[wxruby-users] render natively

[Alex Fenton]

Jim flip wrote:
> I would like to render natively i.e. via a C dll that I have wrapped
> using SWIK.
>
> So I want my c code to receive a buffer that it can render to, and then
> have WXruby display this memory buffer/bitmap.
>   
A drawing context (whether an in-memory buffer, an on-screen canvas, or 
a printout) is represented by a DC [1] instance in wxRuby. MemoryDC is 
the specific class for in-memory buffers.

However the API and class is cross-platform and specific to WxRuby, so 
you're not going to be able to pass this in directly to your dll. You 
don't give a lot of info about the way your API works, but I'd think 
probably the easiest way would be to have your dll render to a ruby 
String in a recognised image format (wxRuby understands PNG, TIF, JPG, 
BMP, TGA) then wrap this in a ruby StringIO object.

Call Wx::Image.read [2] to load this image into an object, then do 
Wx::Bitmap.from_image to convert it to a windows bitmap that can be 
rendered on screen. Lastly, simple draw this onto a window surface using 
its paint method. Have a look at the example in samples/drawing/image.rb 
to see the basics of writing an image to screen.
> Can anyone advise me what would be the best method for doing this, to
> save me having to find out the hard way.
>   
This should probably work, but there's a few other options should this 
not be suitable. Also have a search through the archives as there have 
been a few threads about rendering images from external libraries (eg 
ImageMagick).

cheers
alex


[1] http://wxruby.rubyforge.org/doc/dc.html
[2] http://wxruby.rubyforge.org/doc/image.html#Image_read