The AXIS function adds an axis to an existing IDL Graphic.
The following lines create the graphic shown at the top of this topic.
tstart = JULDAY(1,1,2000,0,0,0)
tend = JULDAY(1,5,2000,0,0,0)
time = TIMEGEN(START=tstart, FINAL=tend, UNITS='Hours')
data = 20*BESELJ(FINDGEN(97)/4, 1)
p = PLOT(time, data, MARGIN=[0.15,0.25,0.15,0.1], $
AXIS_STYLE=1, FILL_COLOR="light blue", $
FILL_BACKGROUND=1, FILL_LEVEL=0, $
YTITLE='$Temperature (\deg C)$', $
XSTYLE=1, XTICKFORMAT='(C(CDI,1x,CMoA))')
; Insert another X axis with time in hours.
; Same units, just a different TICKFORMAT.
xaxis = AXIS('X', LOCATION=[0,-15], $
TITLE='Hour', TICKINTERVAL=0.5, $
MINOR=1, TICKFORMAT='(C(CHI),"h")')
; Insert a Y axis with temperature in Fahrenheit.
; Use COORD_TRANSFORM to convert to different units.
; Use AXIS_RANGE to restrict the axis length.
yaxis = AXIS('Y', LOCATION=[time[-1],0], $
TITLE='$(\deg F)$', TEXTPOS=1, $
COORD_TRANSFORM=[32, 9.0/5.0], $
AXIS_RANGE=[20,50])
graphic = AXIS(Direction, ] [, Keywords=value] [, Properties=variable])
Keywords are applied only during the initial creation of the graphic.
[, LOCATION=array] [, TARGET=variable]
Properties can be set as keywords to the function during creation, or retrieved or changed using the "." notation after creation.
ANTIALIAS, AXIS_RANGE, CLIP, COLOR, COORD_TRANSFORM, DATA, GRIDSTYLE, HIDE, LOG, MAJOR, MINOR, NAME, SHOWTEXT, SUBTICKLEN, TEXT_COLOR, TEXT_ORIENTATION, TEXTPOS, THICK, TICKDIR, TICKFONT_NAME, TICKFONT_SIZE, TICKFONT_STYLE, TICKFORMAT, TICKINTERVAL, TICKLAYOUT, TICKLEN, TICKNAME, TICKUNITS, TICKVALUES, TITLE, TRANSPARENCY, UVALUE, WINDOW
The AXIS function returns a reference to the created graphic. Use the returned reference to manipulate the graphic after creation by changing properties or calling methods.
Set this argument to a string or an integer giving the axis direction. Possible values are:
The LOCATION property may be used to set the axis location.
Keywords are applied only during the initial creation of the graphic.
Set this keyword to a vector [x, y, z] giving the location of the new axis in data coordinates. When drawing an X axis, the x coordinate is ignored, similarly the y and z coordinates are ignored when drawing their respective axes. The z coordinate applies only to three-dimensional graphics.
Set this keyword to the graphic to which the axis should be associated. If TARGET is not specified then the current graphic will be used.
By default anti-aliasing is used when drawing lines. Set this property to 0 to disable anti-aliasing.
A two-element vector giving the visible range of the axis. By default the axis covers the entire dataspace range. Set this property to [0, 0] to revert back to the default behavior. See Axes for an example.
Set this property to 1 to clip portions of the axis that lie outside of the dataspace range, or to 0 to disable clipping. The default is 1. This property is ignored unless the DATA property is set.
Set this property to a string or RGB vector giving the axis color. If the COLOR and the TEXT_COLOR were previously the same, then setting COLOR will also set TEXT_COLOR to the same value. The default is "black".
Set this property to a two-element vector, [a, b], giving the coordinate transform between the dataspace coordinates (in the direction of this axis) and the axis coordinates. The a and b describe a simple linear transform:
AxisCoord = a + b * DataCoord
The default is [0.0, 1.0], which indicates that no transform will take place. The COORD_TRANSFORM is useful for creating an axis where the axis tick units are different than the original graphic units. For example, if your data is in degrees Celcius, you could add a new Y axis with units in degrees Fahrenheit by specifying COORD_TRANSFORM = [32, 9.0/5]. See Axes for an example.
Set this property to 1 to lock the axis location to the dataspace position. In this case, if the dataspace range changes, the axis will move along with the data. The default is 0, which locks the axis location to the position within the window. See Axes for an example.
Set this property to an integer or string giving the linestyle to be used for tickmarks. For the list of linestyle index values, see Formatting IDL Graphics Symbols and Lines.
Set this property to 1 to hide the graphic. Set HIDE to 0 to show the graphic.
Set this property to specify a logarithmic axis. The minimum value of the axis range must be greater than zero.
Set this property to an integer representing the number of major tick marks. The default value is -1, specifying that IDL will compute the number of tickmarks. Setting MAJOR equal to 0 suppresses major tickmarks entirely.
Set this property to an integer representing the number of minor tick marks. The default value is -1, specifying that IDL will compute the number of tickmarks. Setting MINOR equal to 0 suppresses minor tickmarks entirely.
