PDF Text Annotation

How to add Text Annotation into existing PDF file

A Text Annotation is an annotation attached to a specific location in a PDF document. When closed, the annotation is displayed as an icon; when opened, it should display a pop-up window containing the note text in the font and size chosen by the reader.

Annotations are contained by the Annotations collection of a particular Page. This collection contains the annotations for that individual page only; every page has its own Annotations collection.

To add an annotation to a particular page, add it to that page’s Annotations collection with the Add method.

  1. First, create an annotation that you want to add to the PDF.
  2. Then open the input PDF.
  3. Add the annotation to the Page object’s Annotations collection.

The following code snippet shows you how to add an annotation in a PDF page.

using namespace System;
using namespace Aspose::Pdf;
using namespace Aspose::Pdf::Text;

void AddTextAnnotation()
{
    String _dataDir("C:\\Samples\\");

    // Load the PDF file
    auto document = MakeObject<Document>(_dataDir + u"sample.pdf");

    auto page = document->get_Pages()->idx_get(1);
    auto rect = MakeObject<Rectangle>(200, 750, 400, 790);
    auto textAnnotation = MakeObject<Aspose::Pdf::Annotations::TextAnnotation>(page, rect);

    textAnnotation->set_Title(u"Aspose User");
    textAnnotation->set_Subject(u"Sample Subject");
    textAnnotation->set_State(Aspose::Pdf::Annotations::AnnotationState::Accepted);
    textAnnotation->set_Contents(u"Sample contents for the annotation");
    textAnnotation->set_Open(true);
    textAnnotation->set_Icon(Aspose::Pdf::Annotations::TextIcon::Circle);

    auto border = MakeObject<Aspose::Pdf::Annotations::Border>(textAnnotation);
    border->set_Width(5);
    border->set_Dash(MakeObject<Aspose::Pdf::Annotations::Dash>(1, 1));
    textAnnotation->set_Border(border);
    textAnnotation->set_Rect(rect);

    page->get_Annotations()->Add(textAnnotation);
    document->Save(_dataDir + u"sample_textannot.pdf");
}

Get Text Annotation

Please try using the following code snippet to Get Text Annotation in PDF document:

void GetTextAnnotation() {

    String _dataDir("C:\\Samples\\");

    // Load the PDF file
    auto document = MakeObject<Document>(_dataDir + u"sample_textannot.pdf");

    // Filter annotations using AnnotationSelector
    auto page = document->get_Pages()->idx_get(1);

    auto annotationSelector = MakeObject<Aspose::Pdf::Annotations::AnnotationSelector>(
        MakeObject<Aspose::Pdf::Annotations::LineAnnotation>(page, Rectangle::get_Trivial(), Point::get_Trivial(), Point::get_Trivial()));
    page->Accept(annotationSelector);
    auto textAnnotations = annotationSelector->get_Selected();

    // print results
    for (auto fa : textAnnotations) {
        Console::WriteLine(fa->get_Rect());
    }
}

Delete Text Annotation from PDF file

The following code snippet shows how Delete Text Annotation from a PDF file.

void DeleteTextAnnotation() {

    String _dataDir("C:\\Samples\\");
    // Load the PDF file
    auto document = MakeObject<Document>(_dataDir + u"sample_textannot.pdf");

    // Filter annotations using AnnotationSelector
    auto page = document->get_Pages()->idx_get(1);
    auto annotationSelector = MakeObject<Aspose::Pdf::Annotations::AnnotationSelector>(
        MakeObject<Aspose::Pdf::Annotations::LineAnnotation>(page, Rectangle::get_Trivial(), Point::get_Trivial(), Point::get_Trivial()));
    page->Accept(annotationSelector);
    auto textAnnotations = annotationSelector->get_Selected();

    // delete annotations
    for (auto fa : textAnnotations) {
        page->get_Annotations()->Delete(fa);
    }
    document->Save(_dataDir + u"sample_textannot_del.pdf");
}

How to add (or Create) new Free Text Annotation

A free text annotation displays text directly on the page. In the following snippet, we add free text annotation above the first occurrence of the string.

