Begin Area - IBM 6400 Programmer's Reference Manual

Graphics Command Set
The following sections describe the drawing orders.

Begin Area

Description: This order indicates the beginning of the boundary of an area that
the printer shades. The area definition must terminate with an End Area order.
The area boundaries consist of one or more closed figures. Each closed figure
is made up of a continuous set of straight lines, full arcs, and fillets defined using
the Line at Current Position, Fillet at Current Position, and Full Arc at Current
Position orders. The pattern symbol and the shading color for the area are the
attribute values that are current prior to the Begin Area order. Only the
following orders are valid between a Begin Area and an End Area order:
Note: When used between Begin Area and End Area drawing orders, the orders
Set Color, Set Extended Color, Set Line Type, Set Line Width, and Set Fractional
Line Width update the values of their respective current attributes only for the
Area boundary, if drawn. These orders do not update their respective current
values for the area fill pattern after an area has begun.
Use of the Line, Relative Line, Full Arc, and Fillet in the non At Current Position
form can cause the printer to arbitrarily close the area figure. The
recommended orders to use within an area definition are those in the At Current
Position form.
The printer cannot nest Area orders. The Begin Area order does not change any
other graphics drawing attributes. However, orders between a Begin Area/End
Area pair can update the current position.
Parameter P1 is a flag byte that specifies whether boundary lines are to be
drawn, as shown:
The printer uses the current values of color, mix, background mix, pattern, and
pattern set when shading the area. If boundary lines are drawn, the printer uses
the current values of graphics color, line type, and line width. The printer
shades any commented region with an odd number of line crossings from
98
6400 IPDS
68 P1
Comment
•
Line or Relative Line
•
Line at Current Position
•
Relative Line at Current Position
•
Set Arc Parameters
•
Full Arc at Current Position
•
Full Arc or Fillet
•
Fillet at Current Position
•
Set Color or Set Extended Color (see note)
•
Set Line Type, Set Line Width, or Set Fractional Line Width (see note)
•
Set Current Position.
•
Bit 0 Reserved
Bit 1 0 = Do Not Draw Boundary Lines
1 = Draw Boundary Lines
Bit 2 Inside
Bits 3-7 Reserved