Pickpick

Pickpick is a Flutter plugin for selecting a color anywhere on screen through a native desktop or browser picker. It returns an opaque sRGB color without capturing desktop screenshots in your application.

Supported features

• Screen color selection on Linux, macOS, Windows, and supported web browsers.
• A small API: synchronous available detection and asynchronous pick().
• Opaque sRGB results as 0xFFRRGGBB integers, ready to use with Flutter's Color.
• Cancellation represented by null, with one pending request shared by all clients in the same Dart isolate.
• Validation of platform color responses and propagation of permission, portal, native-channel, and browser errors.
• Automatic Flutter plugin registration, with CocoaPods and Swift Package Manager support on macOS.

Platform support

Usage

import 'package:flutter/painting.dart';
import 'package:pickpick/pickpick.dart';

const Pickpick picker = Pickpick();

Future<Color?> pickScreenColor() async {
  if (!picker.available) {
    return null;
  }
  final int? argb = await picker.pick();
  return argb == null ? null : Color(argb);
}

Invoke pick() directly from a button or another user gesture. In browsers, awaiting unrelated work before the call can consume the required user activation. Handle errors in the calling UI; cancellation returns null.

Flutter registers the platform implementations automatically. Initialize Flutter before using the plugin outside a widget callback. Screen sampling belongs on the application's UI isolate.

Result and error semantics

• available is synchronous. On Linux it identifies an implemented platform; it does not promise that the current desktop portal is running or compatible.
• pick() returns an integer in 0xFFRRGGBB format, always opaque sRGB.
• Cancellation and overlapping requests return null. All clients in the same Dart isolate share the pending-request guard.
• Unsupported platforms throw UnsupportedError. Portal, native-channel, browser and malformed-response errors propagate.
• Linux closes unfinished portal requests and its private bus connection on every exit. Waiting for a user response is limited to five minutes.

On Windows, click to select a pixel; Escape, right-click, or switching to another window cancels. Screen layout changes abort the request. The returned value uses the desktop's legacy 8-bit RGB representation and does not expose HDR scene values.

Scope

This is a system screen picker, separate from sampling an application's canvas or decoding image files. It does not convert samples to a document's working color space.

See docs/platform_contract.md for platform behavior, request handling, color semantics, and integration requirements.

Example and development

The example application includes a pick button, cancellation handling, and error feedback. Run it on a supported platform:

cd example
flutter pub get
flutter run -d linux

Use windows, macos, or chrome as the device on the corresponding host. See the contributing guidelines for automated checks and platform validation.

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