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Alyce
Jun 10, 2011
=CLIPBOARD API DEMOS= //[[user:Alyce]] and [[user:DennisMcK]]// [[toc]] ---- ==Clipboard API Functions== //[[user:Alyce]]// These three demos show you how to handle text, bitmaps and wavs with the clipboard. [[ClipboardAPI#text|Text]] [[ClipboardAPI#bitmap|Bitmap]] [[ClipboardAPI#Wav|Wav]] ==OpenClipboard== To access the Windows Clipboard via API, you must first make a call to OpenClipboard. The argument required is your windows's handle and the return is nonzero if the function successds. [[code format="lb"]] CallDll #user32, "OpenClipboard", hWnd as ulong, r as boolean [[code]] ==CloseClipboard== When you have finished, you must call CloseClipboard. It will return nonzero if successful. [[code format="lb"]] CallDll #user32, "CloseClipboard", r as boolean [[code]] ==SetClipboardData== To place something on the clipboard once it is open, use SetClipboardData. You must specify the format of the data, so the clipboard knows if it is receiving text or an image, for instance. Some possible formats we can use: _CF_TEXT _CF_BITMAP _CF_WAVE You must supply the memory handle to the data. If you are sending text to the clipboard, you will use memory allocation functions to create a handle to the text in memory. See the demo by Dennis below for a step-by-step example. You will use the functions "GlobalAlloc", "GlobalLock", "GlobalUnlock", and "GlobalFree". If you are sending a bitmap to the clipboard, you will need the handle to the bitmap, retrieved with Liberty BASIC's HBMP() function. If the function succeeds, the return value is the handle of the data. [[code format="lb"]] calldll #user32, "SetClipboardData", format as long,_ handle as ulong,_ rethandle as long [[code]] ==GetClipboardData== To retrieve data from the clipboard, use GetClipboardData. It requires the type of format you seek as the first argument. You must specify whether you are looking for text, a bitmap or a wave. If data in the specified format is on the clipboard, the function returns a handle to the data. If the return is null, that means that data in the format you specified is not available on the clipboard. [[code format="lb"]] calldll #user32, "GetClipboardData",_ format as long,_ rethandle as ulong calldll #user32, "GetClipboardData",_ _CF_TEXT as long,_ txtHandle as ulong calldll #user32, "GetClipboardData", _CF_BITMAP as long,_ hBmp as ulong calldll #user32, "GetClipboardData",_ _CF_WAVE as long,_ hWav as ulong [[code]] You will need to manage the data differently depending upon the format. If you retrieve text from the clipboard, the return is a memory pointer to the text. Use the winstring() function to retrieve the actual text. If you retrieve a bitmap from the clipboard, use the LOADBMP function to load it from the handle returned by the function. Once you have given it an LB name with LOADBMP, you can use DRAWBMP or BMPSAVE just as you would on a bitmap loaded from disk. If you retrieve the handle of a wav from the clipboard, you cannot play it with PLAYWAVE. Since it is a wav in memory, you must play it with the API function sndPlaySound. See the third program below for examples of retrieving and using data in text, bitmap and wav format. ==Placing Text on the Clipboard== [[user:DennisMcK]] [[#text]] [[code format="lb"]] 'Send text to clipboard with api calls 'by Dennis McKinney 'Note: You can use your window handle here instead of 0 r = ClipboardSetText(0, "Hello World") 'If r is > 0 then the text has been placed on the clipboard end Function ClipboardSetText(hOwner, strText$) 'Puts some text on the Windows clipboard 'In: The text to place on the clipboard 'Out: 0 if fail, > 0 if text placed on clipboard strText$ = strText$ + chr$(0) lngSize = Len(strText$) hMemory = GlobalAlloc(_GMEM_MOVEABLE, lngSize) 'Lock the object into memory lpMemory = GlobalLock(hMemory) 'Move the string into the memory we locked CallDll #kernel32,"RtlMoveMemory", lpMemory as ulong, strText$ as ptr, lngSize as long, ret as void 'Don't send clipboard locked memory. r = GlobalUnlock(hMemory) 'Open the clipboard CallDll #user32, "OpenClipboard", hOwner as ulong, r as