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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
dump("### ViewportHandler.js loaded\n");
// See getViewportMetadata. Blindly copied from Safari
// documentation for now.
const kViewportMinScale = 0;
const kViewportMaxScale = 10;
const kViewportMinWidth = 200;
const kViewportMaxWidth = 10000;
const kViewportMinHeight = 223;
const kViewportMaxHeight = 10000;
/*
* ViewportHandler
*
* Plucks zoom info out of web page metadata and forwards it to the
* browser.
*/
let ViewportHandler = {
init: function init() {
addEventListener("DOMWindowCreated", this, false);
addEventListener("DOMMetaAdded", this, false);
addEventListener("DOMContentLoaded", this, false);
addEventListener("pageshow", this, false);
},
handleEvent: function handleEvent(aEvent) {
let target = aEvent.originalTarget;
let isRootDocument = (target == content.document || target.ownerDocument == content.document);
if (!isRootDocument)
return;
switch (aEvent.type) {
case "DOMWindowCreated":
this.resetMetadata();
break;
case "DOMMetaAdded":
if (target.name == "viewport")
this.updateMetadata();
break;
case "DOMContentLoaded":
case "pageshow":
this.updateMetadata();
break;
}
},
resetMetadata: function resetMetadata() {
sendAsyncMessage("Browser:ViewportMetadata", null);
},
updateMetadata: function updateMetadata() {
sendAsyncMessage("Browser:ViewportMetadata", this.getViewportMetadata());
},
/**
* Returns an object with the page's preferred viewport properties:
* defaultZoom (optional float): The initial scale when the page is loaded.
* minZoom (optional float): The minimum zoom level.
* maxZoom (optional float): The maximum zoom level.
* width (optional int): The CSS viewport width in px.
* height (optional int): The CSS viewport height in px.
* autoSize (boolean): Resize the CSS viewport when the window resizes.
* allowZoom (boolean): Let the user zoom in or out.
* autoScale (boolean): Adjust the viewport properties to account for display density.
*/
getViewportMetadata: function getViewportMetadata() {
let doctype = content.document.doctype;
if (doctype && /(WAP|WML|Mobile)/.test(doctype.publicId))
return { defaultZoom: 1, autoSize: true, allowZoom: true, autoScale: true };
let windowUtils = Util.getWindowUtils(content);
let handheldFriendly = windowUtils.getDocumentMetadata("HandheldFriendly");
if (handheldFriendly == "true")
return { defaultZoom: 1, autoSize: true, allowZoom: true, autoScale: true };
if (content.document instanceof XULDocument)
return { defaultZoom: 1, autoSize: true, allowZoom: false, autoScale: false };
// HACK: Since we can't set the scale in local tabs (bug 597081), we force
// them to device-width and scale=1 so they will lay out reasonably.
if (Util.isLocalScheme(content.document.documentURI))
return { defaultZoom: 1, autoSize: true, allowZoom: false, autoScale: false };
// HACK: Since we can't set the scale correctly in frameset pages yet (bug 645756), we force
// them to device-width and scale=1 so they will lay out reasonably.
if (content.frames.length > 0 && (content.document.body instanceof HTMLFrameSetElement))
return { defaultZoom: 1, autoSize: true, allowZoom: false, autoScale: false };
// viewport details found here
// http://developer.apple.com/safari/library/documentation/AppleApplications/Reference/SafariHTMLRef/Articles/MetaTags.html
// http://developer.apple.com/safari/library/documentation/AppleApplications/Reference/SafariWebContent/UsingtheViewport/UsingtheViewport.html
// Note: These values will be NaN if parseFloat or parseInt doesn't find a number.
// Remember that NaN is contagious: Math.max(1, NaN) == Math.min(1, NaN) == NaN.
let scale = parseFloat(windowUtils.getDocumentMetadata("viewport-initial-scale"));
let minScale = parseFloat(windowUtils.getDocumentMetadata("viewport-minimum-scale"));
let maxScale = parseFloat(windowUtils.getDocumentMetadata("viewport-maximum-scale"));
let widthStr = windowUtils.getDocumentMetadata("viewport-width");
let heightStr = windowUtils.getDocumentMetadata("viewport-height");
let width = Util.clamp(parseInt(widthStr), kViewportMinWidth, kViewportMaxWidth);
let height = Util.clamp(parseInt(heightStr), kViewportMinHeight, kViewportMaxHeight);
let allowZoomStr = windowUtils.getDocumentMetadata("viewport-user-scalable");
let allowZoom = !/^(0|no|false)$/.test(allowZoomStr); // WebKit allows 0, "no", or "false"
scale = Util.clamp(scale, kViewportMinScale, kViewportMaxScale);
minScale = Util.clamp(minScale, kViewportMinScale, kViewportMaxScale);
maxScale = Util.clamp(maxScale, kViewportMinScale, kViewportMaxScale);
// If initial scale is 1.0 and width is not set, assume width=device-width
let autoSize = (widthStr == "device-width" ||
(!widthStr && (heightStr == "device-height" || scale == 1.0)));
return {
defaultZoom: scale,
minZoom: minScale,
maxZoom: maxScale,
width: width,
height: height,
autoSize: autoSize,
allowZoom: allowZoom,
autoScale: true
};
}
};
ViewportHandler.init();
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