Pie Chart and Multi-Value Circular Slider Demo

A classic textbook example, PieDial draws a pie chart, for given colors and angles.

PieControl extends PieDial, as a multi-value circular slider control,
making it able to resize sectors in response to mouse drags,
and report such changes as Action events.

This PieDemo applet shows it in use.

Can't run this? Try the Java 1.0.2 version. But simply following this link may not work, because your browser already has loaded the class files. So, follow and bookmark this link, exit and restart the browser, visit the saved link. PieDemo for Java 1.0.2 event model. You cannot run applets

• A Pie Chart is specified by arrays of colors and starting angles.
  The last pie wedge ends at the start of the first, so the entire circle is always filled.
  Two coordinate systems are available --
• Geometry (and the AWT) measures angles in degrees,
  zero degrees right at "plus X" or "East"
  and ninety degrees up at "plus Y" or "North"
  increasing counter-clockwise.
  Sectors must be specified in counter-clockwise order,
  although the first start can be any value.
• Navigation and surveying measures angles in degrees,
  zero degrees "North" and ninety degrees "East"
  increasing clockwise,
  Sectors must be specified in clockwise order,
  although the first start can be any value.
• For applications that prefer either radians or percent to degrees,
  simply multiply all angles by a conversion constant.
• Drags on a radial separating segments shifts the radial,
  thus changing the relative sizes of those segments.
• You cannot drag a sector boundary across another one,
  but you can use one to "push" others along.
  By dragging some segment down to zero size,
  further drag motion will rotate the entire pie.
  Backing away while in the same drag restores the closed segment.
• Other responses could be programmed,
  for example Click to divide a segment in two,
  when pre-enabled by some other control.
  We would need a new color for it.
• You can provide a set of segment labels,
  and then use a BubbleHelper to display them as pop ups.
• Mapping.java Just an interface requiring

  public String XYToString (int x, int y)
  

Other Java examples.

This code has been back-fit to 1.0

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