sky/sdk/lib/framework/components2/ink_well.dart

// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import '../fn2.dart';
import 'dart:collection';
import 'dart:sky' as sky;
import 'ink_splash.dart';
import 'scrollable.dart';

class InkWell extends Component implements ScrollClient {
  static final Style _containmentStyleHack = new Style('''
    align-items: center;
    transform: translateX(0);''');

  LinkedHashSet<SplashController> _splashes;

  String inlineStyle;
  List<UINode> children;

  InkWell({ Object key, this.inlineStyle, this.children })
      : super(key: key) {
    onDidUnmount(() {
      _cancelSplashes(null);
    });
  }

  UINode build() {
    List<UINode> childrenIncludingSplashes = [];

    if (_splashes != null) {
      childrenIncludingSplashes.addAll(
          _splashes.map((s) => new InkSplash(s.onStyleChanged)));
    }

    if (children != null)
      childrenIncludingSplashes.addAll(children);

    return new EventListenerNode(
      new FlexContainer(
        direction: FlexDirection.Row,
        style: _containmentStyleHack,
        inlineStyle: inlineStyle,
        children: childrenIncludingSplashes),
      onGestureTapDown: _startSplash,
      onGestureTap: _confirmSplash
    );
  }

  void _startSplash(sky.GestureEvent event) {
    setState(() {
      if (_splashes == null)
        _splashes = new LinkedHashSet<SplashController>();
      var splash;
      var root = getRoot();
      splash = new SplashController(root.rect, event.x, event.y,
                                    pointer: event.primaryPointer,
                                    onDone: () { _splashDone(splash); });
      _splashes.add(splash);
      UINode node = parent;
      while (node != null) {
        if (node is Scrollable)
          node.registerScrollClient(this);
        node = node.parent;
      }
    });
  }

  bool ancestorScrolled(Scrollable ancestor) {
    _abortSplashes();
    return false;
  }

  void handleRemoved() {
    UINode node = parent;
    while (node != null) {
      if (node is Scrollable)
        node.unregisterScrollClient(this);
      node = node.parent;
    }
    super.handleRemoved();
  }

  void _confirmSplash(sky.GestureEvent event) {
    if (_splashes == null)
      return;
    _splashes.where((splash) => splash.pointer == event.primaryPointer)
             .forEach((splash) { splash.confirm(); });
  }

  void _abortSplashes() {
    if (_splashes == null)
      return;
    setState(() {
      _splashes.forEach((s) { s.abort(); });
    });
  }

  void _cancelSplashes(sky.Event event) {
    if (_splashes == null)
      return;
    setState(() {
      var splashes = _splashes;
      _splashes = null;
      splashes.forEach((s) { s.cancel(); });
    });
  }

  void _splashDone(SplashController splash) {
    if (_splashes == null)
      return;
    setState(() {
      _splashes.remove(splash);
      if (_splashes.length == 0)
        _splashes = null;
    });
  }
}