gecko/browser/devtools/shared/LayoutHelpers.jsm

314 lines
10 KiB
JavaScript

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ft=javascript ts=2 et sw=2 tw=80: */
/* 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/. */
const Cu = Components.utils;
const Ci = Components.interfaces;
const Cr = Components.results;
var EXPORTED_SYMBOLS = ["LayoutHelpers"];
LayoutHelpers = {
/**
* Compute the position and the dimensions for the visible portion
* of a node, relativalely to the root window.
*
* @param nsIDOMNode aNode
* a DOM element to be highlighted
*/
getDirtyRect: function LH_getDirectyRect(aNode) {
let frameWin = aNode.ownerDocument.defaultView;
let clientRect = aNode.getBoundingClientRect();
// Go up in the tree of frames to determine the correct rectangle.
// clientRect is read-only, we need to be able to change properties.
rect = {top: clientRect.top,
left: clientRect.left,
width: clientRect.width,
height: clientRect.height};
// We iterate through all the parent windows.
while (true) {
// Does the selection overflow on the right of its window?
let diffx = frameWin.innerWidth - (rect.left + rect.width);
if (diffx < 0) {
rect.width += diffx;
}
// Does the selection overflow on the bottom of its window?
let diffy = frameWin.innerHeight - (rect.top + rect.height);
if (diffy < 0) {
rect.height += diffy;
}
// Does the selection overflow on the left of its window?
if (rect.left < 0) {
rect.width += rect.left;
rect.left = 0;
}
// Does the selection overflow on the top of its window?
if (rect.top < 0) {
rect.height += rect.top;
rect.top = 0;
}
// Selection has been clipped to fit in its own window.
// Are we in the top-level window?
if (frameWin.parent === frameWin || !frameWin.frameElement) {
break;
}
// We are in an iframe.
// We take into account the parent iframe position and its
// offset (borders and padding).
let frameRect = frameWin.frameElement.getBoundingClientRect();
let [offsetTop, offsetLeft] =
this.getIframeContentOffset(frameWin.frameElement);
rect.top += frameRect.top + offsetTop;
rect.left += frameRect.left + offsetLeft;
frameWin = frameWin.parent;
}
return rect;
},
/**
* Compute the absolute position and the dimensions of a node, relativalely
* to the root window.
*
* @param nsIDOMNode aNode
* a DOM element to get the bounds for
* @param nsIWindow aContentWindow
* the content window holding the node
*/
getRect: function LH_getRect(aNode, aContentWindow) {
let frameWin = aNode.ownerDocument.defaultView;
let clientRect = aNode.getBoundingClientRect();
// Go up in the tree of frames to determine the correct rectangle.
// clientRect is read-only, we need to be able to change properties.
rect = {top: clientRect.top + aContentWindow.pageYOffset,
left: clientRect.left + aContentWindow.pageXOffset,
width: clientRect.width,
height: clientRect.height};
// We iterate through all the parent windows.
while (true) {
// Are we in the top-level window?
if (frameWin.parent === frameWin || !frameWin.frameElement) {
break;
}
// We are in an iframe.
// We take into account the parent iframe position and its
// offset (borders and padding).
let frameRect = frameWin.frameElement.getBoundingClientRect();
let [offsetTop, offsetLeft] =
this.getIframeContentOffset(frameWin.frameElement);
rect.top += frameRect.top + offsetTop;
rect.left += frameRect.left + offsetLeft;
frameWin = frameWin.parent;
}
return rect;
},
/**
* Returns iframe content offset (iframe border + padding).
* Note: this function shouldn't need to exist, had the platform provided a
* suitable API for determining the offset between the iframe's content and
* its bounding client rect. Bug 626359 should provide us with such an API.
*
* @param aIframe
* The iframe.
* @returns array [offsetTop, offsetLeft]
* offsetTop is the distance from the top of the iframe and the
* top of the content document.
* offsetLeft is the distance from the left of the iframe and the
* left of the content document.
*/
getIframeContentOffset: function LH_getIframeContentOffset(aIframe) {
let style = aIframe.contentWindow.getComputedStyle(aIframe, null);
// In some cases, the computed style is null
if (!style) {
return [0, 0];
}
let paddingTop = parseInt(style.getPropertyValue("padding-top"));
let paddingLeft = parseInt(style.getPropertyValue("padding-left"));
let borderTop = parseInt(style.getPropertyValue("border-top-width"));
let borderLeft = parseInt(style.getPropertyValue("border-left-width"));
return [borderTop + paddingTop, borderLeft + paddingLeft];
},
/**
* Apply the page zoom factor.
