Use Some Annotation for visible (and clickable) objects on screen In this case Component is a dummy used only to provide expected H & V

this filed contains transient information that alters the appearance of the symbol

 What this symbol draws in place of a number, on an ARRAY COMPONENT's sheet.

   - a Join out or Join in: the channel-number EXPRESSION, so a carry chain reads
     `Join[i+1]` against `Join[i]` rather than `Join[1]` against `Join[0]`, which is
     copy 0's answer and says nothing about which copy feeds which.
   - an Output: the sheet's loop variable, so its label reads `SUM.i` - the sheet
     gets one SUM port per copy, and this is the one belonging to copy i.

 **Display only, and transient.** Nothing may read it for semantics: what a join is
 really on is its parameter slot, which lives on the LoadedComponent. That is what
 makes it safe for a missed update to be a stale legend rather than a wrong circuit.
 Derived by SymbolUpdate.syncArrayText from the sheet's own slots and array settings,
 which is the one place that writes it.

 Not saved: SymbolInfo is the part of a Symbol that persists, and this is not in it.
 It is rebuilt whenever the sheet it belongs to is loaded.

Initial coordinates of the symbol's centre when ScaleButton is pressed

This is the electrical component. When the component is loaded into draw block the position is kept as Pos field in symbol However H & W remain important, as the height and width of the symbol. This is anomalous. It would make sure sense for all geometric info to be in fields on the symbol. However X,Y,H,W are used (to some extent) in non-draw-block Issie code. NB HScale, VScale modify V, H The symbol's component, at the values it is drawn AND saved at. Parameter values are resolved into it by ParameterAnalysis.propagateParameterValues before it gets here, so there is one set of values rather than a displayed set over a stored one.

HScale & VScale modify default W (width) and H (height) respectively if not None. They are changed by symbol property box. Horizontal symbol dimension = HScale*W etc They are currently used only on Custom Components and will not work on other omponents.

This, for convenience, is a copy of the component Id string, used as Id for symbol Thus symbol Id = component Id. It is unique within one design sheet.

Width of the wires connected to input ports 0 & 1 This is needed on the symbol only for bus splitter and bus merge symbols These display the bit numbers of their connections. wire widths are calulated by width inference so these values are transient and need not be stored.

for MergeN later

determines whetehr the symbol or its contents (it it is a custom component) contain any clo9cked logic. used to display a clokc symbol

the following fields define the position and size of the component label. labels will rotate when the symbol is rotated. labels can be manually adjusted, if not position is as default (for given rotation)

transient field to show if ports are being dragged in teh UI.

Option to represent a port that is being moved, if it's some, it contains the moving port's Id and its current position. dynamic info used in port move operation.

dynamic info used in port move operation

symbol's centre to the selected components' boundingBox centre when ScaleButton is pressed

These maps contain the order (on and edge), and the symbol edge, of each port. Edge positions are known from the component XYPos and H (height), W (width). Ports are located as fixed equidistant positions along each component edge dependent on number of ports. Therefore port position can be calculated from these maps and XYPos, H, W.

Coordinates of the symbol's top left corner on component save/restore this is also X,Y on Component type.

determines whether symbol is rorated (in 90 degree increments) or flipped (reflected).

HScale & VScale modify W and H respectively if not None. Vertical symbol dimension = VScale*H etc They are currently used only on Custom Components and will not work on other omponents.