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How to create text/image for LED
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How to create text/image for LED

by michellechenmx on Mon Dec 04, 2017 10:49 pm

I have a 16x32 RGB LED Matrix Panel from Adafruit. I'm trying to project a scrolling image with a symbol + text, just like in this tutorial (https://learn.adafruit.com/connecting-a ... ng-message). However, the tutorial does not elaborate on how exactly the image was created in GIMP.

I created my image/text in Photoshop by creating a text box with helvetica font and saved it on JPG. However, despite setting the image to be 16 pixels (height), the words are not as 'clean' as the one in the tutorial. Mine has a lot of grey pixels surrounding the individual white alphabets. So when projected to the LED display, the word does not look clear.

My questions:
How can I create 'clean' text without grey pixels surrounding the individual alphabets?
Do I have to create the text pixel by pixel?
Is there an advisable font type to use?
I converted my JPG image into PPM, which is the format advised in the tutorial, but it still does not work. What should I do?

Thank you!
Attachments
Brooklyn bridge image with text.jpg
Brooklyn bridge image with text.jpg (21.92 KiB) Viewed 78 times

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Re: How to create text/image for LED

by adafruit_support_carter on Tue Dec 05, 2017 3:12 pm

If you zoom in and look at your font at the pixel level it'll look like this:
gimp.jpg
gimp.jpg (116.82 KiB) Viewed 51 times

Note how there are several levels of gray pixels surrounding each character. This is due to anti-aliasing. You just need to turn that off so that the font is basically pure white without any of the gray. You can use whatever font you want, but some will look better with anti-aliasing turned off.

Compare this to the font used in the guide example:
https://learn.adafruit.com/assets/15211
You'll see there is only one color for the pixels. There's no shading or anti-aliasing going on.

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