octave: Plot Annotations
15.2.3 Plot Annotations
-----------------------
You can add titles, axis labels, legends, and arbitrary text to an
existing plot. For example:
x = -10:0.1:10;
plot (x, sin (x));
title ("sin(x) for x = -10:0.1:10");
xlabel ("x");
ylabel ("sin (x)");
text (pi, 0.7, "arbitrary text");
legend ("sin (x)");
The functions ‘grid’ and ‘box’ may also be used to add grid and
border lines to the plot. By default, the grid is off and the border
lines are on.
Finally, arrows, text and rectangular or elliptic boxes can be added
to highlight parts of a plot using the ‘annotation’ function. Those
objects are drawn in an invisible axes, on top of every other axes.
-- : title (STRING)
-- : title (STRING, PROP, VAL, ...)
-- : title (HAX, ...)
-- : H = title (...)
Specify the string used as a title for the current axis.
An optional list of PROPERTY/VALUE pairs can be used to change the
appearance of the created title text object.
If the first argument HAX is an axes handle, then plot into this
axes, rather than the current axes returned by ‘gca’.
The optional return value H is a graphics handle to the created
text object.
DONTPRINTYET See also: 
xlabel XREFxlabel, ylabel XREFylabel, *noteDONTPRINTYET See also: xlabel XREFxlabel, ylabel XREFylabel,
zlabel XREFzlabel, text XREFtext.
-- : legend (STR1, STR2, ...)
-- : legend (MATSTR)
-- : legend (CELLSTR)
-- : legend (..., "location", POS)
-- : legend (..., "orientation", ORIENT)
-- : legend (HAX, ...)
-- : legend (HOBJS, ...)
-- : legend (HAX, HOBJS, ...)
-- : legend ("OPTION")
-- : [HLEG, HLEG_OBJ, HPLOT, LABELS] = legend (...)
Display a legend for the current axes using the specified strings
as labels.
Legend entries may be specified as individual character string
arguments, a character array, or a cell array of character strings.
If the first argument HAX is an axes handle, then plot into this
axes, rather than the current axes returned by ‘gca’. If the
handles, HOBJS, are not specified then the legend’s strings will be
associated with the axes’ descendants. ‘legend’ works on line
graphs, bar graphs, etc. A plot must exist before legend is
called.
The optional parameter POS specifies the location of the legend as
follows:
pos location of the legend
---------------------------------------------------------------------------
north center top
south center bottom
east right center
west left center
northeast right top (default)
northwest left top
southeast right bottom
southwest left bottom
outside can be appended to any location string
The optional parameter ORIENT determines if the key elements are
placed vertically or horizontally. The allowed values are
"vertical" (default) or "horizontal".
The following customizations are available using OPTION:
"show"
Show legend on the plot
"hide"
Hide legend on the plot
"toggle"
Toggles between "hide" and "show"
"boxon"
Show a box around legend (default)
"boxoff"
Hide the box around legend
"right"
Place label text to the right of the keys (default)
"left"
Place label text to the left of the keys
"off"
Delete the legend object
The optional output values are
HLEG
The graphics handle of the legend object.
HLEG_OBJ
Graphics handles to the text and line objects which make up
the legend.
HPLOT
Graphics handles to the plot objects which were used in making
the legend.
LABELS
A cell array of strings of the labels in the legend.
The legend label text is either provided in the call to ‘legend’ or
is taken from the DisplayName property of graphics objects. If no
labels or DisplayNames are available, then the label text is simply
"data1", "data2", ..., "dataN".
Implementation Note: A legend is implemented as an additional axes
object of the current figure with the "tag" set to "legend".
Properties of the legend object may be manipulated directly by
using ‘set’.
-- : text (X, Y, STRING)
-- : text (X, Y, Z, STRING)
-- : text (..., PROP, VAL, ...)
-- : H = text (...)
Create a text object with text STRING at position X, Y, (Z) on the
current axes.
Multiple locations can be specified if X, Y, (Z) are vectors.
Multiple strings can be specified with a character matrix or a cell
array of strings.
Optional property/value pairs may be used to control the appearance
of the text.
The optional return value H is a vector of graphics handles to the
created text objects.
DONTPRINTYET See also: gtext XREFgtext, title XREFtitle, *noteDONTPRINTYET DONTPRINTYET See also: gtext XREFgtext, title XREFtitle,
xlabel XREFxlabel, ylabel XREFylabel, *notezlabel:
DONTPRINTYET DONTPRINTYET See also: gtext XREFgtext, title XREFtitle,
xlabel XREFxlabel, ylabel XREFylabel, zlabel
XREFzlabel.
See Text Properties for the properties that you can set.
-- : xlabel (STRING)
-- : xlabel (STRING, PROPERTY, VAL, ...)
