Normalize dimensions (#527)

* normalize dimensions of non-linear elements

* fix element type check regression

src/element/index.ts

@@ -8,7 +8,11 @@ export {
 
 export { handlerRectangles } from "./handlerRectangles";
 export { hitTest } from "./collision";
-export { resizeTest, getCursorForResizingElement } from "./resizeTest";
+export {
+  resizeTest,
+  getCursorForResizingElement,
+  normalizeResizeHandle,
+} from "./resizeTest";
 export { isTextElement } from "./typeChecks";
 export { textWysiwyg } from "./textWysiwyg";
 export { redrawTextBoundingBox } from "./textElement";
@@ -16,4 +20,5 @@ export {
   getPerfectElementSize,
   isInvisiblySmallElement,
   resizePerfectLineForNWHandler,
+  normalizeDimensions,
 } from "./sizeHelpers";