Go Requires Chilkat v11.7.0+

Why a PDF Text Replacement Is Refused: the Font Rule

See more PDF Text Replacement Examples

A PDF stores glyphs drawn with particular fonts, so new text can only be drawn when the original font can draw it. This example shows the two common refusals. A font embedded as a subset carries only the glyphs the document used: a value made of other characters is refused with the reason missingGlyph, and the report names the font and the characters it lacks. A font that is neither one of the standard 14 nor embedded (here Verdana) is refused with nonStandardUnembeddedFont, because Chilkat cannot know what a viewer will draw for it. A non-embedded Arial, Times New Roman or Courier New is treated as the standard font every viewer substitutes for it. Go

    success := false

    //  This example requires the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    //  The PDF used in this example is available at quote_subset_font.pdf
    //  and letter_verdana.pdf

    //  1. An embedded subset font: only the glyphs the document uses are in the PDF.
    pdf := chilkat.NewPdf()
    success = pdf.LoadFile("qa_data/pdf/quote_subset_font.pdf")
    if success == false {
        fmt.Println(pdf.LastErrorText())
        pdf.DisposePdf()
        return
    }

    json := chilkat.NewJsonObject()
    jsonOut := chilkat.NewJsonObject()

    //  The regular face's subset carries the characters of the quotation's text, among them the digits of
    //  "58341".  A new number made of those digits can be drawn...
    json.UpdateString("labels[0].label","Quote #:")
    json.UpdateString("labels[0].value","58314")
    success = pdf.TextReplace("check",json,jsonOut)
    if success == false {
        fmt.Println(pdf.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        return
    }

    fmt.Println("58314: ok = ", *jsonOut.BoolOf("ok"))

    //  ...but "Q" and "-" are not in the subset (nothing in the quotation's regular text uses them).
    json.UpdateString("labels[0].value","Q-58341")
    success = pdf.TextReplace("check",json,jsonOut)
    if success == false {
        fmt.Println(pdf.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        return
    }

    fmt.Println("Q-58341: ok = ", *jsonOut.BoolOf("ok"))
    if jsonOut.BoolOf("ok") == false {
        //  The problem names the font and the characters it cannot draw.
        fmt.Println("    reason: ", *jsonOut.StringOf("problems[0].reason"))
        fmt.Println("    font: ", *jsonOut.StringOf("problems[0].font"))
        fmt.Println("    missing: ", *jsonOut.StringOf("problems[0].chars"))
    }

    //  "apply" with a problem returns false and changes nothing.
    success = pdf.TextReplace("apply",json,jsonOut)
    fmt.Println("apply returned ", success, ", applied = ", *jsonOut.BoolOf("applied"))

    //  2. A font that is not embedded and not one of the standard 14.
    pdf2 := chilkat.NewPdf()
    success = pdf2.LoadFile("qa_data/pdf/letter_verdana.pdf")
    if success == false {
        fmt.Println(pdf2.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        pdf2.DisposePdf()
        return
    }

    json2 := chilkat.NewJsonObject()
    json2.UpdateString("labels[0].label","Account Number:")
    json2.UpdateString("labels[0].value","0000099999")
    success = pdf2.TextReplace("check",json2,jsonOut)
    if success == false {
        fmt.Println(pdf2.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        pdf2.DisposePdf()
        json2.DisposeJsonObject()
        return
    }

    fmt.Println("Verdana, not embedded: ok = ", *jsonOut.BoolOf("ok"), ", reason: ", *jsonOut.StringOf("problems[0].reason"), ", font: ", *jsonOut.StringOf("problems[0].font"))

    //  Sample output:

    //  58314: ok = true
    //  Q-58341: ok = false
    //      reason: missingGlyph
    //      font: AAAAAA+DejaVuSans
    //      missing: Q-
    //  apply returned false, applied = false
    //  Verdana, not embedded: ok = false, reason: nonStandardUnembeddedFont, font: Verdana

    pdf.DisposePdf()
    json.DisposeJsonObject()
    jsonOut.DisposeJsonObject()
    pdf2.DisposePdf()
    json2.DisposeJsonObject()