Changeset 464 for libcaca/trunk/src/bitmap.cTweet

Timestamp:

Jan 14, 2005, 12:59:55 AM (17 years ago)

Author:

Sam Hocevar

Message:

• src/bitmap.c: + Implemented caca_set_bitmap_gamma().

File:

• libcaca/trunk/src/bitmap.c (modified) (7 diffs)

libcaca/trunk/src/bitmap.c

@@ -46 +46 @@
 #include <limits.h>
 #include <string.h>
+#include <math.h>
 
 #include "caca.h"
@@ -171 +172 @@
     void (*get_hsv)(struct caca_bitmap *, char *, int, int);
     int red[256], green[256], blue[256], alpha[256];
+    float gammaval;
+    int gammatab[4097];
 };
 #endif
@@ -224 +227 @@
 {
     struct caca_bitmap *bitmap;
+    int i;
 
     /* Minor sanity test */
@@ -258 +262 @@
     if(bpp == 8)
     {
-        int i;
         bitmap->has_palette = 1;
         bitmap->has_alpha = 0;
@@ -268 +271 @@
         }
     }
+
+    /* Default gamma value */
+    for(i = 0; i < 4096; i++)
+        bitmap->gammatab[i] = i;
 
     return bitmap;
@@ -312 +319 @@
 
     bitmap->has_alpha = has_alpha;
+}
+
+/**
+ * \brief Set the gamma of a bitmap object.
+ *
+ * Set the gamma of bitmap.
+ *
+ * \param bitmap Bitmap object.
+ * \param red Gamma value.
+ */
+void caca_set_bitmap_gamma(struct caca_bitmap *bitmap, float gammaval)
+{
+    int i;
+
+    if(gammaval <= 0.0)
+        return;
+
+    bitmap->gammaval = gammaval;
+
+    for(i = 0; i < 4096; i++)
+        bitmap->gammatab[i] = 4096.0 * powf((float)i / 4096.0, 1.0 / gammaval);
 }
 
@@ -371 +399 @@
     if(bitmap->has_palette)
     {
-        *r += bitmap->red[bits];
-        *g += bitmap->green[bits];
-        *b += bitmap->blue[bits];
+        *r += bitmap->gammatab[bitmap->red[bits]];
+        *g += bitmap->gammatab[bitmap->green[bits]];
+        *b += bitmap->gammatab[bitmap->blue[bits]];
         *a += bitmap->alpha[bits];
     }
     else
     {
-        *r += ((bits & bitmap->rmask) >> bitmap->rright) << bitmap->rleft;
-        *g += ((bits & bitmap->gmask) >> bitmap->gright) << bitmap->gleft;
-        *b += ((bits & bitmap->bmask) >> bitmap->bright) << bitmap->bleft;
+        *r += bitmap->gammatab[((bits & bitmap->rmask) >> bitmap->rright) << bitmap->rleft];
+        *g += bitmap->gammatab[((bits & bitmap->gmask) >> bitmap->gright) << bitmap->gleft];
+        *b += bitmap->gammatab[((bits & bitmap->bmask) >> bitmap->bright) << bitmap->bleft];
         *a += ((bits & bitmap->amask) >> bitmap->aright) << bitmap->aleft;
     }