Victor Image Processing Library How-to Tips
Victor Image Processing Library How-to Tips
The image created by sendimage.asp |
To access Victor Library functions from an Active Server Page (ASP) running on a Windows NT/2000 web server we create an ActiveX dll using Visual Basic (victorAXdemo.dll) or C/C++ (victorAXdemovc.dll). And an ASP page, sendimage.asp or sendimagevc.asp delivers the JPEG image to the browser with a Response.BinaryWrite.
The ActiveX dll, creates a graphic image from the text string, "hello," saves it to a JPEG file format stored in memory, and delivers it on demand to the ASP page.
The sequence of Victor functions in the ActiveX dll is:
allocimage(myimage, 325, 140, 8) ' Create the image (325 x 140, 8-bit grayscale)
zeroimage(255, myimage) ' Give it a white background
textinimage myimage, "hello" ' Put the text string into the image
savejpgtobuffer(bufferaddress, myimage, 50) ' Put the image into JPEG form in a buffer
In the ASP page the JPEG data are the assigned to the jpegbuffer property for easy delivery from the ASP page to a browser.
VB Source Code | C/C++ Source Code
Download the VB source code and corresponding ASP page for this example: vicaxdemo.zip (11 kb)
' Definitions and declarations ' Image descriptor Type imgdes ibuff As Long stx As Long sty As Long endx As Long endy As Long buffwidth As Long palette As Long colors As Long imgtype As Long bmh As Long hBitmap As Long End Type Private Const NO_ERROR = 0 ' Victor Library functions Private Declare Function allocimage Lib "VIC32.DLL" (image As imgdes, ByVal wid As Long, ByVal leng As Long, ByVal BPPixel As Long) As Long Private Declare Sub freeimage Lib "VIC32.DLL" (image As imgdes) Private Declare Function savejpgtobuffer Lib "VIC32.DLL" (ByRef buffaddr As Long, srcimg As imgdes, ByVal quality As Long) As Long Private Declare Function zeroimage Lib "VIC32.DLL" (ByVal level As Long, image As imgdes) As Long ' Windows API functions Private Declare Function GlobalHandle Lib "kernel32" (ByVal Addr As Long) As Long Private Declare Function GlobalSize Lib "kernel32" (ByVal hMem As Long) As Long Private Declare Function GlobalFree Lib "kernel32" (ByVal hMem As Long) As Long Private Declare Sub RtlMoveMemory Lib "kernel32" (ByVal des As Long, ByVal src As Long, ByVal cnt As Long) Private Declare Sub Copyjpegtobytearray Lib "kernel32" Alias "RtlMoveMemory" (ByRef des As Byte, ByVal src As Long, ByVal cnt As Long) ' Properties Private jpeginmemory() As Byte Private buffersize As Long Public Property Get jpegbuffer() As Byte() jpegbuffer = jpeginmemory End Property Public Property Get bsize() As Long bsize = buffersize End Property ' The function deliverjpeg does all the work Public Function deliverjpeg() As Long Dim rcode As Long Dim myimage As imgdes Dim bufferaddress As Long Dim buffhandle As Long rcode = allocimage(myimage, 325, 140, 8) ' Create the image buffersize = 0 If (rcode = NO_ERROR) Then rcode = zeroimage(255, myimage) ' White background textinimage myimage, "hello" ' Put the text string into the image rcode = savejpgtobuffer(bufferaddress, myimage, 50) ' Put the image into JPEG form in a buffer freeimage myimage ' Free the image If (rcode = NO_ERROR) Then buffhandle = GlobalHandle(bufferaddress) buffersize = GlobalSize(buffhandle) ReDim jpeginmemory(0 To buffersize) As Byte ' Allocate a byte array to hold the JPEG data Copyjpegtobytearray jpeginmemory(0), bufferaddress, buffersize ' Copy the JPEG data to a byte array rcode = GlobalFree(buffhandle) ' Free the original JPEG buffer End If End If deliverjpeg = rcode End Function Public Function releasejpeg() As Long ReDim jpeginmemory(0 To 0) As Byte ' Release the byte array holding the JPEG data releasejpeg = 0 End Function Private Sub textinimage(timage As imgdes, caption As String) ' textinimage function source is not shown here ' but is in zipped source file vicaxdemo.zip End Sub
<html> <head> <title>Sendimage.asp: Victor Library creates and delivers a jpeg image to browser</title> </head> <body> <!--- This is a demonstration of ASP access to the Victor Library through an ActiveX control created with Visual Basic Put sendimage.asp and victoraxdemo.dll together in the same directory on the server. Register victoraxdemo.dll using regsvr32.exe Put vic32.dll into the windows/system directory on the server. (An eval copy of vic32.dll is available at http://www.catenarysystems.com/download/vic5e.html) For more info about the Victor Library visit www.catenarysystems.com ---> <% Dim vt ' the class "victest1" Dim rcode ' the value returned from a function call in victest1 dim vicjpegimage ' jpeg buffer Set vt = Server.CreateObject("victorAXdemo.victest1") rcode = vt.deliverjpeg() ' Create the JPEG data vicjpegimage = vt.jpegbuffer ' Get the JPEG data Response.Expires = 0 Response.Buffer = true Response.Clear Response.ContentType = "image/jpeg" Response.BinaryWrite(vicjpegimage) ' Send the JPEG data to the browser Response.End rcode = vt.releasejpeg() ' Release the memory %> </body> </html>
