Drawing Over A Bitmap?

[hatflyer]

I have a graph that displays varying bars, depending on the user input. The base of the graph (the axes, labels) are always the same. Is it possible to load an icon of the base graph, and then draw over it?

Thanks,

Jim

[indiocolifa]

yes, but load an "icon"???

preferably, load a Bitmap (or more specifically, create a bitmap surface on RAM, load your image, "paste" on the surface and draw the other things you want to superimpose...)

[hatflyer]

Thanks for the reply.

I'm not sure what you mean by the surface of RAM and pasting on the surface. Is this different than doing a standard load bitmap?

Thanks,

JIm

[indiocolifa]

surface, in terms of "directdraw surfaces"... device contexts, in terms of GDI, or Graphics object in the GDI+ world.

But, the bitmap loading is standard of course.

[hatflyer]

I think I tried it and it did not work.

I have a bitmap that is displayed. It was loaded automatically (I placed it using the resource view).

To draw over it, this is what I did in OnPaint():

CPaintDC dc(this); // device context for painting
//...create points

dc.MoveTo(ArrowStart.x,ArrowEnd.y);
dc.LineTo(ArrowEnd);

The line disappears when it gets to the bitmap.

Is it a matter of which gets placed on top of the other?

JIm

[indiocolifa]

yes, check how the lines are superimposing on the bitmap.

Maybe you need to set SetROP2 to an appropiate value.
check out setrop2 function in MSDN.