JustPaste.it - Share Text & Images the Easy Way

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include <xcb/xcb.h>

#define WIDTH 300
#define HEIGHT 150

// https://xorg.freedesktop.org/archive/current/doc/libxcb/tutorial/index.html#pixmaps 3. Complete example

static xcb_gc_t gc_font_get (xcb_connection_t *c,
xcb_screen_t *screen,
xcb_window_t window,
const char *font_name);

static void button_draw (xcb_connection_t *c,
xcb_screen_t *screen,
xcb_window_t window,
int16_t x1,
int16_t y1,
const char *label);

static void text_draw (xcb_connection_t *c,
xcb_screen_t *screen,
xcb_window_t window,
int16_t x1,
int16_t y1,
const char *label);

static void cursor_set (xcb_connection_t *c,
xcb_screen_t *screen,
xcb_window_t window,
int cursor_id);

static void
button_draw (xcb_connection_t *c,
xcb_screen_t *screen,
xcb_window_t window,
int16_t x1,
int16_t y1,
const char *label)
{
xcb_point_t points[5];
xcb_void_cookie_t cookie_gc;
xcb_void_cookie_t cookie_line;
xcb_void_cookie_t cookie_text;
xcb_generic_error_t *error;
xcb_gcontext_t gc;
int16_t width;
int16_t height;
uint8_t length;
int16_t inset;

length = strlen (label);
inset = 2;

gc = gc_font_get(c, screen, window, "7x13");

width = 7 * length + 2 * (inset + 1);
height = 13 + 2 * (inset + 1);
points[0].x = x1;
points[0].y = y1;
points[1].x = x1 + width;
points[1].y = y1;
points[2].x = x1 + width;
points[2].y = y1 - height;
points[3].x = x1;
points[3].y = y1 - height;
points[4].x = x1;
points[4].y = y1;
cookie_line = xcb_poly_line_checked (c, XCB_COORD_MODE_ORIGIN,
window, gc, 5, points);

error = xcb_request_check (c, cookie_line);
if (error) {
fprintf (stderr, "ERROR: can't draw lines : %d\n", error->error_code);
xcb_disconnect (c);
exit (-1);
}

cookie_text = xcb_image_text_8_checked (c, length, window, gc,
x1 + inset + 1,
y1 - inset - 1, label);
error = xcb_request_check (c, cookie_text);
if (error) {
fprintf (stderr, "ERROR: can't paste text : %d\n", error->error_code);
xcb_disconnect (c);
exit (-1);
}

cookie_gc = xcb_free_gc (c, gc);
error = xcb_request_check (c, cookie_gc);
if (error) {
fprintf (stderr, "ERROR: can't free gc : %d\n", error->error_code);
xcb_disconnect (c);
exit (-1);
}
}

static void
text_draw (xcb_connection_t *c,
xcb_screen_t *screen,
xcb_window_t window,
int16_t x1,
int16_t y1,
const char *label)
{
xcb_void_cookie_t cookie_gc;
xcb_void_cookie_t cookie_text;
xcb_generic_error_t *error;
xcb_gcontext_t gc;
uint8_t length;

length = strlen (label);

gc = gc_font_get(c, screen, window, "7x13");

cookie_text = xcb_image_text_8_checked (c, length, window, gc,
x1,
y1, label);
error = xcb_request_check (c, cookie_text);
if (error) {
fprintf (stderr, "ERROR: can't paste text : %d\n", error->error_code);
xcb_disconnect (c);
exit (-1);
}

cookie_gc = xcb_free_gc (c, gc);
error = xcb_request_check (c, cookie_gc);
if (error) {
fprintf (stderr, "ERROR: can't free gc : %d\n", error->error_code);
xcb_disconnect (c);
exit (-1);
}
}

static xcb_gc_t
gc_font_get (xcb_connection_t *c,
xcb_screen_t *screen,
xcb_window_t window,
const char *font_name)
{
uint32_t value_list[3];
xcb_void_cookie_t cookie_font;
xcb_void_cookie_t cookie_gc;
xcb_generic_error_t *error;
xcb_font_t font;
xcb_gcontext_t gc;
uint32_t mask;

font = xcb_generate_id (c);
cookie_font = xcb_open_font_checked (c, font,
strlen (font_name),
font_name);

error = xcb_request_check (c, cookie_font);
if (error) {
fprintf (stderr, "ERROR: can't open font : %d\n", error->error_code);
xcb_disconnect (c);
return -1;
}

gc = xcb_generate_id (c);
mask = XCB_GC_FOREGROUND | XCB_GC_BACKGROUND | XCB_GC_FONT;
value_list[0] = screen->black_pixel;
value_list[1] = screen->white_pixel;
value_list[2] = font;
cookie_gc = xcb_create_gc_checked (c, gc, window, mask, value_list);
error = xcb_request_check (c, cookie_gc);
if (error) {
fprintf (stderr, "ERROR: can't create gc : %d\n", error->error_code);
xcb_disconnect (c);
exit (-1);
}

cookie_font = xcb_close_font_checked (c, font);
error = xcb_request_check (c, cookie_font);
if (error) {
fprintf (stderr, "ERROR: can't close font : %d\n", error->error_code);
xcb_disconnect (c);
exit (-1);
}

