Spiro by Jimmc: Help

Copyright 1996,2004 Jim McBeath



This page briefly describes the commands and parameters for Spiro. Some of these commands or parameters may not be available, depending on the security restrictions your browser or viewer enforces. For example, if your browser does not allow local files to be written, then there will be no Save command; if it does not allow exiting, then there will be no Exit command. These conditional commands or parameters are indicated by a the comment "[if security allows]".


These are the buttons just above the parameter area.
Begin drawing. If already drawing, start over again.
If drawing, stop drawing. If not drawing, does nothing.
Save As [if security allows]
Allows you to enter a file name, then saves the current set of parameters to that file.
Load File [if security allows]
Allows you to enter a file name, then loads the parameters from that file to the current set of parameters.
Exit [if security allows]
Exits from the applet viewer.


These parameters appear in the main window just above the drawing area.

On the left side of the parameter area are the non-wheel values.

The color in which to draw the pattern. This value can be one of the standard Java color names, or a red,green,blue triplet where each value is between 0 and 255 inclusive, such as 255,0,0 for red or 0,255,255 for cyan. The known color values are: black, blue, cyan, darkGray, gray, green, lightGray, magenta, orange, pink, red, white, yellow. Color names are case-insensitive.
Allows specifying a dash pattern for the line segments. The pattern is specified as a sequence of positive integers separated by commas. Each number represents the number of steps that are to be alternately drawn or not drawn. For example, the specification "10" specifies a pattern in which alternating groups of 10 steps are drawn then skipped; the specification "10,10,5" will draw 10, skip 10, draw 5, skip 10, draw 10, skip 5, then repeat. Line segments can be different lengths for each step, so the actual length of the drawn or skipped segments will be variable depending on the size of line segments for each included step.
Controls the number of drawing steps executed. If this number is zero or blank, then Spiro automatically calculates the number of steps required in order to draw a full pattern and displays that number to the right of the Steps field. That number is displayed in parentheses if a non-zero number is entered into the Steps field. The default number of steps is the least common multiple of the number of teeth for all active wheels.
Chain [if security allows]
The chain parameter specifies the location of a parameter file to draw along with the current set of parameters. This allows you to create images composed of multiple single drawings. If a chained drawing itself has a chain, that drawing is also included. The chained item is drawn first, so the current drawing will always appear on top of the chained drawing. Security restrictions may limit the allowable sources for the chain.
The animate button lets you see the wheels in action. When you turn this button on, Spiro immediately clears the drawing area and draws the outlines of the wheels. When you press the draw button, the wheels start turning and the line is drawn. You can see how each wheel turns at a constant rate, and how this affects the drawing point. The resulting line is idential to the line drawn with animation turned off. When animation is on, Spiro pauses briefly between each step to slow down the drawing and let you see better what is happening.
Animate Count
When animating, you can also include the count of steps drawn so far so that you can see how far along it is. Select this check box to do so.
The Status Line
Below the Animate button is the status line. In this area Spiro displays status messages, such as "Drawing" when it is drawing, and "Done" or "Stopped" after it has finished or has been stopped.
On the right side of the parameter area are the wheel values.
The wheel number. Parameters for the wheel appear to the right of the wheel number.
The enable toggle for the wheel. This allows you to select how many wheels to use. Enabling a wheel also enables all wheels with lower wheel numbers. Disabling a wheel also disables all wheels with a higher wheel number.
For each wheel, the radius of that wheel in pixels.
For each wheel, the number of steps that wheel makes in order to complete a single revolution. A higher number makes the wheel turn more slowly. A positive number makes the wheel turn clockwise; a negative number makes the wheel turn counter-clockwise. A value of zero disables that wheel.
For each wheel, the offset of the starting point. An offset of zero means start the point at the top of the circle. A positive offset moves the starting point in the direction of rotation of the wheel. A negative offset moves the starting point in the opposite direction. The units of the offset are the number of teeth. An offset which is the same as the number of teeth is equivalent to zero. An offset greater than the number of teeth is the same as that number modulo the number of teeth.
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jimmc March 26, 2004