Zig Requires Chilkat v11.7.0+

Put a Letterhead Behind the First Page of a PDF

See more PDF Watermark Examples

Demonstrates the pdfPage type, which places a page of another PDF as the watermark. It is the way to use a letterhead, a cover overlay or a vector logo that was saved as a PDF, and unlike an image it stays sharp at any size because it is drawn, not resampled. "zOrder" set to back puts it behind the existing content, where a letterhead belongs, and "pages" set to first restricts it to page one. 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 two_page_memo.pdf

    // The PDF used in this example is available at letterhead.pdf

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

    const json = try chilkat.JsonObject.init();
    defer json.deinit();
    json.updateString("type", "pdfPage") catch {};
    json.updateString("pdf.path", "qa_data/pdf/letterhead.pdf") catch {};

    // The page of the source PDF to use (1 by default).  "match" instead of a number places source
    // page n on target page n, which suits a set of per-page backgrounds.
    json.updateInt("pdf.page", 1) catch {};

    // Behind the memo's own text, on page one, scaled to the page.
    json.updateString("zOrder", "back") catch {};
    json.updateString("pages", "first") catch {};
    json.updateString("scale.fit", "page") catch {};
    json.updateString("id", "letterhead") catch {};

    const json_out = try chilkat.JsonObject.init();
    defer json_out.deinit();
    pdf.watermark("add", json, json_out) catch {
        std.debug.print("{s}\n", .{try pdf.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("id: {s} pages: {s}\n", .{ try json_out.stringOf(alloc, "id"), try json_out.stringOf(alloc, "pages") });

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

    // Sample output:

    // id: letterhead pages: 1
}