I'm writing a program using XLIB and gtk, I'm supposed to implement a function to switch a specific window(using any human identifyable reference, window name, process name or anything that is going to be static everytime that application is run)
I'm completely lost and I cannot find anything to guide me through the beginning of the application
thanks
You can do this with X libraries but it'll be a bit of a pain: you'll have to understand X IPC and properties. Fortunately there's an easier way, assuming you can use other libraries: use Libwnck. Here's a minimal example to list windows (adapted from the "Getting started" page):
WnckScreen *screen = wnck_screen_get_default ();
WnckWindow *active_window = wnck_screen_get_active_window (screen);
GList *l;
for (l = wnck_screen_get_windows (screen); l != NULL; l = window_l->next) {
WnckWindow *window = WNCK_WINDOW (window_l->data);
g_print ("%s%s\n", wnck_window_get_name (window),
window == active_window ? " (active)" : "");
}
Switching to a specific window should be just:
wnck_window_activate (window, 0);
The only gotcha is that wnck is designed to be used with a GLib mainloop. If you are not running one (as would be the case for a simple command line app), you'll need to use wnck_screen_force_update () to fetch the current data from X (see the "Getting started" example).
Related
Is there a way to query the cursor position using the GTK C libraries? I am writing a program where I need to read out the position of the cursor in real time (either through a callback function or by polling the values to look for change). I have scanned through the GTK documentation, but I couldn't find anything obvious that exposes the cursor position.
I am currently writing this program using the GTK C libraries because a) I already have some code written in C to interface with the low level Raspberry Pi peripherals, and I'd rather not rewrite it for a different language if I can avoid it. The low level code is based on mmap(), which I believe still works with C++, so if push comes to shove, I supposed I can rewrite it in C++ with some other GUI library like wxWidgets or QT. (Are there easy ways to read the cursor position with those libraries?)
You can take a look at how it's done in those toy widgets which draw eyes on the panel, e.g. xfce4-eyes-plugin.
gboolean
where (void)
{
gint x, y;
GdkWindow *window;
GdkDevice *mouse_device;
#if GTK_CHECK_VERSION (3,20,0)
GdkSeat *seat = gdk_display_get_default_seat (gdk_display_get_default ());
mouse_device = gdk_seat_get_pointer (seat);
#else
GdkDeviceManager *devman = gdk_display_get_device_manager (gdk_display_get_default ());
mouse_device = gdk_device_manager_get_client_pointer (devman);
#endif
window = gdk_display_get_default_group (gdk_display_get_default ());
gdk_window_get_device_position (window, mouse_device, &x, &y, NULL);
g_message ("pointer: %i %i", x, y);
return G_SOURCE_CONTINUE;
}
I wrote a simple program module to ask a user for a profile name. To do that I create windoww with entry widget, and two buttons (Ok and Cancel) organized in a grid. When user enters a profile name that already exists it informs him of that fact by creating dialog with "ok" button, and after he presses it, it goes back to picking a profile name (the window was not hidden nor destroyed in the meantime). The problem is that when I create a profile, and then spam the ok button (by placing something heavy on enter key and going to make tea) on both profile name chooser and the dialog (making a simple loop with creation and destruction of a dialog) the memory usage of the program increases.
TL;DR
Simply creating and destroying gtk window (and dialog) seems to cause a memory leak. Leaving app in a loop made it increase it's memory usage by ~1900% (from 10mb to 200mb).
No, I didn't test for memory leaks using apps designed for it.
Yes, I've set G_SLICE=always-malloc.
Yes, there is another thread running in the background of the program (but I'm sure it doesn't cause any leaks)
I can post screens from Windows Performance Monitor if you want more info on what happens in the memory.
The question is - is it a memory leak caused by me, or is it GTK's fault (I heard it has a lazy policy of memory management, but after some time memory usage drops from 200mb to 140mb and stays there)?
Here's the code:
// This callback racts to the ok and cancel buttons. If input was correcs
// or the user pressed cancel it destroys the window. Else it show error
// prompt. The showing error prompt seems to be the problem here.
