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significantly improve performance on large strings

this replaces inefficient pattern of `MIN(TEXTW(..), n)` with
drw_fontset_getwidth_clamp() instead, which is far more efficient when
we only want up to a certain width.

dumping a decently sized (unicode) emoji file into dmenu, I see the
startup time drop significantly with this patch.

before -> after
360ms  -> 160ms

this should also noticeably improve input latency (responsiveness) given
that calcoffsets() and drawmenu() are pretty hot functions.
This commit is contained in:
NRK 2022-03-24 02:04:04 +06:00 committed by Hiltjo Posthuma
parent 6be057f060
commit 7269c5355d

13
dmenu.c
View file

@ -58,6 +58,13 @@ static Clr *scheme[SchemeLast];
static int (*fstrncmp)(const char *, const char *, size_t) = strncmp; static int (*fstrncmp)(const char *, const char *, size_t) = strncmp;
static char *(*fstrstr)(const char *, const char *) = strstr; static char *(*fstrstr)(const char *, const char *) = strstr;
static unsigned int
textw_clamp(const char *str, unsigned int n)
{
unsigned int w = drw_fontset_getwidth_clamp(drw, str, n) + lrpad;
return MIN(w, n);
}
static void static void
appenditem(struct item *item, struct item **list, struct item **last) appenditem(struct item *item, struct item **list, struct item **last)
{ {
@ -82,10 +89,10 @@ calcoffsets(void)
n = mw - (promptw + inputw + TEXTW("<") + TEXTW(">")); n = mw - (promptw + inputw + TEXTW("<") + TEXTW(">"));
/* calculate which items will begin the next page and previous page */ /* calculate which items will begin the next page and previous page */
for (i = 0, next = curr; next; next = next->right) for (i = 0, next = curr; next; next = next->right)
if ((i += (lines > 0) ? bh : MIN(TEXTW(next->text), n)) > n) if ((i += (lines > 0) ? bh : textw_clamp(next->text, n)) > n)
break; break;
for (i = 0, prev = curr; prev && prev->left; prev = prev->left) for (i = 0, prev = curr; prev && prev->left; prev = prev->left)
if ((i += (lines > 0) ? bh : MIN(TEXTW(prev->left->text), n)) > n) if ((i += (lines > 0) ? bh : textw_clamp(prev->left->text, n)) > n)
break; break;
} }
@ -172,7 +179,7 @@ drawmenu(void)
} }
x += w; x += w;
for (item = curr; item != next; item = item->right) for (item = curr; item != next; item = item->right)
x = drawitem(item, x, 0, MIN(TEXTW(item->text), mw - x - TEXTW(">"))); x = drawitem(item, x, 0, textw_clamp(item->text, mw - x - TEXTW(">")));
if (next) { if (next) {
w = TEXTW(">"); w = TEXTW(">");
drw_setscheme(drw, scheme[SchemeNorm]); drw_setscheme(drw, scheme[SchemeNorm]);