1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
|
/* Copyright (c) 2006-2013 by OpenLayers Contributors (see authors.txt for
* full list of contributors). Published under the 2-clause BSD license.
* See license.txt in the OpenLayers distribution or repository for the
* full text of the license. */
/**
* @requires OpenLayers/Tile/Image.js
*/
/**
* Constant: OpenLayers.Tile.Image.IFrame
* Mixin for tiles that use form-encoded POST requests to get images from
* remote services. Images will be loaded using HTTP-POST into an IFrame.
*
* This mixin will be applied to <OpenLayers.Tile.Image> instances
* configured with <OpenLayers.Tile.Image.maxGetUrlLength> set.
*/
OpenLayers.Tile.Image.IFrame = {
/**
* Property: useIFrame
* {Boolean} true if we are currently using an IFrame to render POST
* responses, false if we are using an img element to render GET responses.
*/
useIFrame: null,
/**
* Property: blankImageUrl
* {String} Using a data scheme url is not supported by all browsers, but
* we don't care because we either set it as css backgroundImage, or the
* image's display style is set to "none" when we use it.
*/
blankImageUrl: "data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAQAIBRAA7",
/**
* Method: draw
* Set useIFrame in the instance, and operate the image/iframe switch.
* Then call Tile.Image.draw.
*
* Returns:
* {Boolean}
*/
draw: function() {
var draw = OpenLayers.Tile.Image.prototype.shouldDraw.call(this);
if(draw) {
// this.url isn't set to the currect value yet, so we call getURL
// on the layer and store the result in a local variable
var url = this.layer.getURL(this.bounds);
var usedIFrame = this.useIFrame;
this.useIFrame = this.maxGetUrlLength !== null &&
!this.layer.async &&
url.length > this.maxGetUrlLength;
var fromIFrame = usedIFrame && !this.useIFrame;
var toIFrame = !usedIFrame && this.useIFrame;
if(fromIFrame || toIFrame) {
// Switching between GET (image) and POST (iframe).
// We remove the imgDiv (really either an image or an iframe)
// from the frame and set it to null to make sure initImage
// will call getImage.
if(this.imgDiv && this.imgDiv.parentNode === this.frame) {
this.frame.removeChild(this.imgDiv);
}
this.imgDiv = null;
// And if we had an iframe we also remove the event pane.
if(fromIFrame) {
this.frame.removeChild(this.frame.firstChild);
}
}
}
return OpenLayers.Tile.Image.prototype.draw.apply(this, arguments);
},
/**
* Method: getImage
* Creates the content for the frame on the tile.
*/
getImage: function() {
if (this.useIFrame === true) {
if (!this.frame.childNodes.length) {
var eventPane = document.createElement("div"),
style = eventPane.style;
style.position = "absolute";
style.width = "100%";
style.height = "100%";
style.zIndex = 1;
style.backgroundImage = "url(" + this.blankImageUrl + ")";
this.frame.appendChild(eventPane);
}
var id = this.id + '_iFrame', iframe;
if (parseFloat(navigator.appVersion.split("MSIE")[1]) < 9) {
// Older IE versions do not set the name attribute of an iFrame
// properly via DOM manipulation, so we need to do it on our own with
// this hack.
iframe = document.createElement('<iframe name="'+id+'">');
// IFrames in older IE versions are not transparent, if you set
// the backgroundColor transparent. This is a workaround to get
// transparent iframes.
iframe.style.backgroundColor = '#FFFFFF';
iframe.style.filter = 'chroma(color=#FFFFFF)';
}
else {
iframe = document.createElement('iframe');
iframe.style.backgroundColor = 'transparent';
// iframe.name needs to be an unique id, otherwise it
// could happen that other iframes are overwritten.
iframe.name = id;
}
// some special properties to avoid scaling the images and scrollbars
// in the iframe
iframe.scrolling = 'no';
iframe.marginWidth = '0px';
iframe.marginHeight = '0px';
iframe.frameBorder = '0';
iframe.style.position = "absolute";
iframe.style.width = "100%";
iframe.style.height = "100%";
if (this.layer.opacity < 1) {
OpenLayers.Util.modifyDOMElement(iframe, null, null, null,
null, null, null, this.layer.opacity);
}
this.frame.appendChild(iframe);
this.imgDiv = iframe;
return iframe;
} else {
return OpenLayers.Tile.Image.prototype.getImage.apply(this, arguments);
}
},
/**
* Method: createRequestForm
* Create the html <form> element with width, height, bbox and all
* parameters specified in the layer params.
*
* Returns:
* {DOMElement} The form element which sends the HTTP-POST request to the
* WMS.
*/
createRequestForm: function() {
// creation of the form element
var form = document.createElement('form');
form.method = 'POST';
var cacheId = this.layer.params["_OLSALT"];
cacheId = (cacheId ? cacheId + "_" : "") + this.bounds.toBBOX();
form.action = OpenLayers.Util.urlAppend(this.layer.url, cacheId);
form.target = this.id + '_iFrame';
// adding all parameters in layer params as hidden fields to the html
// form element
var imageSize = this.layer.getImageSize(),
params = OpenLayers.Util.getParameters(this.url),
field;
for(var par in params) {
field = document.createElement('input');
field.type = 'hidden';
field.name = par;
field.value = params[par];
form.appendChild(field);
}
return form;
},
/**
* Method: setImgSrc
* Sets the source for the tile image
*
* Parameters:
* url - {String}
*/
setImgSrc: function(url) {
if (this.useIFrame === true) {
if (url) {
var form = this.createRequestForm();
this.frame.appendChild(form);
form.submit();
this.frame.removeChild(form);
} else if (this.imgDiv.parentNode === this.frame) {
// we don't reuse iframes to avoid caching issues
this.frame.removeChild(this.imgDiv);
this.imgDiv = null;
}
} else {
OpenLayers.Tile.Image.prototype.setImgSrc.apply(this, arguments);
}
},
/**
* Method: onImageLoad
* Handler for the image onload event
*/
onImageLoad: function() {
//TODO de-uglify opacity handling
OpenLayers.Tile.Image.prototype.onImageLoad.apply(this, arguments);
if (this.useIFrame === true) {
this.imgDiv.style.opacity = 1;
this.frame.style.opacity = this.layer.opacity;
}
},
/**
* Method: createBackBuffer
* Override createBackBuffer to do nothing when we use an iframe. Moving an
* iframe from one element to another makes it necessary to reload the iframe
* because its content is lost. So we just give up.
*
* Returns:
* {DOMElement}
*/
createBackBuffer: function() {
var backBuffer;
if(this.useIFrame === false) {
backBuffer = OpenLayers.Tile.Image.prototype.createBackBuffer.call(this);
}
return backBuffer;
}
};
|
