axes properties

Description

The Axes entity is the second level of the graphics entities hierarchy. This entity defines the parameters allowing the change of coordinates and the axes drawing as well as the parameters' default values for the children creation.

Axes properties

parent:

This field contains the handle of the parent figure.

children:

FA vector containing the handles of all graphics objects children of the axes These graphics objects are of type "Compound", "Rectangle", "Polyline", "Segs", "Arc", "Grayplot",.. (see Compound_properties, rectangle_properties, champ_properties, axis_properties, polyline_properties, segs_properties, grayplot_properties, surface_properties, fec_properties, text_properties, legend_properties)

visible:

This field contains the visible property value for axes . Its value should be "on" or "off" . By default, axes is visible "on" in case all "visible" children are displayed on the screen, If "off" the axes and all its children are not drawn.

axes_visible:

A 1x3 string vector. This property specifies whether each axis is drawn or not. Its value should be "on" or "off" for a global setting.To act on a single axis, the syntax is axes_visible(N) where N is 1,2 or 3 corresponding to the x,y or z axis. The scaling data and if required the grids are drawn if the value is "on". Note that when creating a simple axes entity using the gca() (shortcut for get"current_axes")) or gcf() (shortcut for get(current_figure)) commands, the axes visibility is set to "off".

axes_reverse:

A 1x3 string vector corresponding to the three axes (X,Y,Z). For each axes, the property specifies the direction of the increasing values. If "off", the default direction is used. If "on", the direction is reverse. It is also possible to use only one string, "on" or "off", to set simultaneously the three data.

grid:

vector of 3 colors indices [xCol, yCol, zCol] used to draw the grid along respective directions. To cancel the grid in a direction, use -1 as index. Default = [-1 -1 -1] (no grid).

grid_style:

vector [xLineStyle, yLineStyle, zLineStyle] of 2 or 3 line styles ids from 1 to 10 (solid, dashes, dots, etc) used to draw the grid along respective directions (in 2D or 3D). Available line styles are described there.

grid_thickness:

vector [xLineThick, yLineThick, zLineThick] of 2 or 3 positive decimal numbers setting the thickness of the grid lines along respective directions (in 2D or 3D).

grid_position:

"background" (default): the grid is drawn behind all other graphical components ; or "foreground: the grid is drawn on the top.

x_location:

Specify the location of the x-axis. The possible values are:

• "bottom". In this case the x axis is drawn at the bottom of the axes rectangle.

• "top". In this case the x axis is drawn at the top of the axes rectangle.

• "middle". In this case the x axis is drawn at the centered position.

• "origin". In this case the x axis is drawn at the origin.

y_location:

Specify the location of the y-axis. The possible values are:

• "left". In this case the y axis is drawn at the left of the axes rectangle.

• "right". In this case the y axis is drawn at the right of the axes rectangle.

• "middle". In this case the y axis is drawn at the centered position.

• "origin". In this case the y axis is drawn at the origin.

title:

An object attached to the Axes entity and returning a graphic handle on a Label structure (see label_properties). This field defines a title with options on this label.

x_label:

An object attached to the Axes entity and returning a graphic handle on a Label structure (see label_properties). This field defines a label on x axis with options on this label.

y_label:

An object attached to the Axes entity and returning a graphic handle on a Label structure (see label_properties). This field defines a label on y axis with options on this label.

z_label:

An object attached to the Axes entity and returning a graphic handle on a Label structure (see label_properties). This field defines a label on z axis with options on this label.

auto_ticks:

Default ["on" "on" "on"]. auto_ticks status for each x, y and z respective axis.

"on" means that the axis is automatically graduated through a computational algorithm. Then, resizing the figure and axes automatically updates accordingly graduations ticks and labels of the given axis.

On the contrary, "off" means that graduations ticks or/and labels are set by hand. Then resizing the figure and axes has no effect on existing graduations ticks and labels.

