OpenEuphoria

2. Re: How to write graphics to MS Windows clipboard

• Posted by Andrew Katz <Akatz712 at gmail.com> May 15, 2007
• 716 views

Andrew Katz wrote:
> 
> Does win32Lib support the writing of graphics to MS Windows clipboard?
> 
> In the documentation, I saw some functions dealing with DIBs, and I saw some
> functions dealing with text to the clipboard.
> 
> I am looking for a way for my program, which generates graphics, to copy it
> so that Paint can paste it.
> 
> Andy Katz
> 
> B.S. Computer Science, 1978
> Rensselaer Polytechnic Institute (RPI)

4. Re: How to write graphics to MS Windows clipboard

• Posted by CChris <christian.cuvier at agriculture.gouv.fr> May 15, 2007
• 740 views

Andrew Katz wrote:
> 
> Does win32Lib support the writing of graphics to MS Windows clipboard?
> 
> In the documentation, I saw some functions dealing with DIBs, and I saw some
> functions dealing with text to the clipboard.
> 
> I am looking for a way for my program, which generates graphics, to copy it
> so that Paint can paste it.
> 
> Andy Katz
> 
> B.S. Computer Science, 1978
> Rensselaer Polytechnic Institute (RPI)

I assume your graphics are displayed on some window.

include win32lib.ew
--  first a simplified version of Guillermo's code
constant
cOpenClipboard      =
    define_c_func(user32,"OpenClipboard",{C_POINTER},C_INT),
    cCloseClipboard     = define_c_func(user32,"CloseClipboard",{},C_INT),
    cEmptyClipboard     = define_c_func(user32,"EmptyClipboard",{},C_INT),
cSetClipboardData   =
    define_c_func(user32,"SetClipboardData",{C_UINT,C_POINTER},C_POINTER),
xGetWindowDC        =
    define_c_func(user32,"GetWindowDC",{C_POINTER},C_POINTER)


-- hBmp must be a bitmap handle

integer void
global procedure bmpToClipboard(atom hBmp)
        if not c_func(cOpenClipboard, {NULL}) then
void=message_box("Failed to open
            clipboard.","Error",MB_ICONERROR+MB_OK)
            return
	end if
        -- current thread now has exclusive access to clipboard
	c_proc(cEmptyClipboard,{})
	if c_func(cSetClipboardData,{CF_BITMAP,hBmp}) != hBmp then
void=message_box("Failed to copy bitmap to
clipboard.","Error",MB_ICONERROR+MB_OK)
	end if
	c_proc(cCloseClipboard,{})
end procedure

global procedure captureToClipboard(integer id,integer x,integer y,integer
cx,integer cy,integer client)
-- id is the surce window; copy rectangle at {x,y}, cx pixel wide and cy poxel
high
-- if client is true, x and y are client coordinates, else absolute window
coordinates
atom hDC,hMemDC,hOldBmp,hBmp,hWnd
-- where's the pic?
hWnd=getHandle(id)
if client then
    hDC=getDC(id)
else
    hDC=c_func(xGetWindowDC,{hWnd})
end if
        if not hDC then
            void=message_box("Not a valid window.","Error",MB_ICONERROR+MB_OK)
            return
        end if
-- create a memory target DC
hMemDC=w32Func(xCreateCompatiblzDC,{hDC})
        if not hMemDC then
void=message_box("Failed to create temporary
            bitmap.","Error",MB_ICONERROR+MB_OK)
            return
        end if
-- create the bitmap we'll send to clipboard, with supplied dimensions.
-- It will be written to using hMemDC.
hBmp=w32Func(xCreateCompatibleBitmap,{hMemDC,cx,cy})
        if not hBmp then
void=message_box("Failed to create temporary
            bitmap.","Error",MB_ICONERROR+MB_OK)
            return
        end if
-- use hMemDC o write to it.
hOldBmp=w32Func(xSelectObject,{hMemDC,hBmp})
-- now copy source rectangle to it
bitBlt(hMemDC,0,0,hDC,x,y,cx,cy,SrcCopy)
-- deselect the bitmap so as to own it
hBmp=w32Func(xSelectObject,{hMemDC,hOldBmp})
-- send bitmap to clipboard
bmpToClipBoard(id,hBmp)
-- now we no longer own it
-- clean up
deleteObject(hOldBmp)
hMemDC=w32Func(xDeleteDC,{hMemDC})
hDC=w32Func(xReleaseDC,{hWnd,hDC})
end procedure

Didn't test it; part of cleanup may be redundant.

