javl
e6e371ad9b
Some images didn't get converted properly. This was easy to spot in smaller image where the last part seemed to be missing. Each of the hex values generated stands for a byte = 8 bits = 8 pixels. But sometimes the size of the image caused the last hex value to contain less than 8 bits (because there weren't enough pixels left). As the hex values represent 8 pixels being drawn right to left, the missing bits would cause the pixels to move out of the canvas. The solution is to always pad the last hex to a length of 8. .
image2cpp
image2cpp is a simple tool to change images into byte arrays to use with (monochrome) displays suchs as OLEDs, like those from Adafruit or Sparkfun. While searching for a way to generate these arrays, I mostly found links to a piece of Windows software. Both the flakey results and the hassle of having to boot a virtual machine just to convert an image lead to me writing this pure html + javascript solution.
Alternatively you can also enter a byte array as input to turn it back into an image. This might be useful for debugging, or when you want to write the byte array yourself. I don't know.
Running the tool
You don't need any special dependencies / internet connection; all the necessary parts sit in a single .html file. So just open this index.html page in a (recent) browser to run the tool. Or you can use the online version at: http://javl.github.io/image2cpp/
Example Arduino code
You can find a simple Arduino example sketch over here in the repository.
Screen types
I wrote the code with my 128x64 pixel monochrome OLED display in mind, but it should work with most similar displays. You might need to change some export settings; those are explained in the tool.
Credit
Initial code by javl, with aditional code by wiredolphin. The example sketch was made by Adafruit.