gianpieroriva
Programmer
Hi everybody!
How can I implement an MDI application with the child windows semitransparent?
Ok, I’m going to explain myself better...
I have implement an MDI application under MFC.
Briefly I have to make my application to do what you can see at:
There you can find a screen shot of my application. How you can observe there are two child windows (in this example, but in general there could be more) displaying each one a bitmap. For each child window the user can set a transparency value (an alpha value) so that, putting that window on another he can compare the two images (medical interest). Obviously what you see in the screen shot is a fake example (otherwise I would not be here
: in this example the “sunset” bitmap has a 70% of opacity and the “bmw” bitmap has 100% o opacity; as you can see the “sunset” window is focused and lays above the “bmw” window. I made this fake example first sizing and positioning the two windows, then I minimized them and I restore the “bmw” window first and then the “sunset” window. But, if I move the windows they not repaint themselves properly. In fact I had subclassed the OnEraseBkgnd and the OnPaint of my child windows and then I had used the AlphaBlend method to paint the bitmap (I’ll have to subclass also the OnMove when a child window hasn’t 100% opacity value). The problem is that on moving, sizing and so on, before repainting with the AlphaBlend method I need to repaint what lays under the focused child windows that is moving, sizing and so on. This means that I had to repaint the parent window (the MDI container) and eventually the sibling windows (the other MDI children) in the moving child client area...
But I don’t know how to do this!
Is there anybody able to help me?
Thank You in advance for all Your answers!
Gianpiero Riva
How can I implement an MDI application with the child windows semitransparent?
Ok, I’m going to explain myself better...
I have implement an MDI application under MFC.
Briefly I have to make my application to do what you can see at:
There you can find a screen shot of my application. How you can observe there are two child windows (in this example, but in general there could be more) displaying each one a bitmap. For each child window the user can set a transparency value (an alpha value) so that, putting that window on another he can compare the two images (medical interest). Obviously what you see in the screen shot is a fake example (otherwise I would not be here
: in this example the “sunset” bitmap has a 70% of opacity and the “bmw” bitmap has 100% o opacity; as you can see the “sunset” window is focused and lays above the “bmw” window. I made this fake example first sizing and positioning the two windows, then I minimized them and I restore the “bmw” window first and then the “sunset” window. But, if I move the windows they not repaint themselves properly. In fact I had subclassed the OnEraseBkgnd and the OnPaint of my child windows and then I had used the AlphaBlend method to paint the bitmap (I’ll have to subclass also the OnMove when a child window hasn’t 100% opacity value). The problem is that on moving, sizing and so on, before repainting with the AlphaBlend method I need to repaint what lays under the focused child windows that is moving, sizing and so on. This means that I had to repaint the parent window (the MDI container) and eventually the sibling windows (the other MDI children) in the moving child client area...But I don’t know how to do this!
Is there anybody able to help me?
Thank You in advance for all Your answers!
Gianpiero Riva