How to manually draw to a transparent dialog

Thanks matonga... I really appreciate all your help. You've been more than helpful.

When you told me about multiple PNG's (which is what I really need to do) by you mean that I should create a Gdiplus::Bitmap which size is the sum of all bitmaps needed, then render the independent bitmaps to that one using maybe Gdiplus::Grpahics and then that resulting bitmap will be passed to the GetAlphaChannelBitmap function I created in the sample code?

Or should I do that with the HBITMAPS? The situation here is that some of these bitmaps should be "stretched" (for covering the borders), when using Gdipus::Graphics.DrawImage the bitmap was streched accordingly to "cover" the designated area... but I am not sure that if I do this the bitmap created that will be passed to GetAlphaChannelBitmap would already have lost the alphachannel information.

Anyway... you have been such a great coder pal! Thanks.

BTW: (Off-topic) I just love alfajores!!! Specially the ones filled with dulce de leche (milk candy)!

Edit: I tried to create the combined bitmap as I proposed before but found that the composed bitmap do losses the alphachannel information... the window is correctly shown but all alphachanned data is shown as opaque... how could I combine the HBITMAPS?

#516772

That's because winuser.h includes the following definition:

[SIZE=2][COLOR=#0000ff][SIZE=2][COLOR=#0000ff]#if[/COLOR][/SIZE][/COLOR][/SIZE][SIZE=2](_WIN32_WINNT >= 0x0500)[/SIZE]
[SIZE=2][COLOR=#0000ff][SIZE=2][COLOR=#0000ff]#define[/COLOR][/SIZE][/COLOR][/SIZE][SIZE=2] WS_EX_LAYERED 0x00080000[/SIZE]
[SIZE=2][COLOR=#0000ff][SIZE=2][COLOR=#0000ff]#endif[/COLOR][/SIZE][/COLOR][/SIZE][SIZE=2][COLOR=#008000][SIZE=2][COLOR=#008000]/* _WIN32_WINNT >= 0x0500 */[/COLOR][/SIZE]
[/COLOR][/SIZE]

Hi, yes I had to add the #define in StdAfx.h... don't know why.

Originally I compiled this with Visual Stuido 2008, which C++ compiler I believe defines that for a value grater than 0x0500... but Visual Stuido's 2005 C++ compiler does not. I think they were preventing to use that style in pre-win 2000 platforms... so VisualStudio 2008 by default assumes that nobody is going to code against something that old!

#516774

To not loose alpha channel information change the compositing mode to CompositingModeSourceCopy.

GpGraphics->SetCompositingMode (CompositingModeSourceCopy);

Then blit all the PNGs to the GpBitmap as usual.

Then just pass the GpBitmap to GetAlphaChannelBitmap and UpdateDialog as usual

Alfajores!!! They're here in every drugstore, mostly in two variants: black and white chocolate. All of them with dulce de leche

#516787

Yes! That was it! It was just a single line needed:

GpGraphics->SetCompositingMode (CompositingModeSourceCopy);

and voila! The comic strip is on it's way!

Thanks so much... I now will review your other comments... specially the tip for laying out child controls.

There's so much I would like to do next, like adding some kind of animation to show the strip comming out of the docklet... but, hey! thanks... I really, really aprreciate your help.

Alfajores... yes! I think I will go some argentinian specialty store and get a couple! A tu salud!

#516803