I have a div containing a list elements, which have static positioning and for each element I want to
Record its absolute positioning using the offset() method
Change its positioning to absolute, move it somewhere else, and later move it back to its original position using the recorded coordinates
First I tried this:
var positions = {};
myDiv.children().each(function(){
var child = $(this);
var id = child.attr('id');
var offset = child.offset();
positions[id] = [offset.left, offset.top];
child .css('position', 'absolute');
var x = ...;
var y = ...;
child.css('left', x);
child.css('top', y);
});
console.log(positions);
In this case, every entry of the 'positions' object have the same coordinates (value for the first element). However, if I comment out the bit that moves the element, the positions objects has the correct coordinates for each child.
So I'm guessing it's a synchronisation issue, because the css function is called before the offset function has terminated.
So what I need really, is to make sure that the block child.css('left', x); child.css('top', y); is only executed when the 'offset' function is done.
I tried things like
$.queue(child, 'foo', function() {
var offset = $(this).offset();
positions[id] = [offset.left, offset.top];
jQuery.dequeue(this);
});
$.dequeue(child, 'foo');
child.promise().done(function() {
child.css('position', 'absolute');
...
});
but with no luck: when I log the positions objects it still has the wrong coordinates.
I am quite new to JS and JQuery so I'm sure how to do the right thing here.
How can I make sure the block child.css('left', x); child.css('top', y); will only be executed after the 'positions' object has been populated with the correct offset coordinates?
EDIT
I just realised that in my case I need to use 'position()' rather than 'offset()' but that doesn't really change the problem that I have described
In .each() changing sibling elements' position could be cause of getting wrong coordinates after the first one.
Why don't you get and store all positions before changing?
I mean you should iterate childrens double times.
Iterate childrens and store position, don't change any css,
Iterate childrens again and change css.
Related
EDIT: I've simplified the code (below and in fiddle) down to the major problem needed to be solved in hope of creating more readability.
I've implemented Bader's solution for correctly using getBoundingClientRect value and using document.querySelector for getting both the class name and the html tag needed for the function. I'd now like to move on to the last five lines of the code beginning with var = style.
I've now corrected the math for the final two variables.
→ I'm trying to achieve creating a snapping function for use alongside Plumber, a baseline-grid Sass plugin.
Basically, I have a vertically centered flex item that needs to -- instead of being perfectly centered -- snap in an upward direction to the closest grid line. This will allow me to have a consistent vertical rhythm between slides in a custom mobile-based experience.
I'm using getBoundingClientRect to calculate the distance between the bottom of an object, and the top of the window.
Then I use Math.floor to round down to the nearest multiple of my rem value.
Then I use this new value to create a CSS bottom margin on the flex-centered container for the alignment fix.
(Then to finish, I'd like to have this function load on $(document).ready and on window resize.)
function() {
var box = document.querySelector('.box-1');
var rect = box.getBoundingClientRect();
var bottomOrig = rect.bottom;
var htmlRoot = document.querySelector('html');
var style = getComputedStyle(htmlRoot);
var remValue = style.getPropertyValue('font-size');
var bottomNew = Math.floor(bottomOrig / remValue) * remValue;
var fix = bottomOrig - bottomNew;
$('.container-2').css("margin-bottom", "fix + 'px'");
}
Here's the fiddle.
I most likely have a syntax problem here, and would greatly appreciate help.
Thanks!
Here are some errors / corrections.
GetBoundingClientRect() is a JS function, not jQuery, so it must be used on a javascript element, not a jquery selector. Using the [0] accessor on the jquery selector (if that's how you want to get it) will give you the JS element.
Also noticed that you were trying to select the "html" tag by id, but it doesn't have any Id. Changed it to getElementsByTagName.
var offsetYOrig = $('.box-1')[0].getBoundingClientRect().bottom;
// or, without jQuery:
// var offsetYOrig = document.getElementsByClassName('box-1')[0].getBoundingClientRect().bottom;
var html = document.getElementsByTagName("html")[0];
var style = window.getComputedStyle(html);
var remValue = style.getPropertyValue('font-size');
Edit: Regarding your edit, if you need to call the javascript to recompute on window resize, you may want to try something like this. I'm not sure if it achieves what you want fully (I don't completely understand your 'snapping' requirements, but this will at least call the code again. You may still have to edit the code in the snapFunction if it doesn't suit your needs.