using namespace System;
using namespace Aspose::Pdf;
using namespace Aspose::Pdf::Text;
using namespace Aspose::Pdf::Annotations;

void FreeTextAnnotations::AddFreeTextAnnotationDemo()
{
    String _dataDir("C:\\Samples\\");

    // Load the PDF file
    auto document = MakeObject<Document>(_dataDir + u"sample.pdf");
    auto page = document->get_Pages()->idx_get(1);

    auto defaultAppearance = MakeObject<DefaultAppearance>();
    defaultAppearance->set_FontName(u"Helvetica");
    defaultAppearance->set_FontSize(12);
    defaultAppearance->set_TextColor(System::Drawing::Color::get_Blue());

    auto freeTextAnnotation = MakeObject<FreeTextAnnotation>(page, new Rectangle(300.0, 770.0, 400.0, 790.0), defaultAppearance);

    freeTextAnnotation->set_RichText(u"Free Text Demo");
    page->get_Annotations()->Add(freeTextAnnotation);
    document->Save(_dataDir + u"sample_freetext.pdf");
}

Get FreeText Annotation

Please try using the following code snippet to Get Text Annotation in PDF document:

void FreeTextAnnotations::GetFreeTextAnnotation() {

    String _dataDir("C:\\Samples\\");

    // Load the PDF file
    auto document = MakeObject<Document>(_dataDir + u"sample_freetext.pdf");
    auto page = document->get_Pages()->idx_get(1);

    // Filter annotations using AnnotationSelector
    auto annotationSelector = MakeObject<AnnotationSelector>(
        new FreeTextAnnotation(page, Rectangle::get_Trivial(), new DefaultAppearance()));
    page->Accept(annotationSelector);
    auto freeTextAnnotations = annotationSelector->get_Selected();

    // print results
    for (auto fa : freeTextAnnotations) {
        Console::WriteLine(fa->get_Rect());
    }
}

Make Free Text Annotation Invisible

Sometimes, it is necessary to create a watermark that isn’t visible in the document when viewing it but should be visible when the document is printed. Use annotation flags for this purpose. The following code snippet shows how.

void FreeTextAnnotations::MakeFreeTextAnnotationInvisble() {

    String _dataDir("C:\\Samples\\");

    // Open document
    auto doc = MakeObject<Document>(_dataDir + u"input.pdf");

    auto annotation = new FreeTextAnnotation(doc->get_Pages()->idx_get(1),
        MakeObject<Rectangle>(50, 600, 250, 650),
        MakeObject<DefaultAppearance>(u"Helvetica", 16,
            System::Drawing::Color::get_Red()));
    annotation->set_Contents(u"ABCDEFG");
    annotation->get_Characteristics()->set_Border(System::Drawing::Color::get_Red());
    annotation->set_Flags (AnnotationFlags::Print | AnnotationFlags::NoView);
    doc->get_Pages()->idx_get(1)->get_Annotations()->Add(annotation);

    // Save output file
    doc->Save(_dataDir + u"InvisibleAnnotation_out.pdf");
}

Delete FreeText Annotation

The following code snippet shows how Delete FreeText Annotation from a PDF file.

void FreeTextAnnotations::DeleteFreeTextAnnotation() {

    String _dataDir("C:\\Samples\\");

    // Load the PDF file
    auto document = MakeObject<Document>(_dataDir + u"sample_freetext.pdf");

    // Filter annotations using AnnotationSelector
    auto page = document->get_Pages()->idx_get(1);

    auto annotationSelector = MakeObject<AnnotationSelector>(
        new FreeTextAnnotation(page, Rectangle::get_Trivial(), new DefaultAppearance()));
    page->Accept(annotationSelector);
    auto freeTextAnnotations = annotationSelector->get_Selected();

    // delete annotations
    for (auto fa : freeTextAnnotations) {
        page->get_Annotations()->Delete(fa);
    }
    document->Save(_dataDir + u"sample_freetext_del.pdf");
}
PDF Highlights Annotation using C++