CChris

6. Re: How to write graphics to MS Windows clipboard

• Posted by Andrew Katz <Akatz712 at gmail.com> May 16, 2007
• 740 views

Andrew Katz wrote:
> 
> CChris wrote:
> > 
> 
> > I assume your graphics are displayed on some window.
> > 
> > Didn't test it; part of cleanup may be redundant.
> > 
> > CChris
> 
> 
> }}}
<eucode>
> -- from my global code:
> constant ptx = 1
> constant pty = 2
> --
> 
> atom hDC,hMemDC,hOldBmp,hBmp
> atom void
> sequence DRAWINsize
> 
> -- place my child window control DRAWIN in clipboard
> 
> hDC=getDC(DRAWIN)
> -- create a memory target DC
> hMemDC=w32Func(xCreateCompatibleDC,{hDC})
> if not hMemDC then
> 	void=message_box("Failed to create temporary
> bitmap.","Error",MB_ICONERROR+MB_OK)
> else
> -- create the bitmap we'll send to clipboard, with supplied dimensions.
> -- It will be written to using hMemDC.
> DRAWINsize = getCtlSize(DRAWIN)
> -- Wrong:
> hBmp=w32Func(xCreateCompatibleBitmap,{hMemDC,DRAWINsize[ptx],DRAWINsize[pty]})
hBmp=w32Func(xCreateCompatibleBitmap,{hDC,DRAWINsize[ptx],DRAWINsize[pty]})
> if not hBmp then
> 	void=message_box("Failed to create temporary
> bitmap.","Error",MB_ICONERROR+MB_OK)
> else
> -- use hMemDC o write to it.
> hOldBmp=w32Func(xSelectObject,{hMemDC,hBmp})
> -- now copy source rectangle to it
> void=w32Func( xBitBlt, {hMemDC, 0, 0, DRAWINsize[ptx], DRAWINsize[pty], hDC,
> 0, 0, SrcCopy} )
> -- send bitmap to clipboard
> if not w32Func(xOpenClipboard, {NULL}) then
> 	void=message_box("Failed to open clipboard.","Error",MB_ICONERROR+MB_OK)
> else
> -- current thread now has exclusive access to clipboard
> void=w32Func(xEmptyClipboard,{})
> if w32Func(xSetClipboardData,{CF_BITMAP,hBmp}) != hBmp then
> 	void=message_box("Failed to copy bitmap to
> clipboard.","Error",MB_ICONERROR+MB_OK)
> end if
> w32Proc(xCloseClipboard,{})
> 
> -- now we no longer own it
> -- clean up
> -- releaseDC(hMemDC) Not sure how to clean up
> -- deselect the bitmap so as to own it
> hBmp=w32Func(xSelectObject,{hMemDC,hOldBmp})
> releaseDC(DRAWIN)
> end if
> end if
> end if
> </eucode>
{{{

> 
> I have made many small changes to CChris's code and tested it. And I have
> managed
> to get the drawing into Paint with Paste. Except that it only has 2 colors -
> white or black - and any color is being seen as black. So, where do we go from
> here?
> 

I found the problem:



B.S. Computer Science, 1978
Rensselaer Polytechnic Institute (RPI)

8. Re: How to write graphics to MS Windows clipboard

• Posted by CChris <christian.cuvier at agriculture.gouv.fr> May 16, 2007
• 703 views

Andrew Katz wrote:
> 
> Andrew Katz wrote:
> > 
> > CChris wrote:
> > > 
> > 
> > > I assume your graphics are displayed on some window.
> > > 

A way nicer version using a Pixmap:

include win32lib.ew

integer void
global procedure bmpToClipboard(atom hBmp) 
-- hBmp must be a bitmap handle
    if not w32Func(xOpenClipboard, {NULL}) then
        void=message_box("Failed to open clipboard.","Error",MB_ICONERROR+MB_OK)
        return
	end if
        -- current thread now has exclusive access to clipboard
	void=w32Func(xEmptyClipboard,{})
	if w32Func(xSetClipboardData,{CF_BITMAP,hBmp}) != hBmp then
void=message_box("Failed to copy bitmap to
clipboard.","Error",MB_ICONERROR+MB_OK)
	end if
	w32Proc(xCloseClipboard,{})
end procedure

global procedure captureToClipboard(integer id,integer x,integer y,integer
cx,integer cy)
-- id is the source window; copy rectangle at {x,y}, cx pixel wide and cy poxel
high
    integer tmpx
-- create a temporary area for the bitmap
    tmpx=create(Pixmap,"",0,0,0,cx,cy,0)
-- copy pic
    bitBlt(tmpx,0,0,id,x,y,cx,cy,SrcCopy)
-- send bitmap to clipboard
    bmpToClipboard(getHandle(tmpx))
-- clean up
    destroy(tmpx)
end procedure

constant
xGetWindowDC        =
    registerw32Function(user32,"GetWindowDC",{C_POINTER},C_POINTER)
global procedure captureToClipboardEx(integer id,integer x,integer y,integer
cx,integer cy,integer
client)
-- id is the surce window; copy rectangle at {x,y}, cx pixel wide and cy poxel
high
-- if client is true, x and y are client coordinates, else absolute window
coordinates
    atom hDC,hWnd
    integer tmpx
    -- where's the pic?
    hWnd=getHandle(id)
    if client then
        hDC=getDC(id)
    else
        hDC=w32Func(xGetWindowDC,{hWnd})
    end if
    if not hDC then
        void=message_box("Not a valid window.","Error",MB_ICONERROR+MB_OK)
        return
    end if
    tmpx=create(Pixmap,"",0,0,0,cx,cy,0)
-- create a target compatible DC
    void=w32Func(xBitBlt,{getDC(tmpx),0,0,cx,cy,hDC,x,y,SrcCopy})
-- send bitmap to clipboard
    bmpToClipboard(getHandle(tmpx))
-- now we no longer own it
-- clean up
    destroy(tmpx)
    if client then
        releaseDC(id)
    else
        hDC=w32Func(xReleaseDC,{hWnd,hDC})
    end if
end procedure   

