FTWL has been completely removed starting from freeciv 2.4, and it had been non-functional for many releases before that.
Freeciv Theme and Widget Layer
Freeciv Theme and Widget Layer (FTWL) is a low-level library for manipulating the graphics and input systems on your computer, and displaying screens with widgets based on themes loaded from configuration files.
A few naming conventions:
- be_* backend functions
- te_* theme engine functions
- sw_* widget related functions
- osda off-screen drawing area buffer
Programming in FTWL is quite simple. Here is an annotated example:
#include <config.h>
- Always remember this one, folks, otherwise you end up with bugs that are horribly difficult to figure out. I speak from experience...
#include <assert.h> #include <stdio.h> #include "shared.h" #include "support.h"
- These are utility files.
#include "back_end.h" #include "widget.h"
- These two contain the public API of FTWL.
struct sw_widget *root;
- A variable to point to the root window.
void nullfunc(int socket); /* prototype */ static bool my_key_handler(struct sw_widget *widget, const struct be_key *key, void *data) { assert(ct_key_is_valid(key)); if (key->type == BE_KEY_NORMAL && key->key == 'q') { exit(0); return TRUE; } return FALSE; }
- The above function is a callback that handles all keypresses that are received on the root window. We use this to add a convenient way to exit our example application.
void nullfunc(int socket) { return; }
- The main loop expects a function pointer that can give it input from outside devices, eg the network. We just use an empty function here.
int main(int argc, char **argv) { struct ct_size res; struct ct_size size; res.width = 640; res.height = 480; sw_init(); be_init(&res, FALSE);
- Now we have set up the main window at 640x480.
/* Error checking */ be_screen_get_size(&size); if (size.width != res.width || size.height != res.height) { die("Instead of the desired screen resolution (%dx%d) " "got (%dx%d). This may be a problem with the window-manager.", res.width, res.height, size.width, size.height); }
- Error checking is always nice.
root = sw_create_root_window();
- Set up the root window.
sw_window_set_key_notify(root, my_key_handler, NULL);
- Register our key handler from above. You need to register key handlers for any widget that is supposed to receive key presses.
sw_mainloop(nullfunc);
- Start the main loop. Unlike more primitive libraries, FTWL has a built-in main loop, and your program must be callback-driven.
return 0; }
- That's it.
TODO:
- Add more documentation!
- Support UNICODE
- Support more depth on the existing backend
- Create a backend with palette mode (no transparency, no AA)
- OpenGL, Quartz and DirectX backends