Fwd: Re: [Question] Colour management

[Alexander Kern <alex.kern@gmx.de>]

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Hello,

here is a very good patch, that correct fbi with 16 bpp(565) mode.
Tested on Mach64. Please commit it.

Regards
Alex Kern

----------  Weitergeleitete Nachricht  ----------

Subject: [Linux-fbdev-devel] Re: [Question] Colour management
Date: Sonntag, 1. August 2004 00:10
From: Ville Syrjälä <syrjala@sci.fi>
To: linux-fbdev-devel@lists.sourceforge.net

On Fri, Jul 30, 2004 at 08:12:36PM +0200, Alexander Kern wrote:
> Hallo Tony,
>
> can you explain the deep mining of fb_setcolreg. Background, I observe
> wrong palette using in 15 and 16 bpp modes, but can not understand, what is
> the right approach. In both cases from penguin logo I can see only contour
> in honey yellow and blue vertical string jsimmons, pretty scury ;-) The
> rest is black! The simple text or ncurses applications have always right
> colours. Additionally and only by 16bpp fbi shows blurry images.

I just had a look at the fbi code and it's wrong. It was initializing the
clut to 555. The attached patch fixes the problem.

I think the boot logo code is broken. No, I haven't actually looked at it
but everything else works... Or does it work on some other directcolor hw?

--
Ville Syrjälä
syrjala@sci.fi
http://www.sci.fi/~syrjala/

-------------------------------------------------------



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--- fbi-1.31/fbi.c	2004-02-22 14:24:29.000000000 +0200
+++ fbi-1.31/fbi.c	2004-08-01 00:57:45.375251160 +0300
@@ -760,12 +760,19 @@
 }
 
 static void
-linear_palette(int bit)
+linear_palette(int r, int g, int b)
 {
-    int i, size = 256 >> (8 - bit);
-    
+    int i, size;
+
+    size = 256 >> (8 - r);
+    for (i = 0; i < size; i++)
+	red[i] = calc_gamma(i,size);
+    size = 256 >> (8 - g);
     for (i = 0; i < size; i++)
-        red[i] = green[i] = blue[i] = calc_gamma(i,size);
+	green[i] = calc_gamma(i,size);
+    size = 256 >> (8 - b);
+    for (i = 0; i < size; i++)
+	blue[i] = calc_gamma(i,size);
 }
 
 static void
@@ -1391,21 +1398,23 @@
 	break;
     case 15:
     case 16:
-        if (fb_fix.visual == FB_VISUAL_DIRECTCOLOR)
-            linear_palette(5);
 	if (fb_var.green.length == 5) {
+	    if (fb_fix.visual == FB_VISUAL_DIRECTCOLOR)
+		linear_palette(5,5,5);
 	    lut_init(15);
 	} else {
+	    if (fb_fix.visual == FB_VISUAL_DIRECTCOLOR)
+		linear_palette(5,6,5);
 	    lut_init(16);
 	}
 	break;
     case 24:
         if (fb_fix.visual == FB_VISUAL_DIRECTCOLOR)
-            linear_palette(8);
+            linear_palette(8,8,8);
 	break;
     case 32:
         if (fb_fix.visual == FB_VISUAL_DIRECTCOLOR)
-            linear_palette(8);
+            linear_palette(8,8,8);
 	lut_init(24);
 	break;
     default: