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1 files changed, 63 insertions, 0 deletions

diff --git a/pkg/plot/crtpict/drawgrey.x b/pkg/plot/crtpict/drawgrey.x
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+++ b/pkg/plot/crtpict/drawgrey.x
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+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+include	<imhdr.h>
+include	<mach.h>
+include	<gset.h>
+include	"wdes.h"
+include	"crtpict.h"
+
+# CRT_DRAW_GREYSCALE -- Draw steps representing greyscale increments on output.
+
+procedure crt_draw_greyscale (gp, cl)
+
+pointer	gp
+pointer	cl
+
+short 	grey[NSTEPS]
+char	label[SZ_LABEL]
+int	ndev_rows, i, dummy
+real	ndc_xs, ndc_xe, ndc_ys, ndc_ye, yres, del_y
+real	delta_grey, delta_x, x_start, x, dz1, dz2
+
+bool	ggetb()
+int	ggeti(), itoc()
+real	ggetr()
+errchk	ggetb, ggeti, ggetr, gpcell, ggetr, gtext
+
+begin
+	if (ggetb (gp, "z1") && ggetb (gp, "z2")) {
+	    dz1 = ggetr (gp, "z1")
+	    dz2 = ggetr (gp, "z2")
+	} else {
+	    dz1 = 0.
+	    dz2 = 255.
+	}
+
+	ndev_rows = ggeti (gp, "yr")
+	yres = (CRT_YE - CRT_YS) * ndev_rows
+
+	# The (NDC) device coordinates of the greyscale_window are calculated.
+
+	ndc_xs = CRT_XS 
+	ndc_xe = CRT_XE
+	ndc_ys = CRT_YS + ((GRAPHICS_FRACTION(cl) + IMAGE_FRACTION(cl) + SPACE)*
+	    yres) / ndev_rows
+	ndc_ye = ndc_ys + ((yres * GREYSCALE_FRACTION(cl)) / ndev_rows) 
+	ndc_ye = min (ndc_ye, CRT_YE)
+	del_y = ndc_ye - ndc_ys
+
+	# Calculate and output grey levels
+	call gseti (gp, G_WCS, 0)
+	delta_grey = (dz2 - dz1) / real(NSTEPS - 1)
+	delta_x = (ndc_xe - ndc_xs) / NSTEPS 
+	x_start = ndc_xs + (delta_x / 2.0)
+	do i = 1, NSTEPS {
+	    grey[i] = short (dz1 + (i-1) * delta_grey + 0.5)
+	    dummy = itoc (int(grey[i]), label, SZ_LABEL)
+	    x = x_start + (i - 1) * delta_x
+	    call gtext (gp, x, ndc_ys, label, "h=c;s=0.25;v=t")
+	}
+	
+	call gpcell (gp, grey, NSTEPS, 1, ndc_xs, ndc_ys + (0.05 * del_y), 
+	    ndc_xe, ndc_ye)
+end