xregion

1-D filled region between x-coordinates

Since R2023a

Syntax

xregion(x1,x2)

xregion(X)

xregion(ax,___)

xregion(___,Name=Value)

xr = xregion(___)

Description

xregion(x1,x2) creates one or more filled regions between x-coordinates. To create one filled region, specify x1 and x2 as scalars. To create multiple filled regions, specify x1 and x2 as vectors of the same length.

xregion(X) specifies multiple regions as a matrix. To create n regions, specify X as a 2-by-n or n-by-2 matrix containing the lower and upper bounds for each region. (since R2023b)

xregion(ax,___) specifies the target axes for the filled region. Specify ax as the first argument in any of the previous syntaxes.

xregion(___,Name=Value) specifies properties for the region using one or more name-value arguments. If you create multiple regions, the property values apply to all of the regions. For example, you can set the color of a region to yellow by using xregion(5,10,FaceColor="yellow"). For a list of properties, see ConstantRegion Properties.

xr = xregion(___) returns one or more ConstantRegion objects. Use xr to set properties of the filled regions after creating them. For a list of properties, see ConstantRegion Properties.

Examples

Create One Filled Region

Plot a parabola and create a filled region between x=-5 and x=5.

x = -10:0.25:10;
y = x.^2;
plot(x,y)
xregion(-5,5)

Customize Colors and Boundary Lines

You can modify aspects of a region by setting properties. You can set properties by specifying name-value arguments when you call xregion, or you can set properties later using dot notation.

For example, plot a parabola with a filled region, and customize the fill and boundary line colors by specifying the FaceColor and EdgeColor name-value arguments. Also, specify an output argument to store the ConstantRegion object.

x = -10:0.25:10;
y = x.^2;
plot(x,y)
xr = xregion(-5,5,FaceColor="b",EdgeColor=[0.4 0 0.7]);

Modify the appearance further by setting properties of the ConstantRegion object xr. Change the opacity of the fill color and boundary line color by setting the FaceAlpha and EdgeAlpha properties to numbers from 0 to 1, where 1 is fully opaque. Then, set the boundary line thickness by setting the LineWidth property.

xr.FaceAlpha = 0.1;
xr.EdgeAlpha = 0.5;
xr.LineWidth = 2;

Move the lower and upper boundaries to -3 and 3.

xr.Value = [-3 3];

Create Multiple Filled Regions with Legend

You can create multiple filled regions by specifying the starting and ending coordinates as vectors of the same size. You can also display entries for these regions in a legend.

For example, create a histogram and two filled regions. Specify an output argument to store both ConstantRegion objects so you can modify them later.

Count = randn(1,1000);
histogram(Count)
xr = xregion([-2 1],[-1 2]);

Specify a color for each region by setting the FaceColor property. Specify a legend entry name for each region by setting the DisplayName property. To access the individual ConstantRegion objects for setting the properties, index into the output argument xr. After setting the properties, display a legend.

xr(1).FaceColor = "r";
xr(1).DisplayName = "Low";
xr(2).FaceColor = "#0073FD";
xr(2).DisplayName = "High";
legend

Create Filled Region Between datetime Values

Create a bar chart with five bars positioned at specific times. Then display a filled region from the second bar to the fourth bar. To contain the three bars within the region, calculate the boundaries by subtracting 30 minutes from the second bar's location and adding 30 minutes to the fourth bar's location.

dt = datetime(2021,1,1,8:12,0,0);
y = [1 5 11 4 3];
bar(dt,y)
xregion(dt(2)-minutes(30), dt(4)+minutes(30))

Create Filled Region Between categorical Values

Create a bar chart of categorical data, and create a filled region that spans the second and third bars. The reordercats function specifies the order of the categories for the bar chart.

