I had the same wish, and implemented a -mul option for multiplying the
intensity by a number; as the number can be either >1 or <1, there's no
need for separate options for increasing and decreasing.
The patch is attached.
The patch also makes -set, -inc and -dec accept non-integer values without
truncating them.
Regards,
Pieter-Tjerk
--- ./man/xbacklight.man.orig 2013-10-08 05:40:38.000000000 +0200
+++ ./man/xbacklight.man 2017-12-25 15:05:20.749299372 +0100
@@ -44,6 +44,10 @@
Increases brightness by the specified amount.
.IP "\-dec \fIpercent\fP"
Decreases brightness by the specified amount.
+.IP "\-mul \fIfactor\fP"
+Multiplies brightness by the specified amount.
+If factor is not 1, the result is rounded such that the brightness does change,
+so this can be bound safely to a hotkey without getting stuck at 0.
.IP \-help
Print out a summary of the usage and exit.
.IP "\-time \fImilliseconds\fP"
--- ./xbacklight.c.orig 2013-10-08 05:40:38.000000000 +0200
+++ ./xbacklight.c 2017-12-25 15:03:32.991542960 +0100
@@ -31,7 +31,7 @@
#include <string.h>
#include <unistd.h>
-typedef enum { Get, Set, Inc, Dec } op_t;
+typedef enum { Get, Set, Inc, Dec, Mul } op_t;
static char *program_name;
@@ -47,6 +47,7 @@
" -set <percentage> or = <percentage>\n"
" -inc <percentage> or + <percentage>\n"
" -dec <percentage> or - <percentage>\n"
+ " -mul <factor> or * <factor> (note that the * may need a shell escape like \\* )\n"
" -get\n"
" -time <fade time in milliseconds>\n"
" -steps <number of steps in fade>\n");
@@ -107,7 +108,7 @@
{
char *dpy_name = NULL;
op_t op = Get;
- int value = 0;
+ double value = 0;
int i;
int total_time = 200; /* ms */
int steps = 20;
@@ -137,39 +138,52 @@
{
if (++i >= argc) usage();
op = Set;
- value = atoi (argv[i]);
+ value = atof (argv[i]);
continue;
}
if (argv[i][0] == '=' && isdigit (argv[i][1]))
{
op = Set;
- value = atoi (argv[i] + 1);
+ value = atof (argv[i] + 1);
continue;
}
if (!strcmp (argv[i], "-inc") || !strcmp (argv[i], "+"))
{
if (++i >= argc) usage();
op = Inc;
- value = atoi (argv[i]);
+ value = atof (argv[i]);
continue;
}
if (argv[i][0] == '+' && isdigit (argv[i][1]))
{
op = Inc;
- value = atoi (argv[i] + 1);
+ value = atof (argv[i] + 1);
continue;
}
if (!strcmp (argv[i], "-dec") || !strcmp (argv[i], "-"))
{
if (++i >= argc) usage();
op = Dec;
- value = atoi (argv[i]);
+ value = atof (argv[i]);
continue;
}
if (argv[i][0] == '-' && isdigit (argv[i][1]))
{
op = Dec;
- value = atoi (argv[i] + 1);
+ value = atof (argv[i] + 1);
+ continue;
+ }
+ if (!strcmp (argv[i], "-mul") || !strcmp (argv[i], "*"))
+ {
+ if (++i >= argc) usage();
+ op = Mul;
+ value = atof (argv[i]);
+ continue;
+ }
+ if (argv[i][0] == '*' && ( isdigit (argv[i][1]) || argv[i][1]=='.' ))
+ {
+ op = Mul;
+ value = atof (argv[i] + 1);
continue;
}
if (!strcmp (argv[i], "-get") || !strcmp (argv[i], "-g"))
@@ -295,6 +309,14 @@
case Dec:
new = cur - set;
break;
+ case Mul:
+ new = cur + (cur - min) * (value - 1);
+ if ((long)(new+0.5) == (long)(cur+0.5)) {
+ // ensure that there is some change after rounding
+ if (value>1) new++;
+ else if (value<1) new--;
+ }
+ break;
default:
xcb_aux_sync (conn);
return 1;
@@ -308,7 +330,7 @@
cur = new;
else
cur += step;
- backlight_set (conn, output, (long) cur);
+ backlight_set (conn, output, (long) (cur+0.5)); // +0.5 for proper rounding
xcb_flush (conn);
usleep (total_time * 1000 / steps);
}
