CODEWITHSUNDEEP
javascript
Sir
Sir

Reputation: 8277

Creating a grid array of co ordinates

I'm a little confused with my array creation. I have a list of items with x:y co ordinates and also their dimensions (in grid sizes) ... for example:

x: 1
y: 7
width: 2 tiles
height: 2 tiles

So the idea im trying to do is create an array of x:y grids that are "occupied". But looping such data so the occupied tiles would there for be:

x: 1
y: 7
//
x: 2
y: 7
//
x: 1
y: 8
//
x: 2
y: 8

Because in the above example the item is 2 by 2 tiles ( a square ).

My object is structured like this (shown in console.log(sdata);)

7: Array[4]
0: "1"
1: "7"
2: "2"
3: "2"

So yeah im trying to make an array to store this kind of grid reference..Hope I explained what I trying to get at, but i can't work out how to structure a loop to create the array.

Upvotes: 0

Views: 4090

Answers (3)

rlemon
rlemon

Reputation: 17667

http://jsfiddle.net/rlemon/JeeV2/ Here is an example of how you could produce this type of 'grid' occupied data.. 

var chords = [ // instead of arrays we'll use objects.. they're nicer. 
    {
    x: 1,
    y: 7,
    h: 2, // height
    w: 2}, // width
{ // ohh look a second plot point.
    x: 4,
    y: 1,
    h: 3,
    w: 2},
];

var occupied = { // will be your cells points occupied
    x: [],
    y: []    
};
chords.forEach(function(chord) { // now lets loop the chords and produce the occupied array
    occupied.x.push( chord.x );
    occupied.x.push( chord.x + (chord.w-1) ); // expand the width of the cell - initial point
    occupied.y.push( chord.y );
    occupied.y.push( chord.y + (chord.h-1) ); // expand the height of the cell - initial point
});
console.log( occupied );
// outputs
​Object
    x: Array[4]
        0: 1
        1: 2
        2: 4
        3: 5

    y: Array[4]
        0: 7
        1: 8
        2: 1
        3: 3

Upvotes: 1

ninjagecko
ninjagecko

Reputation: 91139

function range(a, b) {
    /*
        range(5) -> [0,1,2,3,4]
        range(1,4) -> [1,2,3]
    */
    if (b===undefined)
        var start=0, stop=a;
    else
        var start=a, stop=b;

    var R = [];
    for(var i=start; i<stop; i++)
        R.push(i);
    return R;
}

Then it's a two-liner:

range(x, x+width).map(function(x) {
    return range(y, y+height).map(function(y) {
        return {x:x, y:y}; // anything you'd like
    })
})

Result (obtained via JSON.stringify):

[
    [ {"x":1,"y":7}, {"x":1,"y":8} ],
    [ {"x":2,"y":7}, {"x":2,"y":8} ]
]

Upvotes: 0

Alexander
Alexander

Reputation: 23537

The resulting outputArray array is a collection of objects in the form { x: value, y: value}.

var inputArray = [ [1,7,2,2], ... ];
var outputArray = [];
for(var i = 0; i < inputArray.length; i++) {
    var item = {
      x: inputArray[i][0],
      y: inputArray[i][1],
      width: inputArray[i][2],
      height: inputArray[i][3]
    };
    for(var xx = 0; xx < item.width; xx++) {
        for(var yy = 0; yy < item.height; yy++) {        
            outputArray.push({
                x: item.x + xx,
                y: item.y + yy
            });
        }
    }
}

​I added the x, y, width and height attributes to make it more understandable.

Upvotes: 1

Related Questions