cats = categorical(["Pumpkin" "Apple" "Pecan" "Cherry"]);
cats = reordercats(cats,["Pumpkin" "Apple" "Pecan" "Cherry"]);
barlengths = [15 21 33 12];
bar(cats,barlengths)
xregion(cats(2),cats(3))
title("Favorite Pies")

Create Unbounded Filled Regions

Since R2023b

Create a plot, and add three filled regions. Specify a 2-by-3 matrix with the lower bounds in the first row and the upper bounds in the second row. The first region has a lower bound of -Inf, and the last region has an upper bound of Inf, so the first and last regions are unbounded.

x = 0:0.05:10;
y = sin(x.^2)./(x.^2);
plot(x,y)
X = [-Inf 4 7; 2 5 Inf];
xregion(X)

Input Arguments

x1,x2 — Starting and ending x-coordinates

pair of scalars | pair of vectors

Starting and ending x-coordinates of the filled region, specified as a pair of scalars or a pair of vectors. To create one filled region, specify x1 and x2 as scalars. To create multiple filled regions, specify vectors of equal length. The minimum and maximum region values can be defined in either x1 or x2. Thus, xregion(1,5) and xregion(5,1) produce the same result.

To create an unbounded region, specify one of the coordinates as Inf or -Inf. (since R2023b)

If any coordinates are NaN values, no region appears for those coordinates.

Example: xregion(5,10) creates a filled region from x=5 to x=10.

Example: xregion([1 20],[10 30]) creates two filled regions: one from x=1 to x=10, and the other from x=20 to x=30.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | categorical | datetime | duration

X — Starting and ending coordinates for multiple regions

2-by-n matrix | n-by-2 matrix

Since R2023b

Starting and ending coordinates for multiple regions, specified as a 2-by-n or n-by-2 matrix, where n is the number of regions.

To create an unbounded region, specify one of the coordinates as Inf or -Inf.

If any coordinates are NaN values, no region appears for those coordinates.

Example: xregion([1 3; 2 4]) creates a filled region from x=1 to x=2, and another filled region from x=3 to x=4.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | categorical | datetime | duration

ax — Target axes

Axes object

Target axes for the filled region, specified as an Axes object. Use this argument if you want xregion to plot into a specific Axes object instead of the current axes.

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Example: xregion(5,10,FaceColor="yellow") creates a yellow filled region.

Note

The properties listed here are only a subset. For a complete list, see ConstantRegion Properties.

FaceColor — Fill color

[0.4902 0.4902 0.4902] (default) | RGB triplet | hexadecimal color code | "r" | "g" | "b" | ...

Fill color, specified as an RGB triplet, a hexadecimal color code, or a color name.

For a custom color, specify an RGB triplet or a hexadecimal color code.

• An RGB triplet is a three-element row vector whose elements specify the intensities of the red, green, and blue components of the color. The intensities must be in the range [0,1], for example, [0.4 0.6 0.7].

• A hexadecimal color code is a string scalar or character vector that starts with a hash symbol (#) followed by three or six hexadecimal digits, which can range from 0 to F. The values are not case sensitive. Therefore, the color codes "#FF8800", "#ff8800", "#F80", and "#f80" are equivalent.

Alternatively, you can specify some common colors by name. This table lists the named color options, the equivalent RGB triplets, and hexadecimal color codes.

Color Name	Short Name	RGB Triplet	Hexadecimal Color Code	Appearance
"red"	"r"	[1 0 0]	"#FF0000"
"green"	"g"	[0 1 0]	"#00FF00"
"blue"	"b"	[0 0 1]	"#0000FF"
"cyan"	"c"	[0 1 1]	"#00FFFF"
"magenta"	"m"	[1 0 1]	"#FF00FF"
"yellow"	"y"	[1 1 0]	"#FFFF00"
"black"	"k"	[0 0 0]	"#000000"
"white"	"w"	[1 1 1]	"#FFFFFF"
"none"	Not applicable	Not applicable	Not applicable	No color

Here are the RGB triplets and hexadecimal color codes for the default colors MATLAB^® uses in many types of plots.

