Changeset 2846 for libpipi/trunk/pipi/pixels.c

Timestamp:

09/28/08 19:01:56 (5 years ago)

Author:

sam

Message:

Add a --gamma command to modify the global gamma value. This is a nasty
hack that will hopefully disappear in the future. The default gamma is
now 2.2 again (sRGB approximation).

File:

• libpipi/trunk/pipi/pixels.c (modified) (5 diffs)

libpipi/trunk/pipi/pixels.c

@@ -29 +29 @@
 #include "pipi_internals.h"
 
-#define GAMMA 1.0
-
 static void init_tables(void);
+
+static double global_gamma = 2.2;
+static int done = 0;
 
 static float u8tof32_table[256];
 static inline float u8tof32(uint8_t p) { return u8tof32_table[(int)p]; }
-
 
 /* Return a direct pointer to an image's pixels. */
@@ -153 +153 @@
                     if(p < 0.) d = 0.;
                     else if(p > 1.) d = 255;
-                    else d = (int)(255.999 * pow(p, 1. / GAMMA));
+                    else d = (int)(255.999 * pow(p, 1. / global_gamma));
 
                     dest[4 * (y * img->w + x) + i] = d;
@@ -189 +189 @@
                     if(p < 0.) d = 0.;
                     else if(p > 1.) d = 255;
-                    else d = (int)(255.999 * pow(p, 1. / GAMMA));
+                    else d = (int)(255.999 * pow(p, 1. / global_gamma));
 
                     dest[3 * (y * img->w + x) + i] = d;
@@ -252 +252 @@
 }
 
+void pipi_set_gamma(double g)
+{
+    if(g > 0.)
+    {
+        global_gamma = g;
+        done = 0;
+    }
+}
 
 static void init_tables(void)
 {
-    static int done = 0;
     int i;
 
@@ -262 +269 @@
 
     for(i = 0; i < 256; i++)
-        u8tof32_table[i] = pow((double)i / 255., GAMMA);
+        u8tof32_table[i] = pow((double)i / 255., global_gamma);
 
     done = 1;
 }
+