Local Coordinates

Almost all points specified in a Shape's Shape Sheet are in Local Coordinates, NOT Page Coordinates.

Therefore, when a shape is moved, rotated, flipped or scaled, all of the Dimension2 data in the shape sheet remains the same, with the exception of Shape.Pin (and also Shape.Start and Shape.End for 1D shapes).

For example, if we have a box of size (20mm, 10mm), then the Geometry section may have points : (0mm,0mm) (20mm,0mm) (20mm,10mm) (0mm,10mm) and back to (0mm,0mm).

No matter where we move this box on the page, the geometry will remain the same. The only thing that will change is Shape's Pin field. The Pin field is relative to the Parent (which is either a Page, or a parent Shape.

If we set Pin to (50mm, 50mm), where are the corners of the box in the Page's coordinate system? That depends on where, within the Shape, the box's Pin refers to. Often we want Pin to refer to the middle of the shape, but not always.

This is where Shape's LocPin comes in. LocPin is the Local version of Pin. So the most common value for LocPin is Size / 2, which means that Pin will refer to the center of the shape.

So, setting Pin to (50mm, 50mm) our box's corners will be at (40mm, 45mm) (60mm, 45mm) (60mm, 55mm) and (40mm, 55mm).

To convert from local to page coordinates we can use the method Shape's method localToPage. There are three other transformations : localToParent, pageToLocal and parentToLocal.

Whenever you are designing a Shape1d, imagine its start point is at (0,0), and the line pointing to the right.

So a simple line's Size will be :

( (Start - End).Length, LineWidth )

To be clear Size.Y will always be LineWidth, no matter where the line is pointing on the page.