LW — White box

Fills a rectangle with white, erasing black underneath — used to open readable text inside a reversed block.

Engine status: Rendered

This command produces visible output in the preview.

Syntax

LWx,y,w,h

When to use it

Use LW to clear part of an area that is already black: a window inside a filled LO bar where readable text goes, a gap in a frame, or a white rule across a dark block. It prints nothing by itself — on bare white media it is invisible — so it always comes AFTER the LO (or other black content) it cuts into.

Example

N
q812
Q1218,24
LO50,50,700,160
LW80,90,420,80
A100,110,0,4,1,1,N,"ORDER 4711"
P1

The example draws a 700 × 160 dot black bar with LO; LW clears a 420 × 80 dot window starting at (80,90), and the A command prints the order number inside that window. At 203 dpi 8 dots are 1 mm, so the window is about 52 × 10 mm.

Open this example in the preview →

Open the validator →

Rendered example

Output of the example above in our renderer (203 dpi). Not verified on a physical printer.

Parameters

Parameter	Meaning
`x,y`	Top-left corner of the area to clear, in dots
`w`	Width in dots — a size, not a second corner
`h`	Height in dots; a small h gives a white horizontal line

Common mistake

Writing LW BEFORE the black area, or reading the second pair as a corner: LW only clears black drawn before it. Written first there is nothing to clear, and the LO that follows covers the window again (the preview, which draws commands in order, shows exactly that). LW80,90,420,80 is 420 × 80 dots and reaches x 500, y 170; it does not end at (420,80).

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