Rust Requires Chilkat v11.7.0+

QR Code with a Text Caption

See more QR Code Examples

Demonstrates printing a line of text under a QR code, such as the order number or the address the code holds, so that a person can read it too. render.text turns the caption on and gives its value, which is printable ASCII and is drawn in a built-in font that needs no font files. The caption can go above or below the symbol, be aligned left, center or right, and be scaled. Rust

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

let json = chilkat::JsonObject::new();
let _ = json.update_string("payload.text", "https://www.chilkatsoft.com/order/12345");
let _ = json.update_int("render.moduleSize", 6);

// The caption.  It need not be the same as the text in the QR code.
let _ = json.update_bool("render.text.enabled", true);
let _ = json.update_string("render.text.value", "ORDER 12345");
// position is "below" (the default) or "above".  alignment is "center" (the default), "left" or "right".
let _ = json.update_string("render.text.position", "below");
// Each dot of the caption's font is drawn this many pixels wide.
let _ = json.update_int("render.text.scale", 3);

let _ = json.update_string("output.path", "qa_output/qr_caption.png");
let _ = json.update_bool("output.overwrite", true);
let _ = json.update_string("output.return", "none");

let fmt = chilkat::Formats::new();
let json_out = chilkat::JsonObject::new();
if fmt.qr_code("generate", &json, &json_out).is_err() {
    println!("{}", fmt.last_error_text());
    return;
}

println!("caption: {}", json_out.string_of("measurements[0].text").unwrap_or_default());
println!("caption scale: {}", json_out.int_of("measurements[0].textScale"));
println!("height added for the caption: {} pixels", json_out.int_of("measurements[0].textBandPx"));
println!("image: {} x {} pixels", json_out.int_of("measurements[0].canvasWidth"), json_out.int_of("measurements[0].canvasHeight"));

// The image written to qa_output/qr_caption.png:

// 

// Sample output:

// caption: ORDER 12345
// caption scale: 3
// height added for the caption: 21 pixels
// image: 222 x 243 pixels