535 /* From https://jsfiddle.net/ibowankenobi/1mmh7rs6/6/ */

   536 function getAbsoluteCTM(element){

   537 	var height = svg_root.height.baseVal.value,

   538 		width = svg_root.width.baseVal.value,

   539 		viewBoxRect = svg_root.viewBox.baseVal,

   540 		vHeight = viewBoxRect.height,

   541 		vWidth = viewBoxRect.width;

   542 	if(!vWidth || !vHeight){

   543 		return element.getCTM();

   544 	}

   545 	var sH = height/vHeight,

   546 		sW = width/vWidth,

   547 		matrix = svg_root.createSVGMatrix();

   548 	matrix.a = sW;

   549 	matrix.d = sH

   550 	var realCTM = element.getCTM().multiply(matrix.inverse());

   551 	realCTM.e = realCTM.e/sW + viewBoxRect.x;

   552 	realCTM.f = realCTM.f/sH + viewBoxRect.y;

   553 	return realCTM;

   554 }

   555 

   556 function apply_reference_frames(){

   557     const matches = svg_root.querySelectorAll("g[svghmi_x_offset]");

   558     matches.forEach((group) => {

   559         let [x,y] = ["x", "y"].map((axis) => Number(group.getAttribute("svghmi_"+axis+"_offset")));

   560         let ctm = getAbsoluteCTM(group);

   561         // zero translation part of CTM

   562         // to only apply rotation/skewing to offset vector

   563         ctm.e = 0;

   564         ctm.f = 0;

   565         let invctm = ctm.inverse();

   566         let vect = new DOMPoint(x, y);

   567         let newvect = vect.matrixTransform(invctm);

   568         let transform = svg_root.createSVGTransform();

   569         transform.setTranslate(newvect.x, newvect.y);

   570         group.transform.baseVal.appendItem(transform);

   571         ["x", "y"].forEach((axis) => group.removeAttribute("svghmi_"+axis+"_offset"));

   572     });

   573 }

   574 

   577     apply_reference_frames();