Traditional origami folds are basically lines in diagrams. Therefore, Doodle folds are edges defined between two vertices. In fact, folds have been understood in Doodle context as the line defining an Origami fold. It is important to keep in mind that Doodle doesn't compute any origami fold, in sense of computing new paper layers position after a fold. Doodle remains a graphical tool, it can be seen as a geometrical and graphical assistant for a diagrammer. In the rest of this document, fold can be interpreted as the line which defines an Origami fold, a paper border, an existing fold or a xray line (hidden fold line). Here is the exhaustive Doodle line style list:
Once a fold line is defined by a fold operator of the language (cf. §
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) an edge is added to the edge internal data
structure. This operation can only be made inside a step block meaning
that the new fold is applied on this particular step. As we have seen
in a previous section edge, database is global and edges are still
present for next steps. Thus, the problem is what kind of line a
particular fold should become in further steps. Indeed once a valley
fold has been defined, the fold still exists physically but in an
Origami diagramming sense its dashed style has to be changed to a
permanent style like border or existing fold (crease). The choice done
to issue this problem is that each fold line takes the existing fold
style at the end of the step in which it has been created. This
implicit mechanism can be overridden if it leads to an unexpected
result. In this case the line style of the fold can be explicitly
specified with one of the line operators.