Set this property to a string that specifies the name of the graphic. The name can be used to retrieve the graphic using the brackets array notation. If NAME is not set then a default name is chosen based on the graphic type.
Set this property to 1 to show text labels or to 0 to hide text labels.
Set this property to a floating point scale ratio specifying the length of minor tick marks relative to the length of major tick marks. The default value is 0.5, specifying that the minor tick mark is one-half the length of the major tick mark.
Set this property to a string or RGB vector containing the axis text color. The default value is the same color as the COLOR property.
Set this property to the angle (in degrees) of the tick mark labels. The default is 0.
Set this property to 1 to position the tick labels and axis title above the axis. The default is 0, below the axis.
Tip: The TICKDIR property may be used to control the direction of axis tick marks.
Set this property to a value between 0 and 10 that specifies the line thickness of the plotted lines. The default value is 1.
Set this property to 1 to draw the tickmarks facing outwards. The default is 0, facing inwards.
Tip: The TEXTPOS property may be used to control the position of tick mark data values and axis titles.
Set this property to a string specifying the IDL or system font for the tick labels and axis title.
Set this property to a floating-point number representing the point size of the axis text. The default value is 12 points.
Set this property to an integer or a string specifying the font style for the axis labels and title. Allowed values are: "normal" or "rm" (0), "bold" or "bf" (1), "italic" or "it" (2), and "bold italic" or "bi" (3).
Set this property to a string which represents a format string or the name of a function to be used to format the tick mark labels. TICKFORMAT can also be set to an array of format strings for each tick mark. If an array is provided, each string corresponds to a level of the axis. The TICKUNITS property determines the number of levels for an axis.
If the string begins with an open parenthesis, it is treated as a standard format string.
If the string does not begin with an open parenthesis, it is interpreted as the name of a callback function to be used to generate tick mark labels. This function is defined with either three or four parameters, depending on whether TICKUNITS is specified.
If TICKUNITS is not specified:
If TICKUNITS is specified:
The callback function is called with four parameters: Axis, Index, Value, and Level, where:
Set this property to a floating-point number indicating the interval between major tick marks for the first axis level. The default value is computed according to the axis range and the number of major tick marks (MAJOR). If this property is set then the MAJOR property is ignored.
For example, if TICKUNITS = ['S', 'H', 'D'], and TICKINTERVAL = 30, then the interval between major ticks for the first axis level will be 30 seconds.
Set this property to an integer that indicates the tick layout style to be used to draw each level of the axis. Set this property to 0 (the default) to draw the axis line, tick marks, and tick labels. Set to 1 to only draw the labels. Set to 2 to draw a box around the tick labels.
Note: For all tick layout styles, at least one tick label will appear on each level of the axis (even if no major tick marks fall along the axis line). If there are no major tick marks, the single tick label will be centered along the axis.
Set this property to a floating point value that specifies the length of each major tick mark, measured in normalized units. The default tick mark length is 0.05. Tick lengths of less than 0.25 are in arbitrary fixed-width units and do not scale with the graphic. Tick lengths of 0.25 or greater are normalized relative to the width (or height) of the graphic, and will scale with the graphic. A tick length of 1 will produce tick marks that stretch across the entire graphic.
Set this property to a string array of up to 30 elements that controls the annotation of each tick mark. Set this property to an empty string to set the tick labels back to their default values.
Set this property to a string (or a vector of strings) indicating the units to be used for axis tick labeling. If more than one unit is provided, the axis will be drawn in multiple levels, one level per unit. The order in which the strings appear in the vector determines the order in which the corresponding unit levels will be drawn. The first string corresponds to the first level (the level nearest to the primary axis line).
Valid unit strings include: "" (the default), "Years", "Months", "Days", "Hours", "Minutes", "Seconds", or "Time".
If any of the time units are utilized, then the tick values are interpreted as Julian date/time values. Note that the singular form of each of the time value strings is also acceptable (for example, TICKUNITS = 'Day' is equivalent to TICKUNITS = 'Days').
Note: Julian values must be in the range -1095 to 1827933925, which corresponds to calendar dates 1 Jan 4716 B.C.E. and 31 Dec 5000000 C.E., respectively.
Set this property to an array of tick mark locations. If TICKVALUES is set to 0 (the default value), IDL computes the tick values based on the axis range and the number of major ticks.
Set this property to a string representing the title of the specified axis. You can also add Greek letters and mathematical symbols using a TeX-like syntax. These symbols need to be enclosed within a pair of "$" characters. See Adding Mathematical Symbols and Greek Letters to the Text String for details on the available symbols.
Set this property to an integer between 0 and 100 that specifies the percent transparency of the axis. The default value is 0.
Set this property to an IDL variable of any data type.
This property retrieves a reference to the WINDOW object which contains the graphic.
| 8.0 | Introduced |
| 8.1 |
Added the following properties: UVALUE, SHOWTEXT, TICKNAME The THICK property was changed to accept a value between 0 and 10 Added the Delete method |
| 8.2 | Added the TEXT_ORIENTATION property |
| 8.2.1 | [XYZ]TICKUNITS accepts exponent as a value |
IMAGE, SURFACE, Using IDL Graphics
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