I added some console logs that might help you check your math as it seemed a bit problematic to me, though I was unsure how to fix it because I don't understand your goal.
function snapFunction ()
{
var box = document.querySelector('.box-1');
var rect = box.getBoundingClientRect();
var bottomOrig = rect.bottom;
var htmlRoot = document.querySelector('html');
var style = getComputedStyle(htmlRoot);
var remValue = style.getPropertyValue('font-size');
var bottomNew = Math.floor(bottomOrig / remValue) * remValue;
var fix = bottomOrig - bottomNew;
// open your browser console and check the value of these to check your math and what values you're getting
console.log("bottomOrig: " + bottomOrig )
console.log("remValue: " + remValue)
console.log("bottomNew: " + bottomNew )
// note: no quotes around your variable name fix here
$('.container-2').css("margin-bottom", fix + "px");
};
// call on load
(function() {
snapFunction();
})();
// call on resize
$( window ).resize(function() {
snapFunction();
});
I did notice that the value of your bottomNew variable was logging as "NaN" (Not a Number) so I think something is going wrong there.
I think you're getting a font-size like "36px" instead of just "36". Maybe you could try
var remValue = parseInt(style.getPropertyValue('font-size'), 10);
The 10 in that parseInt function is just specifying we want to use base 10 numbers.
I hope this will help you
Here's the edited fiddle
jsfiddle.net/ztf64mwg/82/
I just edited some variables and fixed some of the errors
I ended up jumping on HackHands and, with help, came up with a great working solution.
This will snap any vertically flex-centered object to a grid with its size set as 1rem.
All you need to do is give the object that is being measured for distance the id attribute "measure", making sure that this object is aligned correctly with a 1rem grid from the top of its own container.
Then give the parent container (or any container higher in the DOM tree) that you'd like to snap to the grid the class of "snap".
If anyone ever finds a use for this and needs further explanation, just let me know.
function snap(object){
var rect = object.getBoundingClientRect();
var bottomOrig = rect.bottom;
var htmlRoot = document.querySelector('html');
var style = getComputedStyle(htmlRoot);
var remValue = parseInt(style.getPropertyValue('font-size'));
var bottomNew = Math.floor(bottomOrig / remValue) * remValue;
var topFixPositive = bottomNew - bottomOrig;
var topFixNegative = -Math.abs(topFixPositive);
$(object).closest('.snap').css("margin-top", topFixNegative);
}
function snapClear(object){
$(object).closest('.snap').css("margin-top", "0");
}
var measureHome = document.querySelector('#measure');
snap(measureHome);
$(window).on('resize', function() {
snapClear(measureHome);
snap(measureHome);
});
I have been working with the following code: http://bl.ocks.org/NPashaP/7683252. This is a graphical representation of a tree. I have stripped away much of the code (the graceful labels), only allowing two nodes per parent, and changed the data structure to an array.
The only problem left now is the repositioning. The original code does that perfectly. But since I want a binary tree, I have let the user choose to insert a left or right child. The original reposition code animates the first child straight down from the parent, but that would be wrong in a binary tree. I want it to either go to the left or right.
reposition = function (v) {
function repos(v) {
var lC = getLeafCount(v.v),
left = v.p.x; //parent's x-position
v.c.forEach(function (d) {
var vc = d; //saving reference of the child in parent object
d = tree.getVerticeById(d.v); //actually fetching the child object
var w = 0;
if(d.d == 'right') { w += 15 * lC }
if(d.d == 'left') { w -= 15 * lC }
d.p = {x: left + w, y: v.p.y + tree.h}; //setting the position
vc.p = d.p; //setting the child's pos in parent obj
repos(d);
});
}
repos(v[0]);
};
Some of the parts of my code are different from the original code, because I have changed the data structure as stated before. I have tried to comment the parts that may be confusing, but what is important is the math of the repositioning.
