Move client/{base, observable, layout, touch, util, view} to samples/ui_lib .

client/layout/ViewLayout.dart

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-/** The interface that the layout algorithms use to talk to the view. */
-interface Positionable {
-  ViewLayout get layout();
-
-  /** Gets our custom CSS properties, as provided by the CSS preprocessor. */
-  Map<String, String> get customStyle();
-
-  /** Gets the root DOM used for layout. */
-  Element get node();
-
-  /** Gets the collection of child views. */
-  Collection<Positionable> get childViews();
-
-  /** Causes a view to layout its children. */
-  void doLayout();
-}
-
-
-/**
- * Caches the layout parameters that were specified in CSS during a layout
- * computation. These values are immutable during a layout.
- */
-class LayoutParams {
-  // TODO(jmesserly): should be const, but there's a bug in DartC preventing us
-  // from calling "window." in an initializer. See b/5332777
-  Future<CSSStyleDeclaration> style;
-
-  int get layer() => 0;
-
-  LayoutParams(Element node) {
-    style = node.computedStyle;
-  }
-}
-
-// TODO(jmesserly): enums would really help here
-class Dimension {
-  // TODO(jmesserly): perhaps this should be X and Y
-  static final WIDTH = const Dimension._internal('width');
-  static final HEIGHT = const Dimension._internal('height');
-
-  final String name; // for debugging
-  const Dimension._internal(this.name);
-}
-
-class ContentSizeMode {
-  /** Minimum content size, e.g. min-width and min-height in CSS. */
-  static final MIN = const ContentSizeMode._internal('min');
-
-  /** Maximum content size, e.g. min-width and min-height in CSS. */
-  static final MAX = const ContentSizeMode._internal('max');
-
-  // TODO(jmesserly): we probably want some sort of "auto" or "best fit" mode
-  // Don't need it yet though.
-
-  final String name; // for debugging
-  const ContentSizeMode._internal(this.name);
-}
-
-/**
- * Abstract base class for View layout. Tracks relevant layout state.
- * This code was inspired by code in Android's View.java; it's needed for the
- * rest of the layout system.
- */
-class ViewLayout {
-  /**
-   * The layout parameters associated with this view and used by the parent
-   * to determine how this view should be laid out.
-   */
-  LayoutParams layoutParams;
-  Future<ElementRect> _cachedViewRect;
-
-  /** The view that this layout belongs to. */
-  final Positionable view;
-
-  /**
-   * To get a perforant positioning model on top of the DOM, we read all
-   * properties in the first pass while computing positions. Then we have a
-   * second pass that actually moves everything.
-   */
-  int _measuredLeft, _measuredTop, _measuredWidth, _measuredHeight;
-
-  ViewLayout(this.view);
-
-  /**
-   * Creates the appropriate view layout, depending on the properties.
-   */
-  // TODO(jmesserly): we should support user defined layouts somehow. Perhaps
-  // registered with a LayoutProvider.
-  factory ViewLayout.fromView(Positionable view) {
-    if (hasCustomLayout(view)) {
-      return new GridLayout(view);
-    } else {
-      return new ViewLayout(view);
-    }
-  }
-
-  static bool hasCustomLayout(Positionable view) {
-    return view.customStyle['display'] == "-dart-grid";
-  }
-
-  CSSStyleDeclaration get _style() => layoutParams.style.value;
-
-  void cacheExistingBrowserLayout() {
-    _cachedViewRect = view.node.rect;
-  }
-
-  int get currentWidth() {
-    return _cachedViewRect.value.offset.width;
-  }
-
-  int get currentHeight() {
-    return _cachedViewRect.value.offset.height;
-  }
-
-  int get borderLeftWidth() => _toPixels(_style.borderLeftWidth);
-  int get borderTopWidth() => _toPixels(_style.borderTopWidth);
-  int get borderRightWidth() => _toPixels(_style.borderRightWidth);
-  int get borderBottomWidth() => _toPixels(_style.borderBottomWidth);
-  int get borderWidth() => borderLeftWidth + borderRightWidth;
-  int get borderHeight() => borderTopWidth + borderBottomWidth;
-
-  /** Implements the custom layout computation. */
-  void measureLayout(Future<Size> size, Completer<bool> changed) {
-  }
-
-  /**
-   * Positions the view within its parent container.
