Objective-C 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. Objective-C

#import <CkoJsonObject.h>
#import <CkoFormats.h>
#import <CkoBinData.h>
#import <CkoStringBuilder.h>

BOOL success = NO;

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

CkoJsonObject *json = [[CkoJsonObject alloc] init];
[json UpdateString: @"payload.text" value: @"CHILKAT"];
[json UpdateBool: @"output.includeModuleData" value: YES];

CkoFormats *fmt = [[CkoFormats alloc] init];
CkoJsonObject *jsonOut = [[CkoJsonObject alloc] init];
success = [fmt QrCode: @"generate" jsonIn: json jsonOut: jsonOut];
if (success == NO) {
    NSLog(@"%@",fmt.LastErrorText);
    return;
}

int width = [[jsonOut IntOf: @"symbols[0].moduleData.width"] intValue];
int height = [[jsonOut IntOf: @"symbols[0].moduleData.height"] intValue];
int rowBytes = [[jsonOut IntOf: @"symbols[0].moduleData.rowBytes"] intValue];
NSLog(@"%@%@",@"kind: ",[jsonOut StringOf: @"symbols[0].moduleData.kind"]);
NSLog(@"%@%d%@%d%@%d%@",@"modules: ",width,@" x ",height,@", ",rowBytes,@" bytes per row");

//  The matrix is height rows of rowBytes bytes.
CkoBinData *bd = [[CkoBinData alloc] init];
success = [bd AppendEncoded: [jsonOut StringOf: @"symbols[0].moduleData.bytesBase64"] encoding: @"base64"];
if (success == NO) {
    NSLog(@"%@",bd.LastErrorText);
    return;
}

CkoStringBuilder *sbRow = [[CkoStringBuilder alloc] init];
int row;
int col;
int b;
int mask = 128;
for (row = 0; row <= height - 1; row++) {
    [sbRow Clear];
    for (col = 0; col <= width - 1; col++) {
        //  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 GetByte: [NSNumber numberWithInt: ((row * rowBytes) + (col / 8))]] intValue];
        if (((b / mask) % 2) == 1) {
            [sbRow Append: @"##"];
        }
        else {
            [sbRow Append: @"  "];
        }

        mask = mask / 2;
    }

    NSLog(@"%@",[sbRow GetAsString]);
}

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

//  

//  Sample output:

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