Fix elements disappearing when scaling them near 0.

element.getCTM() returns `null` if one of the transformation matrices
is zero. This fix uses get_transform_matrix instead.

client-data/js/intersect.js

@@ -28,6 +28,25 @@ if (!SVGGraphicsElement.prototype.transformedBBox || !SVGGraphicsElement.prototy
     [pointInTransformedBBox,
      transformedBBoxIntersects] = (function () {
 
+	 var get_transform_matrix = function (elem) {
+	     // Returns the first translate or transform matrix or makes one
+	     var transform = null;
+	     for (var i = 0; i < elem.transform.baseVal.numberOfItems; ++i) {
+		 var baseVal = elem.transform.baseVal[i];
+		 // quick tests showed that even if one changes only the fields e and f or uses createSVGTransformFromMatrix
+		 // the brower may add a SVG_TRANSFORM_MATRIX instead of a SVG_TRANSFORM_TRANSLATE
+		 if (baseVal.type === SVGTransform.SVG_TRANSFORM_MATRIX) {
+		     transform = baseVal;
+		     break;
+		 }
+	     }
+	     if (transform == null) {
+		 transform = elem.transform.baseVal.createSVGTransformFromMatrix(Tools.svg.createSVGMatrix());
+		 elem.transform.baseVal.appendItem(transform);
+	     }
+	     return transform.matrix;
+	 }
+
 	var transformRelative = function (m,t) {
 	    return [
 		m.a*t[0]+m.c*t[1],
@@ -44,7 +63,7 @@ if (!SVGGraphicsElement.prototype.transformedBBox || !SVGGraphicsElement.prototy
 
 	SVGGraphicsElement.prototype.transformedBBox = function (scale=1) {
 	    bbox = this.getBBox();
-	    tmatrix = this.getCTM();
+	    tmatrix = get_transform_matrix(this);
 	    tmatrix.e /= scale;
 	    tmatrix.f /= scale;
 	    return {
@@ -61,7 +80,7 @@ if (!SVGGraphicsElement.prototype.transformedBBox || !SVGGraphicsElement.prototy
 		width: this.width.baseVal.value,
 		height: this.height.baseVal.value
 	    };
-	    tmatrix = this.getCTM();
+	    tmatrix = get_transform_matrix(this);
 	    tmatrix.e /= scale;
 	    tmatrix.f /= scale;
 	    return {

client-data/tools/hand/hand.js

@@ -166,7 +166,7 @@
 
 	function showSelectionButtons() {
 		var scale = getScale();
-		var selectionBBox = selectionRect.transformedBBox(scale);
+		var selectionBBox = selectionRect.transformedBBox();
 		for (var i = 0; i < selectionButtons.length; i++) {
 			selectionButtons[i].drawCallback(selectionButtons[i],
 				selectionBBox,
@@ -209,14 +209,12 @@
 		evt.preventDefault();
 		hideSelectionButtons();
 		selectorState = selectorStates.transform;
-		var scale = getScale();
-		var bbox = selectionRect.transformedBBox(scale);
+		var bbox = selectionRect.transformedBBox();
 		selected = {
 			x: bbox.r[0],
 			y: bbox.r[1],
 			w: bbox.a[0],
 			h: bbox.b[1],
-			s: scale
 		};
 		transform_elements = selected_els.map(function(el) {
 			var tmatrix = get_transform_matrix(el);
@@ -250,12 +248,11 @@
 
 
 	function calculateSelection() {
-		var scale = getScale();
-		var selectionTBBox = selectionRect.transformedBBox(scale);
+		var selectionTBBox = selectionRect.transformedBBox();
 		var elements = Tools.drawingArea.children;
 		var selected = [];
 		for (var i=0; i < elements.length; i++) {
-			if (transformedBBoxIntersects(selectionTBBox, elements[i].transformedBBox(scale)))
+			if (transformedBBoxIntersects(selectionTBBox, elements[i].transformedBBox()))
 				selected.push(Tools.drawingArea.children[i]);
 		}
 		return selected;
@@ -297,11 +294,10 @@
 	function scaleSelection(x, y) {
 		var rx = (x - selected.x)/(selected.w);
 		var ry = (y - selected.y)/(selected.h);
-		var scale = getScale();
 		var msgs = selected_els.map(function(el, i) {
 			var oldTransform = transform_elements[i];
-			var x = el.transformedBBox(scale).r[0];
-			var y = el.transformedBBox(scale).r[1];
+			var x = el.transformedBBox().r[0];
+			var y = el.transformedBBox().r[1];
 			var a = oldTransform.a * rx;
 			var d = oldTransform.d * ry;
 			var e = selected.x * (1 - rx) - x * a +
@@ -349,7 +345,7 @@
 	}
 
 	function resetSelectionRect() {
-		var bbox = selectionRect.transformedBBox(getScale());
+		var bbox = selectionRect.transformedBBox();
 		var tmatrix = get_transform_matrix(selectionRect);
 		selectionRect.x.baseVal.value = bbox.r[0];
 		selectionRect.y.baseVal.value = bbox.r[1];
@@ -418,7 +414,7 @@
 		}
 		if (button) {
 			button.clickCallback(x, y, evt);
-		} else if (pointInTransformedBBox([x, y], selectionRect.transformedBBox(scale))) {
+		} else if (pointInTransformedBBox([x, y], selectionRect.transformedBBox())) {
 			hideSelectionButtons();
 			startMovingElements(x, y, evt);
 		} else if (Tools.drawingArea.contains(evt.target)) {