capturing windows? - BlitzCoder.net

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Socoder -> Blitz -> capturing windows?
Sat, 12 May 2007, 18:41
spinal	Just wondering for the sake of a screen saver, Is it possible/easy to get a screen grab of each open window and use them as images in a blitz program? -=-=- Check out my excellent homepage!
Sat, 12 May 2007, 18:54
Stealth	Maybe with a DLL.. I don't know of any though.
Sat, 12 May 2007, 18:58
Blitz3Dman	For the program to grab them itself, not that I know of. You can press Print Screen right above insert and delete and it copies the screen to the clipboard. -=-=- There are 10 kinds of people in this world - ( Insert 16 remarks about to what extent people know hex here )
Sat, 12 May 2007, 19:01
bram32	Yes, it seems to be possible. I'm not sure if it will work on every system. MarkCW wrote functions that can capture the screen to the clipboard and also a function that converts the clipboard to an image: CaptureScreen: www.blitzbasic.com/codearcs/codearcs.php?code=1752 PasteFromClipboard: www.blitzbasic.com/codearcs/codearcs.php?code=1767 I made a desktop screenshot with the following code, which is a combination of the two programs above. You also need the .decls files that are mentioned in the links above to get it to work: ;Capture Client function, on 16/7/06 Graphics3D 320,240,0,2 SetBuffer BackBuffer() initime=MilliSecs() done = 0 While Not done 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() hwnd=Api_GetDesktopWindow() 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 ;Paste Image from Clipboard function, by markcw on 29/07/06 Graphics3D 640,480,0,2 SetBuffer BackBuffer() image=PasteImageFromClipboard() ;paste image from clipboard width=ImageWidth(image) ;get image info height=ImageHeight(image) While Not KeyHit(1) Cls DrawImage image,50,50 ;draw the image Text 0,0,"image="+image+" width="+width+" height="+height Flip Wend Function PasteImageFromClipboard() ;Paste the clipboard to a new Blitz3D image ;From "Copying a DIB to the clipboard", by John Simmons ;(https://www.codeproject.com) Local hDIB,himage,pbmi,btmp,sizeInfo,sizePal,width,height,bpp Local sizeBits,sizeDIB,x,y,offset,index,bytespp ;receive the bitmap from the clipboard as a DIB If Api_OpenClipboard(0) ;hwnd hDIB=Api_GetClipboardData(8) ;CF_DIB=8 Api_CloseClipboard() EndIf If Not hDIB ;if we didn't get a DIB, return a dummy image himage=CreateImage(1,1) Return himage EndIf pbmi=Api_GlobalLock(hDIB) ;lock memory and get pointer to it btmp=CreateBank(40) ;initialize bank, we will resize it later Api_RtlMoveMemory(btmp,pbmi,40) ;move info header to bank sizeInfo=PeekInt(btmp,0) ;biSize ;calculate palette, Clipboard DIBs use the BITMAPINFO struct sizePal=PeekInt(btmp,32) ;biClrUsed If Not sizePal If PeekShort(btmp,14)<16 ;no color table for 16/24/32 sizePal=1 Shl PeekShort(btmp,14) ;biBitCount, colors=2/16/256 Else sizePal=PeekInt(btmp,16) ;biCompression, 16/32 use BI_BITFIELDS=3 EndIf EndIf sizePal=sizePal4 ;sizeof(RGBQUAD) width=PeekInt(btmp,4) ;biWidth height=PeekInt(btmp,8) ;biHeight bpp=PeekShort(btmp,14) ;biBitCount bytespp=bpp/8 ;bytes per pixel ;calculate bits, DWORD-aligned scanline (Width BitCount) * Height sizeBits=((widthbpp+31)/324)height sizeDIB=sizeInfo+sizePal+sizeBits ;total size ResizeBank btmp,sizeDIB ;resize bank to store DIB Api_RtlMoveMemory(btmp,pbmi,sizeDIB) ;move DIB to bank Api_GlobalUnlock(hDIB) ;unlock the DIB himage=CreateImage(width,height) ;new image to write ;calculate DWORD-aligned offset of bits for proper alignment ;we'll use biSize to store each pixel, we don't need it any more LockBuffer(ImageBuffer(himage)) For y=0 To