Rust Requires Chilkat v11.7.0+

Get the Modules of a QR Code (Bit Matrix)

See more QR Code Examples

Demonstrates getting the QR code itself, as a grid of dark and light modules, to draw with something other than the built-in PNG and SVG output: on a canvas, in a PDF, on a display, or with a label printer language. With output.includeModuleData the response has symbols[0].moduleData, a bit matrix with one bit per module, each row starting on a new byte, most significant bit first, 1 for dark. The quiet zone is not part of the matrix. The example prints the symbol using two characters per module. 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", "CHILKAT");
let _ = json.update_bool("output.includeModuleData", true);

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;
}

let width = json_out.int_of("symbols[0].moduleData.width");
let height = json_out.int_of("symbols[0].moduleData.height");
let row_bytes = json_out.int_of("symbols[0].moduleData.rowBytes");
println!("kind: {}", json_out.string_of("symbols[0].moduleData.kind").unwrap_or_default());
println!("modules: {} x {}, {} bytes per row", width, height, row_bytes);

// The matrix is height rows of rowBytes bytes.
let bd = chilkat::BinData::new();
if bd.append_encoded(&json_out.string_of("symbols[0].moduleData.bytesBase64").unwrap_or_default(), "base64").is_err() {
    println!("{}", bd.last_error_text());
    return;
}

let sb_row = chilkat::StringBuilder::new();
let mut b: i32 = 0;
let mut mask = 128;
for row in 0..height {
    sb_row.clear();
    for col in 0..width {
        // The module at (col,row) is a bit of the byte at (row * rowBytes) + (col / 8).
        // The leftmost module of each byte is its most significant bit.
        if (col % 8) == 0 {
            mask = 128;
        }

        b = bd.get_byte((row * row_bytes) + (col / 8));
        if ((b / mask) % 2) == 1 {
            let _ = sb_row.append("##");
        } else {
            let _ = sb_row.append("  ");
        }

        mask = mask / 2;
    }

    println!("{}", sb_row.get_as_string().unwrap_or_default());
}

// The same symbol as the PNG that the call also returned:

// 

// Sample output:

// kind: bitMatrix
// modules: 21 x 21, 3 bytes per row
// ##############              ##############
// ##          ##      ####    ##          ##
// ##  ######  ##  ##  ####    ##  ######  ##
// ##  ######  ##  ##          ##  ######  ##
// ##  ######  ##  ##  ##  ##  ##  ######  ##
// ##          ##  ####  ##    ##          ##
// ##############  ##  ##  ##  ##############
//                 ####
// ##  ##########      ####    ##########
//     ####          ##  ########    ######
// ####  ########    ####  ##  ####      ####
//       ##  ##      ############    ####  ##
//   ######  ####  ######  ##    ##  ##
//                 ##  ##  ##    ##  ##    ##
// ##############        ##  ##    ##      ##
// ##          ##  ##  ##        ######  ####
// ##  ######  ##  ####  ##  ##    ##
// ##  ######  ##  ##  ############    ##
// ##  ######  ##  ##      ##  ####  ##
// ##          ##    ##  ########          ##
// ##############  ##      ##      ######