Function Plotter User Interface
The main dialog of Oberon Function Plotter contains all of the controls to define functions, axes, gridlines and other parameters of the plot. The controls can be logically divided in the following groups:
- This control group represents the plot function properties. If there
are more than one function defined in the current plot, these controls
show the definition of the current function selected on the Data
tab of the control group #2 (see below).
- X(t) - represents the function that control the point position along X axis
- Y(t) - represents the function that control the point position along Y axis
- T From - starting value of the parameter
- T To - ending value of the parameter
- T Step - the increment step of the parameter.
When a function is plotted, the parameter T is varied from "T From" value to "T To" in steps of "T Step" and the X and Y coordinates of a current point is calculated in accordance with the functions entered in X(t) and Y(t) fields.
In order to create a plot of function like y = sin(x), you need to enter x(t) = t, and y(t) = sin(t).
- The tabbed dialog pages contain various parameters of the current
plot. See below for more description of these controls.
- Chart Area - properties of the chart area
- X Axis - X axis properties
- Y Axis - Y axis properties
- Gridlines - properties of horizontal/vertical gridlines
- Data - parameters of the current plot functions.
- Functions - the list of custom functions defined in the project
- Various global commands and properties:
- Open... - opens a project file (*.fpp)
- Save... - saves current project
- Reset... - resets all formatting (colors, line styles, fonts) to their default values
- Smoothen Curves - when function plots are drawn in CorelDRAW they come in as a set of small line segments. When this option is enabled, the line segments are converted into smooth curves.
- Auto-Reduce Nodes - if enabled, the many curve nodes generated are reduced automatically so that the resulting curve is simpler.
- Units - the current unit of measurement used by many controls dealing with lengths/sizes.
- Auto - when this button is depressed the plot preview image is updated automatically as soon as any change to parameters is made.
- Preview - if the Auto option is not selected, press this button to update the plot preview image.
- About - shows the version and other information about Function Plotter
- Generate! - generates the plot in CorelDRAW
- Close - closes the program
- This image shows the preview of the plot. It is updated automatically (if the auto preview option is selected)
Chart Area tab
- Chart Area Size - specifies the size of the whole drawing. If Auto Width or Auto Height is enabled, the corresponding size is calculated according to the plot dimensions so that horizontal and vertical scales are equal (1 unit on X axis is of equal size to 1 unit on Y axis)
- Chart Area Properties - specifies the border and background properties of the chart.
- Plot Area Margins - specifies the top, left, upper and lower margins of the plot area.
- Plot Area Properties - specifies the border and background properties of the plot area.
X Axis and Y Axis tabs
These two tabs define X and Y axis properties.
- Line - the axis line properties
- Scale - axis position and scale properties:
- Minimum - the lowest axis value displayed on the plot
- Maximum - the highest axis value displayed on the plot
- Major unit - the distance between major tick marks and gridlines
- Minor unit - the distance between minor tick marks and gridlines
- Y axis at, X axis at - the position where the other axis intersects the current one.
- Auto - when one of the checkboxes is checked, the corresponding value is calculated automatically.
- Major Tick Marks - the properties of the major tick marks
- Minor Tick Marks - the properties of the minor tick marks
- Labels - the text label properties (font, color, and position).
Gridlines tab
Specifies the properties of major and minor gridlines for X and Y axes.
Data tab
Specifies properties of one or more functions to be plotted.
- Plot List - shows the list of functions to be plotted
- New - adds a new function with default properties
- Delete - deletes the currently selected function in the list
- Plot Properties - specifies the actual function graph
properties:
- Line - the function line width, color, and style
- Name - the function name
-
Show Name - when checked, the name of the function is displayed on the plot next to the function graph
- Font - font properties of the function name label.
- Markers - specifies the data marker properties. Markers indicate
certain T values on the function plot
- Show - when checked, the markers are displayed on the function graph
- Type - marker type. Possible values are:
Circle: 
Square: 
Triangle: 
Diamond: 
- Color - Color of the markers
- Size - the size (height) of the markers in points
- Show Every - specifies the frequency of the markers. They are shown every specified T step.
- Show Current Only - when checked, only the current selected function is drawn on the plot. Otherwise all defined functions are drawn.
- Same T for All Plots - by default, each function has its own parameter range and step. When this box is checked, the same T parameter is used for all functions on the plot.
- Show Plots Only - when checked, then only functions are drawn without axes, gridlines, backgrounds, etc.
Functions tab
This dialog tab allows you to define your own custom functions.
- Available Functions - shows the list of custom functions already defined in the project
- Name and Parameters - specified the new function name along with any
number of parameters.
If you want to define a constant, just enter its name here without any parameters. - Declaration - the actual definition of the function body. Can contain any number of standard or other custom functions, operators, numbers or constants.
- This button
allows you to insert a function into the declaration field. When clicked, a
new dialog is displayed that presents available function categories and
functions:
- Description - optional description string for the function. This description is later displayed in the Insert Function dialog (see above).
- Add - adds the new function to the list
- Modify - updates the currently selected function properties
- Delete - removes the currently selected function declaration
- Import... and Export... - allow you to export one or more functions to
an external function list file (*.fnl) and import them back into the
current project. When one of this buttons is clicked you will be asked to
select which functions to import or export:
Specifying fonts, colors, and line styles
When creating a function plot you can customize the way it looks. This includes changing colors, fonts, line styles and other properties.
Colors:
To change a background or other colors, just click the corresponding color button and pick the color from the standard CorelDRAW color selection dialog box.
Line properties:
To change line properties, just click on the line style button. You will be presented with Outline Properties dialog where you can specify the line width, style, and color:
Font properties:
Click on the corresponding font button to see the Font Properties dialog where you can change the font face, style, size and color:
By clicking the font button in Font Properties dialog, you invoke the standard Windows font selection dialog.
