Code archives/User Libs/Capture Screen functions

A CaptureDesktop function, which uses the CaptureScreenArea function.

;Capture Desktop function, by markcw on 16 Jul 06

Graphics3D 320,240,0,2
SetBuffer BackBuffer()

initime=MilliSecs()

While Not KeyHit(1)

 If done=0 And MilliSecs()>initime+50 ;wait for text info
  done=1 : CaptureDesktop()
 EndIf

 Cls
 Text 0,0,"OK, paste the current clipboard data"
 Text 0,12,"to whatever program you use to see"
 Text 0,24,"the results of the screen capture."
 Text 0,36,"done="+done+" initime="+initime

Flip
Wend

Function CaptureDesktop()
 ;Capture the entire desktop area to the clipboard
 ;From PureBasic Forum source, by Droopy on 18/10/2005

 Local dwidth,dheight

 dwidth=Api_GetSystemMetrics(0) ;SM_CXScreen
 dheight=Api_GetSystemMetrics(1) ;SM_CYScreen
 CaptureScreenArea(0,0,dwidth,dheight) ;x,y,width,height

End Function

Function CaptureScreenArea(sx,sy,swidth,sheight)
 ;Capture a given screen area to the clipboard
 ;From PureBasic CodeArchiv source, by wayne1 on 30/1/2002

 Local hdcSrc,hdcDst,hbmp,hold

 hdcSrc=Api_GetDC(0) ;hwnd
 hdcDst=Api_CreateCompatibleDC(hdcSrc) ;hdc
 hbmp=Api_CreateCompatibleBitmap(hdcSrc,swidth,sheight) ;hdc,width,height
 hold=Api_SelectObject(hdcDst,hbmp) ;hdc,hobject[bitmap]
 Api_BitBlt(hdcDst,0,0,swidth,sheight,hdcSrc,sx,sy,$00CC0020) ;SrcCopy
 Api_SelectObject(hdcDst,hold) ;restore old to dc
 If Api_OpenClipboard(0) ;hwnd
  Api_EmptyClipboard() ;free last data
  Api_SetClipboardData(2,hbmp) ;CF_Bitmap,hdata[bitmap]
  Api_CloseClipboard()
 EndIf
 Api_ReleaseDC(0,hdcSrc) ;hwnd,hdc
 Api_DeleteDC(hdcDst) ;hdc

End Function

A CaptureWindow function, which also uses the CaptureScreenArea function.

;Capture Window function, by markcw on 15 Jul 06

Graphics3D 320,240,0,2
SetBuffer BackBuffer()

initime=MilliSecs()

While Not KeyHit(1)

 If done=0 And MilliSecs()>initime+50 ;wait for text info
  done=1 : CaptureWindow()
 EndIf

 Cls
 Text 0,0,"OK, paste the current clipboard data"
 Text 0,12,"to whatever program you use to see"
 Text 0,24,"the results of the screen capture."
 Text 0,36,"done="+done+" initime="+initime

Flip
Wend

Function CaptureWindow()
 ;Capture the entire window area to the clipboard
 ;From PureBasic Forum source, by Droopy on 18/10/2005

 Local hwnd,prect,rx,ry,rwidth,rheight

 hwnd=Api_GetForegroundWindow()
 If hwnd ;window valid
  prect=CreateBank(16) ;bank structure
  Api_GetWindowRect(hwnd,prect) ;hwnd,rect[left,top,right,bottom]
  rx=PeekInt(prect,0) ;rect left
  ry=PeekInt(prect,4) ;rect top
  rwidth=PeekInt(prect,8)-PeekInt(prect,0) ;rect right-left
  rheight=PeekInt(prect,12)-PeekInt(prect,4) ;rect bottom-top
  CaptureScreenArea(rx,ry,rwidth,rheight) ;x,y,width,height
  FreeBank prect ;free from memory
 EndIf

End Function

Function CaptureScreenArea(sx,sy,swidth,sheight)
 ;Capture a given screen area to the clipboard
 ;From PureBasic CodeArchiv source, by wayne1 on 30/1/2002

