1 files changed, 96 insertions, 0 deletions
diff --git a/pkg/plot/crtpict/setxform.x b/pkg/plot/crtpict/setxform.x
new file mode 100644
index 00000000..a6c50dfb
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+++ b/pkg/plot/crtpict/setxform.x
@@ -0,0 +1,96 @@
+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+include	<imhdr.h>
+include	<mach.h>
+include	"wdes.h"
+include	"crtpict.h"
+
+
+# CRT_ESTABLISH_TRANSFORM -- Set up both the spatial and greyscale mapping.
+# The window descriptor "wdes" is filled.
+
+procedure crt_establish_transform (gp, im, cl, wdes)
+
+pointer	gp
+pointer im
+pointer	cl
+pointer	wdes
+
+int	w1, len_stdline
+real	z1, z2
+
+bool	fp_equalr()
+int	strncmp()
+errchk	crt_xy_scale, strcmp, im_minmax, zscale
+
+begin
+	# Procedure xy_scale calculates and stores the spatial
+	# transformation fields of structure wdes.
+
+	call crt_xy_scale (gp, cl, im, wdes)
+
+	w1 = W_WC(wdes, 1)
+
+	# Now for the intensity to greyscale mapping.  Values z1 and z2,
+	# the intensities that map to the lowest and highest greyscale
+	# levels, are calculated and stored in the wdes structure. First,
+	# set up the default values.  These will not be changed if 
+	# ztrans = "user".
+
+	W_ZT(w1) = W_USER
+	z1 = INDEFR
+	z2 = INDEFR
+
+	# Put up to date min, max values in the header structure, if necessary
+	if (IM_LIMTIME(im) < IM_MTIME(im))
+	    call im_minmax (im, IM_MIN(im), IM_MAX(im))
+
+	if (strncmp (ZTRANS(cl), "min_max", 1) == 0) {
+	    W_ZT(w1) = W_LINEAR
+	    if (Z1(cl) != Z2(cl)) {
+		# Use values set by user
+		z1 = Z1(cl)
+		z2 = Z2(cl)
+	    } else {
+		# Use image min and max unless the user has set the contrast
+		# parameter to alter the slope of the transfer function.
+		if (abs (CONTRAST(cl) - 1.0) > EPSILON) {
+		    # CONTRAST = 1.0
+		    z1 = IM_MIN(im)
+		    z2 = IM_MAX(im)
+		} else if (abs (CONTRAST(cl) + 1.0) > EPSILON) {
+		    # CONTRAST = -1.0
+		    z1 = IM_MAX(im)
+		    z2 = IM_MIN(im)
+		} else {
+		    len_stdline = SAMPLE_SIZE / NSAMPLE_LINES(cl)
+		    call zscale (im, z1, z2, CONTRAST(cl), SAMPLE_SIZE, 
+			len_stdline)
+		}
+	    }
+	}
+
+	if (strncmp (ZTRANS(cl), "auto", 1) == 0) {
+	    W_ZT(w1) = W_LINEAR
+	    # Calculate optimum z1 and z2 from image mode
+	    len_stdline = SAMPLE_SIZE / NSAMPLE_LINES(cl)
+	    call zscale (im, z1, z2, CONTRAST(cl), SAMPLE_SIZE, len_stdline)
+	    if (IM_PIXTYPE(im) == TY_SHORT) {
+	        if (short (z1) == short (z2))
+		    call error (0, 
+			"No range in data, ztrans=auto failed: z1 = z2")
+	    }
+	    else if (fp_equalr (z1, z2))
+		call error (0, "No range in data, ztrans=auto failed: z1=z2")
+	}
+
+	# Set the intensity extremes of the window descriptor
+	if (strncmp (ZTRANS(cl), "none", 1) == 0) {
+	    W_ZT(w1) = W_UNITARY
+	    W_ZS(w1) = IM_MIN(im)
+	    W_ZE(w1) = IM_MAX(im)
+	} else {
+	    W_ZS(w1) = z1
+	    W_ZE(w1) = z2
+	}
+end