void pickNameButtCB(GtkWidget *button, gpointer *call)
{
GtkWidget *window = gtk_widget_get_toplevel(button);
if( *((char*)call) == 'k')
{
GList *entryBase = gtk_container_get_children(GTK_CONTAINER(gtk_bin_get_child(GTK_BIN(window)))), *entry = entryBase;
for(size_t i=g_list_length(entry); i>0 && !GTK_IS_ENTRY(entry->data); --i)
entry = g_list_next(entry);
if(gtk_entry_get_text_length(GTK_ENTRY(entry->data)) > 0)
{
const char *temp = gtk_entry_get_text(GTK_ENTRY(entry->data));
char path[266];
strcpy(path, settingsDir);
strcat(path, temp);
strcat(path, ".prof");
if(settProfExists(path))
{
g_list_free(entryBase);
showError(GTK_WINDOW(window), GTK_MESSAGE_ERROR, "Profile with that name already exists!");
return;
}
// nothing here executes as well
}
else
{
/** doesn't execute when the memory leak happens */
}
g_list_free(entryBase);
}
gtk_widget_destroy(window);
gtk_main_quit();
}
void showError(GtkWindow *parent, GtkMessageType type, const char *str)
{
GtkWidget *window = gtk_message_dialog_new(parent, GTK_DIALOG_DESTROY_WITH_PARENT, type, GTK_BUTTONS_OK, str);
g_signal_connect_swapped(window, "response", G_CALLBACK(gtk_widget_destroy), window);
gtk_dialog_run(GTK_DIALOG(window));
}
bool settProfExists(const char *path)
{
if(fileExists(path))
return true;
return false;
}
bool fileExists(const char *path)
{
struct stat info;
errno = 0;
if((stat(path, &info)) != 0)
if(errno == ENOENT)
return false;
return true;
}
Your code is too incomplete to find the root cause.
This line especially is doesn't make sense. We're missing the definition of entry and you're trying to do several operations on the same line (*entry = entryBase;).
GList *entryBase = gtk_container_get_children(GTK_CONTAINER(gtk_bin_get_child(GTK_BIN(window)))), *entry = entryBase;
The leak may however be in functions you call for which you don't provide the code (settProfExists, newProfile). So please provide a minimal compilable example that reproduces the problem.
As for the style, there are several errors: you're traversing a list the way you'd do with an array. See how is implemented GList and you'll see that this is silly (hint: look at entry->prev and entry->next):
for(size_t i=g_list_length(entry); i>0 && !GTK_IS_ENTRY(entry->data); --i)
entry = g_list_next(entry);
Then an architectural problem: don't try to inspect your UI to guess where are the widgets, just create a structure, and pass you call parameter and the GtkEntry you're interested in, in a structure with the gpointer data argument of the callback.
You should also not make paths by hand: you're using a fixed length array that may not be long enough. Use the portable g_build_path provided by the GLib (and free the path with g_free after use), that will handle for you Windows/Linux directories separators.
For your dialog, as you run gtk_run_dialog, you may just directly call gtk_destroy_widget afterwards instead of connecting a signal:
GtkWidget *window = gtk_message_dialog_new(parent, GTK_DIALOG_DESTROY_WITH_PARENT, type, GTK_BUTTONS_OK, str);
gtk_dialog_run(GTK_DIALOG(window));
gtk_widget_destroy(window);
I would like to know if xfce has a function which works similar to gnome's gnome_url_show().
If this isn't the case I would like to know what would be another convenient way of opening a url? For example in case you added a signal handler to a button which upon clicking it opens a website.
Does gtk have such a function? I know it does have something built in at least, because when you create a label with a url in it it can be clicked to open the url. I have looked through various documentation but did not find a solution yet.
gtk_show_uri() is not going to work on xfce because it requires gvfs and I'm not using gnome.
Thanks to the xfce4-weather-plugin source I found this as a practical solution:
gchar *str = g_strdup_printf("exo-open --launch WebBrowser %s", url);
g_spawn_command_line_async(str, NULL);
g_free(str);
Considering the plugin is part of the core xfce apps I will assume it's the appropriate way to do it. I also found out about exo_execute_preferred_application() however I didn't feel like including another library.
A variation on this theme can be found here: http://git.xfce.org/xfce/libxfce4ui/tree/libxfce4ui/xfce-dialogs.c#n66
Which may be preferable because it will fall back to gtk_show_uri() in case exo is not installed. Although it's possible gtk_show_uri() may not work due to lack of gvfs on xfce systems (user is using xfce after all, not gnome). The xfce panel uses this function to load a url.
static void
xfce_dialog_show_help_uri (GdkScreen *screen,
GtkWindow *parent,
GString *uri)
{
GError *error = NULL;
gchar *path;
gchar *cmd;
gboolean result;
g_return_if_fail (GDK_IS_SCREEN (screen));
g_return_if_fail (parent == NULL || GTK_IS_WINDOW (parent));
path = g_find_program_in_path ("exo-open");
if (G_LIKELY (path != NULL))
{
cmd = g_strdup_printf ("%s --launch WebBrowser '%s'", path, uri->str);
result = xfce_spawn_command_line_on_screen (screen, cmd, FALSE, TRUE, &error);
g_free (path);
g_free (cmd);
}
else
{
/* not very likely to happen, but it is possible exo is not installed */
result = gtk_show_uri (screen, uri->str, gtk_get_current_event_time (), &error);
}
if (!result)
{
xfce_dialog_show_error (parent, error,
_("Failed to open web browser for online documentation"));
g_error_free (error);
}
}
A while ago I wrote a script in C that used the Windows API functions EnumWindows, SetWindowPos and SetForegroundWindow to automatically arrange windows (by title) in a particular layout that I commonly wanted.
