Example 3
This is an example of real data (courtesy of
Michael Gregg)
The data is stored in a file on the server and is
retrieved by the applet. There are approximately 2500 data points in the
file.
This applet uses the G2Dint class to build the plot. This allows the user
some interactive control over the plot and the ability to retrieve data points.
- Mouse Down, Drag, Up
- By pressing the mouse button and dragging it across the screen the scale
of the plot can be altered. With the release of the mouse button the
plot is redrawn using the new scale.
This can be used to zoom in on a section of
the plot. Data outside the plot is clipped.
- Keypress R
- By pressing R the plot is rescaled back to the default
scale of the data.
- Keypress r
- By pressing r the plot is repainted. This is useful when scrolling
the page as scrolling can effect the plot in odd ways.
- Keypress d
- This event will popup a window that will display the closest data
point to the cursor. Repeated pressing of the key while moving the cursor
will display the closest data point to the cursor.
A black dot will be plotted over the data point to indicate which data
point has been found.
Use Keypress r to refresh the plot and erase the black dots.
- Keypress D
- This event will hide the closest data point window.
- Keypress m
- This event will popup a window that will allow the user to
set the plot range by entering the xmin,xmax, ymin and ymax limits.
Any field left blank will be ignored. Hitting return in any field
will move the cursor to the next field in the list.
- Keypress h
- This event if it occurs in Any of the popup windows will cause the
window to be hidden. This can be used if the popup windows are
accidentally left behind after the main window has disappeared.