/*
* Copyright 2008 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 com.google.gwt.user.client.ui.impl;
import com.google.gwt.core.client.GWT;
import com.google.gwt.dom.client.Document;
import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.NativeEvent;
import com.google.gwt.user.client.Command;
import com.google.gwt.user.client.DeferredCommand;
import com.google.gwt.user.client.Event;
import com.google.gwt.user.client.ui.Image;
/**
* Implements the clipped image as a IMG inside a custom tag because we can't
* use the IE PNG transparency filter on background-image images.
*
* Do not use this class - it is used for implementation only, and its methods
* may change in the future.
*/
public class ClippedImageImplIE6 extends ClippedImageImpl {
private static String moduleBaseUrlProtocol =
GWT.getHostPageBaseURL().startsWith("https") ? "https://" : "http://";
private static boolean isIE6 = isIE6();
private static native void injectGlobalHandler() /*-{
$wnd.__gwt_transparentImgHandler = function (elem) {
elem.onerror = null;
@com.google.gwt.user.client.DOM::setImgSrc(Lcom/google/gwt/user/client/Element;Ljava/lang/String;)(elem, @com.google.gwt.core.client.GWT::getModuleBaseURL()() + "clear.cache.gif");
};
}-*/;
// Stolen and modified from UserAgent.gwt.xml.
// TODO(jgw): Get rid of this method, and switch to using soft permutations
// once they land in trunk.
private static native boolean isIE6() /*-{
function makeVersion(result) {
return (parseInt(result[1]) * 1000) + parseInt(result[2]);
}
var ua = navigator.userAgent.toLowerCase();
if (ua.indexOf("msie") != -1) {
var result = /msie ([0-9]+)\.([0-9]+)/.exec(ua);
if (result && result.length == 3) {
var v = makeVersion(result);
if (v < 7000) {
return true;
}
}
}
return false;
}-*/;
public ClippedImageImplIE6() {
injectGlobalHandler();
}
@Override
public void adjust(Element clipper, String url, int left, int top, int width,
int height) {
if (!isIE6) {
super.adjust(clipper, url, left, top, width, height);
return;
}
clipper.getStyle().setPropertyPx("width", width);
clipper.getStyle().setPropertyPx("height", height);
// Update the nested image's url.
Element img = clipper.getFirstChildElement();
img.getStyle().setProperty("filter",
"progid:DXImageTransform.Microsoft.AlphaImageLoader(src='" + url
+ "',sizingMethod='crop')");
img.getStyle().setPropertyPx("marginLeft", -left);
img.getStyle().setPropertyPx("marginTop", -top);
// AlphaImageLoader requires that we size the image explicitly.
// It really only needs to be enough to show the revealed portion.
int imgWidth = left + width;
int imgHeight = top + height;
img.setPropertyInt("width", imgWidth);
img.setPropertyInt("height", imgHeight);
}
@Override
public Element createStructure(String url, int left, int top, int width,
int height) {
if (!isIE6) {
return super.createStructure(url, left, top, width, height);
}
// We need to explicitly sink ONLOAD on the child image element, because it
// can't be fired on the clipper.
Element clipper = super.createStructure(url, left, top, width, height);
Element img = clipper.getFirstChildElement();
Event.sinkEvents(img, Event.ONLOAD);
return clipper;
}
public void fireSyntheticLoadEvent(final Image image) {
if (!isIE6) {
super.fireSyntheticLoadEvent(image);
return;
}
// This is the same as the superclass' implementation, except that it
// explicitly checks for the 'clipper' element, and dispatches the event
// on the img (you can't dispatch events on the clipper).
DeferredCommand.addCommand(new Command() {
public void execute() {
NativeEvent evt = Document.get().createLoadEvent();
Element clipper = image.getElement();
Element img = clipper.getFirstChildElement();
img.dispatchEvent(evt);
}
});
}
@Override
public String getHTML(String url, int left, int top, int width, int height) {
if (!isIE6) {
return super.getHTML(url, left, top, width, height);
}
String clipperStyle = "overflow: hidden; width: " + width + "px; height: "
+ height + "px; padding: 0px; zoom: 1";
String imgStyle = "filter: progid:DXImageTransform.Microsoft.AlphaImageLoader(src='"
+ url
+ "',sizingMethod='crop'); margin-left: "
+ -left
+ "px; margin-top: " + -top + "px; border: none";
/*
* We initially set the image URL to an invalid value to force onerror to be
* fired when this string is turned into a DOM structure. At this point, we
* can set the image src using DOM.setImgSrc, which is used to get around
* issue #282. The invalid image URL is either http:// or https://,
* depending on the module's base URL. We have to match the invalid image
* URL's protocol with that of the module's base URL's protocol due to issue
* #1200.
*/
String clippedImgHtml = "<gwt:clipper style=\""
+ clipperStyle
+ "\"><img src='"
+ moduleBaseUrlProtocol
+ "' onerror='if(window.__gwt_transparentImgHandler)window.__gwt_transparentImgHandler(this);else this.src=\"" + GWT.getModuleBaseURL() + "clear.cache.gif\"' style=\""
+ imgStyle + "\" width=" + (left + width) + " height=" + (top + height)
+ " border='0'></gwt:clipper>";
return clippedImgHtml;
}
}