UnityNativeGallery
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yasirkula
LoadImageFromPath: Slow and freezes app
So far, I had been reading the image bytes from the gallery file path manually, i.e. using File.ReadAllBytes, loaded them into a texture via texture.LoadImage(), scaled and rotated them using EXIF data and saved the result as a PNG file. This was quite fast, since some of the operations (orientation, scaling) were done in separate threads (async). However, texture.LoadImage() does not support some media formats, e.g. HEIC, so not all gallery files could be used.
Hence, I was very happy to see that there is an own method LoadImagePath that does all of that at once and supports HEIC files, which is awesome. However, I noticed that this method a) takes much longer than my previous routines (sometimes up to 5 secs), and b) it freezes the GUI of the app. In our case, it's an Augmented Reality app, and the whole camera feed freezes while the operation takes place. Which is not a good UX.
It would be awesome if there was an async version of LoadImage() which operates in a separate thread, so at least the freezing problem is gone.
I am also wondering why the operations take so long, especially if I provide a maxWidth. If I don't use this scaling feature (by setting the maxWidth to -1) and scale the texture myself, it is much faster. Here's the script I am using for bilinear scaling, which scales in a separate thread:
http://wiki.unity3d.com/index.php/TextureScale
Here's the TextureTransform script I am using for orientation changes:
It's compiled from different StackOverflow answers and I enhanced it so it can be used in combination with this ExifLib (optional):
https://github.com/tedbarnett/read-exif-in-unity
I must say that I'm surprised to hear this. I'd also think that maxSize would be faster. I'm not sure if I can optimize its speed, though. The source code is open and I'm open to suggestions. Calling LoadImageAtPath in a separate thread is a possibility but to be honest, currently it is not a priority for me. I want to finish some other projects first 💾 I'll keep this Issue open in the meantime.
Thanks Yasir. I tried to encapsulate the call in an async Task, but this did not work, because Unity's texture operations are only allowed on the main thread. It throws an Exception otherwise. Likewise, encodeToPNG does not work on a separate thread.
Can you run only the following line asynchronously, wait for it to finish and run the rest of the function on the main thread: https://github.com/yasirkula/UnityNativeGallery/blob/0bc6c23925e899e44506f13061287b0f24735957/Plugins/NativeGallery/NativeGallery.cs#L719
Can it be done with Tasks?
Trying to run that in a task causes the app to crash, I am trying to find some other ways to decode the heic format