At first, this code seemed to work well (https://i.stack.imgur.com/gjzOq.png). But after some testing I discovered a huge problem with the repositioning: the nodes crash with each other (https://i.stack.imgur.com/pdQfy.png)!
Conclusion: I have tried to modify the original function to take the in mind the left and right positioning of nodes, but could not do it. I wrote this variant of the method which does, but it still has some problems as illustrated in the pictures. I would be thankful for some input in this matter.
I eventually did a quick fix for this problem.
After running the reposition function as posted in the question, i ran another function which fixed the problem. The new function goes through all levels of the tree and checks if the nodes are too close together. If they are, the algorithm finds closest common ancestor, and increases the distance between its left and right children. After this, there is no more collisions between nodes.
In order to determine the page margin in various positions on the page I need to get the offset, width and height of each DOM element.
I loop over the DOM elements recursively and save each element's attributes.
I tried it with JQuery $(el).offset() but it was very slow. I guess that creating a JQuery object for each element by using the$(...) is very slow.
Then, I tried an old implementation that I got from an old code which uses native JS and it was X4 times faster.
SO what I'm really asking, is there a different method to accomplish that?
I should mention that my script runs on publishers' sites and I don't really know anything about the page that I'm running on.
I guess this is one solution, using map() and getBoundingClientRect():
var elements = document.getElementsByClassName('someclass');
elements.map(function(val, i, arr) {
var doc = document.getBoundingClientRect(),
el = val.getBoundingClientRect(),
coordsX = el.left - doc.left,
coordsY = el.top - doc.top;
return {x: coordsX, y: coordsY};
});
This will return an array of all the coordinates of a given class. You can change document.getElementsByClassName to querySelector if it better suits your needs.
This will also change getBoundingClientRect() to be relative to the document instead of the viewport.
Somehow this doesn't work...
var paper = Raphael("test", 500, 500);
var testpath = paper.path('M100 100L190 190');
var a = paper.rect(0,0,10,10);
a.attr('fill', 'silver');
a.mousedown( function() {
testpath.animate({x: 400}, 1000);
});
I can move rects this way but not paths, why is that, and how do I move a path object then?!
With the latest version of Raphael, you can do this:
var _transformedPath = Raphael.transformPath('M100 100L190 190', 'T400,0');
testpath.animate({path: _transformedPath}, 1000);
This saves you from the trouble of having to clone a temp object.
It seems a path object doesn't get a x,y value - so your animation probably still runs, but does nothing. Try instead animating the path function:
testpath.animate({path:'M400 100L490 190'},1000);
It makes it a bit trickier to write the animation, but you have the benefit of getting rotation and scaling for free!
BTW: I'm sure this is just an example, but in your above code testpath gets put in the global scope because you don't initialize as var testpath
Solved, with thanx to Rudu!
You need to create a new path to animate to. You can do this with clone() and then apply the transformations to that clone. Seems very complex for a simple move like this, but it works...
var paper = Raphael("test", 500, 500);
var testpath = paper.path('M100 100L190 190');
var a = paper.rect(0,0,10,10);
a.attr('fill', 'silver');
a.mousedown( function() {
var temp = testpath.clone();
temp.translate(400,0);
testpath.animate({path: temp.attr('path')}, 1000);
temp.remove();
});
TimDog answer was best solution.
In addition, just remember, transform string in this case means, that it will add 400 points to every path point/line X coordinate, and 0 points to every Y coordinate.
That means, M100 100L190 190 will turn into M500 100L590 190.
So, if you need to move a path element to another position, the difference between current position and new position coordinates should be calculated. You can use first element to do that:
var newCoordinates = [300, 200],
curPos = testpath.path[0],
newPosX = newCoordinates[0] - curPos[1],
newPosY = newCoordinates[1] - curPos[2];
var _transformedPath = Raphael.transformPath(testpath.path, "T"+newPosX+","+newPosY);
testpath.animate({path: _transformedPath});
Hope this will help someone.
Here's some code that generalises the best of the above answers and gives Raphael paths a simple .attr({pathXY: [newXPos, newYPos]}) attribute similar to .attr({x: newXPosition}) and .animate({x: newXPosition}) for shapes.
