/*
sublime-imfix.c
Use LD_PRELOAD to interpose some function to fix sublime input method support for linux.
By Cjacker Huang
 
gcc -shared -o libsublime-imfix.so sublime-imfix.c `pkg-config --libs --cflags gtk+-2.0` -fPIC
LD_PRELOAD=./libsublime-imfix.so subl
*/

#include <gtk/gtk.h>
#include <gdk/gdkx.h>
typedef GdkSegment GdkRegionBox;
 
struct _GdkRegion
{
  long size;
  long numRects;
  GdkRegionBox *rects;
  GdkRegionBox extents;
};
 
GtkIMContext *local_context;
 
void
gdk_region_get_clipbox (const GdkRegion *region,
            GdkRectangle    *rectangle)
{
  g_return_if_fail (region != NULL);
  g_return_if_fail (rectangle != NULL);
 
  rectangle->x = region->extents.x1;
  rectangle->y = region->extents.y1;
  rectangle->width = region->extents.x2 - region->extents.x1;
  rectangle->height = region->extents.y2 - region->extents.y1;
  GdkRectangle rect;
  rect.x = rectangle->x;
  rect.y = rectangle->y;
  rect.width = 0;
  rect.height = rectangle->height;
  //The caret width is 2;
  //Maybe sometimes we will make a mistake, but for most of the time, it should be the caret.
  if(rectangle->width == 2 && GTK_IS_IM_CONTEXT(local_context)) {
        gtk_im_context_set_cursor_location(local_context, rectangle);
  }
}
 
//this is needed, for example, if you input something in file dialog and return back the edit area
//context will lost, so here we set it again.
 
static GdkFilterReturn event_filter (GdkXEvent *xevent, GdkEvent *event, gpointer im_context)
{
    XEvent *xev = (XEvent *)xevent;
    if(xev->type == KeyRelease && GTK_IS_IM_CONTEXT(im_context)) {
       GdkWindow * win = g_object_get_data(G_OBJECT(im_context),"window");
       if(GDK_IS_WINDOW(win))
         gtk_im_context_set_client_window(im_context, win);
    }
    return GDK_FILTER_CONTINUE;
}
 
void gtk_im_context_set_client_window (GtkIMContext *context,
          GdkWindow    *window)
{
  GtkIMContextClass *klass;
  g_return_if_fail (GTK_IS_IM_CONTEXT (context));
  klass = GTK_IM_CONTEXT_GET_CLASS (context);
  if (klass->set_client_window)
    klass->set_client_window (context, window);
 
  if(!GDK_IS_WINDOW (window))
    return;
  g_object_set_data(G_OBJECT(context),"window",window);
  int width = gdk_window_get_width(window);
  int height = gdk_window_get_height(window);
  if(width != 0 && height !=0) {
    gtk_im_context_focus_in(context);
    local_context = context;
  }
  gdk_window_add_filter (window, event_filter, context);
}

[Desktop Entry]
[...]
Exec=env LD_PRELOAD=/opt/sublime_text/libsublime-imfix.so /opt/sublime_text/sublime_text %F
[...]
 
[Desktop Action Window]
[...]
Exec=env LD_PRELOAD=/opt/sublime_text/libsublime-imfix.so /opt/sublime_text/sublime_text -n
[...]
 
[Desktop Action Document]
[...]
Exec=env LD_PRELOAD=/opt/sublime_text/libsublime-imfix.so /opt/sublime_text/sublime_text --command new_file
[...]