Fuzzy node text after resizing

GoJS
1

We got some fuzzy node text on GoJS diagram after resizing. We could reproduce it with one of GoJS example.
Could anybody please suggest some way to avoid/solve it? Thanks a lot!

The step to reproduce it:

  1. zoom out your chrome browser to 50%.
  2. open the link Page Flow
  3. zoom in your chrome browser to 100%.

You could see the fuzzy node text on the diagram.

image.png1106×614 103 KB

2

I don’t know if we can get an event when that happens – we can look.

I know there isn’t any such event when a DIV changes size. That’s why we wrote Resizing Diagrams -- Northwoods Software.

But now that I try it, I’m finding that calling Diagram.requestUpdate() doesn’t help for this situation.

3

Internally we call myDiagram.computePixelRatio() to return the resolution (pixel density) of the Diagram. You can override this to demand a different ratio, but be careful, as it is different on every screen.

We only compute the native pixel ratio once, when the Diagram is created, and so if you create a new Diagram you will get an updated value. This is why its different when you refresh the page, since you’re re-creating the diagram.

You could override computePixelRatio like this:

// note: assumes that an HTML canvas is the first child of the Diagram div (true today, but not necessarily true in the future)
var ctx = myDiagram.div.firstChild.getContext('2d'); 
myDiagram.computePixelRatio = function() {
  var dpr = window['devicePixelRatio'] || 1;
  var bsr = ctx['webkitBackingStorePixelRatio'] ||
      ctx['mozBackingStorePixelRatio'] ||
      ctx['msBackingStorePixelRatio'] ||
      ctx['oBackingStorePixelRatio'] ||
      ctx['backingStorePixelRatio'] || 1;
  return dpr / bsr;
}

And then it will always have the correct value.

This override may make some optimizations impossible (we lower the pixel ratio when panning, for instance), so it may impact performance.

4

Thank you all for your help!

I implemented what Simon suggested in our application and it works!

5

Good. We’ll implement that as the default behavior in the next release, 1.7.25 (currently in beta), which should be coming out in a few days. You’ll then be able to remove that override.

6

It’s now released as “latest”.