git.stevedylan.dev

drw_text: improve performance when there's no match 22511c41

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

NRK · 2022-03-24 00:37 1 file(s) · +12 −1

drw.c +12 −1

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;

	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;

			 * 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);


					curfont->next = usedfont;
				} else {
					xfont_free(usedfont);
					nomatches.codepoint[++nomatches.idx % nomatches_len] = utf8codepoint;
no_match:
					usedfont = drw->fonts;
				}
			}

251	251		int
252	252		drw_text(Drw drw, int x, int y, unsigned int w, unsigned int h, unsigned int lpad, const char text, int invert)
253	253		{
254		-	int ty, ellipsis_x = 0;
	254	+	int i, ty, ellipsis_x = 0;
255	255		unsigned int tmpw, ew, ellipsis_w = 0, ellipsis_len, ellipsis_width;
256	256		XftDraw *d = NULL;
257	257		Fnt usedfont, curfont, *nextfont;

263	263		FcPattern *match;
264	264		XftResult result;
265	265		int charexists = 0, overflow = 0;
	266	+	/* keep track of a couple codepoints for which we have no match. */
	267	+	enum { nomatches_len = 64 };
	268	+	static struct { long codepoint[nomatches_len]; unsigned int idx; } nomatches;
266	269
267	270		if (!drw \|\| (render && !drw->scheme) \|\| !text \|\| !drw->fonts)
268	271		return 0;

346	349		* character must be drawn. */
347	350		charexists = 1;
348	351
	352	+	for (i = 0; i < nomatches_len; ++i) {
	353	+	/* avoid calling XftFontMatch if we know we won't find a match */
	354	+	if (utf8codepoint == nomatches.codepoint[i])
	355	+	goto no_match;
	356	+	}
	357	+
349	358		fccharset = FcCharSetCreate();
350	359		FcCharSetAddChar(fccharset, utf8codepoint);
351	360

374	383		curfont->next = usedfont;
375	384		} else {
376	385		xfont_free(usedfont);
	386	+	nomatches.codepoint[++nomatches.idx % nomatches_len] = utf8codepoint;
	387	+	no_match:
377	388		usedfont = drw->fonts;
378	389		}
379	390		}