This module is provided for compatibility with the book "Programming in Oberon" (-> "Bibliography"). It is useful when learning the language. It is not recommended for use in production programs.
CONST erase
This value can be passed to parameter mode in procedure Dot. It indicates that a white dot should be placed at the given coordinates.
CONST draw
This value can be passed to parameter mode in procedure Dot. It indicates that a white dot should be placed at the given coordinates.
VAR X, Y, W, H
These values define the rectangle in which drawing occurs. (X, Y) is the lower-left corner of the rectangle, (W, H) its size. In Oberon/F, (X, Y) is always (0, 0). Unlike the port model of Oberon/F, XYplane has its origin at the lower-left corner of the drawing area, and positive Y values above the origin.
PROCEDURE Open
Opens a new window for drawing. The window's contents is cleared to white.
PROCEDURE Dot (x, y, mode: INTEGER)
Draws a white dot (mode = erase) or a black dot (mode = draw).
PROCEDURE IsDot (x, y: INTEGER): BOOLEAN
Returns whether the dot at (x, y) is white (FALSE) or black (TRUE).
PROCEDURE ReadKey (): CHAR
If a key has been pressed, it is returned as result. Otherwise, 0X is returned.
PROCEDURE Clear
Erases the whole drawing area (setting it to white).
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