---
title: "Improving Display"
id: 76466
type: "computer_media"
slug: "improving-display"
url: "http://localhost/computer_media/improving-display/"
markdown_url: "http://localhost/computer_media/improving-display.md"
published_at: "2026-11-11T08:02:40+00:00"
modified_at: "2026-11-11T08:02:40+00:00"
author: "David Anderson"
featured_image:
  url: "http://localhost/wp-content/uploads/2026/11/improving-display-1.png"
excerpt: "Move a cursor around the ZX80 screen and drop characters where you like, building a picture on a field of colons."
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  - name: "Downloadable"
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  - name: "ZX80"
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model:
  - name: "Sinclair ZX80"
    slug: "zx80"
    taxonomy: "model"
    url: "http://localhost/model/zx80/"
indiv:
  - name: "Will Hiatt"
    slug: "will-hiatt"
    taxonomy: "indiv"
    url: "http://localhost/indiv/will-hiatt/"
genre:
  - name: "Graphics"
    slug: "graphics"
    taxonomy: "genre"
    url: "http://localhost/type/graphics/"
media_type: "Program"
programmers:
  - name: "Will Hiatt"
    slug: "will-hiatt"
    taxonomy: "indiv"
    url: "http://localhost/indiv/will-hiatt/"
download_url: "https://archive.org/download/timex-sinclair-software-archive/Improving%20Display%20%281981%29%28Hiatt%2C%20Will%29%28ZX80%29%28US%29%28Program%29.zip"
mediadate: "1981"
images:
  - url: "http://localhost/wp-content/uploads/2026/11/improving-display-1.png"
  - url: "http://localhost/wp-content/uploads/2026/11/improving-display-2.png"
article_media:
  - id: 19691
    title: "Improving Display"
    type: "article"
    url: "http://localhost/article/improving-display/"
related_content:
  - id: 19681
    title: "Syntax Error"
    type: "article"
    url: "http://localhost/article/syntax-error-3/"
media_type_tags: "Graphics"
license: false
---

# Improving Display

A screen editor for ZX80 graphics in 1K. RUN fills 14 lines with colons. In direction mode the cursor is an asterisk: R, L, U and D move it, I switches to insert mode, S stops, and NEWLINE repeats the last command. In insert mode the cursor is a question mark and keeps moving in the last direction; type a character, or its character code, to place it, NEWLINE to repeat it, or ND to return to direction mode.

Change the 14 in line 150 for a different background character. A note says the program won’t run with the Syntactic Sum routine loaded. The next month Will Hiatt sent two lines for 16K: a new line 140 and a line 365 that adds an H (hold) command.

Published in Syntax August 1981 ([Improving Display](https://timexsinclair.com/article/improving-display/)).

## Source Code

```
 100 FOR X=1 TO 448
 110 PRINT ":";
 120 NEXT X
 130 LET N=20
 140 LET Q=17083
 150 LET C1=14
 160 INPUT A$
 170 LET X=CODE(A$)
 180 LET A$=TL$(A$)
 190 LET Y=CODE(A$)
 200 LET Z=CODE(TL$(A$))
 210 LET F=0
 220 IF N=20 THEN LET C=C1
 230 IF X=1 THEN GO TO 330
 240 IF N=20 THEN GO TO 300
 250 IF Y=41 THEN GO TO 420
 260 LET C=X*100+Y*10+Z-3108
 270 IF NOT Y=1 THEN LET F=2
 280 IF Y=1 THEN LET C=X
 290 GO TO 330
 300 IF X=46 THEN GO TO 450
 310 IF X=56 THEN STOP
 320 LET D=X
 330 IF D=55 THEN LET P=Q+1
 340 IF D=49 THEN LET P=Q-1
 350 IF D=58 THEN LET P=Q-33
 360 IF D=41 THEN LET P=Q+33
 370 POKE Q+F,C
 380 LET C1=PEEK(P+F)
 390 POKE P+F,N
 400 LET Q=P
 410 GO TO 160
 420 LET N=20
 430 LET F=1
 440 GO TO 390
 450 LET N=15
 460 GO TO 390
```