This mdImageConvert.bas module can use pdfium.dll to render PDFs or can use GDI+ to load PNGs and then converts these bitmaps to ZPL's text based Alternative Data Compression scheme which is used by ZPL compatible thermal printers in their graphics printing commands.
Here is a sample snippet which renders PDF to monochrome bitmap on screen and copies final ZPL content to clipboard so it can be previewed at https://labelary.com/viewer.html
Most of pdfium.dll API declares were shamelessly hoisted from PDFiumViewer by Olaf.
cheers,
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Code:
'--- mdImageConvert.bas
Insane forum restrictions do not allow too big posts in CodeBanks for no apparent reason.
Download from https://gist.github.com/wqweto/91872c81ddb3e2ebe13b48f7ea1ce502Code:
'--- Form1.frm
Option Explicit
Private Declare Function GdipDisposeImage Lib "gdiplus" (ByVal hImage As Long) As Long
Private Sub Form_Click()
Const PDF_FILE As String = "D:\TEMP\label_base64_pdf.pdf"
Const DPI As Long = 203
Const LABEL_WIDTH As Single = 108 ' mm '--- A6 is 105x148 mm
Const TOP_MARGIN As Single = 0 ' mm
Const LEFT_MARGIN As Single = 3 ' mm
Const RIGHT_MARGIN As Single = 3 ' mm
Dim hImg As Long
Dim lDpmm As Long ' Dots-Per-Millimeter
Dim cOutput As Collection
On Error GoTo EH
lDpmm = Int(DPI / 25.4 + 0.5)
hImg = ConvertBitmapToMonochrome(LoadPdfPageToBitmap(ReadBinaryFile(PDF_FILE), (LABEL_WIDTH - LEFT_MARGIN - RIGHT_MARGIN) * lDpmm))
DrawBitmapToHDC hDC, hImg, 0, 0
Set cOutput = New Collection
cOutput.Add "^XA"
cOutput.Add "^FO" & LEFT_MARGIN * lDpmm & "," & TOP_MARGIN * lDpmm
cOutput.Add "^GF" & ConvertBitmapToZplGraphics(hImg): hImg = 0
cOutput.Add "^FS"
cOutput.Add "^PQ1,0,1,Y"
cOutput.Add "^XZ"
Clipboard.Clear: Clipboard.SetText ConcatCollection(cOutput, vbCrLf)
Exit Sub
EH:
If hImg <> 0 Then
Call GdipDisposeImage(hImg)
End If
End Sub
Public Function ReadBinaryFile(sFile As String) As Byte()
Dim baBuffer() As Byte
Dim nFile As Integer
On Error GoTo EH
baBuffer = vbNullString
nFile = FreeFile
Open sFile For Binary Access Read Shared As nFile
If LOF(nFile) > 0 Then
ReDim baBuffer(0 To LOF(nFile) - 1) As Byte
Get nFile, , baBuffer
End If
Close nFile
ReadBinaryFile = baBuffer
EH:
End Functioncheers,
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