Images in Flutter PDF

1 Feb 20224 minutes to read

Images are supported through the PdfImage class, which is an abstract base class that provides functionality for PdfBitmap class.

Inserting an image in PDF document

The following raster images are supported in Flutter PDF:

  • JPEG
  • PNG

You can load image data in PdfBitmap object to draw the images using the drawImage method of the PdfGraphics class. The image data can be initialized as list of bytes or base64 string format.

The following code snippet shows how to draw an image to the PDF document.

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

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

//Draw the image
page.graphics.drawImage(
    PdfBitmap(File('image.jpg').readAsBytesSync()),
    Rect.fromLTWH(
        0, 0, page.getClientSize().width, page.getClientSize().height));

//Saves the document
File('Output.pdf').writeAsBytes(document.save());

//Disposes the document
document.dispose();

    Applying transparency and rotation to the image

    You can add transparency and rotation to the image using the setTransparency and rotateTransform methods of PdfGraphics respectively. This is explained in the following code snippet.

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

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

//Save the current graphics state
PdfGraphicsState state = page.graphics.save();

//Translate the coordinate system to the  required position
page.graphics.translateTransform(20, 100);

//Apply transparency
page.graphics.setTransparency(0.5);

//Rotate the coordinate system
page.graphics.rotateTransform(-45);

//Draw image
page.graphics.drawImage(
    PdfBitmap(File('image.jpg').readAsBytesSync()),
    Rect.fromLTWH(
        0, 0, page.getClientSize().width, page.getClientSize().height));

//Restore the graphics state
page.graphics.restore(state);

//Saves the document
File('Output.pdf').writeAsBytes(document.save());

//Disposes the document
document.dispose();

    Inserting image to PDF using a web URL

    The ‘PdfBitmap’ API accepts List and base64 string as inputs, so you can retrieve the image from the web URL as base64 or List and assign it to the bitmap class.

    Steps to insert an image to the PDF using Web URL:

    1. Add http package to the dependencies section of the pubspec.yaml file
  • DART
    • dependencies: 
http: ^0.13.4
    1. Import the following package into your dart file.
  • DART
    • import 'package:http/http.dart' show get;

    This is explained in the following code snippet.

  • DART
    • //Create a PDF document.
    PdfDocument document = PdfDocument();

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

    
    //Read the image data from the weblink.
    var url =
        "https://cdn.pixabay.com/photo/2015/04/23/22/00/tree-736885_1280.jpg";
    var response = await get(Uri.parse(url));
    var data = response.bodyBytes;

    //Create a bitmap object.
    PdfBitmap image = PdfBitmap(data);

    //Draw an image to the document.
    page.graphics.drawImage(
        image,
        Rect.fromLTWH(
            0, 0, page.getClientSize().width, page.getClientSize().height));

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

    //Dispose the document.
    document.dispose();