# X Y position to array item?

I have an image which is 320x240 px

I have an array of values for each pixel in the image (76,800 points)

If the user hovers over any part of the image I need to look at the array and return the corresponding value for it.

i.e.
X Y position [0,0] of the image = the first value in the array.

If I wanted to find out the X Y position [65,33] of the image, and then look up the  value in the array, what would be the correct forumla to do this
JavaScriptMath / Science

Last Comment
Zakaria Acharki

8/22/2022 - Mon
ste5an

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Zakaria Acharki

You could create a function that will init your array from the given width/height and return it as the output :

``````function initPixelsArray(width, height)
{
var pixels_arr = [];

for (var i = 0; i < width; i++) {
pixels_arr[i] = Array(height).fill().map((x, i) => i);

for (var j = 0; j < height; j++) {
pixels_arr[i][j] = 'INDEX '+i+'/'+j+' VALUE';
}
}

return pixels_arr;
}
``````

Then another function that searches for X/Y in the given array like :

``````function getIndex(arr, X,Y){
return arr[X][Y];
}
``````

Then call them like :

``````var pixels_arr = initPixelsArray(100, 50); //Init array
alert( getIndex(pixels_arr, 65, 33) ); //Get the specific x/y value
``````
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