printing text to the jpg image - Creative Uses of CHDK - CHDK Forum

printing text to the jpg image

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printing text to the jpg image
« on: 04 / August / 2020, 16:03:24 »
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Since canon can print the time and date onto the image recorded, is there a way for us to manipulate that text string and record information into the image the same way with CHDK? For example when doing tests it would be nice to have some parameters burned into the jpg image so there is no doubt what values certain variables are at the time of the shot.

thank you

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Offline reyalp

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Re: printing text to the jpg image
« Reply #1 on: 04 / August / 2020, 16:40:33 »
CHDK doesn't control the Canon time/date string.

You can use https://chdk.fandom.com/wiki/Lua/Raw_Hook_Operations to draw on the raw buffer, which will end up in the jpeg.

Downside is it needs to be done from script, and you'd have to render the text yourself. If you are using a script, it's probably more convenient to write an external log file that includes the image number and whatever values you want to record. The isoinc.lua in the CHDK SCRIPTS/TEST directory has an example that records to CSV file.
Don't forget what the H stands for.

Re: printing text to the jpg image
« Reply #2 on: 05 / August / 2020, 23:28:50 »
You can also poke some information into an image's exif data using a Lua script. There is a demo script that shows how.
Ported :   A1200    SD940   G10    Powershot N    G16

Re: printing text to the jpg image
« Reply #3 on: 04 / September / 2020, 21:00:55 »
Thank you for the responses.


 

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