`visual-wrap--content-prefix' previously returned a column count
computed as
(max (string-width prefix)
(ceiling (string-pixel-width prefix) avg-space-width))
with two problems:
* `string-width' ignores `buffer-invisibility-spec', so an invisible
prefix (hidden ATX markers under `markdown-ts-hide-markup', for
example) still reserved its character count on line 1 via a
`min-width' display property, shifting the visible heading right.
* With variable-pitch fonts, rounding the prefix width up to whole
columns added visible padding whenever the natural width did not
fall on an exact column boundary.
Return the prefix's natural pixel width via `string-pixel-width'
instead, which accounts for any display transformation applied to
the prefix (invisibility, `display' replacements, text scaling,
proportional fonts). Drop the `min-width' property from
`visual-wrap--apply-to-line' so line 1 renders at its natural width.
Switch the continuation `wrap-prefix' to a mixed-unit `:align-to'
sum form:
(space :align-to (+ (PIX) (EXTRA-INDENT . width)))
where PIX is the prefix's pixel width and EXTRA-INDENT is
`visual-wrap-extra-indent' in canonical character widths. The
display engine resolves each term per the active frame and sums
them, so no Lisp-level unit conversion is needed.
Since `min-width' is no longer installed, the accumulation cycle
that commit 81a5beb8af (bug#73882) worked around cannot recur.
Drop the `min-width' strip from `visual-wrap--content-prefix' and
the `min-width' removal from `visual-wrap--remove-properties'.
Keep `min-width' in `visual-wrap--safe-display-specs' so that
lines where other modes install it are not skipped.
* lisp/visual-wrap.el (visual-wrap--content-prefix): Return pixel
width instead of column count; drop the `min-width' strip.
(visual-wrap--apply-to-line): Drop `min-width' on line 1; use
mixed-unit `:align-to' sum form for the continuation wrap-prefix.
(visual-wrap--adjust-prefix): Handle only string prefixes; the
numeric (pixel) case is now handled inline in `--apply-to-line'
via the mixed-unit `:align-to' sum form.
(visual-wrap--remove-properties): Drop `min-width' removal.
(visual-wrap--safe-display-specs): Add note about `min-width'.
* test/lisp/visual-wrap-tests.el: Update expected `wrap-prefix'
values to the new sum form.
(visual-wrap-tests/invisible-prefix): New test motivated by bug#81039.
(visual-wrap-tests/negative-extra-indent): New test; verify that a
large negative `visual-wrap-extra-indent' produces a valid
wrap-prefix (the display engine clamps the stretch to zero).
* test/manual/visual-wrap-test.el: New file. Manual test suite
for visual-eyeball verification of prefix alignment behavior.
Reported-by: Andrea Alberti <a.alberti82@gmail.com>
Co-authored-by: Stefan Monnier <monnier@iro.umontreal.ca>
Before refontifying a region, remove any text properties we care about
so that we don't end up with stray properties. Additionally, make sure
to remove all the properties when deactivating the mode.
* lisp/emacs-lisp/subr-x.el (add-remove--display-text-property): New
function, extracted from...
(add-display-text-property): ... here.
(remove-display-text-property): New function.
* lisp/visual-wrap.el (visual-wrap--remove-properties): New function...
(visual-wrap-prefix-function, visual-wrap-prefix-mode): ... call it.
* test/lisp/emacs-lisp/subr-x-tests.el
(subr-x-test-remove-display-text-property): New test.
* test/lisp/visual-wrap-tests.el
(visual-wrap-tests/wrap-prefix-stickiness, visual-wrap-tests/cleanup):
New tests.
* doc/lispref/display.texi (Display Property): Document
'remove-display-text-property'.
* etc/NEWS: Announce 'remove-display-text-property' (bug#76018).
* lisp/visual-wrap.el (visual-wrap--safe-display-specs): Add
'space-width' and 'min-width'.
(visual-wrap--display-property-safe-p): Use 'member' instead of 'memq'
to more-closely match the behavior of other code that works with display
properties.
