make fcitx work in sublime-text-3

2016-02-16

Preface

Recently I began to use sublime and I found that fcitx couldn’t work in sublime. This is quite weird. After searching online for a while, I found a solution which could solve the problem in a “dirty” way.

Solution

First, thanks to cjacker, save the following script as sublime-imfix.c

/*
sublime-imfix.c
Use LD_PRELOAD to interpose some function to fix sublime input method support for linux.
By Cjacker Huang <jianzhong.huang at i-soft.com.cn>
By whitequark@whitequark.org
 
How to compile:
gcc -shared -o libsublime-imfix.so sublime_imfix.c  `pkg-config --libs --cflags gtk+-2.0` -fPIC
How to use:
LD_PRELOAD=./libsublime-imfix.so sublime_text
 
Changes:
2014 06-09
1, Fix cursor position update for sublime text 3.
2, Combine the codes from whitequark(fix for xim immodule) and add cursor update support for XIM immodule.
*/
 
/*for RTLD_NEXT*/
#define _GNU_SOURCE
 
#include <gtk/gtk.h>
#include <gdk/gdkx.h>
#include <assert.h>
#include <dlfcn.h>
#include <stdio.h>
#include <string.h>
#include <gtk/gtk.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
 
#ifdef VERBOSE
#define DEBUG(fmt, ...) do { \
    FILE* err = fopen("/tmp/libsublime-immethod-fix.log", "a"); \
    if (err) { \
      fprintf(err, fmt, __VA_ARGS__); \
      fclose(err); \
    } \
  } while(0)
#else
#define DEBUG(fmt, ...)
#endif
 
 
typedef GdkSegment GdkRegionBox;
 
struct _GdkRegion
{
  long size;
  long numRects;
  GdkRegionBox *rects;
  GdkRegionBox extents;
};
 
GtkIMContext *local_context;
 
 
//this func is interposed to support cursor position update.
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 in sublime text 2
  //And is 1 in sublime text 3.
  //Maybe sometimes we will make a mistake, but for most of the time, it should be the caret.
  if((rectangle->width == 2 || rectangle->width == 1)  && 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);
 
    //below is our interposed codes to save the context to local_context.
    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;
    }
    //only add this event_filter when using 'fcitx' immodule.
    //for xim immodule, this function is as same as original from gtk2.
    const gchar * immodule = g_getenv("GTK_IM_MODULE");
    if(immodule && !strcmp(immodule, "fcitx")) {
        gdk_window_add_filter (window, event_filter, context);
    }
}
 
 
/*below codes is from whitequark, fix for xim immodule*/
 
/* See gtkimcontextxim.c */
GType gtk_type_im_context_xim = 0;
 
#define GTK_TYPE_IM_CONTEXT_XIM            (gtk_type_im_context_xim)
#define GTK_IM_CONTEXT_XIM(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), GTK_TYPE_IM_CONTEXT_XIM, GtkIMContextXIM))
#define GTK_IM_CONTEXT_XIM_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST ((klass), GTK_TYPE_IM_CONTEXT_XIM, GtkIMContextXIMClass))
#define GTK_IS_IM_CONTEXT_XIM(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GTK_TYPE_IM_CONTEXT_XIM))
#define GTK_IS_IM_CONTEXT_XIM_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), GTK_TYPE_IM_CONTEXT_XIM))
#define GTK_IM_CONTEXT_XIM_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS ((obj), GTK_TYPE_IM_CONTEXT_XIM, GtkIMContextXIMClass))
 
typedef struct _GtkIMContextXIM       GtkIMContextXIM;
typedef struct _GtkIMContextXIMClass  GtkIMContextXIMClass;
 
struct _GtkIMContextXIMClass
{
  GtkIMContextClass parent_class;
};
 
typedef struct _StatusWindow StatusWindow;
typedef struct _GtkXIMInfo GtkXIMInfo;
 
struct _GtkIMContextXIM
{
  GtkIMContext object;
 
  GtkXIMInfo *im_info;
 
  gchar *locale;
  gchar *mb_charset;
 
  GdkWindow *client_window;
  GtkWidget *client_widget;
 
  /* The status window for this input context; we claim the
*    * status window when we are focused and have created an XIC
*       */
  StatusWindow *status_window;
 
  gint preedit_size;
  gint preedit_length;
  gunichar *preedit_chars;
  XIMFeedback *feedbacks;
 
  gint preedit_cursor;
 
