Let me clarify: you want to make the graphics layer transparent outside the area where an image has been drawn, so that the video layer may be seen through that outside region, but not through the image?
1) set the graphics layer to be above the video layer 2) clear the graphics layer to alpha zero opacity 3) draw the image with alpha set to fully opaque Depending what exactly you require, you might be able to use other ways. For example if you only want to see the graphic image, overlaid on the video, then you could set the graphic layer to the size and position of the image and simply use 'AoverB' alpha blending with alpha of the graphics layer fully opaque. But if you have other drawing on the graphics layer which you want to see through where there is video underneath then you might again use AoverB but now make the video layer the size and position of the desired video. Or something like the brute force recipe I gave above. If your review the section on Mixing on our DirectFB training web site you will find details - there are several ways to achieve the effect you describe, all of which depend on using the various alpha blend and color keying combinations. I suggest in particular you review the section on alpha blending rules and Porter Duff rules, these are the key to the different overlay effects. Chris ================================== Chris Bore Training Director BORES Signal Processing ch...@bores.com www.bores.com +44 (0)1483 740138 ________________________________ From: Pasha <khajapasha...@rediffmail.com> To: Chris Bore <chris_b...@yahoo.co.uk> Cc: Defnet Benjamin <benjamin.r.def...@intel.com> Sent: Tue, 4 January, 2011 14:48:21 Subject: Re: [directfb-users] How to Mix Windows to form a Display Layer Hi Chris, Thanks for Your replay. After getting Graphics layer how can i make apart of the Graphic layer transparent so that when i plotting image on the Graphics layer at specific position, have to view video which playing on video layer from remaining graphic layer part (the space which is not filled by image). Thanks In Advance. -- Regards Pasha. On Tue, 04 Jan 2011 17:17:51 , Chris Bore <chris_b...@yahoo.co.uk> wrote You mix layers by setting their alpha blend and color key properties, and their level in the layer stack. Here is an extract that mixes two layers (one fed by a VideoProvider, the other by an ImageProvider in this example): dfb->GetDisplayLayer( dfb, dfbVideoLayer, &dfbI_VideoLayer); dfbI_VideoLayer->SetCooperativeLevel( dfbI_VideoLayer, DLSCL_EXCLUSIVE); dfbI_VideoLayer->SetLevel(1); dfb->GetDisplayLayer( dfb, dfbGfx0Layer, &dfbI_Gfx0Layer); dfbI_Gfx0Layer->SetCooperativeLevel( dfbI_Gfx0Layer, DLSCL_EXCLUSIVE); dfbI_Gfx0Layer->SetLevel(0); dfbI_VideoLayer->GetSurface( dfbI_VideoLayer, &dfbI_VideoSurface); dfbI_VideoProvider->PlayTo(dfbI_VideoProvider, dfbI_VideoSurface, NULL, NULL, NULL); dfbI_Gfx0Layer->GetSurface( dfbI_Gfx0Layer, &dfbI_Gfx0Surface ); dfbI_ImageProvider->RenderTo(dfbI_ImageProvider, dfbI_Gfx0Surface, NULL, NULL, NULL); The extract does not show the blend and key properties being set. Chris ================================== Chris Bore Training Director BORES Signal Processing ch...@bores.com www.bores.com +44 (0)1483 740138 ________________________________ From: Pasha <khajapasha...@rediffmail.com> To: directfbusers <directfb-users@directfb.org> Cc: Defnet Benjamin <benjamin.r.def...@intel.com> Sent: Tue, 4 January, 2011 5:26:25 Subject: [directfb-users] How to Mix Windows to form a Display Layer Hi All, I am unable to mix two windows to form a DisplayLayer, how can i view window content on the screen. Please let me know how to mix 1. a window with a Displayer, 2. How to mix two Displaylayers.3.How to mix multiple of windows to form a layer. Thanks In Advance.... -- Regards Pasha
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