1 files changed, 88 insertions, 0 deletions
diff --git a/converter/ppm/rgb3toppm.c b/converter/ppm/rgb3toppm.c
new file mode 100644
index 00000000..a666553c
--- /dev/null
+++ b/converter/ppm/rgb3toppm.c
@@ -0,0 +1,88 @@
+/* rgb3toppm - combine three portable graymaps into one portable pixmap
+**
+** Copyright (C) 1991 by Jef Poskanzer.
+**
+** Permission to use, copy, modify, and distribute this software and its
+** documentation for any purpose and without fee is hereby granted, provided
+** that the above copyright notice appear in all copies and that both that
+** copyright notice and this permission notice appear in supporting
+** documentation.  This software is provided "as is" without express or
+** implied warranty.
+*/
+
+#include "ppm.h"
+
+int
+main( argc, argv )
+    int argc;
+    char* argv[];
+    {
+    FILE* rfd;
+    FILE* gfd;
+    FILE* bfd;
+    gray* rrow;
+    gray* rP;
+    gray* grow;
+    gray* gP;
+    gray* brow;
+    gray* bP;
+    pixel* pixelrow;
+    register pixel* pP;
+    int rows, cols, trows, tcols, row, col;
+    gray rmaxval, gmaxval, bmaxval;
+    int rformat, gformat, bformat;
+    pixval pmaxval;
+
+
+    ppm_init( &argc, argv );
+
+    if ( argc != 4 )
+	pm_usage( "<red pgmfile> <green pgmfile> <blue pgmfile> " );
+
+    rfd = pm_openr( argv[1] );
+    gfd = pm_openr( argv[2] );
+    bfd = pm_openr( argv[3] );
+
+    pgm_readpgminit( rfd, &cols, &rows, &rmaxval, &rformat );
+    pgm_readpgminit( gfd, &tcols, &trows, &gmaxval, &gformat );
+    if ( tcols != cols || trows != rows )
+	pm_error( "all three graymaps must be the same size" );
+    pgm_readpgminit( bfd, &tcols, &trows, &bmaxval, &bformat );
+    if ( tcols != cols || trows != rows )
+	pm_error( "all three graymaps must be the same size" );
+
+    pmaxval = rmaxval;
+    if ( gmaxval > pmaxval ) pmaxval = gmaxval;
+    if ( bmaxval > pmaxval ) pmaxval = bmaxval;
+    rrow = pgm_allocrow( cols );
+    grow = pgm_allocrow( cols );
+    brow = pgm_allocrow( cols );
+
+    ppm_writeppminit( stdout, cols, rows, pmaxval, 0 );
+    pixelrow = ppm_allocrow( cols );
+
+    for ( row = 0; row < rows; row++ )
+	{
+	pgm_readpgmrow( rfd, rrow, cols, rmaxval, rformat );
+	pgm_readpgmrow( gfd, grow, cols, gmaxval, gformat );
+	pgm_readpgmrow( bfd, brow, cols, bmaxval, bformat );
+
+	for ( col = 0, rP = rrow, gP = grow, bP = brow, pP = pixelrow;
+	      col < cols;
+	      ++col, ++rP, ++gP, ++bP, ++pP )
+	    {
+	    if ( rmaxval != pmaxval ) *rP = (int) *rP * pmaxval / rmaxval;
+	    if ( gmaxval != pmaxval ) *gP = (int) *gP * pmaxval / gmaxval;
+	    if ( bmaxval != pmaxval ) *bP = (int) *bP * pmaxval / bmaxval;
+	    PPM_ASSIGN( *pP, *rP, *gP, *bP );
+	    }
+	ppm_writeppmrow( stdout, pixelrow, cols, pmaxval, 0 );
+	}
+
+    pm_close( rfd );
+    pm_close( gfd );
+    pm_close( bfd );
+    pm_close( stdout );
+
+    exit( 0 );
+    }