Re: Options to cairo driver

[Ben Pfaff]

[adding pspp-dev back, assuming it was just dropped accidentally]

John Darrington <address@hidden> writes:

> On Sat, Dec 17, 2011 at 10:13:30AM -0800, Ben Pfaff wrote:
>
>      I don't understand the problem yet.  If we pass a particular set
>      of options to a driver, then we'll get a particular
>      configuration.  If we need to change one option, then we can do
>      that by updating the set of options slightly (just changing the
>      one value) and then handing the driver the updated set of
>      options.  
>
> This sounds perfectly reasonable.
>
>       The default values should default the same way they did
>      on the first try, right?  
>
> This doesn't sound so good.  I don't want them to default.  I want them
> to remain in their current state.
>
>
> For the current problem, I need a function, to be called in
> psppire-output-window.c (expose_event_callback) which sets the
> font and the foreground colour (perhaps a few other things too)
> but leaves the rest of the options in their current state.
> This doesn't seem possible at the moment without changing code
> in quote a lot of places or by circumventing the interface to
> the cairo xr driver.

So let's use an example, because I still don't see the problem
yet.  Suppose the cairo driver is initially configured as:

        foreground-color: black
        font: Sans
        font-size: 12pt

No background color is specified, so suppose it defaults to
white.  Now something comes along and wants to set the font size
to 10pt.  So we take the original set of options, change the
font-size to 10pt, and hand the updated set of options back to
the driver (using some new "set_options" function I guess).  The
new option set looks like this:

        foreground-color: black
        font: Sans
        font-size: 10pt

No background color is specified now either, so it still defaults
to white.

What's the problem with defaults in this scenario?

Thanks,

Ben.
-- 
Ben Pfaff 
http://benpfaff.org