RGB Triplet	Hexadecimal Color Code	Appearance
[0 0.4470 0.7410]	"#0072BD"
[0.8500 0.3250 0.0980]	"#D95319"
[0.9290 0.6940 0.1250]	"#EDB120"
[0.4940 0.1840 0.5560]	"#7E2F8E"
[0.4660 0.6740 0.1880]	"#77AC30"
[0.3010 0.7450 0.9330]	"#4DBEEE"
[0.6350 0.0780 0.1840]	"#A2142F"

EdgeColor — Boundary line color

"none" (default) | RGB triplet | hexadecimal color code | "r" | "g" | "b" | ...

Boundary line color, specified as an RGB triplet, a hexadecimal color code, or a color name.

For a custom color, specify an RGB triplet or a hexadecimal color code.

• An RGB triplet is a three-element row vector whose elements specify the intensities of the red, green, and blue components of the color. The intensities must be in the range [0,1], for example, [0.4 0.6 0.7].

• A hexadecimal color code is a string scalar or character vector that starts with a hash symbol (#) followed by three or six hexadecimal digits, which can range from 0 to F. The values are not case sensitive. Therefore, the color codes "#FF8800", "#ff8800", "#F80", and "#f80" are equivalent.

Alternatively, you can specify some common colors by name. This table lists the named color options, the equivalent RGB triplets, and hexadecimal color codes.

Color Name	Short Name	RGB Triplet	Hexadecimal Color Code	Appearance
"red"	"r"	[1 0 0]	"#FF0000"
"green"	"g"	[0 1 0]	"#00FF00"
"blue"	"b"	[0 0 1]	"#0000FF"
"cyan"	"c"	[0 1 1]	"#00FFFF"
"magenta"	"m"	[1 0 1]	"#FF00FF"
"yellow"	"y"	[1 1 0]	"#FFFF00"
"black"	"k"	[0 0 0]	"#000000"
"white"	"w"	[1 1 1]	"#FFFFFF"
"none"	Not applicable	Not applicable	Not applicable	No color

Here are the RGB triplets and hexadecimal color codes for the default colors MATLAB uses in many types of plots.

RGB Triplet	Hexadecimal Color Code	Appearance
[0 0.4470 0.7410]	"#0072BD"
[0.8500 0.3250 0.0980]	"#D95319"
[0.9290 0.6940 0.1250]	"#EDB120"
[0.4940 0.1840 0.5560]	"#7E2F8E"
[0.4660 0.6740 0.1880]	"#77AC30"
[0.3010 0.7450 0.9330]	"#4DBEEE"
[0.6350 0.0780 0.1840]	"#A2142F"

FaceAlpha — Fill color transparency

0.3 (default) | scalar in range [0,1]

Fill color transparency, specified as a scalar in the range [0,1]. A value of 1 is opaque and 0 is completely transparent. Values between 0 and 1 are partially transparent.

EdgeAlpha — Boundary line transparency

1 (default) | scalar in range [0,1]

Boundary line transparency, specified as a scalar in the range [0,1]. A value of 1 is opaque and 0 is completely transparent. Values between 0 and 1 are partially transparent.

LineStyle — Boundary line style

"-" (default) | "--" | ":" | "-." | "none"

Boundary line style, specified as one of the options listed in this table.

Line Style	Description	Resulting Line
"-"	Solid line
"--"	Dashed line
":"	Dotted line
"-."	Dash-dotted line
"none"	No line	No line

Version History

Introduced in R2023a

R2023b: Create unbounded regions

Create unbounded filled regions by passing Inf or -Inf to the xregion function.

R2023b: Specify multiple regions as matrix

Create multiple regions by specifying one matrix input argument as an alternative to specifying two vectors of coordinates. For n regions, the matrix must be 2-by-n or n-by-2 and contain the lower and upper bounds for all the regions.