Only in xbrightness-0.3-mika-akk: gammatwister
diff -u xbrightness-0.3/xbrightness.c xbrightness-0.3-mika-akk/xbrightness.c
--- xbrightness-0.3/xbrightness.c	2005-10-15 02:23:21.000000000 -0700
+++ xbrightness-0.3-mika-akk/xbrightness.c	2009-02-28 16:21:29.000000000 -0800
@@ -20,6 +20,9 @@
  * SOFTWARE.
  *
  * Written by Asher Blum <asher@wildspark.com>
+ *
+ * R, G, B argument options were added by Mikael Magnusson.
+ * Print current (default) option and +/- options were added by Akkana Peck.
  */
 
 #include <ctype.h>
@@ -32,13 +35,19 @@
 #include <X11/extensions/xf86vmode.h>
 #include <math.h>
 
+#define MAX_BRIGHTNESS 65535
+
 char *argv0;
 
 static void syntax(void) {
     fprintf (stderr, "%s builds a brightness ramp for X11.\n\n", argv0);
     fprintf (stderr, "usage:  %s BRIGHTNESS [ GBASE ]\n\n", argv0);
-    fprintf (stderr, "where BRIGHTNESS is a number from 0 to 65535.\n");
-    fprintf (stderr, "where GBASE is a float number from 0.0 to 10.0. (default=1.0)\n");
+    fprintf (stderr, "or:  %s RBRIGHTNESS GBRIGHTNESS BBRIGHTNESS\n", argv0);
+    fprintf (stderr, "or:  %s [+change|-change]\n\n", argv0);
+    fprintf (stderr, "where BRIGHTNESS is a number from 0 to 65535\n");
+    fprintf (stderr, "GBASE is a float number from 0.0 to 10.0. (default=1.0)\n");
+    fprintf (stderr, "R G and B are red, green and blue\n");
+    fprintf (stderr, "and change is an increment or decrement.\n");
     exit (1);
 }
 
@@ -47,8 +56,10 @@
     Display *dpy;
     int screen = -1;
     int ramp_size = 0;
-    unsigned short *ramp;
-    unsigned short brightness = 60000;
+    unsigned short *rramp, *gramp, *bramp;
+    unsigned short print_only = 0;
+    unsigned short rinc=0, ginc=0, binc=0;  /* do incremental brightness? */
+    int rbrightness = 60000, gbrightness=60000, bbrightness=60000;
     float k;
     double gbase = 1.0;
 
@@ -56,24 +67,56 @@
 
     argv0 = argv[0];
 
-    if((argc != 2) && (argc !=3)){
-        syntax();
+    if (argc <= 1) {
+        print_only = 1;
     }
 
-    i = atoi(argv[1]);
-    if(!i && (argv[1][1] || !isdigit(argv[1][0]))) {
-        syntax();
-    }
-    if(i<0 || i>65535) {
+    else if (argc > 4) {
         syntax();
     }
-    brightness=i;
 
-    if (argc == 3) {
-	gbase = atof (argv[2]);
-	if (gbase == 0.0) {
-	    syntax();
-	}
+    else if (argc <= 3) {
+        if (argv[1][0] == '-' || argv[1][0] == '+') {
+            int brightness, red, green, blue;
+            int diff = atoi(argv[1]);
+            if (!diff && !isdigit(argv[1][1]))
+                syntax();
+            rinc = ginc = binc = 1;
+            rbrightness = diff;
+            gbrightness = diff;
+            bbrightness = diff;
+        }
+        else {
+            i = atoi(argv[1]);
+            if(!i && (argv[1][1] || !isdigit(argv[1][0]))) {
+                syntax();
+            }
+            if(i<0 || i>MAX_BRIGHTNESS) {
+                syntax();
+            }
+            if (argc == 3) {
+                gbase = atof (argv[2]);
+                if (gbase == 0.0) {
+                    syntax();
+                }
+            }
+            rbrightness=gbrightness=bbrightness=i;
+        }
+
+    } else {
+        rinc = (argv[1][0] == '+' || argv[1][0] == '-');
+        ginc = (argv[2][0] == '+' || argv[2][0] == '-');
+        binc = (argv[3][0] == '+' || argv[3][0] == '-');
+        rbrightness = atoi(argv[1]);
+        gbrightness = atoi(argv[2]);
+        bbrightness = atoi(argv[3]);
+        printf("%d %d %d (%d %d %d)\n", rbrightness, gbrightness,
+               bbrightness, rinc, ginc, binc);
+
+        if ((rbrightness<0 && !rinc) || (gbrightness<0 && !ginc)
+            || (bbrightness<0 && !ginc)) {
+            syntax();
+        }
     }
     
