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drawpoly
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5.7.1 DRAW POLYGON
The DRAW POLYGON command is used to define a closed polygon which can be
filled with a solid colour or a patternfill. A single polygon entity may
consist of up to 64 separate polygons, one main polygon and 63 sub-polygons.
Sub-polygons can be used to define inner boundaries within the main polygon
that act as 'holes' and will be excluded from the fill.
If none of the font modifiers are used, the polygon will be filled with its
layer dependent colour.
COMMAND FORMAT ( except for PARALLEL )
#DRAW POLYGON [modifiers] :Loc x1 x2 ... xn [:Loc x1 ... xn] [CR]
Loc ...
The first set of locations entered define the main polygon boundary. If this
set of locations is delimited with a colon, then a sub-polygon boundary
definition can be entered. Futher sub-polygon boundaries may be entered
until a return is used to terminate the last boundary location list. When
the polygon has been created, a second polygon entity can be defined in the
same way. To terminate the command, a return should be entered at the 'Loc'
prompt which appears when the previously defined polygon has been created.
Polygons can somtimes be required to be drawn using existing entities to
define the boundary of the area to be filled. To create a polygon boundary
using existing entities, the IDENTS point on entity modes - CHAIN, GENERATE,
END, MID, ORG and NEAR - can be used to generate the required boundary. For
more information on this subject see the documentation for IDENTS or use the
command:
#HELP MANUAL IDENTS LOCS
( See figs. 5.46 to 5.48 ).
MODIFIERS
LAYER Requires a layer number. This will override the current
active layer.
DEPTH Requires a depth number. This will override the current
active depth.
PARALLEL Format:
#DRAW POLYGON PARALLEL [value] :Ent x1 :Loc x2 :Ent ...
Will draw a polygon parallel to an exsiting polygon. 'x1'
identifies the existing polygon.
'x2' is used to define on which side of the existing polygon
to draw the new polygon boundary. If a value is entered after
PARALLEL, the new polygon boundary will be drawn at the
specified distance from the existing polygon. ( See fig. 5.49
). If no value is entered, the distance is derived as the
distance between 'x2' and the nearest side of the existing
polygon.
In PARALLEL mode, all sub-polygons are defined in the same
way.
RECTANGLE Will draw rectangular polygons. Two locations are entered
for each sub-polygon, these define the extents of the
rectangle. ( See fig. 5.50 ).
In RECTANGLE mode, all sub-polygons are defined in the same
way.
The following modifiers all define alternative methods for filling the
polygon. The 4 main types of fill are defined with the modifiers COLOURFILL,
PATTERNFILL, HALFTONE and SHADOW.
COLOURFILL Requires a colour number in the range 0 to 7. This indicates
that the polygon will be filled with a specific colour and
not the layer dependent colour.
.HALFTONE This modifier will 'halftone' the colour fill by applying
a mask which lets the background colour show through at every
second pixel in the filled area.
.OUTLINE Will outline the polygon with the layer dependent colour.
PATTERNFILL Requires the name of a patternfill previously defined with
the DEFINE PATTERNFILL command. The polygon area will be
filled with the named patternfill.
The following modifiers only apply to patternfills that
were originally defined using colour 1 only. ( See the
command DEFINE PATTERNFILL ).
.COLOUR Requires a colour number in the range 0 to 7. The colour
specified will be used as the 'foreground' colour for the
patternfill overriding the default layer dependent colour.
..BACKGROUND The background of a patternfill is normally filled with the
background colour, colour 0. This modifier when used with
COLOUR will fill the background of the patternfill with the
layer dependent colour.
.OUTLINE Will outline the patternfilled polygon with the layer
dependent colour.
.TRANSPARENT If this modifier is used, instead of filling the background
of a patternfill with a solid colour, the background will be
made transparent. This will allow any graphics 'beneath' the
patternfill background areas to show through.
.MASK Specifies that the patternfilled polygon is to be used as a
mask. All background areas of the patternfill will be filled
with the background colour blotting out any graphics beneath.
The patterned areas will become transparent allowing any
graphics beneath these areas to show through.
HALFTONE This modifier will 'halftone' a solid colour fill by applying
a mask which lets the background colour show through at every
second pixel in the filled area.
SHADOW Defines a SHADOW polygon. A shadow polygon is a mask used to
block out every second pixel in the polygon area. The mask
is arranged:
* * * * * * *
* * * * * * *
* * * * * * *
* * * * * * * * = pixel
Every 'on' position in the mask will be set to the background
colour. Every 'off' position will allow whatever graphics are
beneath the polygon area to show through.
ATTRIBUTE Used to enter one or more attributes associated with this
entity. For a full description of the ATTRIBUTE option, see
the documentation for the command ADD ATTRIBUTE.