notisrac / filetocarray Goto Github PK

Hello, a TFT display control library has an example of using this PNG image to binary file converter. But it only works when the image is small.

// This example renders a png file that is stored in a FLASH array
// using the PNGdec library (available via library manager).

// Note: The PNGDEC required lots of RAM to work (~40kbytes) so
// this sketch is will not run on smaller memory processors (e.g.
// ESP8266, STM32F103 etc.)

// Image files can be converted to arrays using the tool here:
// https://notisrac.github.io/FileToCArray/
// To use this tool:
// 1. Drag and drop file on "Browse..." button
// 2. Tick box "Treat as binary"
// 3. Click "Convert"
// 4. Click "Save as file" and move the header file to sketch folder
// 5. Open the sketch in IDE
// 6. Include the header file containing the array (panda.h in this example)

https://github.com/Bodmer/TFT_eSPI/blob/master/examples/PNG%20Images/Flash_PNG/Flash_PNG.ino

Bodmer/TFT_eSPI#3185

If I take the basic 50x50 image that is attached here, both my C++ (Arduino) and an online tool are showing data corruption.
Basically a vertical line | is being skewed to /.

This can be tested my uploading the attached 50x50 jpg to the online example https://notisrac.github.io/FileToCArray/ then taking the HEX output and test the conversion back to an image online here https://mischianti.org/images-to-byte-array-online-converter-cpp-arduino/.

Oddly, the example Google.ico in the readme seems to work perfectly.

I have tested both jpg and bmp and was thinking it was me for 2 days until I started to count bits and tested the github test against converters.

Expected output can be created here https://www.digole.com/tools/PicturetoC_Hex_converter.php

These are the expected and actual arrays.

expected.txt
actual.txt

I'm happy to help out in any way that I can, this is a great tool to have JS get images into the correct format for e-Ink displays.

file size 143kB

see https://notisrac.github.io/FileToCArray/

When selecting "Code format" "Decimal (000)" and NOT "unsigned" (i.e. it should be signed values) and
"Data type" "char" or "int8_t", then the Result should NEVER contain values like 250, 202, etc - since these should be
negative numbers! (or there should at least be an option to allow that output)

Very good tool!
I add include guards into the generated header files directly adding them to my project.
It would be nice having them added by the tool.