Call Box Commands
Version 2.0 15 Jan-90


CALL OV the OVAL commands

There are 5 commands that draw ovals. The ovals are drawn with the pen in the current port.

Note: Any command that draws something, draws to a graphics port. You must make sure that the port you want to draw in is the current port before drawing to it. Because you are drawing to a port and not necessarily the screen, the coordinates used to draw are in a coordinate system unique to the port you have selected. This coordinate system is Called LOCAL. GLOBAL coordinates on the other hand refer to the screen coordinates... or the current cursor position. If you choose to draw to the screen then the LOCAL coordinates will equal the GLOBAL coordinates.

COMMAND FUNCTION DESCRIPTION
CALL OV,O,X,Y,W,H FRAME OVAL: draws an oval outline in the current pen color.
CALL OV,1,X,Y,W,H PAINT OVAL: draws an oval and fills it with the current pen color.
CALL OV,2,X,Y,W,H ERASE OVAL: draws an oval and fills it with color O.
CALL QV,3,X,Y,W,H INVERT OVAL: draws an oval and inverts the pixels colors.
CALL QV,4,X,Y,W,H,P FILL OVAL: draws an oval and fills it with the current pen pattern.

X
Left edge of the enclosing rectangle for the oval in LOCAL coordinates.

Y
Top edge of the enclosing rectangle for the oval in LOCAL coordinates.

W
Width of the enclosing rectangle for the oval in pixels.

H
Height of the enclosing rectangle for the oval in pixels.

P
Pattern used to fill the oval (0-15)


Figure 2.10
Figure 2.10 Oval construction

Ovals are constructed inside of an imaginary rectangle (Enclosing rectangle) specified by X, Y, W and H. (refer to Figure 2.10) Ovals made in 320 mode will follow a circular path if the width and height are the same, however ovals created in 640 mode will have to have the width twice the height for the same effect.