bug#46180: Patch to fix input method cursor location for the feature/pgtk branch

[Yichao Yu]

See patch attached below. The pgtk branch carried over some old XIM
code that isn't valid in such configuration. This makes sure the gtk
immodule can get the correct cursor location.

I guess this does mean that the patch I submitted a few months ago to
fix/improve XIM usage would not be useful for much longer but
hopefully it's for the better =).

-----------------------------------

>From be5764d617b2a5fe3b26ddab1e739dad6d393825 Mon Sep 17 00:00:00 2001
From: Yichao Yu <yyc1992@gmail.com>
Date: Fri, 29 Jan 2021 14:38:53 -0500
Subject: [PATCH] Add support for setting cursor location using Gtk IM Context

The existing XIC implementation doesn't work when using Gtk IM Context.
Instead, `gtk_im_context_set_cursor_location` should be used
to update the cursor information for the input method.

Tested with fcitx5.
---
src/pgtkim.c   | 12 ++++++++++++
src/pgtkterm.c | 12 ++++++++----
src/pgtkterm.h |  2 ++
3 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/src/pgtkim.c b/src/pgtkim.c
index 68f83d2c6e..ba69a27501 100644
--- a/src/pgtkim.c
+++ b/src/pgtkim.c
@@ -210,6 +210,18 @@ pgtk_im_filter_keypress (struct frame *f, GdkEventKey * ev)
  return false;
}

+void
+pgtk_im_set_cursor_location (struct frame *f, int x, int y, int width,
+                            int height)
+{
+  struct pgtk_display_info *dpyinfo = FRAME_DISPLAY_INFO (f);
+  if (dpyinfo->im.context != NULL && dpyinfo->im.focused_frame == f)
+    {
+      GdkRectangle area = { x, y, width, height };
+      gtk_im_context_set_cursor_location (dpyinfo->im.context, &area);
+    }
+}
+
static void
pgtk_im_use_context (struct pgtk_display_info *dpyinfo, bool use_p)
{
diff --git a/src/pgtkterm.c b/src/pgtkterm.c
index 44e1f3e296..7d46053d31 100644
--- a/src/pgtkterm.c
+++ b/src/pgtkterm.c
@@ -2878,6 +2878,7 @@ pgtk_draw_window_cursor (struct window *w,
struct glyph_row *glyph_row,
int x,
                        int y, enum text_cursor_kinds cursor_type,
                        int cursor_width, bool on_p, bool active_p)
{
+  struct frame *f = XFRAME (w->frame);
  PGTK_TRACE ("draw_window_cursor: %d, %d, %d, %d, %d, %d.",
             x, y, cursor_type, cursor_width, on_p, active_p);
  if (on_p)
@@ -2922,11 +2923,14 @@ pgtk_draw_window_cursor (struct window *w,
struct glyph_row *glyph_row
, int x,
           }
       }

-#ifdef HAVE_X_I18N
      if (w == XWINDOW (f->selected_window))
-       if (FRAME_XIC (f) && (FRAME_XIC_STYLE (f) & XIMPreeditPosition))
-         xic_set_preeditarea (w, x, y);
-#endif
+       {
+         int frame_x =
+           WINDOW_TO_FRAME_PIXEL_X (w, x) + WINDOW_LEFT_FRINGE_WIDTH (w);
+         int frame_y = WINDOW_TO_FRAME_PIXEL_Y (w, y);
+         pgtk_im_set_cursor_location (f, frame_x, frame_y,
w->phys_cursor_width,
+                                      w->phys_cursor_height);
+       }
    }

}
diff --git a/src/pgtkterm.h b/src/pgtkterm.h
index 5e71f93998..07d7fc10c6 100644
--- a/src/pgtkterm.h
+++ b/src/pgtkterm.h
@@ -653,6 +653,8 @@ #define FIRST_CHAR_POSITION(f)
         \
extern void pgtk_im_focus_in (struct frame *f);
extern void pgtk_im_focus_out (struct frame *f);
extern bool pgtk_im_filter_keypress (struct frame *f, GdkEventKey * ev);
+extern void pgtk_im_set_cursor_location (struct frame *f, int x, int y,
+                                        int width, int height);
extern void pgtk_im_init (struct pgtk_display_info *dpyinfo);
extern void pgtk_im_finish (struct pgtk_display_info *dpyinfo);

--
2.30.0