Setting .auto_ticks="on" or "off" sets the same status for the x, y and z axes. Setting .auto_ticks(2)="off" sets the status only for the y axis. Etc.

Editing ticks (labels and/or locations) via x_ticks, y_ticks or z_ticks automatically sets auto_ticks to "off" for the corresponding axes.

x_ticks, y_ticks, z_ticks:

Each of these properties is a tlist of type "ticks" with 2 fields named "locations" and "labels": tlist(["ticks", "locations", "labels"], Locations, Labels) where

Locations

is a real vector containing the locations of graduations along and according to the data scale of the given x or y or z axis. When the number of ticks does not need to be changed, their locations can be set or changed through the syntax (e.g. along x) Haxes.x_ticks.locations = Locations where Haxes = gca(); and Locations is the complete vector of updated ticks positions. To change just the ith location, just use: Haxes.x_ticks.locations(i) = newLoc

Labels

is a text vector containing the labels to be displayed in front of each related graduation. As for Locations of ticks, Labels can be addressed with (e.g. along y) Haxes.y_ticks.labels = Labels or Haxes.y_ticks.labels(j) = newLabelJ.

Vertical or tilted ticks labels can be yielded using LaTeX formating with \rotatebox{angle}{text}. See the example below.

For an axis, Locations and Labels vectors must have the same number of components. When the number of ticks must be changed, their positions AND labels must be changed at once, in order to avoid any mismatch: The syntax (e.g. along x) Haxes.x_ticks = tlist(["ticks" "locations", "labels"], newLocations, newLabels) must then be used. Changing by hand the Locations or/and Labels of an axis automatically sets its .auto_ticks status to "off". This cancels its auto-regraduation under resizing of the figure.

x_ticks.locations, y_ticks.locations, z_ticks.locations:

Each of these properties is a real vector containing the locations of graduations on the related x or y or z axis. x_ticks.locations must have the same number of components as x_ticks.labels. See x_ticks hereabove for more details.

x_ticks.labels, y_ticks.labels, z_ticks.labels:

Each of these properties is a text vector containing the labels to be displayed in front of ticks on the related x or y or z axis. x_ticks.labels must have the same number of components as x_ticks.locations. See x_ticks hereabove for more details.

ticks_format:

This property specifies the format to use for each axes. It is a row vector with at most 3 columns containing strings format (as specified for mprintf). Each ticks position will be used to format the string used as label.

So, for example ticks_format="%.2e" will print ticks positions in using scientific notation with two decimals.

Labels are actually updated according to the newly set .ticks_format(i) only if the .auto_ticks(i) status of the axis #i is "on". Otherwise, .ticks_format(i) is recorded without being immediately used.

ticks_st:

This property specifies scale-translate factors to apply to each ticks position before to use it in the formatted string used as label. So if the factors are [x_s y_s z_s ; x_t y_t z_t] and if a x_tick is positioned at X, the value used to format the label will be x_s*(X-x_t). It could be particularly useful when the axes bounds are too closed.

It is a matrix with 2 rows and at most 3 columns.

So, for example base=B, labels could be printed with ticks_format=string(base)+"%+.2e" and ticks_st=[1 base]

box:

This property specifies whether to enclose the axes in a box. Its value can be either "off", "hidden_axes", "back_half" or "on". If the property is "off", the box is not draw. If the property is "hidden_axes", only the back frame is drawn. If the property is "back_half", the X, Y and Z axis are also drawn. If the property is "on" the whole box is drawn.

filled:

This property specifies whether the axes background should be drawn or not. Its value can be either "off" or "on". If the property is "off", the background is not drawn, the axes box is transparent. If the property is "on" the background is drawn using the color specified by the background property.

sub_ticks:

This field sets the number of tics to draw between two main tics. The field value is the vector [nx,ny] where nx is the number of sub tics for the x-axis and ny respecting to the y-axis.

font_style:

