CID to RGF Converter

Create LEGO Mindstorms graphics from CID font glyphs online

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Robotics Display

Get CID-keyed CJK characters onto LEGO Mindstorms EV3 screens. RGF format integrates directly with the brick display system.

CID to EV3

Transform your CID font glyphs into LEGO RGF graphics — a fun way to display CJK characters in educational robotics projects.

No EV3 Software Needed

Generate RGF files from CID fonts in your browser. Transfer to the EV3 brick afterwards using standard LEGO tools.

How to convert CID to RGF

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose rgf or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your rgf file right afterwards

About formats

CID (Character Identifier) is a font architecture developed by Adobe Systems and specified in June 1993 to address the challenges of fonts containing very large glyph sets, particularly for CJK (Chinese, Japanese, Korean) scripts. Traditional PostScript fonts identify glyphs by name, which becomes impractical when a font contains tens of thousands of characters — a typical Japanese font may include over 20,000 glyphs. CID-keyed fonts replace glyph names with numeric identifiers organized by a character collection and ordering (such as Adobe-Japan1 or Adobe-GB1), dramatically reducing overhead for glyph access and subsetting. The architecture defines three PostScript font types: Type 9 (CID-keyed Type 1 outlines), Type 10 (CID-keyed Type 3), and Type 11 (CID-keyed Type 42/TrueType). A primary advantage is efficient handling of massive character sets — the numeric CID approach eliminates the memory and processing cost of maintaining thousands of glyph name strings. CID fonts also support sophisticated CMap resources that map encoding values to CIDs, enabling a single font to serve multiple encoding schemes (Unicode, Shift-JIS, Big5) without duplicating glyph data. The architecture integrates well with PDF subsetting, allowing documents to embed only the glyphs actually used. CID-keyed technology laid the foundation for CJK support in both OpenType and modern PDF workflows, and remains active in print production and document processing systems worldwide.
Developer: Adobe Systems
Initial release: June 11, 1993
RGF (Robot Graphics Format) is a simple monochrome bitmap image format used by LEGO Mindstorms EV3 programmable robotics kits, introduced with the EV3 system on September 1, 2013. RGF files store 1-bit (black and white) images designed for display on the EV3 Intelligent Brick's 178x128 pixel monochrome LCD screen. The format uses a minimal structure: a header containing the image width and height as binary values, followed by the pixel data where each bit represents one pixel (1 for black, 0 for white), packed eight per byte in row-major order. RGF images are used as custom display graphics in EV3 programs — students and hobbyists create them for robot status displays, user interfaces, splash screens, and animation frames shown on the brick's screen during program execution. The images are typically designed using LEGO's EV3 software (which includes a built-in image editor) or converted from other formats using community tools. RGF fits within LEGO's broader educational robotics platform, where the Mindstorms system teaches programming, engineering, and computational thinking to students worldwide. One advantage is the format's role in educational technology: RGF provides a simple, concrete example of how digital images are represented as binary data — a concept that students working with Mindstorms can directly observe by examining the file contents and seeing the corresponding image on the brick's screen. The format's simplicity makes it accessible for young programmers learning about file formats and binary data. RGF files can be created and converted using ImageMagick, the EV3 development environment, and community tools like ev3dev.
Developer: The LEGO Group
Initial release: 2013

Frequently Asked Questions

Why convert CID to RGF?

RGF is the LEGO Mindstorms display format. Convert CID characters to RGF for showing CJK glyphs on EV3 brick screens in robotics projects.

How do I use RGF images?

Load the RGF file onto a LEGO EV3 brick via USB or Bluetooth. Use EV3 programming software to display it on the robot screen.

What resolution does RGF support?

RGF matches the EV3 screen — 178x128 pixels monochrome. CID glyph renders are scaled to fit this compact display.

Is RGF monochrome only?

Yes — the EV3 screen is black and white. CJK characters from CID fonts render as clean high-contrast monochrome bitmap graphics.

Is CID to RGF free?

Yes — Convertio converts CID to RGF at no charge. No EV3 software needed for the conversion itself.