  XIMCallback preedit_start_callback;
  XIMCallback preedit_done_callback;
  XIMCallback preedit_draw_callback;
  XIMCallback preedit_caret_callback;
 
  XIMCallback status_start_callback;
  XIMCallback status_done_callback;
  XIMCallback status_draw_callback;
 
  XIMCallback string_conversion_callback;
 
  XIC ic;
 
  guint filter_key_release : 1;
  guint use_preedit : 1;
  guint finalizing : 1;
  guint in_toplevel : 1;
  guint has_focus : 1;
};
 
static GClassInitFunc orig_gtk_im_context_xim_class_init;
static GType (*orig_g_type_module_register_type)(GTypeModule *,
                                                 GType, const gchar *,
                                                 const GTypeInfo *, GTypeFlags);
static gboolean (*orig_gtk_im_context_xim_filter_keypress)(GtkIMContext *context,
                                                           GdkEventKey *event);
 
static gboolean
hook_gtk_im_context_xim_filter_keypress(GtkIMContext *context, GdkEventKey *event) {
  GtkIMContextXIM *im_context_xim = GTK_IM_CONTEXT_XIM(context);
  if (!im_context_xim->client_window) {
    DEBUG("im_context_xim == %p\n", im_context_xim);
    DEBUG("event->window == %p\n", event->window);
 
    gtk_im_context_set_client_window(context, event->window);
  }
 
  return orig_gtk_im_context_xim_filter_keypress(context, event);
}
 
static void
hook_gtk_im_context_xim_class_init (GtkIMContextXIMClass *class) {
  orig_gtk_im_context_xim_class_init(class, NULL); /* wat? */
 
  GtkIMContextClass *im_context_class = GTK_IM_CONTEXT_CLASS (class);
 
  assert(!orig_gtk_im_context_xim_filter_keypress);
  orig_gtk_im_context_xim_filter_keypress = im_context_class->filter_keypress;
  im_context_class->filter_keypress = hook_gtk_im_context_xim_filter_keypress;
  DEBUG("orig_gtk_im_context_xim_filter_keypress: %p\n",
        orig_gtk_im_context_xim_filter_keypress);
}
 
GType
g_type_module_register_type (GTypeModule *module,
                             GType parent_type,
                             const gchar *type_name,
                             const GTypeInfo *type_info,
                             GTypeFlags flags) {
  if (!orig_g_type_module_register_type) {
    orig_g_type_module_register_type = dlsym(RTLD_NEXT, "g_type_module_register_type");
    assert(orig_g_type_module_register_type);
  }
 
  if (type_name && !strcmp(type_name, "GtkIMContextXIM")) {
    assert(!orig_gtk_im_context_xim_class_init);
    orig_gtk_im_context_xim_class_init = type_info->class_init;
 
    assert(sizeof(GtkIMContextXIM) == type_info->instance_size);
 
    const GTypeInfo hook_im_context_xim_info =
    {
      type_info->class_size,
      type_info->base_init,
      type_info->base_finalize,
      (GClassInitFunc) hook_gtk_im_context_xim_class_init,
      type_info->class_finalize,
      type_info->class_data,
      type_info->instance_size,
      type_info->n_preallocs,
      type_info->instance_init,
    };
 
    DEBUG("orig_gtk_im_context_xim_class_init: %p\n", orig_gtk_im_context_xim_class_init);
 
    gtk_type_im_context_xim =
      orig_g_type_module_register_type(module, parent_type, type_name,
                                       &hook_im_context_xim_info, flags);
 
    return gtk_type_im_context_xim;
  }
 
  return orig_g_type_module_register_type(module, parent_type, type_name, type_info, flags);
}

Then compile it.

1	gcc -shared -o libsublime-imfix.so sublime_imfix.c `pkg-config --libs --cflags gtk+-2.0` -fPIC

You will get a file called libsublime-imfix.so, put it in $HOME/.config/sublime-text-3/Packages/. In fact, it doesn’t matter where you put it, as long as you specify the right location of it in the following code. Put the following code in your ~/.bashrc file.

1 2	# sublime fcitx fix alias sublime='LD_PRELOAD=$HOME/.config/sublime-text-3/Packages/libsublime-imfix.so /usr/bin/subl > /dev/null 2>&1 &'

Save, re-source it.

1	. ~/.bashrc

Type in sublime in your terminal and you are good to go!

Showcase

fcitx in sublime-text-3

Coding

Preface

Solution

Showcase