hight memory usage with images on dash

jonnius / camera-scanner

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https://gitlab.com/jonnius/camera-scanner

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hight memory usage with images on dash #27

Open Danfro opened 5 years ago

Danfro commented 5 years ago

If there are several images on the dash the app takes up quite some memory and does take a while to load.

Memory after reboot before start of app:

screenshot20190411_230913454

Memory after starting camera scanner with 5 images on dash:

screenshot20190411_230949690

Memory after deleting 4 images and restarting camera scanner:

screenshot20190411_231213987

Danfro commented 5 years ago

Maybe worth to mention. All images where taken from within the app (that is imported straight from camera).

jonnius commented 5 years ago

Thanks for your hint. I see two ways to reduce storage used by cache:

Reduce image resolution on import (configurable)
Do not cache result images with documents and rerun image processing on app start (configurable)
Do not cache the session at all (configurable)

To reduce RAM usage:

Do not hold images in backend, but read files from cache each time an image is requested (only possible if images are cached)
Reduce image resolution for displaying (configurable, only helpful if images have not already been reduced on import)

Danfro commented 5 years ago

Can maybe thumbnails be loaded/shown on the dash? Gallery app must be doing something in the line.

Then load the full image only for processing/editing. That should at least sort startup time.

jonnius commented 5 years ago

I think loading the images into RAM is what takes most of the time. So the only way to speed that up would be to save a thumbnail along with each image for displaying purpose.

But I don't think the camera scanner should scale up that much. It is not meant as a gallery, just as a session of scans to be exported as a PDF together. Maybe we should ask the user on startup whether he wants to restore the previous sessions and delete it otherwise. Also we are planning to have a "new session" button that clears the session.