constant
w=create(Window,"test",0,50,50,300,300,0)
,b=create(Button,"push",w,20,200,60,30,0)

procedure q(integer self,integer event,sequence data)
setWindowBackColor(w,Green)
setPenColor(w,Red)
drawRectangle(w,w32True,100,100,200,200)
end procedure
setHandler(w,w32HActivate,routine_id("q"))

procedure p(integer self,integer event,sequence data)
captureToClipboard(w,30,80,100,120)
end procedure
setHandler(b,w32HClick,routine_id("p"))

WinMain(w,Normal)

Both routine work and the clipboard holds he expected value.

I'll have to add support for full window DCs in the library so that the
distinction wbetween the non -Ex and -Ex routines is no longer necessary.

Also, I had noticed earlier, and forgotten, that if you call
registerw32function() on some dll routine, then define_c_func() returns -1
if invoked on the same routine thereafter. I'll have to investigate.
Derek, any idea?

CChris

10. Re: How to write graphics to MS Windows clipboard

• Posted by CChris <christian.cuvier at agriculture.gouv.fr> May 17, 2007
• 715 views

DB James wrote:
> 
> CChris wrote:
> > A way nicer version using a Pixmap:
> > }}}
<eucode>
> > include win32lib.ew
> > 
> > integer void
> > global procedure bmpToClipboard(atom hBmp) 
> > -- hBmp must be a bitmap handle
> >     if not w32Func(xOpenClipboard, {NULL}) then
> >         void=message_box("Failed to open
> >         clipboard.","Error",MB_ICONERROR+MB_OK)
> >         return
> > 	end if
> <SNIP>
> > constant
> > w=create(Window,"test",0,50,50,300,300,0)
> > ,b=create(Button,"push",w,20,200,60,30,0)
> > 
> > procedure q(integer self,integer event,sequence data)
> > setWindowBackColor(w,Green)
> > setPenColor(w,Red)
> > drawRectangle(w,w32True,100,100,200,200)
> > end procedure
> > setHandler(w,w32HActivate,routine_id("q"))
> > 
> > procedure p(integer self,integer event,sequence data)
> > captureToClipboard(w,30,80,100,120)
> > end procedure
> > setHandler(b,w32HClick,routine_id("p"))
> > 
> > WinMain(w,Normal)
> > </eucode>
{{{

> > Both routine work and the clipboard holds he expected value.
> > 
> > I'll have to add support for full window DCs in the library so that the
> > distinction wbetween the non -Ex and -Ex routines is no longer necessary.
> > 
> > Also, I had noticed earlier, and forgotten, that if you call
> > registerw32function() on some dll routine, then define_c_func() returns -1
> > if invoked on the same routine thereafter. I'll have to investigate.
> > Derek, any idea?
> > 
> > CChris
> 
> Thanks, that works like a charm.
> 
> Do you think a bitmap-in-memory can be sent (with OLE or DDE or whatever) to
> be pasted into some other program?  It isn't uncommon to see programs do
> this, such as IrfanView's send of an image that does not exist as a disk file
> to some other graphic editor.
> 
> --Quark

There is a dedicated Windows message for that, which is WM_COPYDATA.
The trick there is that the data you pass must be accessible from the
process you are sending this message to, so it must not contain private
pointers. Here is the reference for this message:
<quote>
WM_COPYDATA 
wParam = (WPARAM) (HWND) hwnd;            // handle of sending window 
lParam = (LPARAM) (PCOPYDATASTRUCT) pcds; // pointer to structure with data 
 
The WM_COPYDATA message is sent when an application passes data to another
application. 

Parameters
hwnd:
  Identifies the window passing the data. 
pcds:
   Points to a COPYDATASTRUCT structure that contains the data to be passed. 

Return Value

If the receiving application processes this message, it should return TRUE;
otherwise, it should return FALSE. 

Remarks

An application must use the SendMessage function to send this message, not
the PostMessage function. 
The data being passed must not contain pointers or other references to
objects not accessible to the application receiving the data. 
While this message is being sent, the referenced data must not be changed by
another thread of the sending process. 
The receiving application should consider the data read-only. The pcds
parameter is valid only during the processing of the message. The receiving
application should not free the memory referenced by pcds. If the receiving
application must access the data after SendMessage returns, it must copy the
data into a local buffer. 
</quote>

The COPYDATASTRUCT referred here is very simple:
    DWORD dwData -- single dword to pass: used only if lpData is 0 
    DWORD cbData -- number of bytes pointed by lpData 
    PVOID lpData -- pointer to data

The constant WM_COPYDATA is #004A.
The copying of data must take place inside the raw message handler you'll
set for WM_COPYDATA.
Google for the WM_COPYDATA for more articles on using this message for
interprocess communication.

CChris