Print a BMP file to Printer using command

Question

I need to print a BMP file to USB printer using commands.

C++ signature is

USB_API BOOL Usb_WritePort(BOOL bUseBulkEndp, LPCVOID lpBuffer, DWORD dwNumberOfBytesToWrite, 

LPDWORD lpNumberOfBytesWritten, LPOVERLAPPED lpOverlapped);

This is my C# signature

[DllImport("usbRtb.dll", CallingConvention = CallingConvention.Cdecl)]
        public static extern Boolean Usb_WritePort(bool bUseBulkEndp, IntPtr lpBuffer, UInt32 nNumberOfBytesToWrite,
          out UInt32 lpNumberOfBytesWritten, [In] ref NativeOverlapped lpOverlapped);

I tried

 update = Usb_UpdateConnection(0, ref out1, ref out2);
        char[] files = System.Text.Encoding.ASCII.GetString(File.ReadAllBytes(@"D:\\mailman.BMP")).ToCharArray();
        update = Usb_UpdateConnection(0, ref out1, ref out2);
        byte[] pr = Encoding.BigEndianUnicode.GetBytes(files);
        intpt = Marshal.StringToCoTaskMemAnsi("\x1F\x42\x4D\x50" + ASCIIEncoding.ASCII.GetString(pr));
        count = (UInt32)pr.Count() + 4;
        var read = Usb_WritePort(true, intpt, count, out written, ref natOverlap0);

Attaching printer manual BMP image print command section: enter image description here

C++ SDK Documentation: Usb_WritePort

Syntax:

BOOL Usb_WritePort (BOOL                    bUseBulkEndp,
                                     LPCVOID              lpBuffer, 
                                     DWORD                dwNumberOfBytesToWrite, 
                                     LPDWORD            lpNumberOfBytesWritten, 
                                     LPOVERLAPPED lpOverlapped);

Purpose: Writes data to the currently selected device over the specified output endpoint. Connection needs to have first been established with Usb_UpdateConnection() API. Operation is similar to using WriteFile() in both synchronous and asynchronous modes with overlapped structure.

Parameters:

bUseBulkEndp [in] Set parameter to TRUE to write data over BULK OUT endpoint, to FALSE to write over INTERRUPT OUT endpoint

lpBuffer [in] Pointer to the buffer that contains the data to write to the device.

dwNumberOfBytesToWrite [in] Number of bytes to write to the device. This number must be less than or equal to the size, in bytes, of data buffer

lpNumberOfBytesWritten [out] Pointer to the variable that receives the number of bytes effectively written to the device.

lpOverlapped [in/out] Optional pointer to an OVERLAPPED structure, which is used for asynchronous operations. If this parameter is specified, Usb_WritePort immediately returns, and the event is signaled when the operation is complete.

Return value: TRUE if write operation succeeds, FALSE otherwise. If FALSE, user may call GetLastError() to get additional information

Printer prints nothing. Please help me to solve this.

Note that the first four slahes in your data string are not literal ones, is that correct? — Luizgrs, Feb 04 '15 at 09:36
I don't know alot about printers nor USB, but would the USB printer be able to access "D:\mailman.bmp"? I would imagine you'd have to send the bitmap data at some point. — C.Evenhuis, Feb 04 '15 at 09:42
Very hard to see how this could work. That thing on the other end of the USB cable can't see your file system. It just looks like you are making this up. Surely you need to know some details about the printer. But anyway, why do you want to spew raw data at this printer? Don't you just print using the printer driver like everybody else? — David Heffernan, Feb 04 '15 at 13:33
we need a code similar like this http://stackoverflow.com/questions/17787620/prepare-a-zpl-command-for-printing-the-mono-chrome-bitmap-image — Frebin Francis, Feb 04 '15 at 13:40
So you'll need to read the printer manual and do the coding then I guess — David Heffernan, Feb 04 '15 at 16:18
Why are you asking us? We've no idea what the printer is. You need to read the manual. — David Heffernan, Feb 04 '15 at 17:41
@David Heffernan:In the printer manual command to print the BMP Image is 1F 42 4D 50 [file] Description: This block of bytes is at the start of the file and is used to identify the file. A typical application reads this block first to ensure that the file is actually a BMP file and that it is not damaged. The first two bytes of the BMP file format are the character 'B' then the character 'M' in 1-byte ascii encoding. All of the integer values are stored in little-endian format (i.e. least-significant byte first). — Frebin Francis, Feb 05 '15 at 05:27
@David Heffernan: Can you please tell how to do it..Iam totaly new to this segment. — Frebin Francis, Feb 05 '15 at 07:09
It looks like you need to send the content of the image file. — David Heffernan, Feb 05 '15 at 07:14
@David Heffernan:I tried sending the content of BMP file in byte format.But nothing printed — Frebin Francis, Feb 05 '15 at 09:45
Does the printer understand Windows BMP files? Anyway, I cannot help you. I cannot see the printer documentation. Do consider what it looks like from my side of the keyboard. — David Heffernan, Feb 05 '15 at 09:46
@ Alex Farber: bUseBulkEndp is not a matter. We dont have a working C++ example for BMP image print. Code to print BMP image is 1F 42 4D 50 [file].We dont know what is this file means. — Frebin Francis, Feb 05 '15 at 12:42
@ Alex Farber:This is all the document that I have got. Text printing is working fine with this Usb_WritePort() Command — Frebin Francis, Feb 05 '15 at 12:45
@ Alex Farber:Can you please tell the exact code.I dont' undestand how to send whole bmp file. — Frebin Francis, Feb 05 '15 at 12:49

score 3 · Accepted Answer · answered Feb 05 '15 at 13:01

    Marshal.StringToCoTaskMemAnsi("\x1F\x42\x4D\x50" + ASCIIEncoding.ASCII.GetString(pr));

Your code is not close to correct, using ASCIIEncoding is quite wrong. The bitmap contains byte values that cannot be represented in ASCII. First thing you need to do is change the pinvoke declaration, the 2nd argument needs to be byte[] and you would be wise to avoid overlapped I/O since that requires a lot more pinvoke. So:

    [DllImport("usbRtb.dll", CallingConvention = CallingConvention.Cdecl)]
    public static extern Boolean Usb_WritePort(
        bool bUseBulkEndp, 
        byte[] lpBuffer, 
        int nNumberOfBytesToWrite,
        out int lpNumberOfBytesWritten, 
        IntPtr lpOverlapped
    );

Next thing you need to do is pay close attention to the actual bitmap. The manual demands that this is a monochrome bitmap, that is not so easy to come by these days. But you can still create one with MSPaint, start with something very small and use File + Save As, change the "Save as type" setting to "Monochrome Bitmap (*.bmp, *.dib)".

Next you need to create the proper byte[] before you call the function. It needs to resemble this:

    using (var fs = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read)) {
        byte[] inpt = new byte[fs.Length + 1];
        inpt[0] = 0x1f;
        fs.Read(inpt, 1, (int)fs.Length);
        int written;
        bool ok = Usb_WritePort(true, inpt, inpt.Length, out written, IntPtr.Zero);
        if (!ok || written != inpt.Length) throw new Exception("USB write failed");
    }

Print a BMP file to Printer using command

1 Answers1