Emacs - Create vertical line [duplicate] - emacs

This question already has an answer here:
Emacs -- How to create a vertical strike-through effect
(1 answer)
Closed 8 years ago.
I want to highlight the current column where the cursor is, but there is no default mode in emacs for that. Then, I tried to install vline package, but the highlight color seems confused with the text. I am not sure how to change the color in vline package as well. Is there anyone try to create vertical line in emacs before?

The part of your question that is not a duplicate of, say, this question asks how to change the color of the vline face.
The answer is simple: look at some of the faces and user options defined by vline.el:
Faces:
vline: "A default face for vertical line highlighting."
vline-visual: "A default face for vertical line highlighting in visual lines."
Options:
vline-face: "A face for vertical line highlighting." (default: face vline)
vline-visual-face: "A face for vertical line highlighting in visual lines." (default: vline-visual)
IOW customize one or more of these, to change the appearance of the vertical line. (And of course, option vline-style needs to have value face or mixed if you want to use a face.)

Related

How can I configure auto-dim-other-buffers to dim line number column?

I am using auto-dim-other-buffers-mode, but unfortunately this mode does not change the color of the line number column.
I am using line-number-mode for displaying relative line numbers.
I have tried to customize auto-dim-other-buffers face but have had no success.
I also have tried editing line-number face which allows me to change the color of the column that I wish for auto-dim to take care of.
What options do I have here?

Enlarging text while having line numbers enabled covers the view of the numbers?

Enlarging text while having line numbers enabled covers the view of the numbers?
I've enabled line numbers globally by adding (global-linum-mode t) to init.el.
Zooming in on text using the C-x C-+ keybinding results in the behavior seen below, which is not satisfactory.
What can I do to fix this? Are their working alternatives?
I don't see this problem, using library zoom-frm.el (see also Emacs Wiki page Set Fonts).
But vanilla Emacs clearly has another bug, in that enlarging the text by scaling enlarges the horizontal space used for the line numbers (good), but shrinking the text then does not shrink that space used for line numbers (bad). I've just now filed Emacs bug #24164 for this.

Hide/change Emacs fringe bent arrows due to word wrapping?

I would like to change (or hide entirely) the "bent arrow" character that appears in the Emacs fringe (both on the left and right hand side). I'm using Emacs 24 on a Mac, installed via homebrew. I find it to be visually distracting. A smaller character, like a center dot, might work well.
For context, this is an official description of the small bent arrows (from http://www.gnu.org/software/emacs/manual/html_node/emacs/Continuation-Lines.html):
Sometimes, a line of text in the buffer—a logical line—is too long to fit in the window, and Emacs displays it as two or more screen lines. This is called line wrapping or continuation, and the long logical line is called a continued line. On a graphical display, Emacs indicates line wrapping with small bent arrows in the left and right window fringes. On a text terminal, Emacs indicates line wrapping by displaying a ‘\’ character at the right margin.
The Emacs LineWrap Wiki page does not address my question.
The best information I've found so far is contained in this StackOverflow answer:
When word-wrap is set to nil in a text terminal (-nw) Emacs, the backslash character appears on the right margin.
When word-wrap is set to t in a text terminal Emacs, the backslash character is not shown. Setting visual-line-mode also sets word-wrap to true.
This does not apply when Emacs is running as a GUI window: the small bent arrow appears on the right margin regardless of the value of word-wrap.
Is hiding or changing the bent arrows possible? If not, an answer that says, more or less, "I've looked at X and concluded that it is impossible" is ok too.
Update: Although it is not a terrible work-around, changing the fringes is not what I'm looking for: I want to customize the "bent arrow" character or bitmap.
First, some quick context. From Emacs Fringe Bitmaps: "Fringe indicators are tiny icons displayed in the window fringe to indicate truncated or continued lines, buffer boundaries, etc."
You cannot replace the curly arrow with arbitrary text. According to lunaryorn's answer to "Is It Possible To Replace Fringe Bitmaps With Text in Emacs?":
No, it is not. Fringe “bitmaps” are really bitmaps, that is vectors of 0/1 bits, overlayed over the fringe. There is no way to directly render arbitrary unicode characters onto the fringe. [...] What you can do, is to render a unicode character into a 0/1 bitmap yourself.
Like it says, you can change the bitmap. Fringe Bitmaps contains a list of fringe bitmaps; left-curly-arrow and right-curly-arrow are the ones relevant for this question.
Here is what I drew up. Adjust to your liking. Put this in your Emacs init file.
(define-fringe-bitmap 'right-curly-arrow
[#b00000000
#b00000000
#b00000000
#b00000000
#b01110000
#b00010000
#b00010000
#b00000000])
(define-fringe-bitmap 'left-curly-arrow
[#b00000000
#b00001000
#b00001000
#b00001110
#b00000000
#b00000000
#b00000000
#b00000000])
More documentation is available at Customizing Bitmaps, including set-fringe-bitmap-face which "sets the face for the fringe. If face is nil, it selects the fringe face. The bitmap's face controls the color to draw it in".

