Auto Detect Image for 360 nature in PHP

According to Facebook 360 Group:

There isn't yet a standard for tagging a photo as containing 360 content.

It suggest that you look for the EXIF tag

Projection Type : equirectangular

You can also look for

Use Panorama Viewer : True

Those two tags are present on photos taken with my LG 360.

I faced a similar problem for Unity3D platform, but I figured this considering that Equirectangular images usually have proportion as 2:1.

Likely width 2000px and height 1000px(I already have seen software generating heights a bit higher).

Here is the pseudo code, keep in mind that this code considers posX and posY starting from bottom left:

//this is how much the image should be close the 2:1 proportion, or 0.5-proportionThreshold.proportionThreshold = 0.01;//images smaller than this should not have resolution enough to be a panorama.//it is important here to minimumWidth = 2000;minimumHeight = 1080;//in case of the image is not a panorama, this variable determines the maximum size it could be projectedmaxFill = 0.65;//what is the amount of the view the pamorama should view:scaleX = 1;scaleY = 1;//where the panorama should be positioned in the view:posX = 0;posY = 0;currentWidth = source.width;currentHeight = source.height;if(isFullPanorama()){    Log("Full Panorama");    //the variables are already set for that}else if(isPartialPanorama()){    Log("Partial Panorama");    scale = currentHeight/currentWidth * 2f;    scaleX = 1;    scaleY = scale;    posX = 0;    posY = 0.5-scale/2;}else{    Debug.Log("Not Panorama");    proportion = currentHeight/currentWidth;    w = currentWidth > minimumWidth*maxFill ? minimumWidth*maxFill : currentWidth;    scaleX = w / minimumWidth / 2;    scaleY = scaleX * proportion * 2;    if(scaleY>1) {        h = currentHeight > minimumHeight*maxFill ? minimumHeight*maxFill : currentHeight;        scaleY = h / minimumHeight / 2;        scaleX = scaleY * proportion / 2;    }    posX = 0.5-scaleX/2;    posY = 0.5-scaleY/2;}bool isFullPanorama(){    proportion = currentHeight/currentWidth;    return proportion>=0.5-proportionThreshold &&    proportion<=0.5+proportionThreshold &&    source.height >= minimumHeight;}bool isPartialPanorama(){    return currentHeight/currentWidth<=0.5 &&    source.width >= minimumWidth;}