From 38a5b20fe77c742c57125e039aa70fe4e4a3677d Mon Sep 17 00:00:00 2001
From: Paul Bakaus <paul.bakaus@googlemail.com>
Date: Thu, 8 Jan 2009 12:37:15 +0000
Subject: [PATCH] draggable: re-implemented containment and grid support (fixes
 #3607)

---
 ui/ui.draggable.js | 37 ++++++++++++++++++++++++++++++++++---
 1 file changed, 34 insertions(+), 3 deletions(-)

diff --git a/ui/ui.draggable.js b/ui/ui.draggable.js
index 82d09c77a..78f06e860 100644
--- a/ui/ui.draggable.js
+++ b/ui/ui.draggable.js
@@ -96,6 +96,8 @@ $.widget("ui.draggable", $.extend({}, $.ui.mouse, {
 
 		//Generate the original position
 		this.originalPosition = this._generatePosition(event);
+		this.originalPageX = event.pageX;
+		this.originalPageY = event.pageY;
 
 		//Set a containment if given in the options
 		if(o.containment)
@@ -278,7 +280,7 @@ $.widget("ui.draggable", $.extend({}, $.ui.mouse, {
 
 		if(!pos) pos = this.position;
 		var mod = d == "absolute" ? 1 : -1;
-		var scroll = this[(this.cssPosition == 'absolute' ? 'offset' : 'scroll')+'Parent'], scrollIsRootNode = (/(html|body)/i).test(scroll[0].tagName);
+		var o = this.options, scroll = this.cssPosition == 'absolute' && !(this.scrollParent[0] != document && $.ui.contains(this.scrollParent[0], this.offsetParent[0])) ? this.offsetParent : this.scrollParent, scrollIsRootNode = (/(html|body)/i).test(scroll[0].tagName);
 
 		return {
 			top: (
@@ -309,17 +311,46 @@ $.widget("ui.draggable", $.extend({}, $.ui.mouse, {
 		if(this.cssPosition == 'relative' && !(this.scrollParent[0] != document && this.scrollParent[0] != this.offsetParent[0])) {
 			this.offset.relative = this._getRelativeOffset();
 		}
+		
+		var pageX = event.pageX;
+		var pageY = event.pageY;
+
+		/*
+		 * - Position constraining -
+		 * Constrain the position to a mix of grid, containment.
+		 */
+		 
+		if(this.originalPosition) { //If we are not dragging yet, we won't check for options
+
+			if(this.containment) {
+				if(event.pageX - this.offset.click.left < this.containment[0]) pageX = this.containment[0] + this.offset.click.left;
+				if(event.pageY - this.offset.click.top < this.containment[1]) pageY = this.containment[1] + this.offset.click.top;
+				if(event.pageX - this.offset.click.left > this.containment[2]) pageX = this.containment[2] + this.offset.click.left;
+				if(event.pageY - this.offset.click.top > this.containment[3]) pageY = this.containment[3] + this.offset.click.top;
+			}
+			
+			if(o.grid) {
+				var top = this.originalPageY + Math.round((pageY - this.originalPageY) / o.grid[1]) * o.grid[1];
+				pageY = this.containment ? (!(top - this.offset.click.top < this.containment[1] || top - this.offset.click.top > this.containment[3]) ? top : (!(top - this.offset.click.top < this.containment[1]) ? top - o.grid[1] : top + o.grid[1])) : top;
+
+				var left = this.originalPageX + Math.round((pageX - this.originalPageX) / o.grid[0]) * o.grid[0];
+				pageX = this.containment ? (!(left - this.offset.click.left < this.containment[0] || left - this.offset.click.left > this.containment[2]) ? left : (!(left - this.offset.click.left < this.containment[0]) ? left - o.grid[0] : left + o.grid[0])) : left;
+			}
+
+		}
+
+
 
 		var position = {
 			top: (
-				event.pageY																// The absolute mouse position
+				pageY																// The absolute mouse position
 				- this.offset.click.top													// Click offset (relative to the element)
 				- this.offset.relative.top												// Only for relative positioned nodes: Relative offset from element to offset parent
 				- this.offset.parent.top												// The offsetParent's offset without borders (offset + border)
 				+ ( this.cssPosition == 'fixed' ? -this.scrollParent.scrollTop() : ( scrollIsRootNode ? 0 : scroll.scrollTop() ) )
 			),
 			left: (
-				event.pageX																// The absolute mouse position
+				pageX																// The absolute mouse position
 				- this.offset.click.left												// Click offset (relative to the element)
 				- this.offset.relative.left												// Only for relative positioned nodes: Relative offset from element to offset parent
 				- this.offset.parent.left												// The offsetParent's offset without borders (offset + border)
-- 
2.39.5