IMSL C# Programmers Guide
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2D Drawing Elements >> AxisXY |
AxisXY
The AxisXY
node is the basis of many chart types, including scatter, line, area and
error bar. Its parent node must be the root Chart
node.
When an AxisXY
node is created, it creates two Axis1D
nodes. They can be
obtained by using the properties AxisXY.AxisX
and AxisXY.AxisY
. Each of the
Axis1D
nodes in turn creates additional child nodes, as seen in the diagram below.
Accessor methods can be chained together, so the x-axis line can be retrieved using
axis.AxisX.AxisLine
The code to set the x-axis line to blue is
axis.AxisX.AxisLine.LineColor = Color.Blue;
Axis Layout
The layout of an AxisXY
chart, such as the one below, is controlled by the
attributes Window
, Density
, and Numbe
r.
Window
Window
is a double-array-valued attribute that contains the axis limits. Its value is
{min, max}. For the above chart, the value of the Window
attribute for the x-axis is
[0, 3] and for the y-axis it is [1, 8].
Number
Number is an integer-valued attribute that contains the number of major tick marks
along an axis. In an Axis1D
node its default value is 5, which is also the value in
the above example.
Density
Density is the number of minor tick marks per major tick mark. Its default value is 4, which is also the value in the example.
Transform
The x- and y-axes may be linear, logarithmic, or customized, as specified by the Transform attribute. This attribute can have the values:
TRANSFORM_LINEAR
indicating a linear axis. This is the default.
TRANSFORM_LOG
indicating a logarithmic axis
TRANSFORM_CUSTOM
indicating a custom transformation. The transformation
specified by the CustomTransform
attribute is used.
CustomTransform
A customized transformation is used when the Transform
attribute has the value
TRANSFORM_CUSTOM
. A custom transform is an object implementing the Transform
interface. It defines a mapping from the interval specified by the Window
attribute to and from the interval [0,1]
. See Custom Transform for more
information.
The class TransformDate
implements the Transform
interface. It maps from a
regular calendar to one without weekends, which is useful for charting stock prices
that are defined only on weekdays.
Autoscale
Autoscaling is used to automatically determine the attribute Window
(the range of
numbers along an axis) and the attribute Number
(the number of major tick marks).
The goal is to adjust the attributes so that the data fits on the axes and the axes have
nice numbers as labels.
Autoscaling is done in two phases. In the first (input) phase the actual range is determined. In the second (output) phase chart attributes are updated.
Attribute AutoscaleInput
The action of the input phase is controlled by the value of attribute
AUTOSCALE_INPUT
in the axis node. It can have one of three values.
AUTOSCALE_OFF
turns off autoscaling.
AUTOSCALE_DATA
scans the values in the Data
nodes that are attached to the
axis to determine the data range. This is the default value.
AUTOSCALE_WINDOW
uses the value of the Window attribute to determine the
data range.
Attribute AutoscaleOutput
The value of the AUTOSCALE_OUTPUT
attribute can be the bitwise combination of
the following values.
AUTOSCALE_OFF
no attributes updated.
AUTOSCALE_NUMBER
updates the value of the Number attribute. This is the
number of major tick marks along the axis.
AUTOSCALE_WINDOW
updates the value of the Window attribute. This is the
range of numbers displayed along the axis.
The default is AUTOSCALE_NUMBER
| AUTOSCALE_WINDOW
; both the attributes
Number and Window are adjusted.
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