xfnw/plan9fox
1
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity

libdraw: fix zero stringwidth() bug

Browse source 
stringwidth() and string() sometimes failed spuriously due
to the wrong assumption that cachechars() will only fail
when a different subfont is needed. in fact, cachechars()
can fail for other reasons like when it resizes the fontcache
(or fails todo so).

theres also the case when loadchar() is unable to translate
a character and returns 0. this case needs to be differentiated
from such temporary conditions like fontcache resize or subfont
load to stop the retry loop in string() and stringwidth().

now cachechars() returns -1 to indicate that it cannot
proceed and we test this in string() and stringwidth()
to skip over untranslatable characters to make progress
instead of retrying.
This commit is contained in:
cinap_lenrek 2014-03-10 06:41:45 +01:00
parent 760b3d0667
commit 2c0490a26e
3 changed files with 14 additions and 12 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

22
sys/src/libdraw/font.c
View file

@ -7,10 +7,11 @@ static int freeup(Font*);
#define PJW 0 /* use NUL==pjw for invisible characters */
/* return number of translated cache indices, 0 must retry, -1 on error */
int
cachechars(Font *f, char **ss, Rune **rr, ushort *cp, int max, int *wp, char **subfontname)
{
int i, th, sh, h, w, rw, wid, nc;
int i, j, th, sh, h, w, rw, wid, nc;
char *sp;
Rune r, *rp, vr;
ulong a;
@ -78,14 +79,16 @@ cachechars(Font *f, char **ss, Rune **rr, ushort *cp, int max, int *wp, char **s
}
}
if(c->age == f->age) /* flush pending string output */
if(i > 0 && c->age == f->age) /* flush pending string output */
break;
if(loadchar(f, r, c, h, i, subfontname) <= 0)
break;
j = loadchar(f, r, c, h, i, subfontname);
if(j <= 0){
if(j < 0 || i > 0) /* flush output or retry */
break;
return -1; /* stop retrying */
}
c = &f->cache[h]; /* may have reallocated f->cache */
Found:
wid += c->width;
c->age = f->age;
@ -282,9 +285,8 @@ loadchar(Font *f, Rune r, Cacheinfo *c, int h, int noflush, char **subfontname)
f->width = wid;
if(f->maxdepth < subf->f->bits->depth)
f->maxdepth = subf->f->bits->depth;
i = fontresize(f, f->width, f->ncache, f->maxdepth);
if(i <= 0)
return i;
if(fontresize(f, f->width, f->ncache, f->maxdepth) <= 0)
return -1;
/* c is still valid as didn't reallocate f->cache */
}
c->value = r;
@ -340,7 +342,7 @@ freeup(Font *f)
return nf;
}
/* return whether resize succeeded && f->cache is unchanged */
/* returns whether resize succeeded && f->cache is unchanged */
static int
fontresize(Font *f, int wid, int ncache, int depth)
{

2
sys/src/libdraw/string.c
View file

@ -92,7 +92,7 @@ _string(Image *dst, Point pt, Image *src, Point sp, Font *f, char *s, Rune *r, i
}
}
if((n = cachechars(f, sptr, rptr, cbuf, max, &wid, &subfontname)) <= 0){
if(subfontname){
if(n == 0){
if(++try > 10)
break;
continue;

2
sys/src/libdraw/stringwidth.c
View file

@ -39,7 +39,7 @@ _stringnwidth(Font *f, char *s, Rune *r, int len)
}
}
if((n = cachechars(f, sptr, rptr, cbuf, max, &wid, &subfontname)) <= 0){
if(subfontname){
if(n == 0){
if(++try > 10)
break;
continue;