height-1 offset=((widthbpp+31)/324)y+sizeInfo+sizePal ;start of next scanline For x=0 To width-1 If bpp=1 index=PeekByte(btmp,offset+(x/8)) ;1-bit, looks nasty but it works ;work out the bit, invert it, bitmask the byte and convert to 0/1 index=(index And (1 Shl (7-(x Mod 8)))) Shr (7-(x Mod 8)) EndIf If bpp=4 index=PeekByte(btmp,offset+(x/2)) ;4-bit, work out the nibble If x Mod 2 Then index=index And 15 ;get bits 0-3 If Not x Mod 2 Then index=index Shr 4 ;get bits 4-7 EndIf If bpp=8 index=PeekByte(btmp,offset+x) ;8-bit, we have our index EndIf If bpp=24 Or bpp=32 ;get rgb offset PokeByte btmp,0,PeekByte(btmp,offset+(xbytespp)) ;blue PokeByte btmp,1,PeekByte(btmp,offset+(xbytespp)+1) ;green PokeByte btmp,2,PeekByte(btmp,offset+(xbytespp)+2) ;red ElseIf bpp=16 ;rgb=565 PokeByte btmp,0,(PeekShort(btmp,offset+(xbytespp)) And 31) Shl 3 ;blue PokeByte btmp,1,((PeekShort(btmp,offset+(xbytespp)) And 2016) Shr 5) Shl 2 ;green PokeByte btmp,2,((PeekShort(btmp,offset+(xbytespp)) And 63488) Shr 11) Shl 3 ;red Else ;get palette index, 1/4/8-bit PokeByte btmp,0,PeekInt(btmp,sizeInfo+(index4)) PokeByte btmp,1,PeekInt(btmp,sizeInfo+(index4)+1) PokeByte btmp,2,PeekInt(btmp,sizeInfo+(index*4)+2) EndIf WritePixelFast x,height-1-y,PeekInt(btmp,0),ImageBuffer(himage) ;biSize Next Next UnlockBuffer(ImageBuffer(himage)) FreeBank btmp Return himage ;image handle End Function --v
Sat, 12 May 2007, 19:03
Jayenkai	But that's the whole screen. I think Spinal wants each individual window. And I haven't a clue how to do that, either! -=-=- ''Load, Next List!''
Sat, 12 May 2007, 19:13
JL235	If you could get information on the other windows, such as what windows are open, their position and size, you could easily cut up the desktop screen shot (but then there is a problem with windows that are on top of other windows). Presumably there must be something, possibly in Win32, to find out what other windows are open. Maybe then to send them commands such as to get focus (partly curing the problem I said above). This may also be OLE stuff instead. But I have no idea how to do any of it.
Sat, 12 May 2007, 19:20
bram32	You would need the hwnd for the window you want to capture then. For instance, with Api_FindWindow you can retreive the hwnd for specific windows. If the window is active, you could use Api_GetForeGroundWindow. In the code above I used Api_GetDesktopWindow, which returns the hwnd for the entire desktop. For the .bb window itself, use SystemProperty$("apphwnd") edit: for Api_FindWindow you need to make sure you have the right declaration: API_FindWindow%(lpClassName%,lpWindowName$):"FindWindowA" --v The first one should be lpClassName%, in some .decls it uses lpClassName$ instead. When the function has this declaration, you can omit the first parameter (window class name) and put in a zero instead. The second parameter is the caption (name/title) of the window: hwnd = Api_FindWindow(0, "Socoder - Forum - Mozilla Firefox") Print hwnd WaitKey() --v
Sat, 12 May 2007, 20:06
Stealth	That might actually work.
Sun, 13 May 2007, 10:32
Paul	Use this to get the window position and size. then use the captureclient area function and clip the imge with grabimage in blitz. If you didn't understand then feel free to ask this also needs the .decels in the above link bank=CreateBank(16);create a bank big enough to handle 4 ints api_GetWindowRect(SystemProperty("apphwnd"),bank);(SystemProperty("apphwnd") returns a hadle to the current window. Print PeekInt(bank,0);get the first 4 bytes(integer) of the bank Print PeekInt(bank,4);secon Print PeekInt(bank,8);... Print PeekInt(bank,12);... WaitKey() --v \|edit\| Added cometnts \|edit\|