 Local hdcSrc,hdcDst,hbmp,hold

 hdcSrc=Api_GetDC(0) ;hwnd
 hdcDst=Api_CreateCompatibleDC(hdcSrc) ;hdc
 hbmp=Api_CreateCompatibleBitmap(hdcSrc,swidth,sheight) ;hdc,width,height
 hold=Api_SelectObject(hdcDst,hbmp) ;hdc,hobject[bitmap]
 Api_BitBlt(hdcDst,0,0,swidth,sheight,hdcSrc,sx,sy,$00CC0020) ;SrcCopy
 Api_SelectObject(hdcDst,hold) ;restore old to dc
 If Api_OpenClipboard(0) ;hwnd
  Api_EmptyClipboard() ;free last data
  Api_SetClipboardData(2,hbmp) ;CF_Bitmap,hdata[bitmap]
  Api_CloseClipboard()
 EndIf
 Api_ReleaseDC(0,hdcSrc) ;hwnd,hdc
 Api_DeleteDC(hdcDst) ;hdc

End Function

A CaptureClient function, again using the CaptureScreenArea function.

;Capture Client function, by markcw on 16 Jul 06

Graphics3D 320,240,0,2
SetBuffer BackBuffer()

initime=MilliSecs()

While Not KeyHit(1)

 If done=0 And MilliSecs()>initime+50 ;wait for text info
  done=1 : CaptureClient()
 EndIf

 Cls
 Text 0,0,"OK, paste the current clipboard data"
 Text 0,12,"to whatever program you use to see"
 Text 0,24,"the results of the screen capture."
 Text 0,36,"done="+done+" initime="+initime

Flip
Wend

Function CaptureClient()
 ;Capture the entire client area to the clipboard
 ;From PureBasic CodeArchiv source, by Edwin Knoppert on 24/11/2003

 Local hwnd,prect,rx,ry,rwidth,rheight

 hwnd=Api_GetForegroundWindow()
 If hwnd ;window valid
  prect=CreateBank(16) ;bank structure
  Api_GetClientRect(hwnd,prect) ;hwnd,rect[left,top,right,bottom]
  Api_ClientToScreen(hwnd,prect) ;hwnd,point[x,y]
  rx=PeekInt(prect,0) ;point x
  ry=PeekInt(prect,4) ;point y
  rwidth=PeekInt(prect,8) ;rect right
  rheight=PeekInt(prect,12) ;rect bottom
  CaptureScreenArea(rx,ry,rwidth,rheight) ;x,y,width,height
  FreeBank prect ;free from memory
 EndIf

End Function

Function CaptureScreenArea(sx,sy,swidth,sheight)
 ;Capture a given screen area to the clipboard
 ;From PureBasic CodeArchiv source, by wayne1 on 30/1/2002

 Local hdcSrc,hdcDst,hbmp,hold

 hdcSrc=Api_GetDC(0) ;hwnd
 hdcDst=Api_CreateCompatibleDC(hdcSrc) ;hdc
 hbmp=Api_CreateCompatibleBitmap(hdcSrc,swidth,sheight) ;hdc,width,height
 hold=Api_SelectObject(hdcDst,hbmp) ;hdc,hobject[bitmap]
 Api_BitBlt(hdcDst,0,0,swidth,sheight,hdcSrc,sx,sy,$00CC0020) ;SrcCopy
 Api_SelectObject(hdcDst,hold) ;restore old to dc
 If Api_OpenClipboard(0) ;hwnd
  Api_EmptyClipboard() ;free last data
  Api_SetClipboardData(2,hbmp) ;CF_Bitmap,hdata[bitmap]
  Api_CloseClipboard()
 EndIf
 Api_ReleaseDC(0,hdcSrc) ;hwnd,hdc
 Api_DeleteDC(hdcDst) ;hdc

End Function

A CaptureClientArea function, like the CaptureClient function except lets you capture a given area, ie. an image.

