Templates in Flutter PDF

18 Nov 20186 minutes to read

A PDF template is a drawing surface, where contents can be added. All the elements that can be added to a PdfPage is supported in PdfTemplate as well. The template in turn can be drawn over the page or can be positioned at any part of the page.

Creating a new PDF template

The PdfTemplate class can be used to create a new PDF template. You can add contents to the template using graphics property of the PdfTemplate object.

The following code example explains how to add contents to the PdfTemplate and render into the new PDF page.

DART

//Create a new PDF document.
PdfDocument document = PdfDocument();

//Create a PDF Template.
PdfTemplate template = PdfTemplate(100, 50);

//Draw a rectangle on the template graphics
template.graphics!.drawRectangle(
    brush: PdfBrushes.burlyWood, bounds: Rect.fromLTWH(0, 0, 100, 50));

//Draw a string using the graphics of the template.
template.graphics!.drawString(
    'Hello World', PdfStandardFont(PdfFontFamily.helvetica, 14),
    brush: PdfBrushes.black, bounds: Rect.fromLTWH(5, 5, 0, 0));

//Add a new page and draw the template on the page graphics of the document.
document.pages.add().graphics.drawPdfTemplate(template, Offset(0, 0));

//Save and dispose the PDF document
File('Output.pdf').writeAsBytes(await document.save());
document.dispose();

Creating templates from existing PDF document

Essential PDF supports template creation using the CreateTemplate method, enabling users to extract content from an existing PDF page and seamlessly incorporate it into a new PDF document.

The below code illustrates how to create the template from an existing page and draw it in a new PDF document.

DART

//Load the PDF document.
    PdfDocument loadedDocument =
      PdfDocument(inputBytes: File('Input.pdf').readAsBytesSync());
    //Get the first page from the document.
    PdfPage loadedPage = loadedDocument.pages[0];
    //Create a PDF Template.
    PdfTemplate template = loadedPage.createTemplate();
    //Create a new PDF document.
    PdfDocument document = PdfDocument();
    //Add the page.
    PdfPage page = document.pages.add();
    //Create the graphics.
    PdfGraphics graphics = page.graphics;
    //Draw the template.
    graphics.drawPdfTemplate(template, Offset(0, 0));
    //Save and dispose of the PDF document.
    File('Output.pdf').writeAsBytes(await document.save());
    document.dispose();

Working with PdfPageTemplateElement

The PdfPageTemplateElement is a template element that can be added to any part of the PDF page such as header, footer, and more.

The following code example explains how to add the page template elements to a PDF document.

DART

//Create a new PDF document
PdfDocument document = PdfDocument();

//Add a page to the PDF document
PdfPage page = document.pages.add();

Rect bounds = Rect.fromLTWH(0, 0, page.getClientSize().width, 50);
PdfFont font = PdfStandardFont(PdfFontFamily.helvetica, 7);

//Create a header and draw the image
PdfPageTemplateElement header = PdfPageTemplateElement(bounds);

//Get image data
File imageFile = File('image.jpg');
Uint8List imagebytes = await imageFile.readAsBytes();
String imageData = base64.encode(imagebytes);

//Draw the image in the header
header.graphics.drawImage(
    PdfBitmap.fromBase64String(imageData),
    Rect.fromLTWH(0, 0, 100, 50));

//Add the header at the top
document.template.top = header;

//Create a Page template that can be used as footer
PdfPageTemplateElement footer = PdfPageTemplateElement(bounds);

//Add the fields in composite fields
PdfCompositeField compositeField = PdfCompositeField(
    font: font,
    brush: PdfBrushes.black,
    text: "Page {0} of {1}",
    fields: <PdfAutomaticField>[
      PdfPageNumberField(font: font, brush: PdfBrushes.black),
      PdfPageCountField(font: font, brush: PdfBrushes.black)
    ]);
compositeField.bounds = footer.bounds;

//Draw the composite field in footer
compositeField.draw(footer.graphics, Offset(470, 40));

//Add the footer template at the bottom
document.template.bottom = footer;

//Save and dispose the PDF document
File('SampleOutput.pdf').writeAsBytes(await document.save());
document.dispose();

Adding stamp to the PDF document

The Syncfusion Flutter PDF allows you add stamp to the PDF document using PDF templates.

The following code example explains how to draw text as a stamp to the PDF document.

DART

//Create a new PDF document
PdfDocument document = PdfDocument();

//Add a page to the PDF document
PdfPage page = document.pages.add();

//Create template and draw text in template graphics
final PdfPageTemplateElement custom =
    PdfPageTemplateElement(Offset(0, 0) & page.getClientSize(), page);
custom.dock = PdfDockStyle.fill;
PdfGraphicsState state = custom.graphics.save();
custom.graphics.rotateTransform(-40);
custom.graphics.drawString(
    'STAMP PDF DOCUMENT', PdfStandardFont(PdfFontFamily.helvetica, 20),
    pen: PdfPens.red,
    brush: PdfBrushes.red,
    bounds: Rect.fromLTWH(-150, 450, 400, 400));
custom.graphics.restore(state);

//Add template as a stamp to the PDF document
document.template.stamps.add(custom);

//Draw rectangle to the page graphics
page.graphics.drawRectangle(
    pen: PdfPen(PdfColor(0, 0, 0), width: 5),
    brush: PdfBrushes.lightGray,
    bounds: Offset(0, 0) & page.getClientSize());

//Save the document
final List<int> bytes = await document.save();

//Dispose the document
document.dispose();