Specifies the font used for displaying tics labels. This is a positive integer referencing one of the loaded fonts. Its value must be between 0, referencing the first font, and the number of loaded fonts minus one, referencing the last font. For more information see graphics_fonts.

font_size:

It is a scalar specifying the character size of tics labels. If fractional_font property is "off" only the integer part of the value is used. For more information see graphics_fonts.

font_color:

This property determines the color of the tics labels.

fractional_font:

This property specify whether ticks labels are displayed using fractional font sizes. Its value must be either "on" or "off". If "on" the floating point value of font_size is used for display and the font is anti-aliased. If "off" only the integer part is used and the font is not smoothed.

isoview:

This property is used to have isometric scales on the x, y and z axes (for example to make the display of the curve sin(x) versus cos(x) be a circle not an ellipse). Its value should be "on" or "off". If the value is "on", the axes data_bounds automatically change according to the corresponding figure figure_size property values.

cube_scaling:

This property is used in 3d mode to have a rescaling of the x, y and z axes. Indeed, it allows the data to fit into a 1x1x1 cube ; the goal is to better display 3d graphics in case axes scales are very different from one to another. Its value should be "on" or "off" (which is the default value). In most cases, it helps generating Matlab-like 3d view.

view:

This field is related to the graphics universe. It takes "3d" as value corresponding to the three-dimensional views. In the other case its value can be "2d" for initial 2d plotting (default value). This flag also depends on the plots the user enters : a plot3dcommand, for example, will switch the view flag from "2d" to "3d".

rotation_angles:

Spherical coordinates [alpha, theta] = [polAngle, azimuth] of the observation point, in degrees:

• theta: azimuth angle in the (x,y) plane. Particular angles, for (x,y) seen from (O,z):

  270	: (O,x) to right
  0	: (O,x) to bottom
  90	: (O,x) to left
  180	: (O,x) to top

  
• alpha: polar angle from (Oz), in planes orthogonal to (x,y). Particular values:

  0	= North pole (O,z)	view from above
  90	= Equator (x,y)	view from side
  180	= South pole (O,-z)	view from below

  

log_flags:

3 character string that sets the scale (linear or logarithmic) along the axes. Each character specifies the scale for respectively the X, Y and Z axes. They can be either 'n' for the normal scale, or 'l' for the logarithmic one.

tight_limits:

A 1x3 string vector giving the tight_limits status for each axis. This property specifies whether each axis fits exactly with the minima and maxima values of the data bounds. If an item is "off", the corresponding axis may enlarge boundaries such as to produce pretty tics labels. For a global setting (all axes at once), you have to set its value to "on" or "off" (single string). To act on a single axis, the syntax is tight_limits(N) where N is 1,2 or 3 corresponding to the x,y or z axis.

data_bounds:

This field contains the boundary values for the x, y and z coordinates. It is either the matrix or the vector [xmin,ymin; xmax,ymax], [xmin,ymin,zmin; xmax,ymax,zmax], [xmin,xmax,ymin,ymax], [xmin,xmax,ymin,ymax,zmin,zmax], [xmin;xmax;ymin;ymax] or [xmin;xmax;ymin;ymax;zmin;zmax]. Note that, to strictly have the specified data bounds, tight_limits must be set to "on" value (see above). To manually set data_bounds set auto_scale="off"

zoom_box:

This field contains the current zoom box if any coordinates are given. It is an empty matrix (no zoom) or the vector [xmin,ymin,xmax,ymax,zmin,zmax] (defines a smaller axes box).

margins:

A vector [margin_left,margin_right,margin_top,margin_bottom] specifying the margins portion for this axes. This vector is composed of numbers between [0 1] with default: [0.125 0.125 0.125 0.125]. These numbers are ratios relative to associated values of the axes_bounds property, which are width for margin_left and margin_right, and height for margin_top and margin_bottom.

auto_margins:

A property to allow the automatic computation of the margins accordint to their contents. If value is "on", then the automatic computation is activated.

axes_bounds:

Vector [x_left, y_top, width, height] of four decimal numbers in [0, 1] specifying the portion of figure or frame used by this axes:

• x_left and y_top set the position of the top-left corner of the axes area, with respect to the top-left corner of the embedding figure or frame.
• width and height set the dimensions of the axes area. 1 stands for the full width or height of the embedding figure or frame.