-- : xlabel (HAX, ...)
-- : H = xlabel (...)
Specify the string used to label the x-axis of the current axis.
An optional list of PROPERTY/VALUE pairs can be used to change the
properties of the created text label.
If the first argument HAX is an axes handle, then operate on this
axes rather than the current axes returned by ‘gca’.
The optional return value H is a graphics handle to the created
text object.
DONTPRINTYET See also: ylabel XREFylabel, zlabel XREFzlabel, *noteDONTPRINTYET DONTPRINTYET See also: ylabel XREFylabel, zlabel XREFzlabel,
datetick XREFdatetick, title XREFtitle, *notetext:
DONTPRINTYET DONTPRINTYET See also: ylabel XREFylabel, zlabel XREFzlabel,
datetick XREFdatetick, title XREFtitle, text
XREFtext.
-- : clabel (C, H)
-- : clabel (C, H, V)
-- : clabel (C, H, "manual")
-- : clabel (C)
-- : clabel (..., PROP, VAL, ...)
-- : H = clabel (...)
Add labels to the contours of a contour plot.
The contour levels are specified by the contour matrix C which is
returned by ‘contour’, ‘contourc’, ‘contourf’, and ‘contour3’.
Contour labels are rotated to match the local line orientation and
centered on the line. The position of labels along the contour
line is chosen randomly.
If the argument H is a handle to a contour group object, then label
this plot rather than the one in the current axes returned by
‘gca’.
By default, all contours are labeled. However, the contours to
label can be specified by the vector V. If the "manual" argument
is given then the contours to label can be selected with the mouse.
Additional property/value pairs that are valid properties of text
objects can be given and are passed to the underlying text objects.
Moreover, the contour group property "LabelSpacing" is available
which determines the spacing between labels on a contour to be
specified. The default is 144 points, or 2 inches.
The optional return value H is a vector of graphics handles to the
text objects representing each label. The "userdata" property of
the text objects contains the numerical value of the contour label.
An example of the use of ‘clabel’ is
[c, h] = contour (peaks (), -4 : 6);
clabel (c, h, -4:2:6, "fontsize", 12);
See also: contour XREFcontour, contourf XREFcontourf,
DONTPRINTYET contour3 XREFcontour3, meshc XREFmeshc, *notesurfc:
DONTPRINTYET contour3 XREFcontour3, meshc XREFmeshc, surfc
XREFsurfc, text XREFtext.
-- : box
-- : box on
-- : box off
-- : box (HAX, ...)
Control display of the axes border.
The argument may be either "on" or "off". If it is omitted, the
current box state is toggled.
If the first argument HAX is an axes handle, then operate on this
axes rather than the current axes returned by ‘gca’.
See also: axis XREFaxis, grid XREFgrid.
-- : grid
-- : grid on
-- : grid off
-- : grid minor
-- : grid minor on
-- : grid minor off
-- : grid (HAX, ...)
Control the display of plot grid lines.
The function state input may be either "on" or "off". If it is
omitted, the current grid state is toggled.
When the first argument is "minor" all subsequent commands modify
the minor grid rather than the major grid.
If the first argument HAX is an axes handle, then operate on this
axes rather than the current axes returned by ‘gca’.
To control the grid lines for an individual axes use the ‘set’
function. For example:
set (gca, "ygrid", "on");
See also: axis XREFaxis, box XREFbox.
-- : colorbar
-- : colorbar (LOC)
-- : colorbar (DELETE_OPTION)
-- : colorbar (HCB, ...)
-- : colorbar (HAX, ...)
-- : colorbar (..., "peer", HAX, ...)
-- : colorbar (..., "location", LOC, ...)
-- : colorbar (..., PROP, VAL, ...)
-- : H = colorbar (...)
Add a colorbar to the current axes.
A colorbar displays the current colormap along with numerical
rulings so that the color scale can be interpreted.
The optional input LOC determines the location of the colorbar.
Valid values for LOC are
"EastOutside"
Place the colorbar outside the plot to the right. This is the
default.
"East"
Place the colorbar inside the plot to the right.
"WestOutside"
Place the colorbar outside the plot to the left.
"West"
Place the colorbar inside the plot to the left.
"NorthOutside"
Place the colorbar above the plot.
"North"
Place the colorbar at the top of the plot.
"SouthOutside"
Place the colorbar under the plot.
"South"
Place the colorbar at the bottom of the plot.
To remove a colorbar from a plot use any one of the following
keywords for the DELETE_OPTION: "delete", "hide", "off".
If the argument "peer" is given, then the following argument is
treated as the axes handle in which to add the colorbar.
Alternatively, If the first argument HAX is an axes handle, then
the colorbar is added to this axes, rather than the current axes
returned by ‘gca’.
