How to view real time mosaicing of large image? about pyvips HOT 10 CLOSED

You could allocate a 512x512 (or whatever) preview image in memory, then on each load, paste a shrunk version of that image into your memory image and update the display from that.

libvips supports progress bars, so you could also display an animated "x% complete" message during dzsave.

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Hello @jcupitt ,
Thanks for your immediate response .
I am trying to visualize the image in full resolution so that it can be zoomed and analyzed while mosaicing is in progress. Kind of pyramidal structure is required, I think. This is the link https://youtu.be/fOiUkui5TL8 of WSI system, please go through the video to understand my objective.

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I'm not sure that will work with libvips. It does not mosaic the image in stages in a way you could visualise -- it mosaics in small pieces on demand as the output is generated.

In the same way, dzsave does not generate the layers one after the other. Instead, it writes all the layers simultaneously in a single top-bottom pass.

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Yes, that's what I have understood. So, is there any way to do it? Any suggestion?

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I would just display the mosaic I think. For example:

https://github.com/jcupitt/vipsdisp

will display the output of a vips pipeline and let you zoom and pan around.

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hello @jcupitt,
I am replying a bit late. Vipsdisp can be used only when the whole image is created and saved right? Can we use this while a pipeline is created?
Also can you please suggest how progress bars can be displayed while saving the result?
result.write_to_file('test.tiff',Q=95, compression="lzw", bigtiff=True)

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Hello again, vipsdisp can display pipeline output directly. There's no need to save.

To get progress feedback, you need to listen for eval signals on the output image. That would be a bit tricky from Python, you'd need to extend pyvips a bit.

You can just set the VIPS_PROGRESS environment variable for simple text feedback.

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Ok, but it will show in the last after the pipeline is linked to a sink right? Can't we see in the mapping phase? Is there any example of vips_progress for python script?

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vipsdisp is a sink. You connect the output of the pipeline to the display, and then pixels are calculated as you zoom and scroll around.

Just set the environment variable VIPS_PROGRESS:

https://stackoverflow.com/questions/5971312/how-to-set-environment-variables-in-python

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Thanks @jcupitt

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