With 24/32-bit xwd files, xv swaps the red and blue channels. With 16-bit xwd

files, the image is very dark green (almost black).

Both problems are caused by hard-coding the channel order and offsets, rather
than using the colour masks in the xwd header.

xv reads the input into a 24-bit internal image, which is then displayed.  The
lack of brightness in the 16-bit display is because the colour values are copied
into the low-order bits of the internal pixmap rather than the high order bits.
The green hue is because the green channel has 6 bits, whereas red and blue only
have 5 bits, making the green twice as (relatively) bright.

The new patch solves that problem.

PR:		96971
Submitted by:	Peter Jeremy <peterjeremy@optushome.com.au>
Approved by:	Miguel Mendez <mmendez@gmail.com> (maintainer)

2 files changed, 172 insertions, 1 deletions

diff --git a/graphics/xv/Makefile b/graphics/xv/Makefile
index e53f288d1171..d0ddb2c5fe14 100644
--- a/graphics/xv/Makefile
+++ b/graphics/xv/Makefile
@@ -7,7 +7,7 @@
 
 PORTNAME=	xv
 PORTVERSION=	3.10a
-PORTREVISION=	5
+PORTREVISION=	6
 CATEGORIES+=	graphics
 MASTER_SITES=	${MASTER_SITE_LOCAL}
 MASTER_SITE_SUBDIR=	../distfiles/xv
diff --git a/graphics/xv/files/patch-xvxwd.c b/graphics/xv/files/patch-xvxwd.c
new file mode 100644
index 000000000000..f1c280d6f5cf
--- /dev/null
+++ b/graphics/xv/files/patch-xvxwd.c
@@ -0,0 +1,171 @@
+--- xvxwd.c.orig	Sun Jul  9 18:12:45 2006
++++ xvxwd.c	Mon Jul 10 20:04:55 2006
+@@ -19,7 +19,7 @@
+  */
+ 
+ #include "xv.h"
+-
++#include <sys/endian.h>
+ 
+ /***************************** x11wd.h *****************************/
+ #define X11WD_FILE_VERSION 7
+@@ -66,23 +66,30 @@
+ 
+ typedef byte pixel;
+ 
++#if __FreeBSD_cc_version < 500000
++static CARD16	bs_short(CARD16 x);
++static CARD32	bs_long(CARD32 x);
++#else
++#define    bs_short(x)	bswap16(x)
++#define    bs_long(x)	bswap32(x)
++#endif
++
+ /* local functions */
+ static int    getinit         PARM((FILE *, int*, int*, int*, CARD32 *, 
+ 			                          CARD32, PICINFO *));
+ static CARD32 getpixnum       PARM((FILE *));
+ static int    xwdError        PARM((char *));
+ static void   xwdWarning      PARM((char *));
+-static int    bs_short        PARM((int));
+-static CARD32 bs_long         PARM((CARD32));
+ static int    readbigshort    PARM((FILE *, CARD16 *));
+ static int    readbiglong     PARM((FILE *, CARD32 *));
+ static int    readlittleshort PARM((FILE *, CARD16 *));
+ static int    readlittlelong  PARM((FILE *, CARD32 *));
+ static int    writebigshort   PARM((FILE *, int));
+ static int    writebiglong    PARM((FILE *, CARD32));
+-
++static int    get_shift       PARM((CARD32));
+ static byte  *pic8, *pic24;
+ static CARD32 red_mask, green_mask, blue_mask;
++static int    red_shift, green_shift, blue_shift;
+ static int    bits_per_item, bits_used, bit_shift, bits_per_pixel;
