bug#25943: 21.5 Frame Display Difficulties

[david]

;;; -*-Mode: emacs-lisp; Coding: emacs-mule; fill-column: 100-*-

;;; This file is executable and shows some problems indicated below. 
Execution is addressed further
;;; down.  The generating OS, etc. information is at the end of this file.

;;; Background information: I am updating from emacs 23.2 running on
Trisquel 5.0, to 25.1 running
;;; on Mint 18.1 and Trisquel 7.  So I have jumped over v24.  I have over
50K lines of elisp that
;;; have run successfully for over 20 years.  I have modified, extended,
and updated the code over
;;; the years as necessary, but the code still is basically the original. 
23.2 on Trisquel has been
;;; great, but I am sure that you will understand the need to get up to
date with OS and emacs.
;;; Also, I hope that you understand that it is important to me to keep my
software running
;;; correctly.

;;; Regrettably, 25.1 does not support my code very well, this is in
contrast to 23.2, and, really,
;;; all previous versions dating back at least to v19, where it does work
well.  I am trying to
;;; solve the problems, currently there are two of them that are serious
from my point of view, and
;;; one other that is a nuisance.


;;; The first problem is that 25.1 does not position a new frame correctly
unless the frame is
;;; visible when created.  Starting with a visible frame is tacky because
of the flashing that
;;; results.  Command simple-doit-1 demonstrates this, see below for notes
on execution.

;;; I spent a lot of time looking in the wrong places for a bug, but have
concluded that the problem
;;; is more of a design issue.  I think that I have identified what is
happening, but I leave that
;;; to you to judge.  The problem appears at xterm.c:10971, and is alluded
to in window.c:2335-2340.

;;; This is from window.c
;;;                  /* Yuck!!  If we've just created the frame and the
;;;                     window-manager requested the user to place it
;;;                     manually, the window may still not be considered
;;;                     `visible'.  I'd argue it should be at least
;;;                     something like `iconified', but don't know how to do
;;;                     that yet.  --Stef  */

;;; This is part of x_make_frame_visible at line xterm.c:10963
;;;       Don't do this if the window has never been visible before,
;;;       because the window manager may choose the position
;;;       and we don't want to override it.  */
;;;
;;;    if (! FRAME_VISIBLE_P (f)
;;;     && ! FRAME_ICONIFIED_P (f)
;;;     && ! FRAME_X_EMBEDDED_P (f)
;;;     && f->win_gravity == NorthWestGravity
;;;     && previously_visible)

;;; So, my case is that I create a frame and want to position it before I
make it visible, this is
;;; nothing to do with the window manager.  I can solve the problem by
eliminating the
;;; "previously_visible" part of the test above, and I am doing that as a
temporary get-around.
;;; But, of course, that elimination cuts across your window manager
concern.


;;; The second problem concerns user input, as is required in the current
file.  The (discard-input)
;;; code immediately before the read-event in simple-doit-1, and which has
not been necessary with
;;; previous versions of emacs, has a disadvantage whether or not it is in
place.  If it is not
;;; there (you need to comment the line to see this effect), the effect
can be something like key
;;; bounce, and this can be seen when the first text appears in the popup:
two text lines may
;;; appear, instead of one.  If (discard-input) is in the code, the
performance is better, but if a
;;; series of key entries must be made, a requirement in my code, then the
user must consciously
;;; pause between key entries.  This is a user-nuisance kind of problem.

;;; An additional facet of this problem is that it does not always
manifest itself.  Thus,
;;; sometimes, you will not see the two text lines appear together without
obvious input.  This
;;; second problem is described here for information, you may or may not
be able to reproduce it.
;;; Either way it is a degradation of performance of emacs.  This problem
has appeared in my code's
;;; performance in the change between 23.2 and 25.1.


;;; The third problem was to have been demonstrated with another command,
but I have been unable to
;;; reproduce the problem in a simple function.  The problem is a sometime
occurring,
;;; display-wrecking, problem.  I wonder if it is not even an emacs
problem, but due to underlying
;;; rendering library code.  The problem is repeatable.  Also, it is new
in 25.1 compared with 23.2.

