Sflock: simple X screen locker with basic user feedback

Question

There are several applications out there that lock the X display. On the one side of the spectrum you have xscreensaver and xlockmore which provide screensavers and on the other side you have slock which provides nothing. sflock is an application that is built as an extension to slock, which provides very basic user feedback.
The need for me arrived because I wanted a screen locker that was trustworthy and that looks ok. Because I have no interest in screensavers and the xscreensaver unlock screen is one of the most ugly things I have ever seen, I turned to slock. This works fine, but there is no real way to tell that the screen is locked.  You just type a password on a black screen and if it's correct, the screen gets unlocked. fslock (at least the first version) shows a line on the screen and displays asterisks for every character entered.
The goal of the application is to be simple and small, but still look good. You can install sflock from the AUR under the name sflock-git or download it directly from github. Suggestions are of course welcome.

Answer 1

I've been trying to get this to use Xft for rendering the fonts, but this is essentially my first time doing anything in C. Sflock builds properly but segfaults when I try to run it.
diff --git a/config.mk b/config.mk
index 3a42077..b6a72ed 100644
--- a/config.mk
+++ b/config.mk
@@ -12,8 +12,8 @@ X11INC = /usr/X11R6/include
X11LIB = /usr/X11R6/lib
# includes and libs
-INCS = -I. -I/usr/include -I${X11INC}
-LIBS = -L/usr/lib -lc -lcrypt -L${X11LIB} -lX11 -lXext
+INCS = -I. -I/usr/include -I${X11INC} -I/usr/include/freetype2
+LIBS = -L/usr/lib -lc -lcrypt -L${X11LIB} -lX11 -lXext -lXft
# flags
CPPFLAGS = -DVERSION=\"${VERSION}\" -DHAVE_SHADOW_H
diff --git a/sflock.c b/sflock.c
index 72b076b..3c51823 100644
--- a/sflock.c
+++ b/sflock.c
@@ -12,10 +12,12 @@
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
+#include <fontconfig/fontconfig.h>
#include <X11/keysym.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/extensions/dpms.h>
+#include <X11/Xft/Xft.h>
#if HAVE_BSD_AUTH
#include <login_cap.h>
@@ -79,7 +81,10 @@ main(int argc, char **argv) {
XColor black, red, dummy;
XEvent ev;
XSetWindowAttributes wa;
- XFontStruct* font;
+ XftFont *font;
+ XftColor *xftcolor;
+ XftDraw *xftdraw;
+ XGlyphInfo *extents;
GC gc;
XGCValues values;
@@ -145,14 +150,14 @@ main(int argc, char **argv) {
XDefineCursor(dpy, w, invisible);
XMapRaised(dpy, w);
- font = XLoadQueryFont(dpy, fontname);
+ font = XftFontOpenXlfd(dpy, screen, fontname);
+ XftColorAllocName(dpy, DefaultVisual(dpy, screen), DefaultColormap(dpy, screen), "white", xftcolor);
if (font == 0) {
die("error: could not find font. Try using a full description.\n");
gc = XCreateGC(dpy, w, (unsigned long)0, &values);
- XSetFont(dpy, gc, font->fid);
XSetForeground(dpy, gc, XWhitePixel(dpy, screen));
for(len = 1000; len; len--) {
@@ -187,7 +192,8 @@ main(int argc, char **argv) {
if (update) {
XClearWindow(dpy, w);
XDrawLine(dpy, w, gc, width * 3 / 8 , (height + baroffset) / 2, width * 5 / 8, (height + baroffset) / 2);
- XDrawString(dpy,w,gc, (width - XTextWidth(font, passdisp, len)) / 2, (height+42) / 2, passdisp, len);
+ XftTextExtentsUtf8(dpy, font, (XftChar8 *)passdisp, len, extents);
+ XftDrawStringUtf8(xftdraw, xftcolor, font, (width - extents->width) / 2, (height+42) / 2, (XftChar8 *)passdisp, len);
update = False;
@@ -251,7 +257,9 @@ main(int argc, char **argv) {
XUngrabPointer(dpy, CurrentTime);
XFreePixmap(dpy, pmap);
- XFreeFont(dpy, font);
+ XftFontClose(dpy, font);
+ XftColorFree(dpy, DefaultVisual(dpy, screen), DefaultColormap(dpy, screen), xftcolor);
+ XftDrawDestroy(xftdraw);
XFreeGC(dpy, gc);
XDestroyWindow(dpy, w);
XCloseDisplay(dpy);