Element: Trace.
Icon:
Text: A sequence of points.
Description: A Trace is a drawing element that displays a sequence of points at given coordinates of the parent drawing panel. The points to be displayed are added sequentially, one after the other, and can be visualized using markers or connecting them with segments (or both).
Two traces with no markers and connected
The trace can be instructed to display a maximum number of points, in which case, it will discard old values to accomodate new ones. However, if the property "No Repeat" is set to true, and the new value is identical to the last one, this new value will be ignored. The reception of data can also be (usually temporarily) disabled. Finally, the trace can be instructed to accept only one out of a certain number of points received. This is useful in case the model generates too many data points.
Traces can have memory. This means that they can remember and display data that was generated in a previous run of the simulation. This can be very useful to allow the user to compare diferent trajectories for different initial values of a system. The number of data sets a trace can display, the way it displays them and the color it uses are governed by the memory properties. Data in memory is respected by a call to _initialize(), but is lost by a call to _reset() or _resetView().
Traces respond to user interaction on their position coordinates (which can be different to the coordinates of the points received), changing their position and invoking up to three different actions.
Table of properties |
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Name | Description | Values accepted |
Input | ||
X | The X coordinate of the new point to add to the sequence. | Any constant or variable of type double or int. |
Y | The Y coordinate of the new point to add to the sequence. | Any constant or variable of type double or int. |
Z | The Z coordinate of the new point to add to the sequence. | Any constant or variable of type double or int. |
Position | ||
Position X | The X coordinate of the element as a whole. | Any constant or variable of type double or int. |
Position Y | The Y coordinate of the element as a whole. | Any constant or variable of type double or int. |
Position Z | The Z coordinate of the element as a whole. | Any constant or variable of type double or int. |
Configuration |
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Points | Maximum number of points to display. The special value 0 indicates that there is no such maximum. | Any constant or variable of type int. |
Skip | The number of points to receive before accepting one. | Any constant or variable of type int. |
Active | Whether the trace accepts points. | A boolean variable or one of the constants true or false. |
No Repeat | Whether to ignore an input point identical to the last one. | A boolean variable or one of the constants true or false. |
Connected | Whether to connect input points with a segment. | A boolean variable or one of the constants true or false. |
Visibility and Interaction |
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Visible | The visibility of the element. | A boolean variable or one of the constants true or false. |
Enabled | Whether the element responds to user interaction. | A boolean variable or one of the constants true or false. |
Actions |
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On Press | The action to invoke when the element is pressed. | The Java code to invoke for the action. |
On Drag | The action to invoke when the element is moved. | The Java code to invoke for the action. |
On Release | The action to invoke when the element is released. | The Java code to invoke for the action. |
On Enter | The action to invoke when the pointer enters the element. | The Java code to invoke for the action. |
On Exit | The action to invoke when the pointer leaves the element. | The Java code to invoke for the action. |
Graphical Aspect | ||
Line Color | The color used for the lines of the element. | An Object variable of the class java.awt.Color
or one of the predefined colors: black,
blue, cyan, darkGray, gray, green, lightGray, magenta, orange, pink,
red, white, yellow.
A color can also be specified providing its integer RGB coordinates (between 0 and 255), plus an optional transparency coordinate. The default value is decided by the system. |
Stroke | The thickness for the lines of the element. | Any constant or variable of type double
or int. The default value is 1. Object variables of the class java.awt.Stroke are also accepted. |
Marker Shape | The graphical shape for the markers. | One of the following constants:
Integer constants and variables are also accepted, using any of the values indicated in the parentheses above. This allows changing the shape in run-time. |
Marker Size | The size of the markers in pixels. | Any constant or variable of type int. |
Marker Color | The color for the markers. | See the values for the Line Color property. |
Position | The exact drawing position of the markers relative to the input point. | One of the following constants:
Integer constants and variables are also accepted, using any of the values indicated in the parentheses above. This allows changing the position in run-time. |
Rotate | The (counter-clockwise) rotation angle to apply to the markers. | A constant or variable of type double for an angle in radians, or a constant or variable of type int for an angle in degrees. |
Memory | This is an integer that indicates how many data sets should the trace remember. | 0 : It displays all data sets until a call
to _resetView() is done. 1: It displays only the current data set (default). 2 or more: It displays as many data set as indicated. Subsequent runs cause the oldes data to be discarded. |
Mem Display | How old data is displayed. | One of the following constants:
Integer constants and variables are also accepted, using any of the values indicated in the parentheses above. This allows changing the display mode in run-time.
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Mem Color | The color used to display the old data. | See the values for the Line Color property. |