Using Win32 functions in Visual FoxPro Image Gallery
Code examples:
How to find when the application started
Retrieving the name of the default printer for the current user on the local computer (Win NT/XP)
Retrieving top-child window for the VFP form
Shortcut Menu Class
Start an executable from VFP application by using the CreateProcess
Starting an external application in VFP using WinExec
URL: splitting into its component parts
Verifying a file using the Authenticode policy provider
Bitmap Class for Visual FoxPro application
Converting image file to .ICO file
Drawing cursors for the classes defined by the system (preregistered): BUTTON, EDIT, LISTBOX etc.
Drawing standard Windows icons
GDI+ fun: roach-infested desktop
How to view system icons for the classes installed on the local machine
Minimizing all running applications
Placing On-screen Alert on top of all windows
Pocket PC: custom RAPI class for operating with the System Registry
Printing text on the client area of the main VFP window
Starting external program from VFP and waiting for its termination
Using InternetSetFilePointer when resuming interrupted download from the Internet
Winsock: retrieving directory listing from an FTP server using passive data connection (FTP, port 21)
Creating a window using CreateWindowEx function
Disabling mouse and keyboard input for the main VFP window (with the app still running)
Drawing icons associated with the VFP main window
Displaying bitmap using the AlphaBlend function

User rating: 9/10 (1 votes)
Rate this code sample:
  • ~
More code examples    Listed functions    Add comment     W32 Constants      Translate this page Printer friendly version of this code sample
Before you begin:
The AlphaBlend function displays bitmaps that have transparent or semitransparent pixels.

