Emacs Line Height - emacs

I am trying to set the line height of text in an Emacs buffer so there is space above and below the letters. From the documentation, I infer that the line-height text property may help me to accomplish this.
There is also a line-spacing variable which I can set like (setq-default line-spacing 0.25). This kind of works, except it does not produce space before text, only after it. I don’t like the way this looks when using modes like show-paren-mode, since it “dips” down:
Undesired current behavior (“hanging”)
Desired behavior mockup (vertically-centered)
I'd like to vertically-center the text.
I have discovered that I can temporarily get the effect I want with the following code:
(add-text-properties (point-min) (point-max)
'(line-spacing 0.25 line-height 1.25))
However, in some modes the properties go away in regions where I start typing. How do I make that top and bottom spacing the default? (Hooks won't work.)

Update
TLDR: I've succumbed to the fact that you can't really reliably achieve this natively with Emacs. You need to patch the font itself to include extra spacing. So, I created this script to take care of that.
Old/Incomplete Answer
TLDR: Add this somewhere in init file:
;; Set the padding between lines
(defvar line-padding 3)
(defun add-line-padding ()
"Add extra padding between lines"
; remove padding overlays if they already exist
(let ((overlays (overlays-at (point-min))))
(while overlays
(let ((overlay (car overlays)))
(if (overlay-get overlay 'is-padding-overlay)
(delete-overlay overlay)))
(setq overlays (cdr overlays))))
; add a new padding overlay
(let ((padding-overlay (make-overlay (point-min) (point-max))))
(overlay-put padding-overlay 'is-padding-overlay t)
(overlay-put padding-overlay 'line-spacing (* .1 line-padding))
(overlay-put padding-overlay 'line-height (+ 1 (* .1 line-padding))))
(setq mark-active nil))
(add-hook 'buffer-list-update-hook 'add-line-padding)
Increase or decrease the line-padding value to your liking.
This answer pretty much just summarizes the information in the above question, answer, and comments, so I suggest reading those first.
I use an overlay instead of text properties because it behaves more nicely when adding new text to the buffer (especially via copy/paste).
The buffer-list-update-hook is used as a means of identifying when a new buffer has been created and thus would need to have the overlay applied.
For performance reasons, to not continuously add overlays, the existing padding overlay is deleted if it aleady existed.

As the doc says, line-height is a text (or an overlay) property. It is not a variable.
Try (setq-default line-spacing 20).
line-spacing is a frame parameter or a buffer-local variable. Its value can be an integer number of pixels or a floating-point number specifying spacing relative to the frame's default line height. The doc says nothing about giving it a list value, such as (32 64).
And if you are using Emacs in terminal mode then none of this applies. As the doc says about that:
On text terminals, the line spacing cannot be altered.

Try "Help => More Manuals => Emacs Lisp Reference" and from there type i text properties RET. This will hopefully clarify the situation. As for your specific request, I don't think there's a simple way to get what you want right now. You might like to M-x report-emacs-bug about the display appearence of the paren-highlighting.

Related

Emacs: contextual margin settings or filling text to narrow range of columns?

