On Wed, Mar 21, 2018 at 02:18:53PM -0400, Gary Allen Vollink wrote:
> This patch is over my previous simplification patch
> (https://lists.suckless.org/dev/1803/32601.html), though it could be
> reworked to go in without it.
>
> Problem: When working with text from many languages, it does not take long
> to run out of font slots for Runes that do not exist within any given
> fontconfig. Currently, each rune that is not part of a default set takes up
> another font slot (whether or not that rune is even found).I have found that
> runes in text (not emoji) have a tendency of showing up in sets, for
> instance a whole block of text may be in Cyrillic, which quickly takes up
> the 16 slots available for loaded fonts. This is fine until another rune IS
> found and put on screen. Whenever that happens, the next time a rune isn't
> found that font is closed and a new one inserted (whether or not that font
> includes the required glyph). Unloading an on-screen font at the next
> not-found rune will crash st.
>
>
> What I have is a partial Fix. This patch makes it take longer for this
> problem to manifest by making sure the limited font slots are not kept open
> when a glyph cannot be found. Note that this does not really help the issue
> on MacOS where the noglyph font will always claim a glyph (even though it's
> nothing but a binarybox). I haven't found a way to fix it completely (on
> MacOS and/or over long periods of usage on Linux) without writing something
> that even I think sucks. I personally got over this by /also/ adjusting the
> size of the frc[] array on my own build. Either way, this is what I have to
> offer...
>
>
>
> Patch:
>
> Track runes that are not found separately from the Fontcache, frc[], forget
> not-found runes in fifo, not lifo. Close an opened font if it doesn't
> include the required glyph (not taking up an frc[] slot).
>
>
> diff -U 3 -p a/x.c b/x.c
> --- a/x.c 2018-03-21 13:22:53.549236600 -0400
> +++ b/x.c 2018-03-21 13:32:00.894134500 -0400
> _AT_@ -3,6 +3,7 @@
> #include <math.h>
> #include <limits.h>
> #include <locale.h>
> +#include <wchar.h>
> #include <signal.h>
> #include <sys/select.h>
> #include <time.h>
> _AT_@ -219,9 +220,12 @@ enum {
> typedef struct {
> XftFont *font;
> int flags;
> - Rune unicodep;
> } Fontcache;
>
> +/* Runes not found array. */
> +static wchar_t noglyph[1024];
> +static int noglyphlen = 0;
> +
> /* Fontcache is an array now. A new font will be appended to the array. */
> static Fontcache frc[16];
> static int frclen = 0;
> _AT_@ -1145,7 +1149,7 @@ xmakeglyphfontspecs(XftGlyphFontSpec *sp
> float runewidth = win.cw;
> Rune rune;
> FT_UInt glyphidx;
> - int i, f, numspecs = 0;
> + int i, f, r, numspecs = 0;
>
> for (i = 0, xp = winx, yp = winy + font->ascent; i < len; ++i) {
> /* Fetch rune and mode for current glyph. */
> _AT_@ -1177,7 +1181,8 @@ xmakeglyphfontspecs(XftGlyphFontSpec *sp
>
> /* Lookup character index with default font. */
> glyphidx = XftCharIndex(xw.dpy, font->match, rune);
> - if (glyphidx) {
> + /* OR if already failed to find a glyph for this rune. */
> + if ((glyphidx) || (wmemchr(noglyph, rune, noglyphlen))) {
> specs[numspecs].font = font->match;
> specs[numspecs].glyph = glyphidx;
> specs[numspecs].x = (short)xp;
> _AT_@ -1193,11 +1198,6 @@ xmakeglyphfontspecs(XftGlyphFontSpec *sp
> /* Everything correct. */
> if (glyphidx && frc[f].flags == frcflags)
> break;
> - /* We got a default font for a not found glyph. */
> - if (!glyphidx && frc[f].flags == frcflags
> - && frc[f].unicodep == rune) {
> - break;
> - }
> }
>
> /* Nothing was found. Use fontconfig to find matching font.
> */
> _AT_@ -1208,7 +1208,6 @@ xmakeglyphfontspecs(XftGlyphFontSpec *sp
> if (frclen >= LEN(frc)) {
> frclen = LEN(frc) - 1;
> XftFontClose(xw.dpy, frc[frclen].font);
> - frc[frclen].unicodep = 0;
> }
>
> /*
> _AT_@ -1224,12 +1223,23 @@ xmakeglyphfontspecs(XftGlyphFontSpec *sp
> }
> frc[frclen].font = newFont.match;
> frc[frclen].flags = frcflags;
> - frc[frclen].unicodep = rune;
>
> glyphidx = XftCharIndex(xw.dpy, frc[frclen].font,
> rune);
>
> - f = frclen;
> - frclen++;
> + if (!glyphidx) {
> + XftFontClose(xw.dpy, frc[frclen].font);
> + if (noglyphlen >= LEN(noglyph)) {
> + /* Get rid of the oldest not found
> rune */
> + for (r=1; r <= LEN(noglyph); r++) {
> + noglyph[r-1] = noglyph[r];
> + }
> + noglyphlen = LEN(noglyph) - 1;
> + }
> + noglyph[noglyphlen++] = rune;
> + } else {
> + f = frclen;
> + frclen++;
> + }
> }
>
> specs[numspecs].font = frc[f].font;
>
>
>
I've never had this issue and cannot reproduce it all (still). Can you
provide more information? Recently there are some issues reported by users
using MacOS and st, this makes for wasted debugging sessions: MacOS and it's
ecosystem is not supported.
There are also some code-style issues in the patch (newFont -> newfont name).
--
Kind regards,
Hiltjo
Received on Wed Mar 21 2018 - 20:35:17 CET