OpenEuphoria

Re: WebCam with wxEuphoria

• Posted by raseunew Mar 27, 2011
• 1355 views

I have been able to successfully map from an SDL image buffer
to a wxWidgets buffer and display images.

See below for code snippets.

wxWidgets requires images to be in BGR format, where
the list of bytes is a single sequence buffer.

so, an image buffer of

image = {{{R,G,B},{R,G,B},{R,G,B},{R,G,B}},  
         {{R,G,B},{R,G,B},{R,G,B},{R,G,B}},  
         {{R,G,B},{R,G,B},{R,G,B},{R,G,B}}} 

would need to be 'flattened'. I think eu4 standard library
has a flatten() function

if your opencv image is RGB it will
need to be converted.

 
--// Convert SDL surface from RGB to BGR 
public enum 
		ofsRED   = 1, 
		ofsGREEN, 
		ofsBLUE, 
		ofsALPHA 
 
public function RGBtoBGR(sequence rgbbuf, integer bytesPerPixel=3) 
	--// swap B with R 
	sequence bgrbuf = {} 
	sequence rgb    = {} 
	integer  l = length(rgbbuf) 
	for i = 1 to l by bytesPerPixel do 
		rgb = rgbbuf[i..(i + (bytesPerPixel - 1))] 
		bgrbuf &= { rgb[ofsBLUE], rgb[ofsGREEN], rgb[ofsRED] } 
	end for 
	--// return buffer 
	atom bgr = allocate(length( rgbbuf )) 
	poke(bgr, bgrbuf) 
	return bgr 
end function 
 

something similar to the following will display
a BGR buffer to a wxWidgets DC.

--// convert sdl surface into wx compatible buffer 
-- atom bgr = RGBtoBGR(sdlcanvas, 3) 
 
/* 

    you would probably need to flatten your image  
    here and create your bgr surface 
*/ 
 
atom bgr = RGBtoBGR( flatten(openCVImage), 3)     
 
--// create image from converted bgr surface 
atom img = wx:create(wxImage, { openCVImageWidth, openCVImageHeight, bgr }) 
--// free converted bgr surface 
free(bgr) 
 
--// create bitmap from image 
atom bmp = wx:create(wxBitmap,{ BM_FROM_IMAGE, img, -1 }) 
 
--// update client DC 
atom clientDC = wx:create(wxClientDC, this) 
wx:begin_drawing(clientDC) 
wx:draw_bitmap(clientDC, bmp, 0, 0, true) 
wx:end_drawing(clientDC) 
 
--// clean up 
wx:delete_instance(clientDC) 
wx:delete_instance(bmp) 
wx:delete_instance(img) 
 

HTH