These numbers are relative to the gca().parent.position(3:4) [width, height] dimensions of the figure or of the Uicontrol frame embedding the axes.

hidden_axis_color:

This property defined the color of the hidden axis. It takes an index relative to the current colormap.

user_data:

This field can be use to store any scilab variable in the axes data structure, and to retrieve it.

Properties for high level functions

The plot, plot2dx, grayplot and matplot functions use the following properties to decide how to merge consecutive plots if this is not stated by the frameflag calling argument. The result of the merge is decided through these two following properties:

auto_clear:

If this property value is equal to "on", a call to a high level graphic will re-initialize the current axes and erase all its children before preforming the drawing (log_flags will be reset). If the value is "off" the drawings will be added to current axes according to "auto_scale" property.

auto_scale:

A property to update the axes data boundary. If value is "on", a new plot will adapt the current axes properties to fit with previous and current plots. If its value is "off" the new plot will be drawn in the current axes data boundary.

Children's default values:

hiddencolor:

This property controls the hidden parts' color. It takes as value an index relative to the current colormap. In another case, if it is a negative value, the hidden parts take the same colors as the surface

line_mode:

This field contains the default line_mode property value for Segs Rectangle Legend Axis Plot3d Fac3d and Polyline objects. Its value should be "on"(default) or "off".

line_style:

This field contains the default line_style property value for Segs, Arcs, Rectangle and Polyline objects. line_style selects the type of line to be used to draw lines . Its value should be an integer in [1 10]. 1 stand for solid, the other values stand for a selection of dashes (dash, dash dot, longdash dot, bigdash dot, bigdash longdash, dot, double dot, longblank dot, bigblank dot).

thickness:

This field contains the default thickness property value for all objects using line drawing. It is a positive real specifying the line width in pixels. The displayed width is actually determined by rounding the supplied width to the nearest integer. The only exception is vectorial export where the whole thickness value is considered.

mark_mode:

This field contains the default mark_mode property value for Segs Rectangle Legend Axis Plot3d Fac3d and Polyline objects. Its value should be "on" or "off" (default).

mark_style:

This field contains the default mark_style property value for Segs Rectangle Legend Axis Plot3d Fac3d and Polyline objects. mark_style selects the type of mark to be displayed. Its value should be an integer in [0 9] which stands for: dot, plus, cross, star, filled diamond, diamond, triangle up, triangle down, trefle and circle.

mark_size_unit:

This field contains the default mark_size_unit property value for Segs Rectangle Legend Axis Plot3d Fac3d and Polyline objects. If mark_size_unit is set to "point", then the mark_size value is directly given in points. When mark_size_unit is set to "tabulated", mark_size is computed relative to the font size array: therefore, its value should be an integer in [0 5] which stands for 8pt, 10pt, 12pt, 14pt, 18pt and 24pt. Note that plot2d and pure scilab functions use tabulated mode as default ; when using plot function, the point mode is automatically enabled.

mark_size:

This field contains the default mark_size property value for Segs Rectangle Legend Axis Plot3d Fac3d and Polyline objects. mark_size selects the font size of mark to be displayed. Its value should be an integer in [0 5] which stands for 8pt, 10pt, 12pt, 14pt, 18pt and 24pt.

