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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include "stdgraph.h"
# STG_POLYMARKER -- Draw a polymarker. The polymarker is defined by the array
# of points P, consisting of successive (x,y) coordinate pairs, each of which
# is to be plotted as a point. If the marker start sequence MS is defined the
# polymarker will be drawn as <markstart> <p1> ... <pN> <markend>, otherwise
# ther marker is draw using the polyline move and draw commands to draw each
# individual point.
procedure stg_polymarker (p, npts)
short p[ARB] # points defining line
int npts # number of points, i.e., (x,y) pairs
pointer pm
bool tek_encoding
int lowres_x, lowres_y
int ip, n, sx, sy, len_p, iop, i
int stg_encode()
include "stdgraph.com"
begin
if (g_enable == NO)
call stg_genab()
len_p = npts * 2
# Update polymarker attributes if necessary.
pm = SG_PMAP(g_sg)
if (SG_COLOR(g_sg) != PM_COLOR(pm)) {
call stg_ctrl1 ("MC", PM_COLOR(pm))
SG_COLOR(g_sg) = PM_COLOR(pm)
}
# Tektronix encoding is treated as a special case for max efficiency.
tek_encoding =
(Memc[g_xy] == '%' && Memc[g_xy+1] == 't' && Memc[g_xy+2] == EOS)
# Draw the polymarker. If the startmark sequence is defined we assume
# that the device can draw a multipoint polymarker, else low level move
# and draw sequences are used.
if (Memc[SG_STARTMARK(g_sg)] != EOS) {
for (ip=1; ip <= len_p; ip=ip+2) {
# Output start marker sequence [revised to use the encoder].
call ttyputs (g_out, g_tty, Memc[SG_STARTMARK(g_sg)], 1)
n = len_p
# Encode the points of the polymarker (or move to the single
# point to be drawn).
g_lastx = -1 # clip unresolved points only in the interior
g_lasty = -1 # of the polymarker being drawn.
g_reg[E_IOP] = 1
do i = ip, n, 2 {
sx = p[i]
sy = p[i+1]
# Discard the point if it is not resolved.
lowres_x = sx / g_dxres
lowres_y = sy / g_dyres
if (lowres_x == g_lastx && lowres_y == g_lasty)
next
g_lastx = lowres_x
g_lasty = lowres_y
# Transform point into the device window.
sx = int (sx * g_dx) + g_x1
sy = int (sy * g_dy) + g_y1
# Encode the point, appending encoded bytes to g_mem.
# Tek encoding is treated as a special case since it is
# so common; the encoder is used for non-Tek encodings.
if (tek_encoding) {
iop = g_reg[E_IOP] + 4
g_mem[iop-4] = g_hixy[sy+1]
g_mem[iop-3] = g_loy[sy+1]
g_mem[iop-2] = g_hixy[sx+1]
g_mem[iop-1] = g_lox[sx+1]
g_reg[E_IOP] = iop
} else {
g_reg[1] = sx
g_reg[2] = sy
if (stg_encode (Memc[g_xy], g_mem, g_reg) != OK)
break
}
# Flush buffer if nearly full.
if (g_reg[E_IOP] > FLUSH_MEMORY) {
call write (g_out, g_mem, g_reg[E_IOP] - 1)
g_reg[E_IOP] = 1
}
}
ip = n
# Flush any output remaining in encoder memory.
if (g_reg[E_IOP] > 1) {
call write (g_out, g_mem, g_reg[E_IOP] - 1)
g_reg[E_IOP] = 1
}
# Output end polymarker sequence, or draw the point.
call ttyputs (g_out, g_tty, Memc[SG_ENDMARK(g_sg)], 1)
}
} else {
for (ip=1; ip <= len_p; ip=ip+2) {
sx = p[ip]; sy = p[ip+1]
call stg_move (sx, sy)
call stg_draw (sx, sy)
}
}
end
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