getting the width of a string is an O(n) operation, and in many cases
users only care about getting the width upto a certain number.
instead of calling drw_fontset_getwidth() and *then* clamping the
result, this patch introduces drw_fontset_getwidth_clamp() function,
similar to strnlen(), which will stop once we reach n.
the `invert` parameter was overloaded internally to preserve the API,
however library users should be calling drw_fontset_getwidth_clamp() and
not depend upon internal behavior of drw_text().
this patch makes some non-trivial changes, which significantly improves
the performance of drawing large strings as well as fixes any issues
regarding the printing of the ellipsis when string gets truncated.
* performance:
before there were two O(n) loops, one which finds how long we can go
without changing font, and the second loop would (incorrectly) truncate
the string if it's too big.
this patch merges the overflow calculation into the first loop and exits
out when overflow is detected. when dumping lots of emojies into dmenu,
i see some noticeable startup time improvement:
before -> after
460ms -> 360ms
input latency when scrolling up/down is also noticeably better and can
be tested with the following:
for _ in $(seq 20); do
cat /dev/urandom | base64 | tr -d '\n' | head -c 1000000
echo
done | ./dmenu -l 10
* correctness:
the previous version would incorrectly assumed single byte chars and
would overwrite them with '.' , this caused a whole bunch of obvious
problems, including the ellipsis not getting rendered if then font
changed.
in addition to exiting out when we detect overflow, this patch also
keeps track of the last x-position where the ellipsis would fit. if we
detect overflow, we simply make a recursing call to drw_text() at the
ellipsis_x position and overwrite what was there.
so now the ellipsis will always be printed properly, regardless of
weather the font changes or if the string is single byte char or not.
the idea of rendering the ellipsis on top incase of overflow was
from Bakkeby <bakkeby@gmail.com>, thanks! however the original patch had
some issues incorrectly truncating the prompt (-p flag) and cutting off
emojies. those have been fixed in here.
This reverts commit c585e8e498.
It causes issues with truncation of characters when the text does not fit and
so on. The patch should be reworked and properly tested.
The keypad Enter key was already supported. On some keyboard layouts like my
laptop the page-up and page-down key is more comfortable to use.
This adds a few lines but no complexity.
Calculates len & ew in drw_font_getexts loop by incrementing instead of
decrementing; as such avoids proportional increase in time spent in loop
based on provided strings size.
WM_CLASS is a standard ICCCM property which is used to identify windows.
Window managers and compositors use it to allow per-application
configurable behavior.
This reverts commit 09d0a36e03.
Using strncmp with the length of the user input turns it into a prefix
match rather than an exact match as it's supposed to be.
NRK