return gc;
}

static void
cursor_set (xcb_connection_t *c,
xcb_screen_t *screen,
xcb_window_t window,
int cursor_id)
{
uint32_t values_list[3];
xcb_void_cookie_t cookie_font;
xcb_void_cookie_t cookie_gc;
xcb_generic_error_t *error;
xcb_font_t font;
xcb_cursor_t cursor;
xcb_gcontext_t gc;
uint32_t mask;
uint32_t value_list;

font = xcb_generate_id (c);
cookie_font = xcb_open_font_checked (c, font,
strlen ("cursor"),
"cursor");
error = xcb_request_check (c, cookie_font);
if (error) {
fprintf (stderr, "ERROR: can't open font : %d\n", error->error_code);
xcb_disconnect (c);
exit (-1);
}

cursor = xcb_generate_id (c);
xcb_create_glyph_cursor (c, cursor, font, font,
cursor_id, cursor_id + 1,
0, 0, 0,
0, 0, 0);

gc = xcb_generate_id (c);
mask = XCB_GC_FOREGROUND | XCB_GC_BACKGROUND | XCB_GC_FONT;
values_list[0] = screen->black_pixel;
values_list[1] = screen->white_pixel;
values_list[2] = font;
cookie_gc = xcb_create_gc_checked (c, gc, window, mask, values_list);
error = xcb_request_check (c, cookie_gc);
if (error) {
fprintf (stderr, "ERROR: can't create gc : %d\n", error->error_code);
xcb_disconnect (c);
exit (-1);
}

mask = XCB_CW_CURSOR;
value_list = cursor;
xcb_change_window_attributes (c, window, mask, &value_list);

xcb_free_cursor (c, cursor);

int main ()
{
xcb_screen_iterator_t screen_iter;
xcb_connection_t *c;
const xcb_setup_t *setup;
xcb_screen_t *screen;
xcb_generic_event_t *e;
xcb_generic_error_t *error;
xcb_void_cookie_t cookie_window;
xcb_void_cookie_t cookie_map;
xcb_window_t window;
uint32_t mask;
uint32_t values[2];
int screen_number;
uint8_t is_hand = 0;

/* getting the connection */
c = xcb_connect (NULL, &screen_number);
if (!c) {
fprintf (stderr, "ERROR: can't connect to an X server\n");
return -1;
}

/* getting the current screen */
setup = xcb_get_setup (c);

screen = NULL;
screen_iter = xcb_setup_roots_iterator (setup);
for (; screen_iter.rem != 0; --screen_number, xcb_screen_next (&screen_iter))
if (screen_number == 0)
{
screen = screen_iter.data;
break;
}
if (!screen) {
fprintf (stderr, "ERROR: can't get the current screen\n");
xcb_disconnect (c);
return -1;
}

/* creating the window */
window = xcb_generate_id (c);
mask = XCB_CW_BACK_PIXEL | XCB_CW_EVENT_MASK;
values[0] = screen->white_pixel;
values[1] =
XCB_EVENT_MASK_KEY_RELEASE |
XCB_EVENT_MASK_BUTTON_PRESS |
XCB_EVENT_MASK_EXPOSURE |
XCB_EVENT_MASK_POINTER_MOTION;
cookie_window = xcb_create_window_checked (c,
screen->root_depth,
window, screen->root,
20, 200, WIDTH, HEIGHT,
0, XCB_WINDOW_CLASS_INPUT_OUTPUT,
screen->root_visual,
mask, values);
cookie_map = xcb_map_window_checked (c, window);

/* error managing */
error = xcb_request_check (c, cookie_window);
if (error) {
fprintf (stderr, "ERROR: can't create window : %d\n", error->error_code);
xcb_disconnect (c);
return -1;
}
error = xcb_request_check (c, cookie_map);
if (error) {
fprintf (stderr, "ERROR: can't map window : %d\n", error->error_code);
xcb_disconnect (c);
return -1;
}

cursor_set (c, screen, window, 68);

xcb_flush(c);

while (1) {
e = xcb_poll_for_event(c);
if (e) {
switch (e->response_type & ~0x80) {
case XCB_EXPOSE: {
char *text;

text = "click here to change cursor";
button_draw (c, screen, window,
(WIDTH - 7 * strlen(text)) / 2,
(HEIGHT - 16) / 2, text);

text = "Press ESC key to exit...";
text_draw (c, screen, window, 10, HEIGHT - 10, text);
break;
}
case XCB_BUTTON_PRESS: {
xcb_button_press_event_t *ev;
int length;

ev = (xcb_button_press_event_t *)e;
length = strlen ("click here to change cursor");

if ((ev->event_x >= (WIDTH - 7 * length) / 2) &&
(ev->event_x <= ((WIDTH - 7 * length) / 2 + 7 * length + 6)) &&
(ev->event_y >= (HEIGHT - 16) / 2 - 19) &&
(ev->event_y <= ((HEIGHT - 16) / 2)))
is_hand = 1 - is_hand;

is_hand ? cursor_set (c, screen, window, 58) : cursor_set (c, screen, window, 68);
}
case XCB_KEY_RELEASE: {
xcb_key_release_event_t *ev;

ev = (xcb_key_release_event_t *)e;

switch (ev->detail) {
/* ESC */
case 9:
free (e);
xcb_disconnect (c);
return 0;
}
}
}
free (e);
}
}

return 0;
}