kicad-developers team mailing list archive

[Johannes Pfister <johannes.pfister@xxxxxxxxxxx>]

What about changing the plotter and page_info classes to metric? Like
changing GetSizeMils() to GetSizeUM(), m_IUsPerDecimil to m_nmPerIU
and MIN_PAGE_SIZE to MIN_PAGE_SIZE_UM? I say um because it is the
largest IU (PL-editor) and m_nmPerIU could be an integer (AFAIK). That
would make everything metric, avoid rounding errors for pages and pen
sizes that are on a grid of 1 um or 10 mil, and it would avoid
calculating the conversations factor to convert from metric to
non-metric, only to then convert the conversations factor back to
convert metric to metric, like it is done when starting a gerber plot.
It would not limit maximum page sizes to a lower limit.
Would you accept and welcome this or do you think this is a bad or useless idea?

Johannes

Am Do., 13. Feb. 2020 um 14:46 Uhr schrieb Wayne Stambaugh
<stambaughw@xxxxxxxxx>:
>
> Hi Johannes,
>
> Thank you for your suggestion but the internal units for each format
> were chosen for a specific reason.  There really is no justifiable
> reason to change them as they have been carefully selected based on the
> requirements of the objects they represent.  Conversion code is provided
> for each internal unit so plotting to standard units such as
> millimeters, inches, etc is trivial.  I'm not opposed to adding support
> for changing the plot units.  I am opposed to changing the internal units.
>
> Cheers,
>
> Wayne
>
> On 2/13/20 9:32 AM, Johannes Pfister wrote:
> > The KiCAD code uses all kinds of different units for distances.
> > Amongst other things I found:
> >   nm: pcbnew internal units
> >   10nm: Gerbview internal units
> >   100nm EEschema internal units
> >   1um: PL-Editor internal units
> >   0.1mil (2.54um): SetViewport
> >   1mil (25.4 um): WS_DRAW_ITEM_BASE and GetSizeMils
> > And the native File formats use mm (pcbnew) and mil (EEschema).
> > Something like SVG exports in 0.1 mil steps. I think that this is not
> > very consistent and something like a PLOTTER class needs to handle
> > different IU-sizes.
> >
> > My idea is to rewrite the internal units so that nm are used
> > everywhere inside the source code, and only parts that write or read
> > files and display data to or read data from the user should convert it
> > to another unit system. I don't want to change any file formats.
> > That would make it a bit more straightforward, more consistent, metric
> > and an SVG-Plotter would use a metric step size. The disadvantage
> > would be that there would be an about 2m or 4m limit in every
> > direction, assuming int is 32 bit, which is AFAIK true for all
> > platforms KiCAD current supports.
> >
> > Before i rewrite code, can you say what you guys think about it?
> >
> >
> > Johannes Pfister
> >
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