;Capture Client Area function, by markcw on 16 Jul 06

Graphics3D 320,240,0,2
SetBuffer BackBuffer()

image=CreateImage(128,128) ;new image
For y=0 To ImageHeight(image)-1
 For x=0 To ImageWidth(image)-1
  rgba=y+(y*256)+(x*256^2) ;gradient color
  WritePixel x,y,rgba,ImageBuffer(image)
 Next
Next

initime=MilliSecs()

While Not KeyHit(1)

 If done=0 And MilliSecs()>initime+50 ;wait for text info
  done=1 : CaptureClientArea(64,64,ImageWidth(image),ImageHeight(image))
 EndIf

 Cls
 DrawImage image,64,64 ;draw the image

 Text 0,0,"OK, paste the current clipboard data"
 Text 0,12,"to whatever program you use to see"
 Text 0,24,"the results of the screen capture."
 Text 0,36,"done="+done+" initime="+initime

Flip
Wend

Function CaptureClientArea(cx,cy,cwidth,cheight)
 ;Capture a given client area to the clipboard
 ;From PureBasic CodeArchiv source, by Edwin Knoppert on 24/11/2003

 Local hwnd,ppoint,px,py

 hwnd=Api_GetForegroundWindow()
 If hwnd ;window valid
  ppoint=CreateBank(8) ;bank structure
  Api_ClientToScreen(hwnd,ppoint) ;hwnd,point[x,y]
  px=PeekInt(ppoint,0) ;point x
  py=PeekInt(ppoint,4) ;point y
  CaptureScreenArea(px+cx,py+cy,cwidth,cheight) ;x,y,width,height
  FreeBank ppoint ;free from memory
 EndIf

End Function

Function CaptureScreenArea(sx,sy,swidth,sheight)
 ;Capture a given screen area to the clipboard
 ;From PureBasic CodeArchiv source, by wayne1 on 30/1/2002

 Local hdcSrc,hdcDst,hbmp,hold

 hdcSrc=Api_GetDC(0) ;hwnd
 hdcDst=Api_CreateCompatibleDC(hdcSrc) ;hdc
 hbmp=Api_CreateCompatibleBitmap(hdcSrc,swidth,sheight) ;hdc,width,height
 hold=Api_SelectObject(hdcDst,hbmp) ;hdc,hobject[bitmap]
 Api_BitBlt(hdcDst,0,0,swidth,sheight,hdcSrc,sx,sy,$00CC0020) ;SrcCopy
 Api_SelectObject(hdcDst,hold) ;restore old to dc
 If Api_OpenClipboard(0) ;hwnd
  Api_EmptyClipboard() ;free last data
  Api_SetClipboardData(2,hbmp) ;CF_Bitmap,hdata[bitmap]
  Api_CloseClipboard()
 EndIf
 Api_ReleaseDC(0,hdcSrc) ;hwnd,hdc
 Api_DeleteDC(hdcDst) ;hdc

End Function

Right on Muk, good stuff !

Thanks Wayne. I am going to see if i can copy a FreeImage bitmap directly now.

just updated these examples to use the "Api_" prefix so there are no functions of the same name and so you can tell an api function straight away.

Also, i changed to using Api_GetDC instead of Api_CreateDC because it does the same thing and is simpler to use.

I would of thought create would be functionaly differet from get. hmm

well it's instead of creating a dc you just get an existing one, when you call getdc(0) it gets the display/desktop window, both can be used afaik.

ok, i updated this code again.

it doesn't really make much difference, but apparently you're supposed to put/reselect a dc's original dummy object back before deleting the dc.

also, there was no need to delete the bitmap object as the clipboard uses it, i thought it made a copy but it just becomes the new owner.

Umm... CaptureDesktop doesn't work for me.

It might be because the CaptureWindow/Client/ClientArea functions use Api_GetForegroundWindow to get the window handle which is not as reliable as using Api_FindWindow as there may be another foreground/active window. In order to use Api_FindWindow you need the define the Blitz app class (different in B+) and title, like so. Edit: SystemProperty("AppHWND") does the same thing as FindWindow.

.lib "User32.dll"
Api_FindWindow%(classname$, windowname$):"FindWindowA"

; Const class$="GX_WIN32_CLASS" ;BlitzPlus 1.11
; Const class$="BLITZMAX_WINDOW_CLASS" ;BlitzPlus 1.34
Const class$="Blitz Runtime Class" ;Blitz3D, app class
Const title$ = "My Blitz Window" ;app title

AppTitle title$
hwnd = Api_FindWindow(class$, title$)

As for CaptureDesktop not working I can only assume that Api_GetDC(0) isn't working for some reason.