Java tutorial
/* * Copyright 2009 Google Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); you may not * use this file except in compliance with the License. You may obtain a copy of * the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations under * the License. */ package geogebra.web.gui.app.docklayout; import static com.google.gwt.dom.client.Style.Unit.EM; import static com.google.gwt.dom.client.Style.Unit.EX; import static com.google.gwt.dom.client.Style.Unit.PX; import geogebra.web.gui.app.docklayout.MyLayout.Layer; import com.google.gwt.aria.client.State; import com.google.gwt.dom.client.DivElement; import com.google.gwt.dom.client.Document; import com.google.gwt.dom.client.Element; import com.google.gwt.dom.client.Style; import com.google.gwt.dom.client.Style.Display; import com.google.gwt.dom.client.Style.Position; import com.google.gwt.dom.client.Style.Unit; import com.google.gwt.dom.client.Style.Visibility; /** * Default implementation, which works with all browsers except for IE6. It uses * only the "top", "left", "bottom", "right", "width", and "height" CSS * properties. * * Note: This implementation class has state, so {@link Layout} must create a * new instance for each layout-parent. */ class LayoutImpl { private static DivElement fixedRuler; static { fixedRuler = createRuler(Unit.CM, Unit.CM); Document.get().getBody().appendChild(fixedRuler); } protected static DivElement createRuler(Unit widthUnit, Unit heightUnit) { DivElement ruler = Document.get().createDivElement(); ruler.setInnerHTML(" "); Style style = ruler.getStyle(); style.setPosition(Position.ABSOLUTE); style.setZIndex(-32767); // Position the ruler off the top edge, double the size just to be // extra sure it doesn't show up on the screen. style.setTop(-20, heightUnit); // Note that we are making the ruler element 10x10, because some browsers // generate non-integral ratios (e.g., 1em == 13.3px), so we need a little // extra precision. style.setWidth(10, widthUnit); style.setHeight(10, heightUnit); style.setVisibility(Visibility.HIDDEN); State.HIDDEN.set(ruler, true); return ruler; } protected DivElement relativeRuler; public Element attachChild(Element parent, Element child, Element before) { DivElement container = Document.get().createDivElement(); container.appendChild(child); container.getStyle().setPosition(Position.ABSOLUTE); ///container.getStyle().setOverflow(Overflow.HIDDEN); fillParent(child); Element beforeContainer = null; if (before != null) { beforeContainer = before.getParentElement(); assert beforeContainer.getParentElement() == parent : "Element to insert before must be a sibling"; } parent.insertBefore(container, beforeContainer); return container; } public void fillParent(Element elem) { Style style = elem.getStyle(); style.setPosition(Position.ABSOLUTE); style.setLeft(0, PX); style.setTop(0, PX); style.setRight(0, PX); style.setBottom(0, PX); } /** * @param parent the parent element */ public void finalizeLayout(Element parent) { } public double getUnitSizeInPixels(Element parent, Unit unit, boolean vertical) { if (unit == null) { return 1; } switch (unit) { case PCT: return (vertical ? parent.getClientHeight() : parent.getClientWidth()) / 100.0; case EM: return relativeRuler.getOffsetWidth() / 10.0; case EX: return relativeRuler.getOffsetHeight() / 10.0; case CM: return fixedRuler.getOffsetWidth() * 0.1; // 1.0 cm / cm case MM: return fixedRuler.getOffsetWidth() * 0.01; // 0.1 cm / mm case IN: return fixedRuler.getOffsetWidth() * 0.254; // 2.54 cm / in case PT: return fixedRuler.getOffsetWidth() * 0.00353; // 0.0353 cm / pt case PC: return fixedRuler.getOffsetWidth() * 0.0423; // 0.423 cm / pc default: case PX: return 1; } } public void initParent(Element parent) { parent.getStyle().setPosition(Position.RELATIVE); parent.appendChild(relativeRuler = createRuler(EM, EX)); } public void layout(Layer layer) { Style style = layer.container.getStyle(); if (layer.visible) { style.clearDisplay(); } else { style.setDisplay(Display.NONE); } style.setProperty("left", layer.setLeft ? (layer.left + layer.leftUnit.getType()) : ""); style.setProperty("top", layer.setTop ? (layer.top + layer.topUnit.getType()) : ""); style.setProperty("right", layer.setRight ? (layer.right + layer.rightUnit.getType()) : ""); style.setProperty("bottom", layer.setBottom ? (layer.bottom + layer.bottomUnit.getType()) : ""); style.setProperty("width", layer.setWidth ? (layer.width + layer.widthUnit.getType()) : ""); style.setProperty("height", layer.setHeight ? (layer.height + layer.heightUnit.getType()) : ""); style = layer.child.getStyle(); switch (layer.hPos) { case BEGIN: style.setLeft(0, Unit.PX); style.clearRight(); break; case END: style.clearLeft(); style.setRight(0, Unit.PX); break; case STRETCH: style.setLeft(0, Unit.PX); style.setRight(0, Unit.PX); break; } switch (layer.vPos) { case BEGIN: style.setTop(0, Unit.PX); style.clearBottom(); break; case END: style.clearTop(); style.setBottom(0, Unit.PX); break; case STRETCH: style.setTop(0, Unit.PX); style.setBottom(0, Unit.PX); break; } } @SuppressWarnings("unused") public void onAttach(Element parent) { // Do nothing. This exists only to help LayoutImplIE6 avoid memory leaks. } @SuppressWarnings("unused") public void onDetach(Element parent) { // Do nothing. This exists only to help LayoutImplIE6 avoid memory leaks. } public void removeChild(Element container, Element child) { container.removeFromParent(); // We want this code to be resilient to the child having already been // removed from its container (perhaps by widget code). if (child.getParentElement() == container) { child.removeFromParent(); } // Cleanup child styles set by fillParent(). Style style = child.getStyle(); style.clearPosition(); style.clearLeft(); style.clearTop(); style.clearWidth(); style.clearHeight(); } }