     /**** Setup ****/
@@ -94,25 +137,68 @@
         exit (2);
     }
     
-    ramp = (unsigned short *) malloc (ramp_size * sizeof(unsigned short));
-    if (ramp == NULL) {
-	fprintf(stderr, "could not allocate %lu bytes, aborting\n", (unsigned long)(ramp_size * sizeof(unsigned short)));
+    rramp = (unsigned short *) malloc (ramp_size * sizeof(unsigned short));
+    gramp = (unsigned short *) malloc (ramp_size * sizeof(unsigned short));
+    bramp = (unsigned short *) malloc (ramp_size * sizeof(unsigned short));
+    if (rramp == NULL || gramp == NULL || bramp == NULL) {
+	fprintf(stderr, "could not allocate %lu bytes x 3, aborting\n", (unsigned long)(ramp_size * sizeof(unsigned short)));
 	XCloseDisplay (dpy);
 	exit (2);
     }
 
-    if (!XF86VidModeGetGammaRamp(dpy, screen, ramp_size, ramp, ramp, ramp)) {
+    if (!XF86VidModeGetGammaRamp(dpy, screen, ramp_size, rramp, gramp, bramp)) {
         fprintf(stderr, "Unable to query brightness\n");
         XCloseDisplay (dpy);
         exit (2);
     }
 
+    if (print_only) {
+        int total, av, maxg;
+        int r = rramp[ramp_size-1];
+        int g = gramp[ramp_size-1];
+        int b = bramp[ramp_size-1];
+
+        /* Make a guess at perceived total based on the three colors */
+        /* For now, use the average of the max and the average */
+        av = (r + g + b) / 3;
+        maxg = (r > g ? r : g);
+        if (b > maxg) maxg = b;
+        total = (av + maxg) / 2;
+	
+        printf("%d: %d %d %d\n", total, r, g, b);
+        XCloseDisplay (dpy);
+        exit(0);
+    }
+
+    /* Adjust for incremental mode */
+    if (rinc) rbrightness += rramp[ramp_size-1];
+    if (ginc) gbrightness += gramp[ramp_size-1];
+    if (binc) bbrightness += bramp[ramp_size-1];
+
+    /* guard against wrapping around */
+    if (rbrightness > MAX_BRIGHTNESS) rbrightness = MAX_BRIGHTNESS;
+    if (gbrightness > MAX_BRIGHTNESS) gbrightness = MAX_BRIGHTNESS;
+    if (bbrightness > MAX_BRIGHTNESS) bbrightness = MAX_BRIGHTNESS;
+    if (rbrightness < 0) rbrightness = 0;
+    if (gbrightness < 0) gbrightness = 0;
+    if (bbrightness < 0) bbrightness = 0;
+
+    for(i=0; i<ramp_size; i++) {
+	double p = ((double) i)/ramp_size;
+        rramp[i] = (unsigned short)(rbrightness * pow (p, gbase));
+    }
+
+    for(i=0; i<ramp_size; i++) {
+	double p = ((double) i)/ramp_size;
+        gramp[i] = (unsigned short)(gbrightness * pow (p, gbase));
+    }
+
     for(i=0; i<ramp_size; i++) {
 	double p = ((double) i)/ramp_size;
-        ramp[i] = (unsigned short)(brightness * pow (p, gbase));
+        bramp[i] = (unsigned short)(bbrightness * pow (p, gbase));
     }
 
-    if(!XF86VidModeSetGammaRamp(dpy, screen, ramp_size, ramp, ramp, ramp)) {
+    if(!XF86VidModeSetGammaRamp(dpy, screen, ramp_size, rramp, gramp, bramp)) {
         fprintf(stderr, "Unable to set brightness");
         XCloseDisplay (dpy);
         exit (2);
diff -u xbrightness-0.3/xbrightness.man xbrightness-0.3-mika-akk/xbrightness.man
--- xbrightness-0.3/xbrightness.man	2005-10-15 02:24:02.000000000 -0700
+++ xbrightness-0.3-mika-akk/xbrightness.man	2008-11-26 11:04:12.000000000 -0800
@@ -14,7 +14,7 @@
 .\" OTHER DEALINGS IN THE SOFTWARE.
 .\" 
 .\"
-.TH xbrightness 1 Version 0.3
+.TH xbrightness 1 Version 0.3.mika-akk
 .SH NAME
 xbrightness - Adjust a monitor's brightness for XFree86
 .SH SYNOPSIS
@@ -41,11 +41,17 @@
 .B BRIGHTNESS
 A number from 0 to 65535, where 0 means complete darkness, and 65535
 means normal functioning - full brightness.
+Add + or - to increment or decrement current values.
 .PP
 .TP 8
 .B GAMMA
 A float number from 0.0 to 10.0, which gives the exponent used for
 building the gamma ramp. The default is 1.0 (linear).
+.PP
+.TP 8
+.B RED, GREEN, BLUE
+Brightness for the relative colors, from 0 to 65535.
+Add + or - to increment or decrement current values.
 
 .SH ENVIRONMENT
 .PP
@@ -64,9 +70,6 @@
 environment variable if necessary.
 .PP
 .TP 8
-Does not query brightness, only sets it.
-.PP
-.TP 8
 Does not play well with xgamma - xbrightness will erase xgamma's
 settings and vice versa.
 .PP