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Re: Display origin transforms for DRC reports?



The alternate origins themselves (Place & Drill / Aux origin, and Grid origin) in Pcbnew are stored in the BOARD_DESIGN_SETTINGS class and saved in the board file. Of course, the Page origin location doesn't need to be stored; it's always (0,0).

My initial thought last year was to store the user's choice of display origin in the board file, but after some discussion we reached consensus that the choice of display origin was more like millimeters/inches and thus should be a user option rather than a board property. In the proposed implementation, the user's preference for which origin is used for display is stored in the PCB_DISPLAY_OPTIONS class and saved in the pcbnew.json file. I think a case could be made that this should be saved per-project, but no one has made a good argument for that.

The primary user of the display origin transforms is the UNIT_BINDER class. This class has a pointer to the EDA_DRAW_FRAME object.  Since UNIT_BINDER is common, I added a virtual function "GetOriginTransforms()" to the EDA_DRAW_FRAME class. This function returns a reference to an ORIGIN_TRANSFORMS class. The base implementation of the ORIGIN_TRANSFORMS class contains functions that return their coordinate arguments unchanged. This way none of the KiCad applications see a change in behavior unless they override the GetOriginTransforms() function.

In the case of Pcbnew, the EDA_DRAW_FRAME parameter is actually a pointer to a PCB_BASE_FRAME object. In this class, the GetOriginTransforms() function is overridden and returns a reference to a PCB_ORIGIN_TRANSFORMS object. This object's functions know how to access the BOARD_DESIGN_SETTINGS and PCB_DISPLAY_OPTIONS objects through the PCB_BASE_FRAME object and perform the needed transformations.

This works for everything that can find the EDA_DRAW_FRAME object, like UNIT_BINDER. The GetMsgPanelInfo functions take an EDA_DRAW_FRAME pointer as a parameter, so this isn't a problem. However, the GetSelectMenuText() functions take only an EDA_UNITS parameter. Thus my problem.


On 7/10/20 1:25 PM, Jon Evans wrote:
Shouldn't the origin be stored in the design data (BOARD / SCHEMATIC)
rather than the base frame?

It seems like all data about objects, including their coordinates in
the coordinate space defined by the user, should be available just by
parsing a board or schematic file (which should be independent of the


On Fri, Jul 10, 2020 at 1:18 PM Reece R. Pollack <reece@xxxxxxx> wrote:

Thanks for the follow-up.

I'm finding some of the GetSelectMenuText() implementations format
coordinate addresses for display. That means they need to use display
origin transforms so the displayed coordinate matches what the user sees
on the status line and elsewhere. However, there does not appear to be a
path from these functions to the EDA_BASE_FRAME class where these
transforms are currently available.

Might someone more familiar with the data structures and calling
sequences could suggest how this can best be accomplished?

Seth, I'd appreciate it if you could bring your knowledge and expertise
to bear.


On 7/10/20 6:35 AM, Jeff Young wrote:
No, the DRC re-write won’t affect GetSelectMenuText().  It originated for describing items in the Clarify Selection menu, but it’s now used whenever we want to describe an item to the user.

On 10 Jul 2020, at 00:51, Reece R. Pollack <reece@xxxxxxx> wrote:

On 7/9/20 7:09 PM, Tomasz Wlostowski wrote:
On 10/07/2020 00:58, Reece R. Pollack wrote:
I'm looking at display origin transformations for DRC reports.

With the 5.1.x branch Pcbnew, the DRC report dialog box message texts
contained the Cartesian coordinates of each flagged item. It appears
that the 5.99 branch no longer displays the coordinates of DRC items.
However, the Cartesian coordinates are still listed in the report file.
Unlike the display in a dialog box, this report is persistent and could
be passed to someone using different display origin settings.

   1. Should these coordinates be reported relative to the page origin, or
      transformed per the user-selected origin and axis directions?
   2. If the coordinates are transformed, should the report include the
      user settings?



I wouldn't introduce any changes to the current DRC code, we're
designing a new DRC engine for KiCad V6 and many things in DRC interface
will likely change.

IMHO the DRC coordinate transform belongs to the UI, not the DRC itself:
- the DRC engine generates an internal report with coordinates in board
coordinate space
- whatever displays the report to the user (i.e. the DRC dialog)
converts the board coordinates to UI coordinates.

- my 5 cents


I'm not hard to convince, especially when it means doing less work.

This sounds like the RC_ITEM::ShowCoord function will be removed or replaced. It's one of the two troublesome function groups.

The other troublesome function group is the GetSelectMenuText function. Last year I knew what they did but I've forgotten in the interim. Will this DRC rewrite replace these?


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