fill

Create filled 2-D patches

• 

Syntax

fill(X,Y,C)

fill(X1,Y1,C1,...,Xn,Yn,Cn)

fill(___,Name,Value)

fill(ax,___)

p = fill(___)

Description

fill(X,Y,C) plots filled polygonal regions as patches with vertices at the (x,y) locations specified by X and Y.

• To plot one region, specify X and Y as vectors.

• To plot multiple regions, specify X and Y as matrices where each column corresponds to a polygon.

C determines the fill colors for the regions.

fill(X1,Y1,C1,...,Xn,Yn,Cn) plots multiple two-dimensional filled polygonal regions on the same axes.

fill(___,Name,Value) modifies the patches using one or more name-value arguments to set properties. Patches can be specified using any of the input argument combinations in previous syntaxes. For example, fill(X,Y,C,'LineWidth',2) specifies a two-point border around all the patches. For a list of properties, see Patch Properties.

fill(ax,___) plots the polygonal regions in the axes specified by ax instead of in the current axes (gca). The argument ax can precede any of the input argument combinations in the previous syntaxes.

p = fill(___) returns a Patch object or a vector of Patch objects. Use p to query and modify properties after plotting a region. For a list of properties, see Patch Properties.

Examples

Create Filled Pentagon

Define the (x,y) coordinates for the vertices of the pentagon as vectors x and y. Then plot the pentagon with the specified fill color, red.

x = [0 4 5 2 1];
y = [0 0 2 4 3];
fill(x,y,'r')

Specify Color by Vertex

Create vectors of x- and y-coordinates for a square. Specify a column vector of colormap indices, with one row for each vertex in the square. The fill function interpolates the remaining fill colors from the default colormap using the surrounding vertices.

x = [0 2 2 0];
y = [0 0 2 2];
c = [1; 0.5; 0; 0.75];
fill(x,y,c)

Specify Multiple Fill Colors

Define matrices x and y as the (x,y) coordinates of the vertices for two triangles, where each column corresponds to one of the triangles. Specify c as a matrix of the same dimensions as x and y. Each value in c specifies the colormap index for the corresponding vertex.

x = [0 2; 0 2; 4 4];
y = [2 0; 4 1; 2 0];
c = [1 0; 1 0; 0.3 0];
fill(x,y,c)

Create Semitransparent Hexagons

Specify (x,y) coordinates for the vertices of a hexagon as vectors x and y. Plot these coordinates as a hexagon. Then plot two additional translations of this hexagon on the same axes to create three partially overlapping hexagons. Specify the FaceAlpha property for each hexagon as a value less than 1 to plot semitransparent hexagons.

x = [1 3 4 3 1 0];
y = [0 0 2 4 4 2];
hold on
fill(x,y,'cyan','FaceAlpha',0.3)
fill(x+2,y,'magenta','FaceAlpha',0.3)
fill(x+1,y+2,'yellow','FaceAlpha',0.3)

Modify Patch After Creation

Plot a filled octagon by specifying vectors of (x,y) coordinates x and y, and an RGB triplet c. Store the resulting patch as p.

t = (1/16:1/8:1)'*2*pi;
x = cos(t);
y = sin(t);
c = [0.8 0.7 0.8];
p = fill(x,y,c);

Use p to modify properties of the plotted octagon. Specify a thicker outline by setting the LineWidth property to 3, and change the color of the outline to a custom RGB triplet by modifying the EdgeColor property.

p.LineWidth = 3;
p.EdgeColor = [0.5 0.2 0.55];

Input Arguments

X — x-coordinates of patch vertices

vector | matrix

x-coordinates of the patch vertices, specified as a vector or matrix.

Number of Patches	Description	Example
One patch	Specify X and Y as vectors of the same length. The vectors can have any orientation.	Plot one triangular patch. X = [0 0 4]; Y = [2 4 2]; C = 1; fill(X,Y,C)
Two or more patches (shared X or Y)	Specify the shared coordinates as a vector. Specify the other coordinates as a matrix. The length of the vector must match the length of one dimension of the matrix. If the matrix is square, MATLAB® plots the columns of the matrix against the vector.	Plot two triangular patches with shared x- coordinates. X = [0 0 4]; Y = [0 -0; 2 -2; 0 0]; C = [0 1]; fill(X,Y,C)
Two or more patches (X and Y are unique)	Specify X and Y as matrices of the same size. MATLAB plots the corresponding columns of the matrices.	Plot two triangular patches with unique x- and y-coordinates. X = [0 5; 0 5; 4 9]; Y = [2 0; 4 2; 2 0]; C = [0 1]; fill(X,Y,C)

If the data does not define closed regions, then fill closes the regions.

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

Y — y-coordinates of patch vertices

vector | matrix

y-coordinates of the patch vertices, specified as a vector or matrix.

