Device APIsUpdated 2026-07-24

Cronus Zen OLED functions

Draw pixels, lines, rectangles, circles, characters, and strings with the official Zen OLED functions.

Overview

Zen OLED functions let a script render compact status interfaces directly on the device. Clear or redraw intentionally to avoid stale pixels and unnecessary work.

OLED APIs are Zen-only. printf draws a string on the OLED from string data; it is not a console diagnostic logger.

Key facts

OLED functions are Zen-only.
Coordinates must fit the display's documented bounds.
putc_oled fills the string buffer used by puts_oled.
printf draws a string on the OLED.

GPC syntax examples

Examples are intentionally small. Replace identifiers only with values documented for your target.

Clear the displayexample.gpc

init {
    cls_oled(OLED_BLACK);
}

Functions, commands, and terms

Names below are catalog entries, not guessed signatures. Open the official sources for current parameter and return-value details.

NameKindPurpose

cls_oledfunction · Zen only

Clears the Zen OLED using a documented color.

pixel_oledfunction · Zen only

Draws a pixel on the Zen OLED.

line_oledfunction · Zen only

Draws a line on the Zen OLED.

rect_oledfunction · Zen only

Draws a rectangle on the Zen OLED.

circle_oledfunction · Zen only

Draws a circle on the Zen OLED.

putc_oledfunction · Zen only

Places a character in the string buffer used by puts_oled.

puts_oledfunction · Zen only

Draws characters supplied through putc_oled.

printffunction · Zen only

Draws a string from the data section on the OLED.

Common mistakes

Using printf as diagnostic console output.

Compiling OLED calls for a non-Zen target.

Drawing outside display bounds.

Copying unsupported ellipse or image helpers from another dialect.

Official GPC sources

Use these first-party references to confirm exact syntax and runtime behavior for your installed firmware and Studio version.

Official documentationOfficial OLED display functionsgpc.cronusmax.com/functions-and-commands/internal-functions/oled-display-functions ↗