Rectangular selection visual glitch

When I start a rectangular selection (C-x SPS), firstly, a thin line appears at the side of the rectangle which shifts lines to the right.
Is there a way to make rectangular selection seamless?
The thin line is put "on purpose" to visually show where is the empty rectangle. We could make it optional (in which case the 0-width rectangles would simply not be displayed). Please use M-x report-emacs-bug since that's where this discussion should take place.

Emacs Scrolling Bug on OS X

Update
This problem disappeared after upgrading from Mountain Lion to Mavericks, while also updating Emacs from 23.4 to 24.3.
End-update
With a .emacs file containing
(set-foreground-color "white")
(set-background-color "black")
(setq mouse-wheel-scroll-amount '(1 ((shift) . 1) ((control) . nil)))
(setq mouse-wheel-progressive-speed nil)
as I scroll up or down with the reduced step, I see the strange patterns
Magnifying one of the patterns reveals
This problem has been present in Emacs 22, 23, and now 24 for several versions of OSX—up to and including Mountain Lion. Is it a known rendering bug? Is there a fix?
Neither the suggestion to modify fringes nor linum works for me. Where else can I look?
If I use the default white background and black foreground, these lines either do not appear or are imperceptible (to me).
What is most pesky about this problem is that redrawing (C-l) does not result in clean text.
The problem is related to the interaction between OS X's LCD Font Smoothing algorithm and the algorithm that emacs uses to implement scrolling.
The figure below shows font smoothing turned off (left) and on (right). You will find this setting in System Preferences \ general. In both cases I scrolled the program by one line. When OS X draws the "#" with font smoothing turned on, it does not only use the pixels dedicated to the "#" but also uses the blue pixels of the adjacent (blank) character.
When emacs scrolls, it only modifies the characters that it believes need to be modified. If the character is blank and will remain blank after scrolling, it does not modify it. This optimization remains valid in 2013. In other words, testing that two characters are blank is still cheaper than drawing one character. But this optimization is hardly necessary today, and it results in the buggy display.
If the hypothesis above holds, the sequel question becomes whether one can turn off the optimization. Is it possible to ask emacs to redraw the full screen at each scroll or to at least redraw characters that remain blank if they were adjacent to a non-blank character.
One could of course simply turn off font smoothing. The magnified image may even suggest that the non-smoothed image is better. In practice, when the fonts appear in their natural (unmagnified) size, smoothing makes the characters far more legible, eliminating the need to use larger fonts.
The pattern on either side of "c();" in the image below is consistent with the bug. OS X uses blue pixels on the left side and red/tan pixels on the right (possibly this is related to the RGB pattern on the display). The vertical lines left over when scrolling are either blue or red/tan/brick, depending on whether they have dropped out of the left or right side of scrolled characters.
Update
The problem is now solved in this nightly. The magnified c(); produced by Emacs 24.3.50.1 shows that the font smoothing remains identical to that produced by Emacs 24.3.1. But the output is not identical. There is at least one extra horizontal line of pixels between each two lines of text.