When I use the pinch gesture to make the diagram smaller, it can suddenly start getting smaller and smaller, even though I am no longer moving my fingers. The entire diagram quickly shrinks down to a small square in the upper left corner of the screen, and that's it - there is no way to get it back to a viewable size again.

This on an Acer Iconia B1-A71 tablet running Android 4.1.2 and in landscape orientation.

Edit: More information: It seems to happen when the diagram is initially too large to be shown in the viewing area. When I use the pinch gesture it works fine, making more and more of the diagram visible, until the diagram is completely visible, and then it goes crazy and shrinks down to almost nothing in the upper left corner of the viewing area.

Edit 2: No, it can also happen even if the diagram is initially small enough to be completely visible.

OK, that seems to work. Here's what I've done:

    // Method used to prevent the diagram from shrinking too much when being resized. See here:
    // http://mindfusion.eu/Forum/YaBB.pl?num=1383096222
    @Override
    public void viewportChanged() {
        RectF r = _mindFusionDiagram.getBounds();
        float zoomLimitX = _diagramView.getWidth() / r.width();
        float zoomLimitY = _diagramView.getHeight() / r.height();
        float zoomLimit = Math.min(zoomLimitX,  zoomLimitY) * 100;
        if (zoomLimit > _diagramView.getZoomFactor()) {
            _diagramView.setZoomFactor(zoomLimit);
        }
    }
 

This requires that the DiagramView be defined in the layout with

        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
 

I.e., don't specify "wrap_content" for either width or height.

Only problem with this is that in order to use the viewportChanged() event method you have to define about 80 other methods belonging to the DiagramListener interface. Is there any way to avoid that? (I'm very new to Java.)

Thanks for the solution.

OK, thanks.