I have a small example program written in C that opens a window using the XCB API.
Strictly AFTER I have created and shown the window, I would (at a later time) like to hide the window.
(Obviously in this specific example, I could remove the call to xcb_map_window, and the window would be hidden, but I want to do it at a later point in my larger application, like a toggle to show/hide the window, NOTE: I do NOT want to minimize it).
Here is the sample code (NOTE: this code now works thanks to the answer):
#include <unistd.h>
#include <stdio.h>
#include <stdbool.h>
#include <xcb/xcb.h>
void set_window_visible(xcb_connection_t* c, xcb_window_t win, bool visible) {
xcb_generic_event_t *event;
if(visible) {
// Map the window on the screen
xcb_map_window (c, win);
// Make sure the map window command is sent
xcb_flush(c);
// Wait for EXPOSE event.
//
// TODO: add timeout in-case X server does not ever send the expose event.
while(event = xcb_wait_for_event(c)) {
bool gotExpose = false;
switch(event->response_type & ~0x80) {
case XCB_EXPOSE:
gotExpose = true;
break;
default:
break; // We don't know the event type, then.
}
free(event);
if(gotExpose) {
break;
}
}
} else {
// Hide the window
xcb_unmap_window(c, win);
// Make sure the unmap window command is sent
xcb_flush(c);
}
}
int main() {
xcb_connection_t *c;
xcb_screen_t *screen;
xcb_window_t win;
xcb_generic_event_t *event;
// Open the connection to the X server
c = xcb_connect (NULL, NULL);
// Get the first screen
screen = xcb_setup_roots_iterator (xcb_get_setup (c)).data;
// Ask for our window's Id
win = xcb_generate_id(c);
// Create the window
uint32_t mask = XCB_CW_EVENT_MASK;
uint32_t valwin[] = {XCB_EVENT_MASK_EXPOSURE | XCB_BUTTON_PRESS};
xcb_create_window(
c, // Connection
XCB_COPY_FROM_PARENT, // depth (same as root)
win, // window Id
screen->root, // parent window
0, 0, // x, y
150, 150, // width, height
10, // border_width
XCB_WINDOW_CLASS_INPUT_OUTPUT, // class
screen->root_visual, // visual
mask, valwin // masks
);
bool visible = true;
set_window_visible(c, win, true);
while(1) {
sleep(2);
// Toggle visibility
visible = !visible;
set_window_visible(c, win, visible);
printf("Window visible: ");
if(visible) {
printf("true.\n");
} else {
printf("false.\n");
}
}
// pause until Ctrl-C
pause();
return 0;
}
Which I compile and run with:
gcc xcbwindow.c -o xcbwindow -lxcb
./xcbwindow
From anything I can find on Google or here, I am doing everything correctly. So for clarification I am using Unity and Ubuntu 12.04 LTS:
unity --version reports:
unity 5.20.0
uname -a reports:
Linux [redacted] 3.2.0-32-generic #51-Ubuntu SMP Wed Sep 26 21:33:09 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
Can anyone explain where I've gone wrong in this code?
EDIT: updated code with a flush() at the end after xcb_unmap_window(); still doesn't work.
EDIT2: Tried code with cinnamon WM; still doesn't work (It's not a Unity bug).
EDIT3: Code updated in this post now works.