I'd like to quickly generate text in a buffer that looks like this:
(fact "This is some text which will hang out
only on this part of the screen, ideally
automatically flowing to the correct
margins as I type."
(+ 1 1) => 2
;; more Clojure tests...
)
I have an Elisp keybinding which quickly spits out a starting template and puts my cursor in the right place:
(global-set-key "\C-of" (lambda ()
(interactive)
(insert "(fact \"\"\n\n )")
(backward-char 6)))
Now, when I am typing in the string portion ("This is some text..."), it'd be awesome if I could get Emacs to automatically flow text to the "correct" margins. Is there some way Emacs can be made to adjust margins and wraparound behavior based on where you're typing? At least, the first time you are typing there?
Barring that, for a given selection of text, how can I do the equivalent of fill-region, but with the desired left and right margins? Currently fill-region deletes all space between fact and "This is...., and left-justifies the rest.
There might be a simpler way that I'm overlooking now, but I would just do this:
Configure the text block in a temporary buffer, by doing this there:
a. Set fill-column to the width of the text block that you want.
b. Put the text at the beginning of the line, i.e., not indented.
c. Fill the text.
d. Use indent-rigidly to indent the text to the column you want, except for the first line.
Insert into your target buffer (fact followed by the indentation you want for the first line of the text block. Then insert the contents of the temporary buffer. Then insert whatever other text/code you need.
IOW, I would separate filling the text block from indenting it.
The following seems to work for the moment for my alternative (weaker) case:
;; Set up Midje fact with mark inserted at beginning of comment text
;; (refill as needed in appropriate columns, using C-oF).
(global-set-key "\C-of" (lambda ()
(interactive)
(insert "(fact \"\"\n\n )")
(backward-char 6)
(set-mark (point))))
;; Perform the refill operation to properly reformat the text string
;; in a Midje fact, started with C-of:
(global-set-key "\C-oF" (lambda ()
(interactive)
(set-left-margin (mark) (point) 37)
(fill-region (mark) (point))))
I expect I'll have to tweak this as I get experience using it, but it is pretty close. Still, it'd be nice to figure out how to have this happen automatically, while I'm typing inside the string.

emacs: second toolbar (row)

this is my first question, so apologies for breaking any rules.
I've just started writing some functions in elisp to help me navigate certain types of text files more efficiently. To make these accessible, I've added some buttons to the tool-bar. As it's now becoming busy, I'd like to either: 1) move some of these additional buttons to a second line; or 2) instantiate a second tool-bar that could be placed somewhere else in the frame (either under the existing tool-bar, or perhaps vertically along the side where the scrollbar is).
I've searched high and low but am unable to find an existing example of this and, as I don't yet really know what I'm doing, I wonder if somebody has a code snippet from which I might start to hack a solution together.
Many thanks in advance.
System: CentOS 5/6, emacs for linux 23.1
Edit:
Thanks for the comment, William. Here's a simple example representing what my tool-bar code might do:
;
; functions used by the toolbar
;
;
(defun copy-paste-whole-line ()
"copies and pastes the whole of the current into a new line underneath"
(interactive)
(beginning-of-line)
(set-mark (point))
(end-of-line)
(setq temp (buffer-substring (region-beginning) (region-end)))
(message " copying: %s" temp )
(newline)
(insert temp))
;
;
; population of the toolbar:
;
;
(when (find-image '((:type xpm :file "copy_paste_line.xpm")))
(unless tool-bar-mode (tool-bar-mode 1))
; (setq tool-bar-map (make-sparse-keymap)) ; <- uncomment this line to have only this button present
(tool-bar-add-item
"copy_paste_line"
'copy-paste-whole-line
'copy-paste-whole-line
:help "copies and pastes the whole of the current line into a new line underneath"))
so, as you can see (actually, I'm not allowed to post images until I have 10 reputation points, so you won't be able to see), the code adds an extra button to the end of the existing tool-bar buttons. I believe this to be a reasonable way to achieve this, but I'm not an experienced elisp programmer, so if you think it's poorly written, please comment - I'd like to understand why... :)
If I only had 1 button, it would be ok like that, however, I have multiple buttons. I would, thus, like to add them to a second instance of a similar tool-bar (or, perhaps a vertical one placed where the scrollbars are).
Thanks again for any input.
Frame parameter tool-bar-lines is supposed to control this. You can, for instance, customize option default-frames-alist if you want to change the number of tool-bar rows to 2 or 3 everywhere. Or you can do this on a mode-by-mode or frame-by-frame basis. You can, for instance, use M-: (set-frame-parameter nil 'tool-bar-lines 3).
Depending on your platform (and toolkit), the behavior might be variable. See the Elisp manual, node Layout Parameters and node Tool Bars.
I believe you are out of luck. It seems to me that (at least on ubuntu and cygwin) only one row of buttons in the tool-bar is supported.
Here is what I have tried without luck on both systems:
(progn
(set-frame-parameter nil 'tool-bar-lines 3)
(loop for i from 1 upto 20 do
(setcdr tool-bar-map (cons (cadr tool-bar-map) (cdr tool-bar-map)))))
The following picture shows what I get:
The other buttons appear in a pull-down menu if you click on the little triangle at the right end of the toolbar:
You can restore the old tool-bar with the following commands:
(progn
(setq tool-bar-map (make-sparse-keymap))
(tool-bar-setup))
Finally, I have 3 rows of buttons. This is possible with emacs-w32:
So it is the gtk+ / nextstep problem.