;;; What I have done is take a screen shot showing the problem, a .jpg
image is attached, the screen
;;; shot is cropped.  What is shown is two frames, the green frame is a
frame generated by executing
;;; code (similar to simple-doit-1, but considerably more complicated),
the cream frame is the main
;;; emacs frame.  The black is the xterm background.  The frame windows
are displaying the same
;;; buffer, at the same time, normally these displays are identical
because the buffer is the same.
;;; The green frame in the image shows a distorted text display, this
frame always is correctly
;;; sized for the correct text.  The break at the sixty-first column is
repeatable, but other
;;; displays break at other places.

;;; I realize that solving this problem may be, at least, very difficult. 
I am hoping that you have
;;; some insight into the how and why.  I am simply letting you know that
what is happening, and it
;;; is new, after twenty-odd years.


;;; To run this code, first check the lines immediately below to
understand what they do, and modify
;;; the binding if desired.  Then, evaluate the file, press the bound key,
and follow the
;;; instructions in the echo area, pressing any key several times until
the left value (shown in the
;;; popup as l:-NN) goes positive.  The problem is the first display of
the popup.  Next, change the
;;; value of the visibility switch below, re-evaluate. and repeat the key
press, etc.


;; Change to see different performance under 25.1 (also 24.5, I checked
24.5 at some point).
(defconst  simple-visibility  'nil)

;; Binding.  Change as required.
(global-set-key  [f11]  'simple-doit-1)



;; A service variable.
(defvar  .emacs-current-emacs-version
  (let  ((lead-in  "GNU Emacs ")  ; an assumption, correct for 23.2, 24.5,
and 25.1
         (dot      "\\.")
         (version  (emacs-version))
         (dummy    "NOT INITIALIZED"))
    (setq  dummy  (substring  version  (length  lead-in)))         
    (substring  dummy  0  (string-match  dot  dummy  (1+  (string-match 
dot  dummy))) ))
  "The current emacs version, as a string, with format NN.N")



(defun  simple-doit-1  ()
  
  "Tests frame sizing and positioning."
  
  (interactive)
  
  (let  ((simple-frame   (make-frame  `((name       . "Simple Frame")
                                        (visibility .
,simple-visibility))) )
         (simple-buffer  (get-buffer-create  "Simple Buffer")))
    
    (set-window-buffer  (frame-selected-window  simple-frame) 
simple-buffer)    
    (with-current-buffer  simple-buffer  (erase-buffer)
                          (insert  (format  "version %s" 
.emacs-current-emacs-version)))
    
    (let*  ((invoking-frame  (selected-frame))
            (newish          (<=  25.1  (string-to-number 
.emacs-current-emacs-version)))
            (invoke-origin   (if  newish
                                 (frame-position  invoking-frame)
                               '(0 . 25)))
            (invoke-left  (car  invoke-origin))
            (invoke-top   (cdr  invoke-origin))
            (left         -41)
            (top          invoke-top)
            (width        60)
            (height       6))
      
      (unwind-protect
          (while  (progn
                    (set-frame-size  simple-frame  width  height)
                    (set-frame-position  simple-frame  left  top)
                    (select-frame-set-input-focus  simple-frame)
                    (set-buffer  simple-buffer)
                    (goto-char  (point-max))
                    (insert  (format  "\n%s  l:%3d  t:%3d  w:%3d  h:%3d"
                                      (selected-frame)  left  top  width 
height))
                    (setq  left   (+  left  10)                   
                           top    (+  top   10)
                           height (+  height 1))
;;;                    (if  newish  (discard-input))
                    
                    ;; loop test
                    (not  (equal
                           (read-event  "press any key to continue, escape
to terminate")
                           'escape))) )
        ;; end no body while
        
        ;; Protected.
        (select-frame  invoking-frame)
        (delete-frame  simple-frame))) ))



;;; The End.

