Objective-C 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. Objective-C

#import <CkoJsonObject.h>
#import <CkoFormats.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: @"https://www.chilkatsoft.com/order/12345"];
[json UpdateInt: @"render.moduleSize" value: [NSNumber numberWithInt: 6]];

//  The caption.  It need not be the same as the text in the QR code.
[json UpdateBool: @"render.text.enabled" value: YES];
[json UpdateString: @"render.text.value" value: @"ORDER 12345"];
//  position is "below" (the default) or "above".  alignment is "center" (the default), "left" or "right".
[json UpdateString: @"render.text.position" value: @"below"];
//  Each dot of the caption's font is drawn this many pixels wide.
[json UpdateInt: @"render.text.scale" value: [NSNumber numberWithInt: 3]];

[json UpdateString: @"output.path" value: @"qa_output/qr_caption.png"];
[json UpdateBool: @"output.overwrite" value: YES];
[json UpdateString: @"output.return" value: @"none"];

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;
}

NSLog(@"%@%@",@"caption: ",[jsonOut StringOf: @"measurements[0].text"]);
NSLog(@"%@%d",@"caption scale: ",[[jsonOut IntOf: @"measurements[0].textScale"] intValue]);
NSLog(@"%@%d%@",@"height added for the caption: ",[[jsonOut IntOf: @"measurements[0].textBandPx"] intValue],@" pixels");
NSLog(@"%@%d%@%d%@",@"image: ",[[jsonOut IntOf: @"measurements[0].canvasWidth"] intValue],@" x ",[[jsonOut IntOf: @"measurements[0].canvasHeight"] intValue],@" pixels");

//  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