-   * Also performs a layout of its children.
-   */
-  void setBounds(int left, int top, int width, int height) {
-    assert(width >= 0 && height >= 0);
-
-    _measuredLeft = left;
-    _measuredTop = top;
-
-    // Note: we need to save the client height
-    _measuredWidth = width - borderWidth;
-    _measuredHeight = height - borderHeight;
-    final completer = new Completer<Size>();
-    completer.complete(new Size(_measuredWidth, _measuredHeight));
-    measureLayout(completer.future, null);
-  }
-
-  /** Applies the layout to the node. */
-  void applyLayout() {
-    if (_measuredLeft != null) {
-      // TODO(jmesserly): benchmark the performance of this DOM interaction
-      final style = view.node.style;
-      style.position = 'absolute';
-      style.left = '${_measuredLeft}px';
-      style.top = '${_measuredTop}px';
-      style.width = '${_measuredWidth}px';
-      style.height = '${_measuredHeight}px';
-      style.zIndex = '${layoutParams.layer}';
-
-      _measuredLeft = null;
-      _measuredTop = null;
-      _measuredWidth = null;
-      _measuredHeight = null;
-
-      // Ensure we can handle our custom layout when it is a child of a
-      // DOM-positioned node. For example, say we have a View tree like this:
-      //
-      //   ViewWithLayout   <-- uses our layout engine
-      //     childView1     <-- is positioned by our layout engine, but uses
-      //                        HTML layout internally
-      //       childOfChild <-- uses our layout engine for its own children
-      if (!hasCustomLayout(view)) {
-        for (final child in view.childViews) {
-          child.doLayout();
-        }
-      }
-    }
-  }
-
-  int measureContent(ViewLayout parent, Dimension dimension,
-                     [ContentSizeMode mode = null]) {
-    switch (dimension) {
-      case Dimension.WIDTH:
-        return measureWidth(parent, mode);
-      case Dimension.HEIGHT:
-        return measureHeight(parent, mode);
-    }
-  }
-
-  int measureWidth(ViewLayout parent, ContentSizeMode mode) {
-    final style = layoutParams.style.value;
-    switch (mode) {
-      case ContentSizeMode.MIN:
-        return _styleToPixels(
-            style.minWidth, currentWidth, parent.currentWidth);
-
-      case ContentSizeMode.MAX:
-        return _styleToPixels(
-            style.maxWidth, currentWidth, parent.currentWidth);
-    }
-  }
-
-  int measureHeight(ViewLayout parent, ContentSizeMode mode) {
-    final style = layoutParams.style.value;
-    switch (mode) {
-      case ContentSizeMode.MIN:
-        return _styleToPixels(
-            style.minHeight, currentHeight, parent.currentHeight);
-
-      case ContentSizeMode.MAX:
-        return _styleToPixels(
-            style.maxHeight, currentHeight, parent.currentHeight);
-    }
-  }
-
-  static int _toPixels(String style) {
-    if (style.endsWith('px')) {
-      return Math.parseInt(style.substring(0, style.length - 2));
-    } else {
-      // TODO(jmesserly): other size units
-      throw new UnsupportedOperationException(
-          'Unknown min/max content size format: "$style"');
-    }
-  }
-
-  static int _styleToPixels(String style, num size, num parentSize) {
-    if (style == 'none') {
-      // For an unset max-content size, use the actual size
-      return size;
-    }
-    if (style.endsWith('%')) {
-      num percent = Math.parseDouble(style.substring(0, style.length - 1));
-      return ((percent / 100) * parentSize).toInt();
-    }
-    return _toPixels(style);
-  }
-}