US Presidents

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This example shows the terms of each President of the United States. It is similar to the EnglandRuler example in that it shows a single category with simple non-overlapping events.

This example demonstrates multiple windows and an aspect of data hiding.

  • A single category with simple events.
  • Off-axis hiding of categories.
  • Multiple qviewer windows
things to try:
  • Change the view direction to the past missing image.
  • Grab the x/y movement control (the square target) and move it to the left. Notice how after the near part of the timeline moves off the display, the entire timeline gradually starts to fade away until it disappears. This demonstrates one of the "hiding" mechanisms that the qviewer uses to reduce clutter on the display. The assumption is that you are moving in the x/y (category) plane to look at other timelines that are of more immediate interest.
  • Move the x/y movement control to the right. The timeline will become visible again.
  • Hit the reset command missing image. The view direction is now facing the future.
  • Hit the "create new viewer window" command missing image. Move the new window somewhere on your display. You may need to re-size the windows to make them visible. The windows can overlap if necessary.
  • Set the view direction of the new window towards the past missing image.
  • Hit the "create new viewer window" command missing image again. Adjust the qviewer windows to make them all visible.
  • Set the view direction of the new window towards the right missing image.
  • Choose one of the windows and make it active by clicking on its titlebar with the mouse.
  • In that window, decrease the time scale (triangle target down until time scale is about 0.05) to show more presidents. Note that all the windows redraw their views.
  • Choose a window, move in the x/y plane (square target) and change the x/y scale (diamond target). Note that only the active window is changed.
  • In the same window, move the display time (circle target) towards the past (down) and then towards the future (up). Note that all the windows update their display time and redraw their views.
  • Close two of the three windows using the "close this window" command missing image.
  • Click the reset command missing image. Remove the timeline with the "delete all timelines" command missing image.
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