image 4.1.7

Dart Image Library provides server and web apps the ability to load, manipulate, and save images with various image file formats.

Dart Image Library

Overview

The Dart Image Library provides the ability to load, save, and manipulate images in a variety of image file formats.

The library can be used with both dart:io and dart:html, for command-line, Flutter, and web applications.

NOTE: 4.0 is a major revision from the previous version of the library.

Documentation

Supported Image Formats

Read/Write

• JPG
• PNG / Animated APNG
• GIF / Animated GIF
• BMP
• TIFF
• TGA
• PVR
• ICO

Read Only

• WebP / Animated WebP
• PSD
• EXR

Write Only

• CUR

Examples

Create an image, set pixel values, save it to a PNG.

import 'dart:io';
import 'package:image/image.dart' as img;
void main() async {
  // Create a 256x256 8-bit (default) rgb (default) image.
  final image = img.Image(width: 256, height: 256);
  // Iterate over its pixels
  for (var pixel in image) {
    // Set the pixels red value to its x position value, creating a gradient.
    pixel..r = pixel.x
    // Set the pixels green value to its y position value.
    ..g = pixel.y;
  }
  // Encode the resulting image to the PNG image format.
  final png = img.encodePng(image);
  // Write the PNG formatted data to a file.
  await File('image.png').writeAsBytes(png);
}

To asynchronously load an image file, resize it, and save it as a thumbnail:

import 'package:image/image.dart' as img;

void main(List<String> args) async {
  final path = args.isNotEmpty ? args[0] : 'test.png';
  final cmd = img.Command()
    // Decode the image file at the given path
    ..decodeImageFile(path)
    // Resize the image to a width of 64 pixels and a height that maintains the aspect ratio of the original. 
    ..copyResize(width: 64)
    // Write the image to a PNG file (determined by the suffix of the file path). 
    ..writeToFile('thumbnail.png');
  // On platforms that support Isolates, execute the image commands asynchronously on an isolate thread.
  // Otherwise, the commands will be executed synchronously.
  await cmd.executeThread();
}