This makes sure we don't interfere with other display specs, e.g. for
images displayed in 'image-mode' (bug#73600).
* lisp/visual-wrap.el (visual-wrap--safe-display-specs): New variable.
(visual-wrap--display-property-safe-p): New function.
(visual-wrap--apply-to-line): Use 'pos-eol'; we don't want to respect
field boundaries here.
(visual-wrap-prefix-function): Check for unsafe display properties at
the end of the line and skip past them if present.
* test/lisp/visual-wrap-tests.el: New test file.
Previously, the display spec for the "average space" was wrong. It used
a plain number for the width of the specified space, which means "N
times the normal character width for the buffer", but we want "N times
the normal character width for the *current face*" (bug#76008).
* lisp/visual-wrap.el (visual-wrap--content-prefix): Specify the width
of the "average space" in terms of the average width of the current
face.
* lisp/net/shr.el (shr-indent): As above, and call 'string-pixel-width'
without specifying the buffer, to match 'shr-string-pixel-width'.
Now, we get the average-width of the current font using
'string-pixel-width' and a specified space display spec, which doesn't
require the buffer to be displayed in a window (bug#72771).
* lisp/net/shr.el (shr-indent):
* lisp/visual-wrap.el (visual-wrap--content-prefix): Fix getting the
font when the buffer isn't displayed in a window.
(visual-wrap-fill-context-prefix): Fix indentation.
* lisp/visual-wrap.el (visual-wrap--apply-to-line): Use
'add-display-text-property' so we don't clobber other display
properties.
(visual-wrap--content-prefix): Remove special-case for spaces-only
indent prefix; this was an attempt to be helpful for variable-pitch
fonts, but in practice just interferes with matters. This case now
falls back to the one immediately following it (return the string of
spaces). Use 'string-pixel-width' instead of 'string-width'.
* lisp/net/shr.el (shr-indent): Set 'shr-prefix-length' here to help
keep track of the prefixes of nestedly-indented elements. Set the
specified space width in terms of the default width of the current face.
* lisp/net/shr.el (shr-adaptive-fill-function): Use 'shr-prefix-length'
as set above to return a fill prefix.
* lisp/net/eww.el (eww-render): Enable 'visual-wrap-prefix-mode'
alongside of 'visual-line-mode'.
(eww-mode): Set 'adaptive-fill-function' to
'shr-adaptive-fill-function'.
* etc/NEWS: Announce this change (bug#72485).
* lisp/emacs-lisp/subr-x.el (string-pixel-width): Allow passing BUFFER
to use the face remappings from that buffer when calculating the width.
* lisp/visual-wrap.el (visual-wrap--prefix): Rename to...
(visual-wrap--adjust-prefix): ... this, and support PREFIX as a number.
(visual-wrap-fill-context-prefix): Make obsolete in favor of...
(visual-wrap--content-prefix): ... this.
(visual-wrap-prefix-function): Extract inside of loop into...
(visual-wrap--apply-to-line): ... this.
* doc/lispref/display.texi (Size of Displayed Text): Update
documentation for 'string-pixel-width'.
* etc/NEWS: Announce this change.
* doc/emacs/basic.texi (Continuation Lines):
* etc/NEWS:
* lisp/visual-wrap.el (visual-wrap-prefix-mode): Document this
new global minor mode.
(global-visual-wrap-prefix-mode): New global minor mode.
* lisp/visual-wrap.el (visual-wrap-extra-indent): Add :version.
(visual-wrap-fill-context-prefix): Doc fix.
* lisp/menu-bar.el (menu-bar-line-wrapping-menu): Move the menu to
a better place, improve the help-echo text.
* etc/NEWS:
* doc/emacs/basic.texi (Continuation Lines): Improve documentation
and indexing of 'visual-wrap-prefix-mode'.
* lisp/menu-bar.el (menu-bar-line-wrapping-menu): Insert new
menu item controlling visual-wrap-prefix-mode.
* lisp/visual-wrap.el: Remove menu bar autoload.
