Zig Requires Chilkat v11.7.0+

Replace the Second (or Every) Occurrence of a Label in a PDF

See more PDF Text Replacement Examples

Demonstrates the "occurrence" member of a label entry. By default the first occurrence of a label, in reading order across the selected pages, is replaced; "occurrence" can be a number for the nth, or "all" for every occurrence. The invoice template has "Ref:" twice. Zig

const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

    // 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 invoice_template.pdf

    const pdf = try chilkat.Pdf.init();
    defer pdf.deinit();
    pdf.loadFile("qa_data/pdf/invoice_template.pdf") catch {
        std.debug.print("{s}\n", .{try pdf.getLastErrorText(alloc)});
        return;
    };

    const json = try chilkat.JsonObject.init();
    defer json.deinit();
    const json_out = try chilkat.JsonObject.init();
    defer json_out.deinit();

    // This template's {{placeholders}} are not being filled here: "keep" leaves them as they are
    // (the default, "error", would refuse to apply while a placeholder on the page has no value).
    json.updateString("unusedPlaceholders", "keep") catch {};

    // "Ref:" appears twice on the page (A-1 near the top, A-2 below the totals).
    // The default replaces the first occurrence only.
    json.updateString("labels[0].label", "Ref:") catch {};
    json.updateString("labels[0].value", "B-7") catch {};
    pdf.textReplace("check", json, json_out) catch {
        std.debug.print("{s}\n", .{try pdf.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("default: {d} occurrence replaced\n", .{json_out.intOf("replacements[0].count")});

    // The second occurrence only.
    json.updateString("labels[0].occurrence", "2") catch {};
    pdf.textReplace("check", json, json_out) catch {
        std.debug.print("{s}\n", .{try pdf.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("occurrence 2: {d} occurrence replaced\n", .{json_out.intOf("replacements[0].count")});

    // Every occurrence.
    json.updateString("labels[0].occurrence", "all") catch {};
    pdf.textReplace("apply", json, json_out) catch {
        std.debug.print("{s}\n", .{try pdf.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("occurrence all: {d} occurrences replaced\n", .{json_out.intOf("replacements[0].count")});

    pdf.writeFile("qa_output/invoice_refs.pdf") catch {
        std.debug.print("{s}\n", .{try pdf.getLastErrorText(alloc)});
        return;
    };

    // Sample output:

    // default: 1 occurrence replaced
    // occurrence 2: 1 occurrence replaced
    // occurrence all: 2 occurrences replaced
}