Update ArtQRCode.cs

[Tragen]

Fixed dot size calculation where the size is divided instead of multiplied.

[Shane32]

Previously the pixel size factor does not appear to have any effect.

With pixel size factor of 0.7: (default is 0.8)

Before:

After:

Demo of default size factor of 0.8:

It would seem that this PR should be merged, assuming this is the intent of the pixel size factor. However, any user code will now generate with smaller dots than previously, as previously it acted as though pixelSizeFactor was 1, and the default is 0.8. Test hashes will need to be updated.

Perhaps the default should be set to 1.0 going forward, to match the previous version's default behavior (??)

[Shane32]

Closes:

• Module size (note pixelsPerModule) #463
• How to create a QR with a small pixel size. #396

[Shane32]

Looks good to me