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# pcb-rnd - routing style fixes

## Number of styles

In the original code there are a compile-time fixed number (4) of routing styles. This is often not enough for more complex designs. While in theory this limit can be raised, the resulting .pcb files will be incompatible with pcb compilations using a different number of styles.

Pcb-rnd uses a dynamic vector for storing styles and allows any number of styles from 0 up to a very large value (2^31-1). There is no compile-time configurable limit. The number of default styles (and the actual style configuration) is coming from the template pcb file.

Creating a new style in the Route Styles dialog is not "for this session only" anymore - styles are saved with the design.

## Explicit custom style

Pcb had 4 explicit styles and a hidden, implicit style. All drawing action uses the hidden style. When the user selects one of the explicit styles, its properties are copied into the implicit style. Any drawing action uses the implicit style, this it's sort of the "pen style".

In mainline PCB the implicit (or pen) style is hidden. As long as it always matches one of the existing styles, the user doesn't even know about it. However, if there are objects that do not conform to any of the existing styles, it is possible to bump into this. For example:

- draw a line using one of the existing styles
- increase the width (with the 's' key) a few times - now the style of the line does not match any of the existing styles
- use the SetSame() action over the line (hover the pointer over the line and press 'a') - it will try to set the style that corresponds to the line
- since no style matches the line's, the radio button gets deselected - that's good
- now click on the Route Style button - it will show the properties of the last selected route style, even tho it is not selected at the moment

In contrast, pcb-rnd offers an explicit routing style called <custom>. If SetSame() is invoked on an object that doesn't match any of the existing styles, the <custom> style is selected:

- no style marked on the radio button (just like in mainline)
- the Route Style button opens with the <custom> style, with the values picked up from the object by SetSame
- the user can change the values, which will affect the implicit pen style
- this means the user can draw with the new settings, without having to create a permanent style

In other words, it is now possible to use the implicit pen style as temporal style, to explicitly set a line width, via diameter before placing a few unusual lines or vias, without having to create a new style. It is also possible to pick up the style of such an unusual object later, without the GUI confusing it with any of the existing styles.

## SetSame() bugs fixed

A line does not have drill parameters. When mainline tries to pick up object properties for a line, it will pick thickness and clearance but will leave hole and ring diameters unchanged. This very often results in a mixed style: e.g. "signal" line properties picked up from a line while "power" hole/ring properties left over from the current style selection. Such a mixed pickup will result in the GUI get confused and not selecting any of the styles. The expected behaviour is to select the "signal" style if the line width/clearance matches the parameters of that style, and ignore the drill/ring parameters.

The same mixup happens for picking up arc parameters, and a similar mixup for via parameters (a via doesn't have a line width).

Pcb-rnd fixes this by searching for the matching style using only the parameters that the given object really had. This results in valid style selection the way the user may expect.

## save/load and compatibility

Saving a design with number of styles not equal to 4 may cause problems when loading with mainline. The rest of these features do not affect compatibility.

## plans

No plans - these features are fully implemented.