+ static char   buf[4];
+ static char   *byteP;
+@@ -181,24 +188,9 @@
+ 	CARD32 ul;
+ 	
+ 	ul = getpixnum(ifp);
+-	switch (bits_per_pixel) {
+-	case 16:
+-	  *xP++ = ((ul & red_mask)   >> 0);
+-	  *xP++ = ((ul & green_mask) >> 5);
+-	  *xP++ = ((ul & blue_mask)  >> 10);
+-	  break;
+-	  
+-	case 24:
+-	case 32:
+-	  *xP++ = (ul    ) & 0xff;
+-	  *xP++ = (ul>> 8) & 0xff;
+-	  *xP++ = (ul>>16) & 0xff;
+-	  break;
+-	  
+-	default:
+-	  xwdError("True/Direct only supports 16, 24, and 32 bits");
+-	  return 0;
+-	}
++	*xP++ = ((ul & red_mask)   << red_shift) >> 24;
++	*xP++ = ((ul & green_mask) << green_shift) >> 24;
++	*xP++ = ((ul & blue_mask)  << blue_shift) >> 24;
+       }
+ 
+       for (col=0; col<padright; col++) getpixnum(ifp);
+@@ -266,6 +258,8 @@
+     byte_swap = 1;
+     h11P->header_size      = bs_long(h11P->header_size);
+     h11P->file_version     = bs_long(h11P->file_version);
++    if (h11P->file_version != X11WD_FILE_VERSION)
++	return(xwdError("unsupported X11 XWD file version"));
+     h11P->pixmap_format    = bs_long(h11P->pixmap_format);
+     h11P->pixmap_depth     = bs_long(h11P->pixmap_depth);
+     h11P->pixmap_width     = bs_long(h11P->pixmap_width);
+@@ -427,6 +421,10 @@
+   green_mask = h11P->green_mask;
+   blue_mask  = h11P->blue_mask;
+ 
++  red_shift   = get_shift(red_mask);
++  green_shift = get_shift(green_mask);
++  blue_shift  = get_shift(blue_mask);
++
+   byteP  = (char   *) buf;
+   shortP = (CARD16 *) buf;
+   longP  = (CARD32 *) buf;
+@@ -534,39 +532,21 @@
+  * Byte-swapping junk.
+  */
+ 
+-union cheat {
+-  CARD32 l;
+-  CARD16 s;
+-  CARD8  c[sizeof(CARD32)];
+-};
+-
+-static int bs_short(s)
+-     int s;
++#if __FreeBSD_cc_version < 500000
++static CARD32   bs_long(CARD32 x)
+ {
+-  union cheat u;
+-  unsigned char t;
+-
+-  u.s = (CARD16) s;
+-  t = u.c[0];  u.c[0] = u.c[1];  u.c[1] = t;
+-  return (int) u.s;
++  return (((x & 0xff000000U) >> 24) |
++          ((x & 0x00ff0000U) >>  8) |
++          ((x & 0x0000ff00U) <<  8) |
++          ((x & 0x000000ffU) << 24));
+ }
+ 
+-static CARD32 bs_long(l)
+-     CARD32 l;
++
++static CARD16   bs_short(CARD16 x)
+ {
+-  union cheat u;
+-  unsigned char t;
+-  
+-  u.l = l;
+-  t = u.c[0];  u.c[0] = u.c[3];  u.c[3] = t;
+-  t = u.c[1];  u.c[1] = u.c[2];  u.c[2] = t;
+-  return u.l;
++  return (((x & 0xff00U) >> 8) | ((x & 0x00ffU) << 8));
+ }
+-
+-
+-
+-
+-
++#endif
+ 
+ /* 
+  * Endian I/O.
+@@ -623,7 +603,7 @@
+ }
+ 
+ 
+-static int writebiglong(out, l)
++	static int writebiglong(out, l)
+      FILE* out;
+      CARD32 l;
+ {
+@@ -642,4 +622,17 @@
+   putc((s>>8)&0xff, out);
+   putc(s&0xff, out);
+   return 0;
++}
++
++
++static int get_shift(val)
++    CARD32 val;
++{
++    int		shift;
++
++if (!val)
++	return (0);
++    for (shift = 0; !(val & 0x80000000); shift++)
++	val <<= 1;
++    return (shift);
+ }
+