Lua 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. Lua

local chilkat = require("chilkat")

-- 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.
local pdf = chilkat.Pdf.new()
local success = pdf:load_file("qa_data/pdf/quote_subset_font.pdf")
if not success then
    print(pdf.last_error_text)
    return
end

local json = chilkat.JsonObject.new()
local jsonOut = chilkat.JsonObject.new()

-- 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:update_string("labels[0].label", "Quote #:")
json:update_string("labels[0].value", "58314")
success = pdf:text_replace("check", json, jsonOut)
if not success then
    print(pdf.last_error_text)
    return
end

print("58314: ok = " .. tostring(jsonOut:bool_of("ok")))

-- ...but "Q" and "-" are not in the subset (nothing in the quotation's regular text uses them).
json:update_string("labels[0].value", "Q-58341")
success = pdf:text_replace("check", json, jsonOut)
if not success then
    print(pdf.last_error_text)
    return
end

print("Q-58341: ok = " .. tostring(jsonOut:bool_of("ok")))
if not jsonOut:bool_of("ok") then
    -- The problem names the font and the characters it cannot draw.
    print("    reason: " .. jsonOut:string_of("problems[0].reason"))
    print("    font: " .. jsonOut:string_of("problems[0].font"))
    print("    missing: " .. jsonOut:string_of("problems[0].chars"))
end

-- "apply" with a problem returns false and changes nothing.
success = pdf:text_replace("apply", json, jsonOut)
print("apply returned " .. tostring(success) .. ", applied = " .. tostring(jsonOut:bool_of("applied")))

-- 2. A font that is not embedded and not one of the standard 14.
local pdf2 = chilkat.Pdf.new()
success = pdf2:load_file("qa_data/pdf/letter_verdana.pdf")
if not success then
    print(pdf2.last_error_text)
    return
end

local json2 = chilkat.JsonObject.new()
json2:update_string("labels[0].label", "Account Number:")
json2:update_string("labels[0].value", "0000099999")
success = pdf2:text_replace("check", json2, jsonOut)
if not success then
    print(pdf2.last_error_text)
    return
end

print("Verdana, not embedded: ok = " .. tostring(jsonOut:bool_of("ok")) .. ", reason: " .. jsonOut:string_of("problems[0].reason") .. ", font: " .. jsonOut:string_of("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