fix an auto-complete-mode and linum-mode annoyance

I'm using auto-complete-mode which I think is totally fantastic. I'm also a big fan of linum-mode but I've got a very irritating issue when the two are used together, especially when I'm working in a new buffer (or a buffer with very few lines).
Basically the buffer is 'x' lines long but when auto-complete kicks in it "adds" lines to the buffer, so linum-mode keeps switching, for example, between displaying line numbers on one column or two columns, depending on whether auto-complete is suggesting a completion or not.
So you type a sentence and you see your buffer's content frantically shifting from left to right at every keypress. It is really annoying.
I take it the solution involves configuring the linum-format variable but I don't know how.
Ideally it would be great if my linum-format was:
dynamic
right-aligned
considering there are 'y' more lines to the buffer than what the buffer actually has
My rationale being that auto-complete shall not suggest more than 'y' suggestion and that, hence, the two shall start playing nicely together.
For example, if 'y' is set to 20 and my buffer has 75 lines, then linum should use two columns: because no matter where I am auto-complete shall not make the buffer 'bigger' than 99 lines.
On the contrary, if 'y' is still set to 20 and my buffer has 95 lines, then linum should use three columns because otherwise if I'm near the end of the buffer and auto-complete kicks in my buffer shall start "wobbling" left and right when I type.
I'd rather not hardcode "3 columns wide" for linum.
I guess using "dynamic but always at least two columns" would somehow fix most annoyances but still something as I described would be great.
P.S: I realize that my 'fix' would imply that linum would always display on at least two columns, and I'm fine with that... As long as it stays right-aligned and use 2, 3 or 4 columns depending on the need.
Simply put the following line in .emacs which resolves this issue. It is in auto-complete.el.
(ac-linum-workaround)
I've written a couple of previous answers on modifying the linum-mode output, which you could probably adapt to your purposes.
Relative Line Numbers In Emacs
Colorize current line number
Edit: Here's the most basic version of that code (also on EmacsWiki, albeit somewhat buried), which doesn't modify the default output at all, but uses the techniques from those other answers to be more efficient than the default code. That's probably a more useful starting point for you.
(defvar my-linum-format-string "%4d")
(add-hook 'linum-before-numbering-hook 'my-linum-get-format-string)
(defun my-linum-get-format-string ()
(let* ((width (length (number-to-string
(count-lines (point-min) (point-max)))))
(format (concat "%" (number-to-string width) "d")))
(setq my-linum-format-string format)))
(setq linum-format 'my-linum-format)
(defun my-linum-format (line-number)
(propertize (format my-linum-format-string line-number) 'face 'linum))
Just have the same problem, after seeing 'patching the source' I believe it could be done with advice. Here is what I come up with
(defadvice linum-update
(around tung/suppress-linum-update-when-popup activate)
(unless (ac-menu-live-p)
ad-do-it))
I would like to use popup-live-p as mentioned but unfortunately it requires the variable for the popup, which we couldn't know in advance.
Update:
I ended up patching the source for linum.el. I added an extra hook that runs before updates.
Here's the patched file: linum.el (github)
Here's the code I have in my init.el:
;; Load custom linum.
(load-file "~/.emacs.d/linum.el")
;; Suppress line number updates while auto-complete window
;; is displayed.
(add-hook 'linum-before-update-hook
'(lambda ()
(when auto-complete-mode
(if (ac-menu-live-p)
(setq linum-suppress-updates t)
(setq linum-suppress-updates nil)))))
Hope it helps!