This lets you move your path to a fixed, absolute position or move it by a relative amount in a standard way without hardcoding path strings or custom calculations.
Edit: Code below works in IE7 and IE8. An earlier version of this failed in IE8 / VML mode due to a Raphael bug that returns arrays to .attr('path') in SVG mode but strings to .attr('path') in VML mode.
Code
Add this code (Raphael customAttribute, and helper function) after defining paper, use as below.
paper.customAttributes.pathXY = function( x,y ) {
// use with .attr({pathXY: [x,y]});
// call element.pathXY() before animating with .animate({pathXY: [x,y]})
var pathArray = Raphael.parsePathString(this.attr('path'));
var transformArray = ['T', x - this.pathXY('x'), y - this.pathXY('y') ];
return {
path: Raphael.transformPath( pathArray, transformArray)
};
};
Raphael.st.pathXY = function(xy) {
// pass 'x' or 'y' to get average x or y pos of set
// pass nothing to initiate set for pathXY animation
// recursive to work for sets, sets of sets, etc
var sum = 0, counter = 0;
this.forEach( function( element ){
var position = ( element.pathXY(xy) );
if(position){
sum += parseFloat(position);
counter++;
}
});
return (sum / counter);
};
Raphael.el.pathXY = function(xy) {
// pass 'x' or 'y' to get x or y pos of element
// pass nothing to initiate element for pathXY animation
// can use in same way for elements and sets alike
if(xy == 'x' || xy == 'y'){ // to get x or y of path
xy = (xy == 'x') ? 1 : 2;
var pathPos = Raphael.parsePathString(this.attr('path'))[0][xy];
return pathPos;
} else { // to initialise a path's pathXY, for animation
this.attr({pathXY: [this.pathXY('x'),this.pathXY('y')]});
}
};
Usage
For absolute translation (move to fixed X,Y position) - Live JSBIN demo
Works with any path or set of paths including sets of sets (demo). Note that since Raphael sets are arrays not groups, it moves each item in the set to the defined position - not the centre of the set.
// moves to x=200, y=300 regardless of previous transformations
path.attr({pathXY: [200,300]});
// moves x only, keeps current y position
path.attr({pathXY: [200,path.pathXY('y')]});
// moves y only, keeps current x position
path.attr({pathXY: [path.pathXY('x'),300]});
Raphael needs to handle both x and y co-ordinates together in the same customAttribute so they can animate together and so they stay in sync with each other.
For relative translation (move by +/- X,Y) - Live JSBIN demo
// moves down, right by 10
path.attr({pathXY: [ path.pathXY('x')+10, path.pathXY('y')+10 ]},500);
This also works with sets, but again don't forget that Raphael's sets aren't like groups - each object moves to one position relative to the average position of the set, so results may not be what are expected (example demo).
For animation (move a path to relative or absolute positions)
Before animating the first time, you need to set the pathXY values, due to a bug/missing feature up to Raphael 2.1.0 where all customAttributes need to be given a numeric value before they are animated (otherwise, they will turn every number into NaN and do nothing, failing silently with no errors, or not animating and jumping straight to the final position).
Before using .animate({pathXY: [newX,newY]});, run this helper function:
somePath.pathXY();
Yet another way is to use "transform" attribute:
testpath.animate({transform: "t400,0"}, 1000);
to move the path to the right by 400px, relative to the original position.
This should work for all shapes, including paths and rectangles.
Note that:
"transform" attribute is independent of x, y, cx, cy, etc. So these attributes are not updated by the animation above.
The value of "transform" attribute is always based on the original position, not the current position. If you apply the animation below after the animation above, it will move it 800px to the left relatively, instead of moving it back to its original position.
testpath.animate({transform: "t-400,0"}, 1000);
I have build a grid of div's as playground for some visual experiments. In order to use that grid, i need to know the x and y coordinates of each div. That's why i want to create a table with the X and Y position of each div.
