Generate numbers in side div at random position without overlapping

I want to display random numbers inside a div at random positions without overlapping. I am able to display random number at random position but its going outside the box and overlapping each other.

Here is my code:

JS Fiddle

var width = $('.container').innerWidth();
var height = $('.container').innerHeight();

(function generate() {     // vary size for fun
    for (i = 0; i < 15; i++) {
        var divsize = 12;
        var color = '#' + Math.round(0xffffff * Math.random()).toString(16);
        $newdiv = $('<div/>').css({
            'width': divsize + 'px',
                'height': divsize + 'px'
        });

        // make position sensitive to size and document's width
        var posx = (Math.random() * (width - divsize)).toFixed();
        var posy = (Math.random() * (height - divsize)).toFixed();

        $newdiv.css({
            'position': 'absolute',
                'left': posx + 'px',
                'top': posy + 'px',
                'float': 'left'
        }).appendTo('.container').html(Math.floor(Math.random() * 9));
    }
})();

How can I do this?

Answers:

Answer

You've got most of it figured out. You just need to think of the .container div as a grid to avoid any overlap or outlying items.

Just check out this fiddle.

Here's what the code looks like:

var tilesize = 18, tilecount = 15;
var gRows = Math.floor($(".container").innerWidth()/tilesize);
var gCols = Math.floor($('.container').innerHeight()/tilesize);

var vals = _.shuffle(_.range(tilecount));
var xpos = _.shuffle(_.range(gRows));
var ypos = _.shuffle(_.range(gCols));

_.each(vals, function(d,i){
    var $newdiv = $('<div/>').addClass("tile");
    $newdiv.css({
        'position':'absolute',
        'left':(xpos[i] * tilesize)+'px',
        'top':(ypos[i] * tilesize)+'px'
    }).appendTo( '.container' ).html(d);  
});

PS:I have used underscore in my fiddle to make things easier for me and because I personally hate writing for loops.

Answer

If the number of divs you need to create is small enough (i.e. you're not risking that they won't fit) then a simple algorithm is:

  • pick a random position (x0, y0)-(x1, y1)
  • check if any previously selected rect overlaps
  • if none overlaps then add the rect, otherwise loop back and choose another random position

in code

var selected = [];

for (var i=0; i<num_divs; i++) {
    while (true) {
        var x0 = Math.floor(Math.random() * (width - sz));
        var y0 = Math.floor(Math.random() * (height - sz));
        var x1 = x0 + sz;
        var y1 = y0 + sz;
        var i = 0;
        while (i < selected.length &&
               (x0 >= selected[i].x1 ||
                y0 >= selected[i].y1 ||
                x1 <= selected[i].x0 ||
                y1 <= selected[i].y0)) {
            i++;
        }
        if (i == selected.length) {
            // Spot is safe, add it to the selection
            selected.push({x0:x0, y0:y0, x1:x1, y1:y1});
            break;
        }
        // The choice collided with a previously added div
        // just remain in the loop so a new attempt is done
    }
}

In case the elements are many and it's possible to place n-1 of them so that there's no position where to put n-th element then things are a lot more complex.

For the solution of the 1-dimensional version of this problem see this answer.

Answer

You can add to array position of each number. And then when ou generate new position for digit you should check if posx posy in array, if false place number there, if true generate new posx and posy

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