;;; david@ngdr.net
;;; 2 March 2017
 
;;; In GNU Emacs 25.1.13 (x86_64-unknown-linux-gnu, GTK+ Version 3.18.9)
;;;  of 2017-02-25 built on Erota
;;; Windowing system distributor 'The X.Org Foundation', version
11.0.11804000
;;; System Description: Linux Mint 18.1 Serena
;;; 
;;; Configured using:
;;;  'configure CFLAGS=-g'
;;; 
;;; Configured features:
;;; XPM JPEG TIFF GIF PNG SOUND DBUS GSETTINGS NOTIFY FREETYPE XFT ZLIB
;;; TOOLKIT_SCROLL_BARS GTK3 X11
;;; 
;;; Important settings:
;;;   value of $LANG: en_US.UTF-8
;;;   locale-coding-system: utf-8-unix
;;; 
;;; Major mode: Info
;;; 
;;; Minor modes in effect:
;;;   display-time-mode: t
;;;   show-paren-mode: t
;;;   shell-dirtrack-mode: t
;;;   tooltip-mode: t
;;;   global-eldoc-mode: t
;;;   electric-indent-mode: t
;;;   mouse-wheel-mode: t
;;;   tool-bar-mode: t
;;;   menu-bar-mode: t
;;;   file-name-shadow-mode: t
;;;   global-font-lock-mode: t
;;;   font-lock-mode: t
;;;   blink-cursor-mode: t
;;;   auto-composition-mode: t
;;;   auto-encryption-mode: t
;;;   auto-compression-mode: t
;;;   buffer-read-only: t
;;;   column-number-mode: t
;;;   line-number-mode: t
;;;   transient-mark-mode: t

;;; Load-path shadows:
;;; None found.
;;; 
;;; Features:
;;; (shadow sort mail-extr emacsbug message format-spec rfc822 mml mml-sec
;;; password-cache epg epg-config gnus-util mm-decode mm-bodies mm-encode
;;; mail-parse rfc2231 mailabbrev gmm-utils mailheader browse-url ispell
;;; image-mode sh-script smie executable sgml-mode cl-extra cc-mode
;;; cc-fonts cc-guess cc-menus cc-cmds cc-styles cc-align cc-engine
;;; cc-vars cc-defs dabbrev misearch multi-isearch mailalias sendmail
;;; rfc2047 rfc2045 ietf-drums mm-util help-fns help-mode mail-prsvr
;;; mail-utils advice effective-impressive-communications Favourites
;;; fileset-Web fileset-Emacs25 fileset-Nepenthes fileset-VTrack
;;; fileset-NDM Local-filesets MinorTools time paren Load-Nepenthes
;;; Load-Environ MoreTools fileset-NavigationShellExtensionsCompilable
;;; fileset-NavigationShellKernelCompilable ConfigViews MaintenanceHelp
;;; FileProcessing ExtendedHelp DocumentMap Spawn ManInfo Logging
;;; GenericTools Fileset tex-mode shell pcomplete makeinfo texinfo compile
;;; comint ansi-color ring Common Maintenance SearchAndMod Path-Environ
;;; Load-NavigationShell FixupKeymaps Texinfo NewFile find-func
;;; HelpAtPoint Customize ToolsHelp noutline outline easy-mmode Tools
;;; ModeChange ModeChangeHelp NavShellHelp KeyDisplayEdit KeyDisplayHelp
;;; EmacsHelp dired NavigationShell PopEdit KeyDisplay Path-NavShell info
;;; speedbar sb-image ezimage dframe derived easymenu cl-macs gv
;;; cl-loaddefs pcase cl-lib Basis time-date mule-util tooltip eldoc
;;; electric uniquify ediff-hook vc-hooks lisp-float-type mwheel x-win
;;; term/common-win x-dnd tool-bar dnd fontset image regexp-opt fringe
;;; tabulated-list newcomment elisp-mode lisp-mode prog-mode register page
;;; menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock font-lock
;;; syntax facemenu font-core frame cl-generic cham georgian utf-8-lang
;;; misc-lang vietnamese tibetan thai tai-viet lao korean japanese
;;; eucjp-ms cp51932 hebrew greek romanian slovak czech european ethiopic
;;; indian cyrillic chinese charscript case-table epa-hook jka-cmpr-hook
;;; help simple abbrev minibuffer cl-preloaded nadvice loaddefs button
;;; faces cus-face macroexp files text-properties overlay sha1 md5 base64
;;; format env code-pages mule custom widget hashtable-print-readable
;;; backquote dbusbind inotify dynamic-setting system-font-setting
;;; font-render-setting move-toolbar gtk x-toolkit x multi-tty
;;; make-network-process emacs)
;;; 
;;; Memory information:
;;; ((conses 16 307931 161132)
;;;  (symbols 48 29413 0)
;;;  (miscs 40 323 2286)
;;;  (strings 32 48593 29093)
;;;  (string-bytes 1 1599176)
;;;  (vectors 16 20546)
;;;  (vector-slots 8 568963 16849)
;;;  (floats 8 292 1019)
;;;  (intervals 56 10070 3360)
;;;  (buffers 976 157)
;;;  (heap 1024 437759 51414))

Screenshot from 2017-02-25 10-08-23.jpg
Description: Binary data