Re: [GSoC] Impress Remote and Bonjour

Hi Siqi,

On Sat, 2013-07-20 at 11:18 +0200, Siqi Liu wrote:
> What I've wanted to do but failed:
>     1. Draw a point on the running slideshow (like the pen feature),
> based on the "pointer_coordination x y" command. I've tried to find
> out how to do some drawing on the canvas but I didn't really
> understand the code there... not sure if we can add a small red
> rectangle and move that to the position corresponding to the
> "pointer_coordination", for now it just prints out the coordination
> received. 

        Has anyone managed to help you with some code pointers here yet ?
Trying to use the XCanvas for rendering is ... in my experience deeply
problematic. Something as simple as 'draw a rectangle' is ... acutely
non-obvious in my experience ;-)

        In the absence of better advice (and I'm no impress expert) I'd
personally try hooking off the existing 'scribble on slides' code -
which if you right click during a presentation allows you to draw over
the current slide:

        git grep -10 CM_PEN_MODE

        This disappears into a set of UNO properties set on the slideshow code
eg.

            // for Pen Mode
            beans::PropertyValue aPenPropSwitchPenMode;
            aPenPropSwitchPenMode.Name = "SwitchPenMode";
            aPenPropSwitchPenMode.Value <<= sal_True;
            mxShow->setProperty( aPenPropSwitchPenMode );

        Which lives in slideshow/

source/engine/slideshowimpl.cxx:    if ( rProperty.Name == "SwitchPenMode" )
source/engine/slideshowimpl.cxx-    {
source/engine/slideshowimpl.cxx:        bool nSwitchPenMode(false);
source/engine/slideshowimpl.cxx:        if (rProperty.Value >>= nSwitchPenMode)
source/engine/slideshowimpl.cxx-        {

        Presumably the mouse event code there goes down a different path that
builds out some goodness to render on top of the slides in this mode
that we could hook / use a different event for.

        Does that make sense ?

        Personally I'd be inclined to load a bitmap that has a nice central
point & alpha pattern around it and composite it on top and let the
artists go wild with that :-)

        Hope that's helpful, Thorsten is really the expert here :-)

        ATB,

                Michael.

-- 
michael.meeks@suse.com  <><, Pseudo Engineer, itinerant idiot