introduce drw_fontset_getwidth_clamp()

getting the width of a string is an O(n) operation, and in many cases
users only care about getting the width upto a certain number.

instead of calling drw_fontset_getwidth() and *then* clamping the
result, this patch introduces drw_fontset_getwidth_clamp() function,
similar to strnlen(), which will stop once we reach n.

the `invert` parameter was overloaded internally to preserve the API,
however library users should be calling drw_fontset_getwidth_clamp() and
not depend upon internal behavior of drw_text().
main^2
NRK 1 year ago committed by Hiltjo Posthuma
parent 41fdabbf7c
commit 6be057f060

19
drw.c

@ -268,7 +268,7 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lp
return 0;
if (!render) {
w = ~w;
w = invert ? invert : ~invert;
} else {
XSetForeground(drw->dpy, drw->gc, drw->scheme[invert ? ColFg : ColBg].pixel);
XFillRectangle(drw->dpy, drw->drawable, drw->gc, x, y, w, h);
@ -300,7 +300,13 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lp
if (ew + tmpw > w) {
overflow = 1;
utf8strlen = ellipsis_len;
/* called from drw_fontset_getwidth_clamp():
* it wants the width AFTER the overflow
*/
if (!render)
x += tmpw;
else
utf8strlen = ellipsis_len;
} else if (curfont == usedfont) {
utf8strlen += utf8charlen;
text += utf8charlen;
@ -397,6 +403,15 @@ drw_fontset_getwidth(Drw *drw, const char *text)
return drw_text(drw, 0, 0, 0, 0, 0, text, 0);
}
unsigned int
drw_fontset_getwidth_clamp(Drw *drw, const char *text, unsigned int n)
{
unsigned int tmp = 0;
if (drw && drw->fonts && text && n)
tmp = drw_text(drw, 0, 0, 0, 0, 0, text, n);
return MIN(n, tmp);
}
void
drw_font_getexts(Fnt *font, const char *text, unsigned int len, unsigned int *w, unsigned int *h)
{

@ -35,6 +35,7 @@ void drw_free(Drw *drw);
Fnt *drw_fontset_create(Drw* drw, const char *fonts[], size_t fontcount);
void drw_fontset_free(Fnt* set);
unsigned int drw_fontset_getwidth(Drw *drw, const char *text);
unsigned int drw_fontset_getwidth_clamp(Drw *drw, const char *text, unsigned int n);
void drw_font_getexts(Fnt *font, const char *text, unsigned int len, unsigned int *w, unsigned int *h);
/* Colorscheme abstraction */

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