PixelCanvas.io downloader

This utility lets you download the http://pixelcanvas.io bitmap and export regions of it to .png files.

Requirements

pip install -r requirements.txt

Usage

This tool is run from the command line, where you provide the coordinates you want to download and render.

The format for typing coordinates is UPPERLEFT--LOWERRIGHT. The format for each of those pieces is X.Y.

Sometimes, argparse gets confused by negative coordinates because it thinks you're trying to provide another argument. Sorry. If this happens, use a tilde ~ as the negative sign instead.

Remember, because this is an image, up and left are negative; down and right are positive.

Commands:

update:
    Download chunks into the database.

    > pixelcanvas.py update ~100.~100--100.100

render:
    Export an image as PNG.

    > pixelcanvas.py render 0.0--100.100 <flags>

    flags:
    --show:
        Instead of saving the image, display it on the screen.
        https://pillow.readthedocs.io/en/stable/reference/Image.html#PIL.Image.Image.show

    --update:
        Update the chunks before exporting them.

So, for example:

> pixelcanvas.py update 0.0--100.100
> pixelcanvas.py update ~100.~100--100.100
> pixelcanvas.py update ~1200.300--~900.600

> pixelcanvas.py render 0.0--100.100
> pixelcanvas.py render ~100.~100--100.100 --update
> pixelcanvas.py render ~1200.300--~900.600 --show

To do

Here are some things we might like to improve:

• Some way to get a statistics overview or visual map of which chunks we have in the database, so we know what we're missing.
• Render the image is it appeared at some point in the past, taking advantage of the updated_at column.
• Probably never going to happen: A GUI application to browse the db just like the site.