Prepare text and images
Text and graphics are composed into one complete image by the app. There is no separate text-rendering service on the device. A text-only label uses the same upload and refresh sequence as a picture.
Match the connected panel
Read Metadata before preparing the image. Use its width, height, color count, and format, not a size chosen from memory.
A 2.13-inch panel has 122 × 250 visible pixels. Its image encoding includes row padding, which the app handles; the extra bits are not extra visible canvas space.
Use the exact palette: black and white; black, white, and red; or black, white, yellow, and red. Enclosure color does not add a display color. Preview any color conversion before uploading.
Check the canvas
- Fit the artwork within the reported pixel dimensions.
- Choose orientation deliberately. If the layout needs rotation, the app must rotate the canvas before encoding.
- Keep text and graphics inside the canvas boundary.
- Check every character, especially names, symbols, and non-Latin text. The app must support the chosen font and characters; unsupported glyphs must be rejected or replaced before transfer, not silently left blank.
- Inspect the complete preview before starting an update.
The firmware's reference text example uses a small pixel-aligned bitmap font. It is a test style, not a promise of a particular font menu in a released app. Apps may render another font into the canvas without changing the transfer workflow.
Send one complete image
The app encodes the finished canvas using Metadata's format and required image length, then checks the encoded image's integrity during transfer. Do not use Display Text or Display Fill commands: Display Text is unsupported and Display Fill is not a production update method.
Follow the safe transfer sequence. If text looks cut off or colors are wrong, correct the preview and verify the panel identity before sending another image.