boolean 'Remove the current contents of the clipboard CallDll #user32, "EmptyClipboard", r as boolean 'Add our string to the clipboard as text 'If hSuccess > 0 then we have set the clipboard data CallDll #user32, "SetClipboardData", _CF_TEXT as long, hMemory as ulong, hSuccess as long 'Close the clipboard CallDll #user32, "CloseClipboard", r as boolean 'If we have set the clipboard data, we no longer own 'the memory--Windows does, so don't free it unless we failed. If hSuccess = 0 Then r = GlobalFree(hMemory) End If ClipboardSetText = hSuccess End Function '--- Supporting functions --- Function GlobalAlloc(type, dwBytes) CallDll #kernel32, "GlobalAlloc", type as long, dwBytes as ulong, GlobalAlloc as long End Function Function GlobalLock(hMem) CallDll #kernel32, "GlobalLock", hMem as ulong, GlobalLock as long End Function Function GlobalUnlock(hMem) CallDll #kernel32, "GlobalUnlock", hMem as ulong, GlobalUnlock as long End Function Function GlobalFree(hMem) CallDll #kernel32, "GlobalFree", hMem as ulong, GlobalFree as long End Function [[code]] Editor's note: an example that retrieves text from the clipboard is included in the third demo, below. ==PLACE BITMAP ON CLIPBOARD AND RETRIEVE BITMAP FROM CLIPBOARD== [[user:Alyce]] [[#bitmap]] [[code format="lb"]] 'This little demo shows how to send a bitmap to the clipboard. 'It also shows how to grab a bitmap from the clipboard and 'display it in our Liberty BASIC program. nomainwin WindowWidth=340:WindowHeight=480 graphicbox #1.g, 10,10,300,300 statictext #1.s, "",10,320,600,50 open "Clipboard Demo" for window as #1 print #1, "trapclose [quit]" h=hwnd(#1) filedialog "Open","*.bmp",bmpfile$ if bmpfile$="" then [quit] loadbmp "forclip",bmpfile$ hBitmap=hbmp("forclip")'get bmp handle 'open clipboard: calldll #user32, "OpenClipboard",h as ulong, result as long 'put bmp data on clipboard: calldll #user32, "SetClipboardData",_CF_BITMAP as long,_ hBitmap as ulong, rethandle as ulong 'see if bmp data is on clipboard calldll #user32, "GetClipboardData",_CF_BITMAP as long,_ hBmp as ulong 'if bmpdata is on clipboard, load the bmp and draw it if hBmp<>0 then loadbmp "demo",hBmp print #1.g, "down;fill lightgray;drawbmp demo 0 0;flush" end if calldll #user32, "CloseClipboard", result as void msg$="Return for CF_BITMAP ";hBmp print #1.s, msg$ wait [quit] if hBmp<>0 then unloadbmp "demo" close #1:end [[code]] ==RETRIEVE TEXT, BITMAP AND WAV DATA FROM THE CLIPBOARD== [[user:Alyce]] [[#wav]] [[code format="lb"]] 'to use this demo, do one of the following: ' 'open notepad, type some text, and choose COPY ' OR 'open MS Paint, open a picture, then select all 'or part of it and choose COPY ' OR 'open a wav in sound recorder, then choose COPY ' ' 'if you have copied text to the clipboard, it will 'appear in the texteditor. ' 'if you have copied an image to the clipboard, 'it will be drawn in the graphicbox ' 'if you have copied a wav, it will play ' nomainwin WindowWidth=640:WindowHeight=480 texteditor #1.t, 10,10,300,300 graphicbox #1.g, 320,10,300,300 statictext #1.s, "",10,320,600,50 button #1.b, "Do another!",[again],UL,10,380 open "Clipboard Demo" for window as #1 print #1, "trapclose [quit]" h=hwnd(#1) [again] calldll #user32, "OpenClipboard",h as ulong, result as long calldll #user32, "GetClipboardData",_CF_TEXT as long,_ txt as long if txt<>0 then print #1.t, "!cls" print #1.t, "Text content of clipboard:" print #1.t, "" print #1.t, winstring(txt) print #1.t, "!origin 1 1" end if calldll #user32, "GetClipboardData",_CF_BITMAP as long,_ hBmp as ulong if hBmp<>0 then loadbmp "demo",hBmp print #1.g, "cls;down;drawbmp demo 0 0;flush" end if calldll #user32, "GetClipboardData",_CF_WAVE as long,_ hWav as ulong if hWav<>0 then SND.SYNC = 0 SND.ASYNC = 1 SND.NODEFAULT = 2 SND.MEMORY = 4 mode=SND.MEMORY or SND.ASYNC OR SND.NODEFAULT calldll #winmm, "sndPlaySoundA",_ hWav as ulong,mode as long,result as long end if calldll #user32, "CloseClipboard", result as void msg$="Return for CF_TEXT ";txt msg$=msg$+ chr$(13)+"Return for CF_BITMAP ";hBmp msg$=msg$+chr$(13)+"Return for CF_WAVE ";hWav print #1.s, msg$ wait [quit] if hBmp<>0 then unloadbmp "demo" close #1:end [[code]]