LMI Forth Product Catalog

UR/FORTH Graphics Support

The graphics drivers built into LMI's UR/FORTH systems for DOS and the 80386/486/Pentium give you full control over the video graphics capabilities of the IBM PC family. These high-performance packages include device-independent, structured video mode commands and graphics drawing primitives.

The LMI Forth graphics drivers support the following video controllers:

• IBM Color/Graphics Adapter (CGA)

• IBM Enhanced Graphics Adapter (EGA)

• IBM Video Graphics Array/Adapter (VGA)

• Hercules Monochrome Graphics Card

Features of Color Graphics Support

• Entirely implemented in native machine code for maximum performance

• Loaded as a memory-resident system driver (does not reduce amount of Forth dictionary workspace available)

• Graphics primitives include pel addressing, line, circle, arc, ellipse, pattern flood fill, bit-block move and graphics text strings

• Supports all documented graphics display modes except for the 256-color modes of the VGA adapter

• Smooth pel-by-pel panning and scrolling (EGA, VGA)

• RAM-loadable character sets (EGA, VGA)

• Dynamic palette programming (EGA, VGA)

• Virtual video screen display (EGA, VGA)

Partial List of Graphics Extension Functions

All of the functions listed below work symmetrically in any legal graphics or text mode (if applicable) on the active video display. It should be noted that the "Display Attributes" and "Display Control" directives are also available for text modes.

Display Attributes

-BLINK	Disable blink attribute
-COLOR	Disable color burst
-INTENSITY	Disable intensity attribute
?COLORS	Return number of colors for current mode
!PALETTE	Program palette registers
AND-OFF	Disable AND mode for drawing primitives (EGA, VGA)
AND-ON	Enable AND mode for drawing primitives (EGA, VGA)
B/W	Return to default foreground/background colors
BACKGROUND	Select background color
BLINK	Enable blink attribute
BORDER	Select border color
FOREGROUND	Select foreground color
I/B	Toggle between intensity or blink attribute
INTENSITY	Enable intensity (highlight) attribute)
OR-OFF	Disable OR mode for drawing primitives (EGA, VGA)
OR-ON	Enable OR mode for drawing primitives (EGA, VGA)
PALETTE	Select current color palette
REVERSE	Interchange foreground/background colors
XOR-OFF	Disable XOR mode for drawing primitives
XOR-ON	Enable XOR mode for drawing primitives

Display Control

?VMODE	Return the current video display mode
?VPAGE	Return active video page
?VSEG	Return the segment of the current display buffer
?XMAX	Return maximum legal X coordinate for mode
?YMAX	Return maximum legal Y coordinate for mode
CLS	Clear screen with current background attribute
GOTOXY	Position cursor
REDRAW	Refresh active display from shadow buffer
SET-VSEG	Set segment address of shadow buffer
SET-VXY	Set virtual screen origin (EGA, VGA)
VIDEO-IO	Hook to ROM video driver
VMODE	Set current display mode
VPAGE	Select active video page

Drawing Primitives

!BLOCK	Write bit block
GEMIT	Character display at graphic coordinate
GTYPE	String output at graphics coordinate
!PEL	Write pixel
@PEL	Read pixel value
@BLOCK	Fetch bit block to local buffer
ARC	General purpose arc primitive with clipping
CIRCLE	Draws circle given origin and point on edge
ELLIPSE	Draws ellipse given origin and x and y radius
FLOOD	Solid or pattern fill of any bounded region
LINE	Solid line between specified endpoints

Created January 1, 1996 / Last Modified January 12, 1996
Copyright (C) 1996 Laboratory Microsystems Inc.

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