Java tutorial
/* * Copyright 2000-2018 Vaadin Ltd. * * 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 com.vaadin.client; import com.google.gwt.core.client.JavaScriptObject; import com.google.gwt.dom.client.Element; public class ComputedStyle { private static final String CONTENT_BOX = "content-box"; protected final JavaScriptObject computedStyle; private final Element elem; /** * Gets this element's computed style object which can be used to gather * information about the current state of the rendered node. * <p> * Note that this method is expensive. Wherever possible, reuse the returned * object. * * @param elem * the element */ public ComputedStyle(Element elem) { computedStyle = getComputedStyle(elem); this.elem = elem; } private static native JavaScriptObject getComputedStyle(Element elem) /*-{ if (elem.nodeType != 1) { return {}; } if ($wnd.document.defaultView && $wnd.document.defaultView.getComputedStyle) { return $wnd.document.defaultView.getComputedStyle(elem, null); } if (elem.currentStyle) { return elem.currentStyle; } }-*/; /** * Gets the value of the given property. * * @param name * name of the CSS property in camelCase * @return the value of the property, normalized for across browsers (each * browser returns pixel values whenever possible). */ public final native String getProperty(String name) /*-{ var cs = this.@com.vaadin.client.ComputedStyle::computedStyle; var elem = this.@com.vaadin.client.ComputedStyle::elem; // Border values need to be checked separately. The width might have a // meaningful value even if the border style is "none". In that case the // value should be 0. if (name.indexOf("border") > -1 && name.indexOf("Width") > -1) { var borderStyleProp = name.substring(0,name.length-5) + "Style"; if (cs.getPropertyValue) var borderStyle = cs.getPropertyValue(borderStyleProp); else // IE var borderStyle = cs[borderStyleProp]; if (borderStyle == "none") return "0px"; } if (cs.getPropertyValue) { // Convert name to dashed format name = name.replace(/([A-Z])/g, "-$1").toLowerCase('en'); var ret = cs.getPropertyValue(name); } else { var ret = cs[name]; var style = elem.style; // From the awesome hack by Dean Edwards // http://erik.eae.net/archives/2007/07/27/18.54.15/#comment-102291 // If we're not dealing with a regular pixel number // but a number that has a weird ending, we need to convert it to pixels if ( !/^\d+(px)?$/i.test( ret ) && /^\d/.test( ret ) ) { // Remember the original values var left = style.left, rsLeft = elem.runtimeStyle.left; // Put in the new values to get a computed value out elem.runtimeStyle.left = cs.left; style.left = ret || 0; ret = style.pixelLeft + "px"; // Revert the changed values style.left = left; elem.runtimeStyle.left = rsLeft; } } // Normalize margin values. This is not totally valid, but in most cases // it is what the user wants to know. if (name.indexOf("margin") > -1 && ret == "auto") { return "0px"; } // Some browsers return undefined width and height values as "auto", so // we need to retrieve those ourselves. if (name == "width" && ret == "auto") { ret = elem.clientWidth + "px"; } else if (name == "height" && ret == "auto") { ret = elem.clientHeight + "px"; } return ret; }-*/; /** * Retrieves the given computed property as an integer. * * Returns 0 if the property cannot be converted to an integer * * @param name * the property to retrieve * @return the integer value of the property or 0 */ public final int getIntProperty(String name) { Profiler.enter("ComputedStyle.getIntProperty"); String value = getProperty(name); int result = parseIntNative(value); Profiler.leave("ComputedStyle.getIntProperty"); return result; } /** * Retrieves the given computed property as a double. * * Returns NaN if the property cannot be converted to a double * * @since 7.5.1 * @param name * the property to retrieve * @return the double value of the property */ public final double getDoubleProperty(String name) { Profiler.enter("ComputedStyle.getDoubleProperty"); String value = getProperty(name); double result = parseDoubleNative(value); Profiler.leave("ComputedStyle.getDoubleProperty"); return result; } /** * Get current margin values from the DOM. * * @return an array containing four values for the four edges, in the * default CSS order: top, right, bottom, left. */ public final int[] getMargin() { int[] margin = { 0, 0, 0, 0 }; margin[0] = getIntProperty("marginTop"); margin[1] = getIntProperty("marginRight"); margin[2] = getIntProperty("marginBottom"); margin[3] = getIntProperty("marginLeft"); return margin; } /** * Get current padding values from the DOM. * * @return an array containing four values for the four edges, in the * default CSS order: top, right, bottom, left. */ public final int[] getPadding() { int[] padding = { 0, 0, 0, 0 }; padding[0] = getIntProperty("paddingTop"); padding[1] = getIntProperty("paddingRight"); padding[2] = getIntProperty("paddingBottom"); padding[3] = getIntProperty("paddingLeft"); return padding; } /** * Get current border values from the DOM. * * @return