The ConstantProvider is a collection of magic numbers,
shapes and strings used by all of the other renderer components, as well as
other parts of Blockly like the built-in fields.
All constant values are assumed to be constant! Changing values at runtime causes rendering bugs.
Connection shapes
The constant provider contains definitions for the standard shapes of different
connections. Notches define the shapes of next and previous
connections. And the PuzzleTabs define the shapes of input
and output connections. (These names are based on the shapes provided by
the default renderer.)
Connection shapes based on checks
The constant provider can also define the shapes of connections dynamically
based on their connection check. This is done using the
shapeFor method.
Other various paths
The constant provider also defines paths for other various parts of the block, like jagged edges for collapsed blocks.
Other various values
And finally, the constant provider also defines various values for things like the padding between different elements, or the minimum heights of rows.