X:0 & Y:0 = div:eq(0), X:0 Y:1 = div:eq(1), X:0 Y:2 = div:eq(2), X:0 Y:3 = div:eq(3), X:1 Y:0 = div:eq(4) etc..
What is the best way to do a table like that? Creating a OBJECT like this:
{
00: 0,
01: 1,
02: 2,
etc..
}
or is it better to create a array?
position[0][0] = 0
the thing is i need to use the table in multiple way's.. for example the user clicked the div nb: 13 what are the coordinates of this div or what is the eq of the div x: 12 y: 5.
Thats how i do it right now:
var row = 0
var col = 0
var eq = 0
c.find('div').each(function(i){ // c = $('div#stage')
if (i !=0 && $(this).offset().top != $(this).prev().offset().top){
row++
col = 0
}
$(this).attr({'row': row, 'col': col })
col++
})
I think it would be faster to build a table with the coordinates, instead of adding them as attr or data to the DOM. but i cant figure out how to do this technically.
How would you solve this problem width JS / jQuery?
A few questions:
Will the grid stay the same size or will it grow / shrink?
Will the divs stay in the same position or will they move around?
Will the divs be reused or will they be dynamically added / removed?
If everything is static (fixed grid size, fixed div positions, no dynamic divs), I suggest building two indices to map divs to coordinates and coordinates to divs, something like (give each div an id according to its position, e.g. "x0y0", "x0y1"):
var gridwidth = 20, gridheight = 10,
cells = [], // coordinates -> div
pos = {}, // div -> coordinates
id, i, j; // temp variables
for (i = 0; i < gridwidth; i++) {
cells[i] = [];
for (j = 0; j < gridheight; j++) {
id = 'x' + i + 'y' + j;
cells[i][j] = $('#' + id);
pos[id] = { x: i, y: j };
}
}
Given a set of coordinates (x, y) you can get the corresponding div with:
cells[x][y] // jQuery object of the div at (x, y)
and given a div you can get its coordinates with:
pos[div.attr('id')] // an object with x and y properties
Unless you have very stringent performance requirements, simply using the "row" and "col" attributes will work just fine (although setting them through .data() will be faster). To find the div with the right row/col, just do a c.find("div[row=5][col=12]"). You don't really need the lookup.
Let me elaborate on that a little bit.
If you were to build a lookup table that would allow you to get the row/col for a given div node, you would have to specify that node somehow. Using direct node references is a very bad practice that usually leads to memory leaks, so you'd have to use a node Id or some attribute as a key. That is basically what jQuery.data() does - it uses a custom attribute on the DOM node as a key into its internal lookup table. No sense in copying that code really. If you go the jQuery.data() route, you can use one of the plugins that allows you to use that data as part of the selector query. One example I found is http://plugins.jquery.com/project/dataSelector.
Now that I know what it's for...
It might not seem efficient at first, but I think It would be the best to do something like this:
Generate the divs once (server side), give them ids like this: id="X_Y" (X and Y are obviously numbers), give them positions with CSS and never ever move them. (changing position takes a lot of time compared to eg. background change, and You would have to remake the array I describe below)
on dom ready just create a 2D array and store jquery objests pointing the divs there so that
gridfields[0][12] is a jQuery object like $('#0_12'). You make the array once and never use selectors any more, so it's fast. Moreover - select all those divs in a container and do .each() on them and put them to proper array fields splitting their id attributes.
To move elements You just swap their css attributes (or classes if You can - it's faster) or simply set them if You have data that has the information.
Another superfast thing (had that put to practice in my project some time ago) is that You just bind click event to the main container and check coordinates by spliting $(e.target).attr('id')
If You bind click to a grid 100x100 - a browser will probably die. Been there, did that ;)
It may not be intuitive (not changing the div's position, but swapping contents etc.), but from my experience it's the fastest it can get. (most stuff is done on dom ready)
Hope You use it ;) Good luck.
I'm not 100% sure that I understand what you want, but I'd suggest to avoid using a library such as jQuery if you are concerned about performance. While jQuery has become faster recently, it still does has more overhead than "pure" JS/DOM operations.
Secondly - depending on which browsers you want to support - it may even be better to consider using a canvas or SVG scripting.