Zig Requires Chilkat v11.7.0+

QR Code with Non-English Text (UTF-8 and ECI)

See more QR Code Examples

Demonstrates text outside ASCII. QrCode always stores text as UTF-8 bytes, which is what phones expect. A QR code can also say so explicitly with an ECI header: setting encoding.eci to 26 declares the bytes to be UTF-8, for readers that would otherwise assume another character set. The header costs a little space, and a few older readers do not understand it, so it is off by default. 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 text is "Gruesse aus Muenchen" written with u-umlaut and sharp s.  It is given here with
    // JSON escapes only so that this source is plain ASCII.  Decode turns the escapes into characters.
    const sb_text = try chilkat.StringBuilder.init();
    defer sb_text.deinit();
    sb_text.append("Gr\u{00fc}\u{00df}e aus M\u{00fc}nchen") catch {};
    sb_text.decode("json", "utf-8") catch {};

    const json = try chilkat.JsonObject.init();
    defer json.deinit();
    json.updateSb("payload.text", sb_text) catch {};
    json.updateString("output.path", "qa_output/qr_utf8.png") catch {};
    json.updateBool("output.overwrite", true) catch {};
    json.updateString("output.return", "none") catch {};

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

    // 17 characters, three of which take two bytes in UTF-8.
    std.debug.print("characters: {d}\n", .{sb_text.getLength()});
    std.debug.print("bytes encoded: {d}\n", .{json_out.intOf("symbols[0].payloadBytes")});
    std.debug.print("ECI header: {}\n", .{json_out.hasMember("symbols[0].selectedEncoding.eci")});

    // Without an ECI header (qa_output/qr_utf8.png):

    // 

    // The same text with an ECI header declaring UTF-8.
    json.updateInt("encoding.eci", 26) catch {};
    json.updateString("output.path", "qa_output/qr_utf8_eci.png") catch {};
    fmt.qrCode("generate", json, json_out) catch {
        std.debug.print("{s}\n", .{try fmt.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("with encoding.eci = 26, ECI header: {}, value {d}\n", .{ json_out.hasMember("symbols[0].selectedEncoding.eci"), json_out.intOf("symbols[0].selectedEncoding.eci") });

    // With the ECI header (qa_output/qr_utf8_eci.png).  Both scan as the same text:

    // 

    // Sample output:

    // characters: 17
    // bytes encoded: 20
    // ECI header: False
    // with encoding.eci = 26, ECI header: True, value 26
}