ghostscript PDF to Png crop x and y

Question

i use ghostscript for my convertion PDF to PNG in vb.net when i crop my pdf then i convert this in png but ghostscript keep x and y position cropping in my picture.

I have solved this problem when i use gswin64.exe in cmd with : -c "<</Install {-48 -87 translate}>> setpagedevice"

but with dll Ghostcript.NET when i add this command in my code : oGSImage.CustomSwitches.Add("-c ""<</Install {-48 -87 translate}>> setpagedevice""") i have error message

Ghostscript.NET.GhostscriptAPICallException: An error occured when call to 'gsapi_init_with_args' is made: -100

my device is pngAlpha, if anyone could help me :)

Answer 1

I have found a solution : Initialize variable with the desired crop values

Dim nLeft as integer = 20
Dim nRight as integer = 20
Dim nBoth as integer = 40
Dim nUp as integer = 20

i created rasterize object with Ghostscript.NET dll : I Get Height and width size page without CustomSwitches ("-dPDFFitPage")

Dim rasterize As Rasterizer.GhostscriptRasterizer = New Rasterizer.GhostscriptRasterizer()
    rasterize.Open("PDFPath")
    Dim nHeightBased As Integer = rasterize.GetPage(72, 72, 1).Height
    Dim nWidthBased As Integer = rasterize.GetPage(72, 72, 1).Width
    rasterize.Close()

then, i create a new rasterize for get height and width size page with CustomSwitches ("-dPDFFitPage")

        rasterize = New Rasterizer.GhostscriptRasterizer()
        rasterize.CustomSwitches.Add("-dPDFFitPage")
        rasterize.Open(cPathPDF)

        Dim nHeightBound As Integer = nHeightBased - rasterize.GetPage(72, 72, 1).Height
        Dim nWidthBound As Integer = nWidthBased - rasterize.GetPage(72, 72, 1).Width
        Dim nWidthPDF As Integer = rasterize.GetPage(72, 72, 1).Width
        Dim nHeightPDF As Integer = rasterize.GetPage(72, 72, 1).Height
        rasterize.Close()

        Dim nWidthCrop As Integer = (nWidthPDF + nWidthBound) - (nLeft + nRight)
        Dim nHeightCrop As Integer = (nHeightPDF + (nHeightBound / 2)) - (nBoth + nUp)

        CropPDF("PathPDF", nLeft, nBoth, nWidthCrop, nHeightCrop)

And i Create function CropPDF :

Now we take gswinc32.exe or gswinc64.exe and .dll and copy/paste in a new path in my example i use "PathEXE"

Public Function CropPDF(ByVal cPathPDF As String, ByVal nLeft As Integer, ByVal nBoth As Integer, ByVal nWidthCrop As Integer, ByVal nHeightCrop As Integer)

    Dim cPathWithoutExtension = Path.GetDirectoryName("PDFPath") & "/" & Path.GetFileNameWithoutExtension("PDFPath")

    Dim gsPath As String = HttpContext.Current.Server.MapPath("PathEXE")
        Dim gsArgsList As List(Of String) = New List(Of String)

        gsArgsList.Add("-sDEVICE=pdfwrite")
        gsArgsList.Add(" -dFIXEDMEDIA")
        gsArgsList.Add(" -dDEVICEWIDTHPOINTS=" & nWidthCrop)
        gsArgsList.Add(" -dDEVICEHEIGHTPOINTS=" & nHeightCrop)
        gsArgsList.Add(" -o """ & cPathWithoutExtension & "_Crop.pdf""")
        gsArgsList.Add(" -c ""<</Install {-" & nLeft & " -" & nBoth & " translate} >> setpagedevice """)
        gsArgsList.Add(" -f " & cPathPDF)

        Dim gsArgs As String = String.Join(Nothing, gsArgsList)

        Process.Start(gsPath, gsArgs).WaitForExit()

        Dim OFI As FileInfo = New FileInfo(cPathPDF)
        OFI.Delete()

        Dim DestOFI As FileInfo = New FileInfo(cPathWithoutExtension & "_Crop.pdf")
        DestOFI.MoveTo(cPathPDF)

        Return cPath

End Function

Now perfect work with nLeft nRight nBoth nUp crop, hoping that it will help some people :D