Objective-C Requires Chilkat v11.7.0+

Add an Image (Logo) Watermark to a PDF

See more PDF Watermark Examples

Demonstrates an image watermark placed in a corner of every page. The image is a PNG or JPEG given either by path ("image.path") or, as here, as base64 in the JSON itself ("image.base64"), which suits a server that keeps its logo in a database rather than on disk. PNG transparency is kept. Giving only a width keeps the aspect ratio, and the units member says those numbers are inches rather than points. Objective-C

#import <CkoPdf.h>
#import <CkoJsonObject.h>

BOOL success = NO;

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

//  The PDF used in this example is available at four_pages.pdf

CkoPdf *pdf = [[CkoPdf alloc] init];
success = [pdf LoadFile: @"qa_data/pdf/four_pages.pdf"];
if (success == NO) {
    NSLog(@"%@",pdf.LastErrorText);
    return;
}

CkoJsonObject *json = [[CkoJsonObject alloc] init];
[json UpdateString: @"type" value: @"image"];

//  A small PNG logo, base64 encoded.  Use "image.path" instead to name a PNG or JPEG file:
//     ignore = json.UpdateString("image.path","logo.png");
[json UpdateString: @"image.base64" value: @"iVBORw0KGgoAAAANSUhEUgAAAGAAAAAgCAYAAADtwH1UAAAApElEQVR42u3a7QmAIBgAYTdpo/ZphhZti6IBylLrlXoO/G3cIeFHSgAAFDKM08rCy8Jzg6Ug8UJ0JF+EDuSXRGgxX8+jufxlTk0nFuCCiF360aidXICMiDP5uQgCXAxQI782ggAHEu7IP4sgQOcBIMA35ItgBQhQEqBmtbX6xl//hAUI3gcIELwTFiD4LEiA4NNQAYLvA+BGzJ0wvIrwLggA8DgbwPbrr8c7+lkAAAAASUVORK5CYII="];

//  The size to draw it at.  Give only the width and the height follows the aspect ratio.
[json UpdateString: @"units" value: @"in"];
[json UpdateNumber: @"image.width" numericStr: @"1.5"];

//  Bottom-right, half an inch in from the page edges.
[json UpdateString: @"position.align" value: @"bottomRight"];
[json UpdateNumber: @"position.margin" numericStr: @"0.5"];
[json UpdateNumber: @"opacity" numericStr: @"0.85"];
[json UpdateString: @"id" value: @"logo"];

CkoJsonObject *jsonOut = [[CkoJsonObject alloc] init];
success = [pdf Watermark: @"add" jsonIn: json jsonOut: jsonOut];
if (success == NO) {
    NSLog(@"%@",pdf.LastErrorText);
    return;
}

NSLog(@"%@%@%@%@",@"id: ",[jsonOut StringOf: @"id"],@" pages: ",[jsonOut StringOf: @"pages"]);

success = [pdf WriteFile: @"qa_output/four_pages_logo.pdf"];
if (success == NO) {
    NSLog(@"%@",pdf.LastErrorText);
    return;
}

//  Sample output:

//  id: logo pages: 1-4