In the special case where mark_style and mark_size are 0, a dot of one pixel is drawn.

mark_foreground:

This field contains the default mark_foreground property value for all objects created under this axes. Polyline, rectangle, legend, surface, segment and axis objects are using this property to specify a foreground (edge) color for their marks. Its value should be a color index (relative to the current color_map) or 0 for transparent edge. Note that the default value is -1 (default black) and, even if you change the color_map, this -1 value will always point onto the default black color.

mark_background:

This property controls the default mark_background property value for all objects created under this axes. Polyline, rectangle, legend, surface, segment and axis objects are using this property to specify a background (face) color for their marks. It takes as value an index relative to the current colormap or 0 for transparent face. Note that the default value is -2 (default white) and, even if you change the color_map, this -2 value will always point onto the default white color.

foreground:

This field contains the default foreground property value for axes and all objects created under this axes. Its value should be a color index (relative to the current color_map). Note that the default value is -1 (default black) and, even if you change the color_map, this -1 value will always point onto the default black color.

background:

This property controls the default background property value for axes and all objects created under this axes. It takes as value an index relative to the current colormap.Note that the default value is -2 (default white) and, even if you change the color_map, this -2 value will always point onto the default white color.

arc_drawing_mode:

This property controls the default arc_drawing_mode property value for all created Arc objects under this Axes object. Its value should be either "nurbs" or "lines".

clip_state:

This field contains the default clip_state property value for all objects. Its value should be :

• "off" this means that all objects created after that are not clipped (default value).

• "clipgrf" this means that all objects created after that are clipped outside the Axes boundaries.

• "on" this means that all objects created after that are clipped outside the rectangle given by property clip_box.

clip_box:

This field contains the default clip_box property value for all objects. Its value should be an empty matrix if clip_state is "off". Other case the clipping is given by the vector [x,y,w,h] (upper-left point width height).

Note on default values :

All these listed properties and fields inherit from default values stored in an axes model. These default values can be seen and changed. To do so, use the get("default_axes") command : it returns a graphic handle on the axes model. Note that no graphic window is created by this command. The next created axes will inherit from this model (see "Example on axes model" below).

Examples

lines(0) // disables vertical paging
a=get("current_axes")//get the handle of the newly created axes
a.axes_visible="on"; // makes the axes visible
a.font_size=3; //set the tics label font size
a.x_location="top"; //set the x axis position
a.data_bounds=[-100,-2,-1;100,2,1]; //set the boundary values for the x, y and z coordinates.
a.sub_tics=[5,0];
a.labels_font_color=5;
a.grid=[2,2];
a.box="off";

// Example with 3D axes
clf(); //clear the graphics window
x=0.1:0.1:2*%pi;plot2d(x-.3,sin(x)*7+.2);
a=gca(); // get the handle of the current axes
a.grid=[1 -1 -1]; //make x-grid
a.rotation_angles=[70 250]; //turn the axes with giving angles
a.grid=[1 6 -1]; //make y-grid
a.view="2d"; //return te the 2d view
a.box="back_half";
a.labels_font_color=5;
a.children.children.thickness=4;
a.children.children.polyline_style=3;
a.view="3d"; //return te the 3d view
a.children.children.thickness=1;
a.children.children.foreground=2;
a.grid=[1 6 3]; //make z-grid
a.parent.background=4;
a.background=7;
plot2d(cos(x)+1,3*sin(x)-3);
plot2d(cos(x)+7,3*sin(x)+3);
a.children(2).children.polyline_style=2;
a.children(1).children.polyline_style=4;
a.children(1).children.foreground=5;
a.children(2).children.foreground=14;
a.parent.figure_size= [1200,800];
a.box="on";
a.labels_font_size=4;
a.parent.background=8;
a.parent.figure_size= [400,200];
a.rotation_angles=[0 260];
delete(a.children(2));
delete(); // delete current object

a = gca();
a.labels_font_size=1;
a.auto_clear= "on";
x=0:0.1:2.5*%pi;plot2d(10*cos(x),sin(x));

a.data_bounds(:,1) = [1;15] ; // set positive bounds for X axe
a.log_flags = "lnn" ; // set X axes to logarithmic scale
a.log_flags = "nnn" ; // switch back to linear scale

