Re: Default Plot Characteristics, was Re: [OctDev] zplane.m marker size

[Shai Ayal]

On Tue, Nov 17, 2009 at 6:14 AM, Daniel J Sebald <address@hidden> wrote:
> Simon Schwarz wrote:
>>
>> In the version of zplane.m the marker size was set explicitly to 2 I
>> just changed this value to 12 and added a parameter for it.
>>
>> I just tried to remove the markersize code - it works also. The markers
>> are tiny but bigger than before.
>
> That's odd.  Perhaps a marker size of 2 is some legacy code not updated to
> fit the new Octave graphics scheme.  I just tried
> id = plot(1:10, 'ro')
> get(id)
>
> and found a marker size of 6.  I can't find exactly where the default
> properties are set searching through the Octave source.

the defaults for properties are set in src/graphics.h.in. search for
markersize inside this file and you'll find it.

> Anyone on the maintainers list familiar with graphics, should scripts be
> setting any absolute sizes anymore?  Or just relative (e.g., divide by 2,
> multiply by 3)?
I'm not sure where the default came from, and also I'm not sure that
marker size is consistent across backends. for the open-gl based
backends (currently fltk) markersize is in points (i.e. 1/72 inch),
assuming 72dpi for the screen.
There still remains some work to be done ...

>
> Perhaps.  However, if a plot is the main result of the zplane() command, the
> output of the plot command could be returned as the output of zplane().
>  Then one would have access to all the plot properties, not just marker
> size.  One could use gcf() just as easily too.
>
>  zplane();
>  id = gcf();
>  set(id, 'markersize', 1234)
This would not work -- markersize is a property of the line object,
not the figure object, so you would have to get the handle of the line
object into id

Shai