How to put images into cache that are already loaded

[gnoeyp]

I'm trying to load volume using cornerstoneWADOImageLoader.wadouri.loadImage rather than streaming-wadors because wadors protocol is not available in my server environment.

After I loaded images and extracted meta data, I realized that I can't find a function to cache images. So currently my implementation loads images twice (for prefetch and volume generation). I wish there was a function like this: cornerstone.cacheImage(imageId, image)

[sedghi]

Hey, the caching is done automatically if you have registered image loaders and using cornerstone to load them. If you can't initiate the load from cornerstone, you can look into the cach.putImageLoadObject

[gnoeyp]

If I directly call cornerstone.createAndCacheVolume(volumeId, { imageIds }) before the images are loaded, I got an error that metadata does not exist. I think it's because the volumeLoader executes makeVolumeMetaData before loading prefetchIds. Thus I need to call cornerstone.imageLoader.loadAndCacheImage or cornerstone.imageLoader.loadImage before creating a volume.

I tried both ways, and only cornerstone.imageLoader.loadImage worked well.
What I found is, if cached images exist, cornerstone would rescale the image, which was an unexpected behavior in my app's scenario. It results the viewport looks completely white.

I am not sure the dicom files were loaded twice, because chrome network tab shows only one request per file, even though I used cornerstone.imageLoader.loadImage.

If the images are cached, no problem. Otherwise, it will be perfect if I can pass an argument needToRescale: boolean to createAndCacheVolume so that unexpected rescaling would not occur.

[sgielen]

I believe this issue can be closed as soon as #1509 is merged.

• Retrieving and storing the image data is now done manually when the image is displayed using the viewport API.
• Caching the metadata is performed by the WADO image loader (metadata provider), if this behaviour needs to be changed then feat(image loaders): Allow reusing DICOM image loader code for custom image loaders #1509 can be used to write a custom metadata provider and/or image loader which performs the correct behaviour. Update: This has been merged. This example now shows how to do this yourself.
• Whether to perform prescaling is now chosen automatically on main.