_t * ctx = cairo_create(surface);

	while (!glfwWindowShouldClose(window)) {
		// on framebuffer size change, resize the surface
		glfwGetFramebufferSize(window, &fb_w, &fb_h);
		cairo_xlib_surface_set_size(surface, fb_w, fb_h);

		// have to group, else the x server does weird queueing
		cairo_push_group(ctx);

		//clear
		cairo_set_source_rgb(ctx, 1.0, 0.0, 0.0);
		cairo_set_operator(ctx, CAIRO_OPERATOR_SOURCE);
		cairo_paint(ctx);

		// RENDER HERE

		// ungroup and actually display
		cairo_pop_group_to_source(ctx);
		cairo_paint(ctx);
		cairo_surface_flush(surface);
		glfwSwapBuffers(window);

		glfwPollEvents();

		glfwSetWindowShouldClose(window, 1);
	}

	cairo_destroy(ctx);
	cairo_surface_finish(surface);
	cairo_surface_destroy(surface);
	glfwDestroyWindow(window);
	glfwTerminate();

	return 0;
}