a=gca();
a.rotation_angles=[45 45];
a.data_bounds=[-20,-3,-2;20 3 ,2];
xrect([-4 0.5 8 1]);
a.auto_clear = "off" ;
a.isoview="on"; // isoview mode
xrect([-2 0.25 4 0.5]);
a.children(1).fill_mode="on";
a.axes_visible="off";
a.children(1).data=[-2 0.25 -1 4 0.5];
a.children(2).data=[-4 0.5 1 8 1];
x=2*%pi*(0:7)/8;
xv=[.2*sin(x);.9*sin(x)];yv=[.2*cos(x);.9*cos(x)];
xsegs(10*xv,yv,1:8)
s=a.children(1);
s.arrow_size=1;
s.segs_color=5;
a.data_bounds //the boundary values for the x,y and z coordinates
a.view="2d";
a.data_bounds=[-10,-1; 10,1]; // set the boundary values for the two-dimensional views

// Example on axes model
da=gda() // get the handle on axes model to view and edit the fields
// title by default
da.title.text="My Default@Title"
da.title.foreground = 12;
da.title.font_size = 4;
// x labels default
da.x_label.text="x";
da.x_label.text="x"; // Latex or MathML can be used here also
da.x_label.font_style = 8;
da.x_label.font_size = 2;
da.x_label.foreground = 5;
da.x_location = "middle";
// y labels default
da.y_label.text="y";
da.y_label.font_style = 3;
da.y_label.font_size = 5;
da.y_label.foreground = 3;
da.y_location = "right";
da.thickness = 2;
da.foreground = 7;
// the plot
x=(0:0.1:2*%pi)';
plot2d(x,[sin(x),sin(2*x),sin(3*x)],style=[1,2,3],rect=[0,-2,2*%pi,2]);
sda() // back to default axes model

// Example with LaTeX / MathML ticks:
plot2d();
a=gca();

mathml = "<mrow><mfrac><mrow><mi>d</mi>  <mi>y</mi></mrow><mrow>  <mi>d</mi>  <mi>x</mi></mrow></mfrac> <mo>=</mo>" + ...
    "<mfrac><mn>1</mn><msup> <mi>y</mi>  <mn>2</mn></msup> </mfrac> </mrow>";
// Only LaTeX expression
a.x_ticks = tlist(["ticks", "locations", "labels"], (0:6)', [mathml;"1";"$\sin(x)$";"3";"$\cos(a) - test$";"5";"6"]);

// Mixed expression: MathML and LaTex
a.y_ticks = tlist(["ticks", "locations", "labels"], (-2:0.5:2)', ["0";"1";"2";"3";"$\cos(a)$";"5";"6";mathml;"8"]);

m = [66.425514; 66.425513];
plot([69;70], m);
a = gca();
a.ticks_format = ["" sprintf("%.2f", m(2))+"%+.1e"];
a.ticks_st = [1 1;0 m(2)];

Example with vertical x_ticks labels:

rain_Nice  = [51  45  39 69 45 34 12 18 73 133 104 93 ];
months = _(["January" "February" "March" "April" "May" "June" "July" ...
            "August" "September" "October" "November" "December"]);
clf
bar(rain_Nice,1,"cyan");
title(_("Rain - Nice (France)"), "fontsize",3)
ylabel("[mm]")
gca().x_ticks.labels = "$\rotatebox{90}{\mathsf{"+months'+"}}$";
set(gca(), "tight_limits", "on", "font_size", 2);
gcf().axes_size = [460 320];

See also

• axis_properties — description of the axis entity properties
• drawaxis — draw an axis
• set — set properties of some graphic objects or uimenus or uicontrol interactive components
• get — Retrieve a property value from a graphics entity or an User Interface object.
• gca — Return handle of current axes.
• gda — Return handle of default axes.
• sda — Set default axes.
• polyline_properties — description of the Polyline entity properties
• graphics_entities — description of the graphics entities data structures

History