Edge/Collision Detection in ASCII character templates - Part 2

I experimenting with edge detection in ASCII characters, to use for manipulating text data (for example, creating mazes).

Here was Part I:  http://sevkeifert.blogspot.com/2015/11/i-wrote-that-turns-ascii-tessellation.html

Then I noticed that a lot of character patterns have implied white space, such as a pattern with pipes and underscores.  This pattern contains visual whitespace, but no actual whitespace character data:

So, here's an experiment to generalize the parser to handle cases like this.  The simplest approach I found was to add an option to  translate all characters into an exploded map of the data.  One character can translate to a block of 9 characters that represent the solid and non-solid properties of the font shape.  For example:

Then, the edge detection code works as usual, just in an exploded view of the ASCII data.


For example:

1. First transform text to exploded view
2. Parse as usual
3. Then apply an inverse transform to collapse back to normal.

The transform looks like:

Load template:

Apply Transform:

Apply pre-processing filters (sharpen edges)

Parse and apply post-processing filters

Apply inverse transform:

Then I added some code to detect the "outside" of a shape.  Also, I added pre and post image filtering rules, so loose edges like /_ can be automatically detected and closed.

Here's another example parsing implied whitespace in a template:

Parser Hints

Now, the parser can automatically detect inside/outside of closed shapes.

Also, I added a special character ~ that flags a region as closed within another shape (such as holes in the template).   The special character ` acts as non-useable whitespace.

summary:
    ~ means outside of shape
    ` means don't use whitespace

For example, to protect the closed shape of the eye, add a ~ inside of it:

Updated code at:

Python2: https://github.com/sevkeifert/text-utils/blob/master/maze-ify-ascii.py
Python3: https://github.com/sevkeifert/text-utils/blob/master/maze-ify-ascii-v3.py