Are there Linux equivalents for these functions? I will be using Kubuntu, so KDE-specific and/or Ubuntu-specific solutions are fine.
The best way to do this is either in the window manager itself (if yours supports extensions) or with the protocols and hints designed to support "pagers" (pager = any non-window-manager process that does window organization or navigation things).
The EWMH spec includes a _NET_MOVERESIZE_WINDOW designed for use by pagers. http://standards.freedesktop.org/wm-spec/wm-spec-1.3.html#id2731465
Raw Xlib or Xcb is pretty rough but there's a library called libwnck specifically designed to do the kind of thing you're talking about. (I wrote the original library long ago but it's been maintained by others forever.) Even if you don't use it, read the code to see how to do stuff. KDE may have an equivalent with KDE-style APIs I'm not sure.
There should be no need to use anything KDE or GNOME or distribution specific since the needed stuff is all spelled out in EWMH. That said, for certain window managers doing this as an extension may be easier than writing a separate app.
Using old school X calls directly can certainly be made to work but there are lots of details to handle there that require significant expertise if you want to iron out all the bugs and corner cases, in my opinion, so using a WM extension API or pager library would be my advice.
#andrewdotn has a fine answer there but you can do this old school as well fairly simply by walking the tree starting at the root window of the display using XQueryTree and fetching the window name with XFetchName then moving it with XMoveWindow. Here is an example that will list all the windows and if any are called 'xeyes' they get moved to the top left. Like most X programs, there is more to it and this should probably be calling XGetWindowProperty to fetch the _NET_WM_NAME extended window manager property but the example works ok as a starter. Compile with gcc -Wall -g -o demo demo.c -lX11
#include <X11/Xlib.h>
#include <stdio.h>
#include <string.h>
static int
EnumWindows(Display *display, Window window, int depth)
{
Window parent, *children;
unsigned int count = 0;
int r = 1, n = 0;
char *name = NULL;
XFetchName(display, window, &name);
for (n = 0; n < depth; ++n) putchar(' ');
printf("%08x %s\n", (int)window, name?name:"(null)");
if (name && strcmp("xeyes", name) == 0) {
XMoveWindow(display, window, 5, 5);
}
if (name) XFree(name);
if (XQueryTree(display, window, &window, &parent, &children, &count) == 0) {
fprintf(stderr, "error: XQueryTree error\n");
return 0;
}
for (n = 0; r && n < count; ++n) {
r = EnumWindows(display, children[n], depth+1);
}
XFree(children);
return r;
}
int
main(int argc, char *const argv[])
{
Display *display = NULL;
if ((display = XOpenDisplay(NULL)) == NULL) {
fprintf(stderr, "error: cannot connect to X server\n");
return 1;
}
EnumWindows(display, DefaultRootWindow(display), 0);
XCloseDisplay(display);
return 0;
}
Yes, you can do this using the X Windows protocol. It’s a very low-level protocol so it will take some work. You can use xcb_query_tree to find the window to operate on, and then move it with xcb_configure_window. This page gives some details on how to do it. There’s a basic tutorial on using the library those functions come from, but you’ll probably want to Google for a better one.
It may seem daunting, but it’s not too bad. Here’s a 50-line C program that will move all your xterms 10px to the right:
#include <stdio.h>
#include <string.h>
#include <xcb/xcb.h>
void handle(xcb_connection_t* connection, xcb_window_t window) {
xcb_query_tree_reply_t *tree = xcb_query_tree_reply(connection,
xcb_query_tree(connection, window), NULL);
xcb_window_t *children = xcb_query_tree_children(tree);
for (int i = 0; i < xcb_query_tree_children_length(tree); i++) {
xcb_get_property_reply_t *class_reply = xcb_get_property_reply(
connection,
xcb_get_property(connection, 0, children[i], XCB_ATOM_WM_CLASS,
XCB_ATOM_STRING, 0, 512), NULL);
char* class = (char*)xcb_get_property_value(class_reply);
class[xcb_get_property_value_length(class_reply)] = '\0';
if (!strcmp(class, "xterm")) {
/* Get geometry relative to parent window */
xcb_get_geometry_reply_t* geom = xcb_get_geometry_reply(
connection,
xcb_get_geometry(connection, window),
NULL);
/* Move 10 pixels right */
uint32_t values[] = {geom->x + 10};
xcb_configure_window(connection, children[i],
XCB_CONFIG_WINDOW_X, values);
}
/* Recurse down window tree */
handle(connection, children[i]);
}
}
int main() {
xcb_connection_t *connection;
const xcb_setup_t *setup;
connection = xcb_connect(NULL, NULL);
setup = xcb_get_setup(connection);
xcb_screen_iterator_t screen = xcb_setup_roots_iterator(setup);
handle(connection, screen.data->root);
return 0;
}
There’s no error-checking or memory management, and what it can do is pretty limited. But it should be straightforward to update into a program that does what you want, or to turn it into a general-purpose helper program by adding command-line options to specify which windows to operate on and which operations to perform on them.