Centering text in emacs window

Inside just one lonely emacs frame I switch frequently between editting 70-column text files (LaTeX) and 120-column programs (.h/.cpp files). I'd like to continue to use just one emacs frame, without resizing it or creating additional frames.
Here is the problem. The width of my window is about right for editting the 120-column programs, but during the extended text editting sessions, the 70 columns appear on the left side of the window. At the end of the day in front of a laptop, my neck seems to have acquired a semi-permanent tilt to the left.
Are you aware of a method to make the text appear centered, while still making the text files remain jagged on the right?
You could try narrowing the frame by increasing the fringe size. For example:
(set-fringe-style '(200 . 200))
would shave 200 pixels off each side of the main text area, leaving the work area 400 pixels narrower but still centered. To return to the regular view,
(set-fringe-style 'default)
will revert the fringe to the normal size.
And you can wrap that up inside some advice, which might work well for you if you stick to using just a single window:
(defadvice switch-to-buffer (after switch-to-buffer-adjust-fringe activate)
"depending on major mode, switch fringe style"
(if (memq major-mode '(latex-mode))
(set-fringe-style '(200 . 200))
(set-fringe-style 'default)))
Note: Update the list (latex-mode) to contain whatever modes you want to have the large fringes.
EmacsWiki has a page on shrink-wrapping frames. You could use the libraries and code referenced there to automatically shrink and grow your Emacs frame as necessary.
;; Add left and right margins, when file is markdown or text.
(defun center-window (window) ""
(let* ((current-extension (file-name-extension (or (buffer-file-name) "foo.unknown")))
(max-text-width 80)
(margin (max 0 (/ (- (window-width window) max-text-width) 2))))
(if (and (not (string= current-extension "md"))
(not (string= current-extension "txt")))
;; Do nothing if this isn't an .md or .txt file.
()
(set-window-margins window margin margin))))
;; Adjust margins of all windows.
(defun center-windows () ""
(walk-windows (lambda (window) (center-window window)) nil 1))
;; Listen to window changes.
(add-hook 'window-configuration-change-hook 'center-windows)
Add your file extensions above, below "md" and "txt".

Emacs :TODO indicator at left side

I want to have sort of indiacator at left side of the line wherever I have in the source code
#TODO: some comment
//TODO: some comments
The indicator could be a just mark and I already enabled line numbers displayed at emacs.
This command will do something like you want.
(defun annotate-todo ()
"put fringe marker on TODO: lines in the curent buffer"
(interactive)
(save-excursion
(goto-char (point-min))
(while (re-search-forward "TODO:" nil t)
(let ((overlay (make-overlay (- (point) 5) (point))))
(overlay-put overlay 'before-string (propertize "A"
'display '(left-fringe right-triangle)))))))
You can customize the bitmap as desired.
To get this to apply to all files, you could add it to the 'find-file-hooks
(add-hook 'find-file-hooks 'annotate-todo)
Or, if you want it just for certain modes, you could add it to those mode hooks.
See Fringes, The 'display' Property, Overlays, and most importantly the before-string property.
Note: The code was updated 27/02/2010 to use overlays instead of directly adding text properties to the current text.
I like the approach described in this post on emacs-fu, which adds TODO/FIXME/... to the font-lock settings of the modes where you need it. In contrast to Trey's approach this should highlight the words as you type, whereas his approach should only highlight them when you open a file (or do I get this wrong).
Anyway its up to you. A good google search gives you probably even more ideas: http://www.google.com/search?q=emacs+highlight+todo
Update: Your question has already been answered: Emacs, highlight all occurences of a word