See also:
  • Bitmap Class for Visual FoxPro application
  • Semi-transparent Form
  • Form Magnifier
  • GDI+: Color Transparency
    DO declare
    LOCAL lcBitmap
    *lcBitmap = "C:\WinNT\system32\setup.bmp"
    lcBitmap = "C:\Windows\Forest.bmp"
    = LoadAndShowBitmap(lcBitmap, LR_LOADFROMFILE, 20,100)
    * end of main
    PROCEDURE LoadAndShowBitmap(lcBitmap, lnLoadOptions, lnX,lnY)
        LOCAL hBitmap
        hBitmap = LoadImage(0, lcBitmap, IMAGE_BITMAP,;
            0,0, lnLoadOptions)
        IF hBitmap <> 0
            = ShowBitmap(hBitmap, lnX,lnY)
            = DeleteObject(hBitmap)
            = MESSAGEBOX(lcBitmap + Chr(13) + Chr(13) +;
                "Check if this is a valid bitmap file.",;
                32, " Unable to load an image from file")
    PROCEDURE ShowBitmap(hBitmap, lnX, lnY)
    *|typedef struct _BLENDFUNCTION {
    *|  BYTE     BlendOp;
    *|  BYTE     BlendFlags;
    *|  BYTE     SourceConstantAlpha;
    *|  BYTE     AlphaFormat;
        LOCAL hWindow, hDC, hMemDC, lnWidth, lnHeight
        STORE 0 TO lnWidth, lnHeight
        = GetBitmapSize(hBitmap, @lnWidth, @lnHeight)
        hWindow = GetActiveWindow()
        hDC = GetWindowDC(hWindow)
        hMemDC = CreateCompatibleDC(hDC)
        = SelectObject(hMemDC, hBitmap)
        LOCAL lnAlphaBlend, lnResult,;
            lnBlendOp, lnBlendFlags, lnSrcConstAlpha, lnAlphaFormat
        lnBlendOp = AC_SRC_OVER  && always
        lnBlendFlags = 0         && always
        lnSrcConstAlpha = 48     && intensity, up to 255
        lnAlphaFormat = 0        && try AC_SRC_ALPHA on non-white background
        * assembling the BLENDFUNCTION structure 
        lnAlphaBlend = lnBlendOp +;
            BitLShift(lnBlendFlags, 8) +;
            BitLShift(lnSrcConstAlpha, 16) +;
            BitLShift(lnAlphaFormat, 24)
        lnResult = AlphaBlend(hDC, lnX,lnY, lnWidth,lnHeight,;
            hMemDC, 0,0, lnWidth,lnHeight,;
        IF lnResult = 0
        *  6 = The handle is invalid
        * 87 = The parameter is incorrect
            ? "Error:", GetLastError()
        = DeleteDC(hMemDC)
        = ReleaseDC(hWindow, hDc)
    RETURN .T.
    FUNCTION GetBitmapSize(hBitmap, lnWidth, lnHeight)
        LOCAL lcBuffer
        lcBuffer = Repli(Chr(0), BITMAP_STRU_SIZE)
        IF GetObjectA(hBitmap, BITMAP_STRU_SIZE, @lcBuffer) <> 0
            lnWidth  = buf2dword(SUBSTR(lcBuffer, 5,4))
            lnHeight = buf2dword(SUBSTR(lcBuffer, 9,4))
    FUNCTION buf2dword(lcBuffer)
    RETURN Asc(SUBSTR(lcBuffer, 1,1)) + ;
        BitLShift(Asc(SUBSTR(lcBuffer, 2,1)),  8) +;
        BitLShift(Asc(SUBSTR(lcBuffer, 3,1)), 16) +;
        BitLShift(Asc(SUBSTR(lcBuffer, 4,1)), 24)
    PROCEDURE declare
        DECLARE INTEGER CreateCompatibleDC IN gdi32 INTEGER hdc
        DECLARE INTEGER DeleteDC IN gdi32 INTEGER hdc
        DECLARE INTEGER GetActiveWindow IN user32
        DECLARE INTEGER GetWindowDC IN user32 INTEGER hWindow
        DECLARE INTEGER ReleaseDC IN user32 INTEGER hWindow, INTEGER dc
        DECLARE INTEGER DeleteObject IN gdi32 INTEGER hObject
        DECLARE INTEGER SelectObject IN gdi32 INTEGER hdc, INTEGER hObject
        DECLARE INTEGER LoadImage IN user32;
            INTEGER hinst, STRING lpszName, INTEGER uType,;
            INTEGER cxDesired, INTEGER cyDesired, INTEGER fuLoad
        DECLARE INTEGER GetObject IN gdi32 AS GetObjectA;
            INTEGER hgdiobj, INTEGER cbBuffer, STRING @lpvObject
        DECLARE INTEGER AlphaBlend IN Msimg32;
            INTEGER hDestDC, INTEGER x, INTEGER y,;
            INTEGER nWidth, INTEGER nHeight, INTEGER hSrcDC,;
            INTEGER xSrc, INTEGER ySrc, INTEGER nWidthSrc,;
            INTEGER nHeightSrc, INTEGER blendFunction
        DECLARE INTEGER GetLastError IN kernel32

    User rating: 9/10 (1 votes)
    Rate this code sample:
    • ~
    3476 bytes  
    Created: 2002-03-23 10:43:13  
    Modified: 2009-01-17 11:17:30  
    Visits in 7 days: 84  
    Listed functions:
    Printer friendly API declarations
    Word Index links for this example:
    Translate this page:
      Spanish    Portuguese    German    French    Italian offers instant, free translations of text or web pages.
    User Contributed Notes:
    There are no notes on this subject.

    Copyright 2001-2015 News2News, Inc. Before reproducing or distributing any data from this site please ask for an approval from its owner. Unless otherwise specified, this page is for your personal and non-commercial use. The information on this page is presented AS IS, meaning that you may use it at your own risk. Microsoft Visual FoxPro and Windows are trade marks of Microsoft Corp. All other trademarks are the property of their respective owners. 

    Privacy policy
    Credits: PHP (4.4.9), an HTML-embedded scripting language, MySQL (5.5.44), the Open Source standard SQL database, AceHTML Freeware Version 4, freeware HTML Editor of choice.   Hosted by Korax Online Inc.
    Last Topics Visited (
    32 sec.Function: 'CreateSolidBrush'
    2.7 min.Function: 'CryptEnumProviders'
    Function group: 'Cryptography Reference'
    2 day(s)Example: 'GDI+: loading image file, drawing on it, saving the result to another file'
    Function group: 'Data Decompression Library'
     Function: 'GetWindowLong'
    Function group: 'Window Class'
    Advertise here!