Ben
Tue Jun 12 00:07:37 CDT 2007
I'm glad it helped. If custom draw worked properly in children but not the
panel itself, then the panel's WM_PAINT must clip to the visible area
instead of using the clipping region you gave it. Does your OnPaint do
anything like that? That part about having to call OnPaint yourself seems
to be the most hacky part of this, and still not too bad. WM_PRINT is
definitely intended for this purpose.
"she_prog" <puffy_chris@yahoo.com> wrote in message
news:1181512107.859587.152170@m36g2000hse.googlegroups.com...
You're great, Ben, thank you very much! I did play with flags and all,
but here I'm displaying the code that's working for me for every case
- it might help someone sometime in the future :)
[DllImport("user32.dll")]
public static extern int SendMessage(
IntPtr hWnd, // handle to destination window
int Msg, // message
int wParam, // first message parameter
int lParam // second message parameter
);
const int WM_PRINT = 0x317;
[Flags]
enum DrawingOptions
{
PRF_CHECKVISIBLE = 0x01,
PRF_NONCLIENT = 0x02,
PRF_CLIENT = 0x04,
PRF_ERASEBKGND = 0x08,
PRF_CHILDREN = 0x10,
PRF_OWNED = 0x20
}
private void command_Click(object sender, EventArgs e)
{
// get filename
c_panel.AutoScrollPosition = new Point(0, 0);
Bitmap l_bmpPanel = new
Bitmap(c_panel.DisplayRectangle.Width,
c_panel.DisplayRectangle.Height);
Graphics l_grpSrc = Graphics.FromImage(l_bmpPanel);
c_panel.ForcePaint(new PaintEventArgs(l_grpSrc,
c_panel.DisplayRectangle));
SendMessage(c_panel.Handle, WM_PRINT,
(int)l_grpSrc.GetHdc(), (int)(DrawingOptions.PRF_OWNED |
DrawingOptions.PRF_CHILDREN | DrawingOptions.PRF_CLIENT |
DrawingOptions.PRF_NONCLIENT));
l_grpSrc.ReleaseHdc();
l_bmpPanel.Save(filename);
}
I had to set AutoScrollPosition to (0,0), but I don't think it's
against the user-friendliness of the application.
ForcePaint is simple:
public void ForcePaint(PaintEventArgs pe)
{
OnPaint(pe);
}
It's only needed because I have some custom painting in this OnPaint
and that was only drawn in the visible area of the panel, I don't
really know why. All children have custom painting as well, and those
drawings are done both on visible and invisible area. Although I don't
think it's elegant programming, I couldn't think of any other
solution.
So thank you again for the help, Ben!
Regards, Chris
Ben Voigt [C++ MVP] írta:
> Did you Dispose the Graphics object before trying to use the Bitmap?
>
> "she_prog" <puffy_chris@yahoo.com> wrote in message
> news:1181425407.830351.320850@k79g2000hse.googlegroups.com...
> Great, now I can see stepping through OnPaint when debugging. Still,
> the resulted Bitmap is all blank :(
> Right after SendMessage I'm calling l_bmp.Save(filename); so there's
> no code overdrawing the result of SendMessage. The same OnPaint draws
> the panel and its children just fine onto the screen.
> Right now I'm just testing without scrollbars, so that shouldn't cause
> the problem. I might try to do a small sample application to try to
> narrow down the cause.
>
> Thank you very much for the help! If you could think of anything that
> could cause the problem, please let me know!
> Regards,
> Chris
>
> Ben Voigt [C++ MVP] írta:
> > You should also use the CLIENT and CHILDREN flags (OR-ed together), to
> > get
> > the content of the window and all contained windows.
> >
> >
> > "she_prog" <puffy_chris@yahoo.com> wrote in message
> > news:1181418208.451963.154800@c77g2000hse.googlegroups.com...
> > Thank you very much, Ben!
> > I tried your solution, but it didn't work for me. Maybe the problem is
> > that I'm trying to save a class of my own, derived from Panel and
> > OnPaint method is overriden in this new class. When trying to debug,
> > OnPaint is not called as a result of SendMessage. Here's my code:
> >
> > [DllImport("user32.dll")]
> > public static extern int SendMessage(
> > IntPtr hWnd, // handle to destination window
> > int Msg, // message
> > int wParam, // first message parameter
> > int lParam // second message parameter
> > );
> >
> > const int WM_PRINT = 0x317;
> >
> > [Flags]
> > enum DrawingOptions
> > {
> > PRF_CHECKVISIBLE = 0x01,
> > PRF_NONCLIENT = 0x02,
> > PRF_CLIENT = 0x04,
> > PRF_ERASEBKGND = 0x08,
> > PRF_CHILDREN = 0x10,
> > PRF_OWNED = 0x20
> > }
> >
> > ...
> > Bitmap l_bmp = new Bitmap(c_panel.Width, c_panel.Height);
> > Graphics l_grp = Graphics.FromImage(l_bmp);
> > IntPtr hdc = l_grp.GetHdc();
> > SendMessage(c_panel.Handle, WM_PRINT, (int)hdc,
> > (int)DrawingOptions.PRF_OWNED);
> >
> > Could you please advice further?
> > Regards,
> > Chris
> >
> > Ben Voigt [C++ MVP] írta:
> > > "she_prog" <puffy_chris@yahoo.com> wrote in message
> > > news:1181411906.558071.296830@m36g2000hse.googlegroups.com...
> > > > Dear All,
> > > >
> > > > I need to save the content of a panel to a bitmap. The panel can
> > > > have
> > > > many child controls which also need to be saved. The problem would
> > > > be
> > > > solved if I could have the panel saved to a Graphics object, which
> > > > is
> > > > the same as if I'd need to print it. It'd be easy using
> > > > Control.DrawToBitmap, but I also need the invisible part of the
> > > > panel
> > > > (which is hidden because of scrolling) and DrawToBitmap just takes a
> > > > screenshot.
> > > >
> > > > I've been reading about this. Many samples uses BitBlt, but that
> > > > also
> > > > skips the invisible part. I've also seen some posts stating that
> > > > this
> > > > is not a simple thing and I'd need to programatically scroll to all
> > > > needed position and combine the screenshots taken from all the
> > > > scroll-
> > > > positions. These posts were from 2003 or 2004.
> > > >
> > > > So my question: Is there any new solutions provided by VS2005? Or do
> > > > I
> > > No, there aren't. However, Windows has always had a solution for
> > > this:
> > > WM_PRINT.
> > >
> > > Try creating a bitmap of the app