Download the C/C++ source code and corresponding ASP page for this example: vicaxdemovc.zip (19 kb)
// victest1.cpp : Implementation of Cvictest1 #include "stdafx.h" #include "atlbase.h" #include "VictorAXdemoVC.h" #include "victest1.h" #include <vicdefs.h> void textinimage(imgdes *timage, char *caption); ///////////////////////////////////////////////////////////////////////////// // Cvictest1 // Global variables int Buffersize = 0; UCHAR *Bufferaddress; VARIANT Jpeginmemory; STDMETHODIMP Cvictest1::deliverjpeg() { int rcode; imgdes myimage; HGLOBAL buffhandle; SAFEARRAYBOUND rgsabound[1]; rcode = allocimage(&&myimage, 325, 140, 8); Buffersize = 0; if (rcode == NO_ERROR) { zeroimage(255, &myimage); // White background textinimage(&myimage, "hello"); rcode = savejpgtobuffer(&Bufferaddress, &myimage, 50); freeimage (&myimage); if (rcode == NO_ERROR) { buffhandle = GlobalHandle(Bufferaddress); Buffersize = GlobalSize(buffhandle); if (Buffersize > 0) { VariantInit(&Jpeginmemory); Jpeginmemory.vt = VT_ARRAY | VT_UI1; rgsabound[0].cElements = Buffersize; rgsabound[0].lLbound = 0; Jpeginmemory.parray = SafeArrayCreate(VT_UI1,1,rgsabound); if(Jpeginmemory.parray != NULL) { void * pArrayData = NULL; //Get a pointer to beginning of data area in Jpeginmemory SafeArrayAccessData(Jpeginmemory.parray,&pArrayData); //Copy jpeg data to it memcpy(pArrayData, Bufferaddress, Buffersize); GlobalFree(buffhandle); //Unlock the data SafeArrayUnaccessData(Jpeginmemory.parray); } rcode = S_OK; // S_OK same as NO_ERROR } else rcode = S_FALSE; } } return (rcode); } STDMETHODIMP Cvictest1::releasejpeg() { if(Buffersize > 0) { VariantClear(&Jpeginmemory); return (S_OK); } else return (S_FALSE); } STDMETHODIMP Cvictest1::get_jpegbuffer(VARIANT *pVal) { if(Buffersize > 0) { *pVal = Jpeginmemory; return (S_OK); } else return (S_FALSE); } STDMETHODIMP Cvictest1::get_jpegsize(VARIANT *pVal) { CComVariant bsize((long)Buffersize); *pVal = bsize; return (S_OK); } void textinimage(imgdes *timage, char *caption) { static LOGFONT lf = { // Use font described by LOGFONT struct 0, 0, 0, 0, FW_HEAVY, 0, 0, 0, ANSI_CHARSET, OUT_DEFAULT_PRECIS, CLIP_DEFAULT_PRECIS, DEFAULT_QUALITY, DEFAULT_PITCH | FF_SWISS, "ARIAL" }; HANDLE hFont, hOldFont; HANDLE hOldBitmap; HWND hWnd; HDC hdc, hMemDC; RECT rc; int captionHt, captionWd, imageareaHt, imageareaWd; int rcode; lf.lfHeight = 100; hWnd = GetActiveWindow(); hdc = GetDC(hWnd); hMemDC = CreateCompatibleDC(hdc); hFont = CreateFontIndirectA(&lf); // Create our font SetBkMode(hMemDC, TRANSPARENT); hOldFont = (HANDLE)::SelectObject(hMemDC, hFont); // Select font into DC // Don't write any text, just fill rc with text dimensions DrawText(hMemDC, caption, -1, &rc, DT_CALCRECT | DT_LEFT | DT_EXPANDTABS | DT_NOPREFIX); // Calculate the text size captionHt = rc.bottom - rc.top + 1; captionWd = rc.right - rc.left + 1; // Calculate image area size imageareaHt = timage->endy - timage->sty + 1; imageareaWd = timage->endx - timage->stx + 1; // Set the rect for adding the text // Center text in image if text is smaller than image area SetRect(&rc, 0, 0, timage->endx, timage->endy); if (captionHt < imageareaHt) rc.top = (imageareaHt - captionHt) / 2; if (captionWd < imageareaWd) rc.left = (imageareaWd - captionWd) / 2; // Select image into the memory DC hOldBitmap = (HANDLE)::SelectObject(hMemDC, timage->hBitmap); // Write the text rcode = ::DrawText(hMemDC, caption, -1, &rc, DT_LEFT | DT_EXPANDTABS | DT_NOPREFIX); // Restore the original bitmap and font and delete the new font SelectObject(hMemDC, hOldBitmap); DeleteObject (SelectObject(hMemDC, hOldFont)); DeleteDC (hMemDC); // Delete memory DC ReleaseDC(hWnd, hdc); }
<html> <head> <title>Sendimagevc.asp: Victor Library creates and delivers a jpeg image to browser</title> </head> <body> <!--- This is a demonstration of ASP access to the Victor Library through an ActiveX control created with C/C++ Put sendimagevc.asp and victoraxdemovc.dll together in the same directory on the server. Register victoraxdemovc.dll using regsvr32.exe Put vic32.dll into the windows/system directory on the server. (An eval copy of vic32.dll is available at http://www.catenarysystems.com/download/vic5e.html) For more info about the Victor Library visit www.catenarysystems.com ---> <% Dim vt ' the class "victest1" Dim rcode ' the value returned from a function call in victest1 dim vicjpegimage ' jpeg buffer Set vt = Server.CreateObject("victorAXdemovc.victest1") rcode = vt.deliverjpeg() ' Create the JPEG data vicjpegimage = vt.jpegbuffer ' Get the JPEG data Response.Expires = 0 Response.Buffer = true Response.Clear Response.ContentType = "image/jpeg" Response.BinaryWrite(vicjpegimage) ' Send the JPEG data to the browser Response.End rcode = vt.releasejpeg() ' Release the memory %> </body> </html>
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