fast_image_editor

Native C image editing for Flutter. Blur, sepia, saturation, brightness, contrast, sharpen, grayscale — all with region-based effects via Dart FFI.

Features

• 7 image filters: blur, sepia, saturation, brightness, contrast, sharpen, grayscale
• Region-based effects: apply filters to rectangular or circular areas
• Bicubic resize: high-quality image resizing via flutter_bicubic_resize
• Native performance: all processing in C via FFI — no Dart pixel loops
• Sync & async: every operation has a sync and Isolate.run async variant
• Format support: JPEG and PNG with automatic detection

Installation

dependencies:
  fast_image_editor: ^1.0.0

Quick Start

import 'package:fast_image_editor/fast_image_editor.dart';

// Blur entire image
final blurred = FastImageEditor.blur(bytes: imageBytes, radius: 15);

// Sepia on top 30% and bottom 30%
final sepia = FastImageEditor.sepia(
  bytes: imageBytes,
  intensity: 0.8,
  region: EditRegion(top: 0.3, bottom: 0.3),
);

// Resize with bicubic interpolation
final resized = FastImageEditor.resize(
  bytes: imageBytes,
  outputWidth: 800,
  outputHeight: 600,
);

// Async variant (runs in isolate)
final result = await FastImageEditor.blurAsync(bytes: imageBytes, radius: 10);

API

Filters

Method	Parameters	Description
blur	radius (1+)	Box blur, 3 passes for Gaussian approximation
sepia	intensity (0.0-1.0)	Sepia tone filter
saturation	factor (0.0=gray, 1.0=original, 2.0=double)	Color saturation
brightness	factor (-1.0 to 1.0)	Brightness adjustment
contrast	factor (0.0-2.0, 1.0=original)	Contrast adjustment
sharpen	amount (0.0-5.0), radius (1-10)	Unsharp mask
grayscale	—	Luminance: 0.2126R + 0.7152G + 0.0722B

Every filter has an async variant (e.g., blurAsync, sepiaAsync).

Resize

Method	Parameters	Description
resize	outputWidth, outputHeight	Bicubic resize with auto format detection

Optional: filter, edgeMode, crop, cropAnchor, cropAspectRatio, quality, compressionLevel.

Region-Based Effects

// Blur top 30% only
FastImageEditor.blur(
  bytes: imageBytes,
  radius: 20,
  region: EditRegion(top: 0.3),
);

// Grayscale left half
FastImageEditor.grayscale(
  bytes: imageBytes,
  region: EditRegion(left: 0.5),
);

// Sepia on edges (top 20% + bottom 20% + left 10% + right 10%)
FastImageEditor.sepia(
  bytes: imageBytes,
  region: EditRegion(top: 0.2, bottom: 0.2, left: 0.1, right: 0.1),
);

// Radial blur — circle in center
FastImageEditor.blur(
  bytes: imageBytes,
  radius: 20,
  radialRegion: RadialRegion(centerX: 0.0, centerY: 0.0, radius: 0.3),
);

Format Detection

final format = FastImageEditor.detectFormat(bytes);
// Returns ImageFormat.jpeg, ImageFormat.png, or null

Common Parameters

Parameter	Default	Description
bytes	required	JPEG or PNG image data
region	null (full image)	Area to apply effect
quality	90	JPEG output quality (1-100). Ignored for PNG.

Platform Support

Platform	Supported
Android	✅
iOS	✅

License

MIT License. See LICENSE.