Commit: 59705d6ed3be6a21e08d9b0a973507896495f311
Parent: fd053aae17e3c898fddbf9846652477c8c9e3aac
Author: NRK
Date: Thu, 24 Mar 2022 00:37:55 +0600
drw_text: improve performance when there's no match
this was the last piece of the puzzle, the case where we can't find any
font to draw the codepoint.
in such cases, we use XftFontMatch() which is INSANELY slow. but that's
not the real problem. the real problem was we were continuously trying
to match the same thing over and over again.
this patch introduces a small cache, which keeps track a couple codepoints
for which we know we won't find any matches.
with this, i can dump lots of emojies into dmenu where some of them don't
have any matching font, and still not have dmenu lag insanely or FREEZE
completely when scrolling up and down.
this also improves startup time, which will of course depend on the
system and all installed fonts; but on my system and test case i see
the following startup time drop:
before -> after
60ms -> 34ms
Diffstat:
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drw.c b/drw.c
@@ -251,7 +251,7 @@ drw_rect(Drw *drw, int x, int y, unsigned int w, unsigned int h, int filled, int
int
drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lpad, const char *text, int invert)
{
- int ty, ellipsis_x = 0;
+ int i, ty, ellipsis_x = 0;
unsigned int tmpw, ew, ellipsis_w = 0, ellipsis_len, ellipsis_width;
XftDraw *d = NULL;
Fnt *usedfont, *curfont, *nextfont;
@@ -263,6 +263,9 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lp
FcPattern *match;
XftResult result;
int charexists = 0, overflow = 0;
+ /* keep track of a couple codepoints for which we have no match. */
+ enum { nomatches_len = 64 };
+ static struct { long codepoint[nomatches_len]; unsigned int idx; } nomatches;
if (!drw || (render && !drw->scheme) || !text || !drw->fonts)
return 0;
@@ -346,6 +349,12 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lp
* character must be drawn. */
charexists = 1;
+ for (i = 0; i < nomatches_len; ++i) {
+ /* avoid calling XftFontMatch if we know we won't find a match */
+ if (utf8codepoint == nomatches.codepoint[i])
+ goto no_match;
+ }
+
fccharset = FcCharSetCreate();
FcCharSetAddChar(fccharset, utf8codepoint);
@@ -374,6 +383,8 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lp
curfont->next = usedfont;
} else {
xfont_free(usedfont);
+ nomatches.codepoint[++nomatches.idx % nomatches_len] = utf8codepoint;
+no_match:
usedfont = drw->fonts;
}
}