#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <xcb/xcb.h>
#include <xcb/xproto.h>

int main(int argc, char *argv[])
{
    int screen;
    xcb_connection_t *c = xcb_connect(NULL, &screen);
    if (!c || xcb_connection_has_error(c)) {
	fprintf(stderr, "Cannot open default display \"%s\"\n", getenv("DISPLAY"));
	return EXIT_FAILURE;
    }

    // Find root window
    const xcb_setup_t *setup = xcb_get_setup(c);
    if (screen >= setup->roots_len)
	screen = 0;
    xcb_screen_iterator_t si = xcb_setup_roots_iterator(setup);
    for (int i=0; i < screen; i++)
	xcb_screen_next(&si);
    xcb_window_t root = si.data->root;

    // Create window and gc
    xcb_window_t window = xcb_generate_id(c);
    uint32_t list[] = { si.data->black_pixel, XCB_EVENT_MASK_EXPOSURE };
    xcb_create_window(c, XCB_COPY_FROM_PARENT, window, root, 0, 0, 100, 100,
	    0, XCB_WINDOW_CLASS_INPUT_OUTPUT, XCB_COPY_FROM_PARENT,
	    XCB_CW_BACK_PIXEL | XCB_CW_EVENT_MASK, list);
    xcb_map_window(c, window);

    xcb_gc_t gc = xcb_generate_id(c);
    uint32_t gc_list[] = { si.data->white_pixel, 2, XCB_LINE_STYLE_DOUBLE_DASH, XCB_JOIN_STYLE_BEVEL };
    xcb_create_gc(c, gc, root, 
	    XCB_GC_FOREGROUND|XCB_GC_LINE_WIDTH|XCB_GC_LINE_STYLE|XCB_GC_JOIN_STYLE, gc_list);
    uint8_t dashes[] = { 10, 4, 4, 4 };
    xcb_set_dashes(c, gc, 0, sizeof(dashes)/sizeof(*dashes), dashes);

    // Wait for window to be mapped
    xcb_flush(c);
    for (xcb_generic_event_t *ev = xcb_wait_for_event(c); ev; ev = xcb_wait_for_event(c)) {
	int type = ev->response_type;
	free(ev);
	if (type == XCB_EXPOSE)
	    break;
    }

    xcb_clear_area(c, 0, window, 0, 0, 0, 0);

    // Draw problematic line
    xcb_point_t line[] = {
	{ -851, -1200 },
	{ -757, -875 },
	{ -738, -812 },
	{ -675, -596 },
    };
    xcb_poly_line(c, XCB_COORD_MODE_ORIGIN, window, gc, sizeof(line)/sizeof(*line), line);
    xcb_flush(c);
    
    sleep(1);

    return EXIT_SUCCESS;
}