If the first argument HCB is a handle to a colorbar object, then
operate on this colorbar directly.
Additional property/value pairs are passed directly to the
underlying axes object.
The optional return value H is a graphics handle to the created
colorbar object.
Implementation Note: A colorbar is created as an additional axes to
the current figure with the "tag" property set to "colorbar". The
created axes object has the extra property "location" which
controls the positioning of the colorbar.
See also: colormap XREFcolormap.
-- : annotation (TYPE)
-- : annotation ("line", X, Y)
-- : annotation ("arrow", X, Y)
-- : annotation ("doublearrow", X, Y)
-- : annotation ("textarrow", X, Y)
-- : annotation ("textbox", POS)
-- : annotation ("rectangle", POS)
-- : annotation ("ellipse", POS)
-- : annotation (..., PROP, VAL)
-- : annotation (HF, ...)
-- : H = annotation (...)
Draw annotations to emphasize parts of a figure.
You may build a default annotation by specifying only the TYPE of
the annotation.
Otherwise you can select the type of annotation and then set its
position using either X and Y coordinates for line-based
annotations or a position vector POS for others. In either case,
coordinates are interpreted using the "units" property of the
annotation object. The default is "normalized", which means the
lower left hand corner of the figure has coordinates ‘[0 0]’ and
the upper right hand corner ‘[1 1]’.
If the first argument HF is a figure handle, then plot into this
figure, rather than the current figure returned by ‘gcf’.
Further arguments can be provided in the form of PROP/VAL pairs to
customize the annotation appearance.
The optional return value H is a graphics handle to the created
annotation object. This can be used with the ‘set’ function to
customize an existing annotation object.
All annotation objects share two properties:
• "units": the units in which coordinates are interpreted.
Its value may be one of "centimeters" | "characters" |
"inches" | "{normalized}" | "pixels" | "points".
• "position": a four-element vector [x0 y0 width height].
The vector specifies the coordinates (x0,y0) of the origin of
the annotation object, its width, and its height. The width
and height may be negative, depending on the orientation of
the object.
Valid annotation types and their specific properties are described
below:
"line"
Constructs a line. X and Y must be two-element vectors
specifying the x and y coordinates of the two ends of the
line.
The line can be customized using "linewidth", "linestyle", and
"color" properties the same way as for ‘line’ objects.
"arrow"
Construct an arrow. The second point in vectors X and Y
specifies the arrowhead coordinates.
Besides line properties, the arrowhead can be customized using
"headlength", "headwidth", and "headstyle" properties.
Supported values for "headstyle" property are: ["diamond" |
"ellipse" | "plain" | "rectangle" | "vback1" | "{vback2}" |
"vback3"]
"doublearrow"
Construct a double arrow. Vectors X and Y specify the
arrowhead coordinates.
The line and the arrowhead can be customized as for arrow
annotations, but some property names are duplicated:
"head1length"/"head2length", "head1width"/"head2width", etc.
The index 1 marks the properties of the arrowhead at the first
point in X and Y coordinates.
"textarrow"
Construct an arrow with a text label at the opposite end from
the arrowhead.
Use the "string" property to change the text string. The line
and the arrowhead can be customized as for arrow annotations,
and the text can be customized using the same properties as
‘text’ graphics objects. Note, however, that some text
property names are prefixed with "text" to distinguish them
from arrow properties: "textbackgroundcolor", "textcolor",
"textedgecolor", "textlinewidth", "textmargin",
"textrotation".
"textbox"
Construct a box with text inside. POS specifies the
"position" property of the annotation.
Use the "string" property to change the text string. You may
use "backgroundcolor", "edgecolor", "linestyle", and
"linewidth" properties to customize the box background color
and edge appearance. A limited set of ‘text’ objects
properties are also available; Besides "font..." properties,
you may also use "horizontalalignment" and "verticalalignment"
to position the text inside the box.
Finally, the "fitboxtotext" property controls the actual
extent of the box. If "on" (the default) the box limits are
fitted to the text extent.
"rectangle"
Construct a rectangle. POS specifies the "position" property
of the annotation.
You may use "facecolor", "color", "linestyle", and "linewidth"
properties to customize the rectangle background color and
edge appearance.
"ellipse"
Construct an ellipse. POS specifies the "position" property
of the annotation.
See "rectangle" annotations for customization.
DONTPRINTYET See also: xlabel XREFxlabel, ylabel XREFylabel, *noteDONTPRINTYET See also: xlabel XREFxlabel, ylabel XREFylabel,
zlabel XREFzlabel, title XREFtitle, text XREFtext,
DONTPRINTYET gtext XREFgtext, legend XREFlegend, *notecolorbar:
DONTPRINTYET gtext XREFgtext, legend XREFlegend, colorbar
XREFcolorbar.
Info Catalog
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