an array containing four values for the four edges, in the * default CSS order: top, right, bottom, left. */ public final int[] getBorder() { int[] border = { 0, 0, 0, 0 }; border[0] = getIntProperty("borderTopWidth"); border[1] = getIntProperty("borderRightWidth"); border[2] = getIntProperty("borderBottomWidth"); border[3] = getIntProperty("borderLeftWidth"); return border; } /** * Returns the current width from the DOM. * * @since 7.5.1 * @return the computed width */ public double getWidth() { return getDoubleProperty("width"); } /** * Returns the current height from the DOM. * * @since 7.5.1 * @return the computed height */ public double getHeight() { return getDoubleProperty("height"); } /** * Takes a String value e.g. "12px" and parses that to Integer 12. * * @param value * a value starting with a number * @return Integer the value from the string before any non-numeric * characters. If the value cannot be parsed to a number, returns * <code>null</code>. * * @deprecated Since 7.1.4, the method {@link #parseIntNative(String)} is * used internally and this method does not belong in the public * API of {@link ComputedStyle}. {@link #parseInt(String)} might * be removed or moved to a utility class in future versions. */ @Deprecated public static native Integer parseInt(final String value) /*-{ var number = parseInt(value, 10); if (isNaN(number)) return null; else // $entry not needed as function is not exported return @java.lang.Integer::valueOf(I)(number); }-*/; /** * Takes a String value e.g. "12px" and parses that to int 12. * * <p> * This method returns 0 for <code>NaN</code>. * * @param String * a value starting with a number * @return the value from the string before any non-numeric characters. If * the value cannot be parsed to a number, returns 0. */ private static native int parseIntNative(final String value) /*-{ var number = parseInt(value, 10); if (isNaN(number)) return 0; else return number; }-*/; /** * Takes a String value e.g. "12.3px" and parses that to a double, 12.3. * * @param String * a value starting with a number * @return the value from the string before any non-numeric characters or * NaN if the value cannot be parsed as a number */ private static native double parseDoubleNative(final String value) /*-{ return parseFloat(value); }-*/; /** * Returns the sum of the top and bottom border width. * * @since 7.5.3 * @return the sum of the top and bottom border */ public double getBorderHeight() { double borderHeight = getDoubleProperty("borderTopWidth"); borderHeight += getDoubleProperty("borderBottomWidth"); return borderHeight; } /** * Returns the sum of the left and right border width. * * @since 7.5.3 * @return the sum of the left and right border */ public double getBorderWidth() { double borderWidth = getDoubleProperty("borderLeftWidth"); borderWidth += getDoubleProperty("borderRightWidth"); return borderWidth; } /** * Returns the sum of the top and bottom padding. * * @since 7.5.3 * @return the sum of the top and bottom padding */ public double getPaddingHeight() { double paddingHeight = getDoubleProperty("paddingTop"); paddingHeight += getDoubleProperty("paddingBottom"); return paddingHeight; } /** * Returns the sum of the top and bottom padding. * * @since 7.5.3 * @return the sum of the left and right padding */ public double getPaddingWidth() { double paddingWidth = getDoubleProperty("paddingLeft"); paddingWidth += getDoubleProperty("paddingRight"); return paddingWidth; } /** * Returns the sum of the top and bottom margin. * * @since 7.5.6 * @return the sum of the top and bottom margin */ public double getMarginHeight() { double marginHeight = getDoubleProperty("marginTop"); marginHeight += getDoubleProperty("marginBottom"); return marginHeight; } /** * Returns the sum of the left and right margin. * * @since 7.5.6 * @return the sum of the left and right margin */ public double getMarginWidth() { double marginWidth = getDoubleProperty("marginLeft"); marginWidth += getDoubleProperty("marginRight"); return marginWidth; } /** * Returns the current height, padding and border from the DOM. * * @return the computed height including padding and borders */ public double getHeightIncludingBorderPadding() { double h = getHeight(); if (BrowserInfo.get().isIE() || isContentBox()) { // IE11 always returns only the height without padding/border h += getBorderHeight() + getPaddingHeight(); } return h; } /** * Returns the current width, padding and border from the DOM. * * @return the computed width including padding and borders */ public double getWidthIncludingBorderPadding() { double w = getWidth(); if (BrowserInfo.get().isIE() || isContentBox()) { // IE11 always returns only the width without padding/border w += getBorderWidth() + getPaddingWidth(); } return w; } private boolean isContentBox() { return getBoxSizing().equals(CONTENT_BOX); } /** * Returns the value of the boxSizing property. * * @return the value of the boxSizing property */ private String getBoxSizing() { return getProperty("boxSizing"); } }