GeezerVison

The World Wide Web, restored to 800 pixels of glory.

GeezerVison is showing octave.sourceforge.io — Function Reference: annotation

	Octave-Forge - Extra packages for GNU Octave
	Home · Packages · Developers · Documentation · FAQ · Bugs · Mailing Lists · Links · Code

Navigation

Operators and Keywords

Function List:

C++ API

: 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.

See also: xlabel, ylabel, zlabel, title, text, gtext, legend, colorbar.

Demonstration 1

The following code

 clf; axes ("visible", "off");
 annotation ("textbox", [.25 .9 .5 .09], "string", ...
             {"Right Click on annotation objects", ...
              "to customize their appearance"}, ...
             "horizontalalignment", "center", "fitboxtotext", "off");
 annotation ("ellipse", [.2 .2 .6 .6], "linewidth", 4);
 ang = pi/2:-pi/2:-pi;
 lab = {"N", "W", "S", "E"};
 x0 = 0.5;
 y0 = 0.5;
 r = 0.3;
 for ii = 1:4
   x = r * cos (ang(ii)) + x0;
   y = r * sin (ang(ii)) + y0;
   annotation ("textarrow", [x x0], [y y0], ...
               "string", lab{ii},  "fontsize", 20);
 endfor

 h = annotation ("doublearrow", [x0 x0], [y0-r y0+r], ...
                 "head1style", "diamond", "head1length", 60, ...
                 "head2style", "diamond", "head2length", 60);

Produces the following figure

Figure 1

Demonstration 2

The following code

 clf; axes ("visible", "off");
 plot (1:10);
 xlabel ("X-LABEL");
 ylabel ("LARGE Y-LABEL", "fontsize", 20);
 title ("FIGURE LAYOUT", "fontsize", 24);

 ti = get (gca, "tightinset");
 pos = get (gca, "position");
 pos(1:2) = pos(1:2) - ti(1:2);
 pos(3) = pos(3) + ti (1) + ti (3);
 pos(4) = pos(4) + ti (2) + ti (4);

 ht = annotation ("textbox", pos, "string", " Position + tighinset", ...
                  "fitboxtotext", "off", "linestyle", "--", ...
                  "edgecolor", "g", "linewidth", 3, "color", "g", ...
                  "verticalalignment", "bottom", "fontsize", 15);

 ho = annotation ("textbox", get (gca, "outerposition"), ...
                  "string", " Outerposition","fitboxtotext", "off", ...
                  "linestyle", "--", "edgecolor", "r", ...
                  "linewidth", 3, "color", "r", ...
                  "verticalalignment", "bottom", "fontsize", 15);

 hi = annotation ("textbox", get (gca, "position"), ...
                  "string", " Position","fitboxtotext", "off", ...
                  "linestyle", "--", "edgecolor", "b", ...
                  "linewidth", 3, "color", "b", ...
                  "verticalalignment", "bottom", "fontsize", 15);

Produces the following figure

Figure 1

Demonstration 3

The following code

 clf; axes ("visible", "off");
 h = annotation ("arrow");

 ## Get allowed headstyles
 styles = set (h, "headstyle");
 delete (h);

 ## Textbox for the title
 annotation ("textbox", [0.1 0 0.8 1], "string", ...
             '"headstyle" property:', ...
             "backgroundcolor", [0.7 0.7 0.7], "fontsize", 20, ...
             "fitboxtotext", "off", "verticalalignment", "top", ...
             "horizontalalignment", "center");

 ## Textarrows
 ns = numel (styles);
 nrows = ceil (ns/2);
 dy = 1/nrows;
 y = 1 - dy/2;

 jj = 1;
 for ii = 1:nrows
   annotation ("textarrow", [0.3 0.5], [y y], ...
               "string", styles{jj}, "fontsize", 15, ...
               "headstyle", styles{jj}, "textcolor", "b");
   jj = jj + 1;
   if (jj <= ns)
     annotation ("textarrow", [0.7 0.5], [y y], ...
                 "string", styles{jj}, "fontsize", 15, ...
                 "headstyle", styles{jj}, "textcolor", "b");
   jj = jj + 1;
   endif
   y = y - dy;
 endfor
 annotation ("line", [0.5 0.5], [dy/2 1-dy/2], "linestyle", "-.");

Produces the following figure

Figure 1

Demonstration 4

The following code

 clf; axes ("visible", "off");

 ## Textbox for the title
 annotation ("textbox", [0.1 0 0.8 1], "string", ...
             "Text arrows: text rotation", ...
             "backgroundcolor", [0.7 0.7 0.7], "fontsize", 20, ...
             "fitboxtotext", "off", "verticalalignment", "top", ...
             "horizontalalignment", "center");

 ## Textarrows
 for ii = 1:10
   rot = floor (rand (1) * 360 / 90) * 90;
   annotation ("textarrow", 0.5 + [(0.6 * (rand(1) - .5)) 0], ...
               0.5 + [(0.6 * (rand(1) - .5)) 0], ...
               "string", "A text", ...
               "headstyle", "none", "textrotation", rot);
 endfor

Produces the following figure

Figure 1

Demonstration 5

The following code

 clf; axes ("visible", "off");

 ## Textbox for the title
 annotation ("textbox", [0.1 0 0.8 1], "string", ...
             "Text arrows: text alignment", ...
             "backgroundcolor", [0.7 0.7 0.7], "fontsize", 20, ...
             "fitboxtotext", "off", "verticalalignment", "top", ...
             "horizontalalignment", "center");

 ## Textarrows
 halig = {"right", "center", "left"};
 ii = 1;
 for x = .3:.2:.7
   annotation ("textarrow", [x .5], [.5 .9], ...
               "string", {"Multiple lines", "text"}, ...
               "headstyle", "none", "horizontalalignment", halig{ii});
   ii = ii + 1;
 endfor

Produces the following figure

Figure 1

Demonstration 6

The following code

 clf; axes ("visible", "off");

 x = 0:0.01:2*pi;
 y = sin (x);
 plot (x, y);

 ## Extrema
 x0 = [pi/2 3*pi/2];
 y0 = [1 -1];

 ## Convert axes coordinates into normalized coordinates
 xl = xlim ();
 yl = [-1.2 1.5];
 ylim (yl);
 x0 = (x0 - xl(1)) / diff(xl);
 y0 = (y0 - yl(1)) / diff(yl);

 pos = get (gca (), "position");
 x0 = x0*pos(3) + pos(1);
 y0 = y0*pos(4) + pos(2);


 ## Textarrows
 for ii = 1:2
   annotation ("doublearrow", [(x0(ii) - .05) (x0(ii) + .05)], ...
               [y0(ii) y0(ii)], "head1style", "vback3", ...
               "head2style", "vback3", ...
               "head1width", 4, "head2width", 4)
   h = annotation ("textarrow", [0.5 x0(ii)], [.85 y0(ii)], ...
                   "linestyle", "--", "headstyle", "none");
 endfor
 set (h, "string", "Extrema", "fontsize", 15);

Produces the following figure

Figure 1

Package: octave

You are visitor 01402503 — GeezerVison does not store the pages you look up.
Best viewed with Netscape Navigator 4.7 or Internet Explorer 6 at 800×600. No cookies required.