As it seems you are not looking specifically for a solution in code, but rather in a desktop environment, you need to take a look at one of the window managers that handle the window placement in such a desktop environment.
KDE's KWin's Window Attributes
Compiz (GNOME) has "Window Rules" and "Place Windows" in the CompizConfig Settings Manager application. See e.g. here
Openbox seems a lot harder to get right, although they link to a GUI tool at the bottom of this page.
The problem with using X directly is that X in itself knows nothing about your desktop environment (panels, shortcuts, etc.) and you'll have to compensate manually.
After googling for this, I'm surprised KDE is the only one that has a simple way to do this.
How do I enumerate the shell context menu item using Windows API? I need to do it in pure C.
It is a little unclear to me if you want to show a menu or just enumerate the items, this does the latter (Excluding submenus)
HRESULT GetContextMenuForFSItem(PCTSTR path,IContextMenu**ppCM)
{
PIDLIST_ABSOLUTE pidlAbs;
HRESULT hr = SHParseDisplayName(path,0,&pidlAbs,0,0);
if (!hr)
{
IShellFolder*pSF;
PCUITEMID_CHILD pidlLast;
hr = SHBindToParent(pidlAbs,&IID_IShellFolder,(void**)&pSF,&pidlLast);
if (!hr)
{
hr = pSF->lpVtbl->GetUIObjectOf(pSF,0,1,&pidlLast,&IID_IContextMenu,0,(void**)ppCM);
pSF->lpVtbl->Release(pSF);
}
ILFree(pidlAbs);
}
return hr;
}
int main()
{
CoInitialize(0);
WCHAR buf[MAX_PATH];
GetWindowsDirectory(buf,MAX_PATH); /* Arbitrary filesystem item */
IContextMenu*pCM;
HRESULT hr = GetContextMenuForFSItem(buf,&pCM);
if (!hr)
{
HMENU hMenu = CreatePopupMenu();
hr = pCM->lpVtbl->QueryContextMenu(pCM,hMenu,0,1,0x7fff,0);
if (hr > 0)
{
UINT c=GetMenuItemCount(hMenu), i=0;
for (; i<c; ++i)
{
GetMenuString(hMenu,i,buf,MAX_PATH,MF_BYPOSITION);
if (GetMenuState(hMenu,i,MF_BYPOSITION)&MF_SEPARATOR) lstrcpy(buf,_T("--separator--"));
printf("%.2u=%ws\n",i,buf);
/*
Call IContextMenu::GetCommandString to get the verb
or IContextMenu::InvokeCommand to execute
*/
}
}
pCM->lpVtbl->Release(pCM);
DestroyMenu(hMenu);
}
CoUninitialize();
return 0;
}
On my system this prints:
00=&Open
01=--separator--
02=S&hare with
03=Restore previous &versions
04=&Include in library
05=--separator--
06=Se&nd to
07=--separator--
08=Cu&t
09=&Copy
10=--separator--
11=Create &shortcut
12=&Delete
13=--separator--
14=P&roperties
Using COM in C is not fun, switch to C++ if you can...
You need to do exactly what Explorer does: for the item in question (file, folder, other shell namespace location) you identify the list of shell extensions. These are COM classes and they implement IContextMenu interface. For every shell extension applicable, you can provide your own menu and request that such extension (handler) populates the menu with its additional items (IContextMenu::QueryContextMenu).
Later on you are free to decide when, where and if you are going to pop this menu up. Should there a need in handle one of those additional handler's commands, you are responsible to fowrward the command to the handler via IContextMenu::InvokeCommand. If you for some reason prefer to automate certain command and invoke it without popping up the menu, you can do it as well.
Links you might be interested in:
How to access Windows shell context menu items?
Creating Shortcut Menu Handlers
Raymond Chen wrote an eleven part series explaining how to do this. It's really not straightforward.