*/
getZoomedRect: function LH_getZoomedRect(aWin, aRect) {
// get page zoom factor, if any
let zoom =
aWin.QueryInterface(Components.interfaces.nsIInterfaceRequestor)
.getInterface(Components.interfaces.nsIDOMWindowUtils)
.screenPixelsPerCSSPixel;
// adjust rect for zoom scaling
let aRectScaled = {};
for (let prop in aRect) {
aRectScaled[prop] = aRect[prop] * zoom;
}
return aRectScaled;
},
/**
* Find an element from the given coordinates. This method descends through
* frames to find the element the user clicked inside frames.
*
* @param DOMDocument aDocument the document to look into.
* @param integer aX
* @param integer aY
* @returns Node|null the element node found at the given coordinates.
*/
getElementFromPoint: function LH_elementFromPoint(aDocument, aX, aY) {
let node = aDocument.elementFromPoint(aX, aY);
if (node && node.contentDocument) {
if (node instanceof Ci.nsIDOMHTMLIFrameElement) {
let rect = node.getBoundingClientRect();
// Gap between the iframe and its content window.
let [offsetTop, offsetLeft] = LayoutHelpers.getIframeContentOffset(node);
aX -= rect.left + offsetLeft;
aY -= rect.top + offsetTop;
if (aX < 0 || aY < 0) {
// Didn't reach the content document, still over the iframe.
return node;
}
}
if (node instanceof Ci.nsIDOMHTMLIFrameElement ||
node instanceof Ci.nsIDOMHTMLFrameElement) {
let subnode = this.getElementFromPoint(node.contentDocument, aX, aY);
if (subnode) {
node = subnode;
}
}
}
return node;
},
/**
* Scroll the document so that the element "elem" appears in the viewport.
*
* @param Element elem the element that needs to appear in the viewport.
* @param bool centered true if you want it centered, false if you want it to
* appear on the top of the viewport. It is true by default, and that is
* usually what you want.
*/
scrollIntoViewIfNeeded:
function LH_scrollIntoViewIfNeeded(elem, centered) {
// We want to default to centering the element in the page,
// so as to keep the context of the element.
centered = centered === undefined? true: !!centered;
let win = elem.ownerDocument.defaultView;
let clientRect = elem.getBoundingClientRect();
// The following are always from the {top, bottom, left, right}
// of the viewport, to the {top, …} of the box.
// Think of them as geometrical vectors, it helps.
// The origin is at the top left.
let topToBottom = clientRect.bottom;
let bottomToTop = clientRect.top - win.innerHeight;
let leftToRight = clientRect.right;
let rightToLeft = clientRect.left - win.innerWidth;
let xAllowed = true; // We allow one translation on the x axis,
let yAllowed = true; // and one on the y axis.
// Whatever `centered` is, the behavior is the same if the box is
// (even partially) visible.
if ((topToBottom > 0 || !centered) && topToBottom <= elem.offsetHeight) {
win.scrollBy(0, topToBottom - elem.offsetHeight);
yAllowed = false;
} else
if ((bottomToTop < 0 || !centered) && bottomToTop >= -elem.offsetHeight) {
win.scrollBy(0, bottomToTop + elem.offsetHeight);
yAllowed = false;
}
if ((leftToRight > 0 || !centered) && leftToRight <= elem.offsetWidth) {
if (xAllowed) {
win.scrollBy(leftToRight - elem.offsetWidth, 0);
xAllowed = false;
}
} else
if ((rightToLeft < 0 || !centered) && rightToLeft >= -elem.offsetWidth) {
if (xAllowed) {
win.scrollBy(rightToLeft + elem.offsetWidth, 0);
xAllowed = false;
}
}
// If we want it centered, and the box is completely hidden,
// then we center it explicitly.
if (centered) {
if (yAllowed && (topToBottom <= 0 || bottomToTop >= 0)) {
win.scroll(win.scrollX,
win.scrollY + clientRect.top
- (win.innerHeight - elem.offsetHeight) / 2);
}
if (xAllowed && (leftToRight <= 0 || rightToLeft <= 0)) {
win.scroll(win.scrollX + clientRect.left
- (win.innerWidth - elem.offsetWidth) / 2,
win.scrollY);
}
}
if (win.parent !== win) {
// We are inside an iframe.
LH_scrollIntoViewIfNeeded(win.frameElement, centered);
}
},
/**
* Check if a node and its document are still alive
* and attached to the window.
*
* @param aNode
*/
isNodeConnected: function LH_isNodeConnected(aNode)
{
try {
let connected = (aNode.ownerDocument && aNode.ownerDocument.defaultView &&
!(aNode.compareDocumentPosition(aNode.ownerDocument.documentElement) &
aNode.DOCUMENT_POSITION_DISCONNECTED));
return connected;
} catch (e) {
// "can't access dead object" error
return false;
}
},
};