Number of Patches	Description	Example
One patch	Specify X and Y as vectors of the same length. The vectors can have any orientation.	Plot one triangular patch. X = [0 0 4]; Y = [2 4 2]; C = 1; fill(X,Y,C)
Two or more patches (shared X or Y)	Specify the shared coordinates as a vector. Specify the other coordinates as a matrix. The length of the vector must match the length of one dimension of the matrix. If the matrix is square, MATLAB plots the columns of the matrix against the vector.	Plot two triangular patches with shared x- coordinates. X = [0 0 4]; Y = [0 -0; 2 -2; 0 0]; C = [0 1]; fill(X,Y,C)
Two or more patches (X and Y are unique)	Specify X and Y as matrices of the same size. MATLAB Plots the corresponding columns of the matrices.	Plot two triangular patches with unique x- and y-coordinates. X = [0 5; 0 5; 4 9]; Y = [2 0; 4 2; 2 0]; C = [0 1]; fill(X,Y,C)

If the data does not define closed regions, then fill closes the regions.

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

C — Patch colors

color name | RGB triplet | vector of colormap indices | matrix of colormap indices | ...

Patch colors, specified as a color name, RGB triplet, vector of colormap indices, or a matrix of colormap indices.

• Color name — A color name such as 'red', or a short name such as 'r'.

• RGB triplet — 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]. RGB triplets are useful for creating custom colors.

• Vector of colormap indices — A vector of numeric values that has one element for each region.

• Matrix of colormap indices — A matrix of numeric values that has the same dimensions as X and Y.

The way you specify the color depends on the color scheme and whether you are plotting one polygonal region or multiple regions. This table describes the most common situations.

Color Scheme	How to Specify the Color	Example
Single color for all regions	Specify a color name or a short name from the table below, or specify one RGB triplet.	Create matrices x and y. Then plot the filled region in red. x = [2 0; 2 0; 4 4]; y = [0 2; 1 4; 0 2]; fill(x,y,'r')
One color per region	Specify an n-by-1 or 1-by-n vector of colormap indices, where n is the number of polygonal regions.	Create matrices x and y and vector c. Then plot the filled region in the specified colormap colors. x = [2 0; 2 0; 4 4]; y = [0 2; 1 4; 0 2]; c = [1; 0]; fill(x,y,c)
Interpolated face colors	Specify an m-by-n matrix of colormap indices, where [m,n] = size(X). Specify one color per vertex.	Create matrices x, y, and c. Then plot the filled region with fill color interpolated from vertex colors c. x = [2 0; 2 0; 4 4]; y = [0 2; 1 4; 0 2]; c = [0.5 1; 0 1; 1 0]; fill(x,y,c)

Color Names and RGB Triplets for Common Colors

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"

This table lists the default color palettes for plots in the light and dark themes.

Palette	Palette Colors
"gem" — Light theme default Before R2025a: Most plots use these colors by default.
"glow" — Dark theme default

You can get the RGB triplets and hexadecimal color codes for these palettes using the orderedcolors and rgb2hex functions. For example, get the RGB triplets for the "gem" palette and convert them to hexadecimal color codes.

RGB = orderedcolors("gem");
H = rgb2hex(RGB);

Before R2023b: Get the RGB triplets using RGB = get(groot,"FactoryAxesColorOrder").

Before R2024a: Get the hexadecimal color codes using H = compose("#%02X%02X%02X",round(RGB*255)).

ax — Axes to plot into

Axes object | PolarAxes object

Axes to plot into, specified as an Axes or PolarAxes object. If you do not specify the axes, then fill plots into the current axes or creates an Axes object (Cartesian 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.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: fill(x,y,c,'FaceAlpha',.5,'LineStyle',':') creates semitransparent polygons with dotted edges.

Note

The properties listed here are only a subset of patch properties. For a complete list, see Patch Properties.

FaceColor — Face color

'interp' | 'flat' | RGB triplet | hexadecimal color code | 'r' | 'g' | 'b' | ...

Face color, specified as 'interp', 'flat' an RGB triplet, a hexadecimal color code, a color name, or a short name.

To create a different color for each face, specify the CData or FaceVertexCData property as an array containing one color per face or one color per vertex. The colors can be interpolated from the colors of the surrounding vertices of each face, or they can be uniform. For interpolated colors, specify this property as 'interp'. For uniform colors, specify this property as 'flat'. If you specify 'flat' and a different color for each vertex, the color of the first vertex you specify determines the face color.

To designate a single color for all of the faces, specify this property as an RGB triplet, a hexadecimal color code, a color name, or a short name.

• 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 character vector or a string scalar 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. Thus, the color codes '#FF8800', '#ff8800', '#F80', and '#f80' are equivalent.

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

This table lists the default color palettes for plots in the light and dark themes.

Palette	Palette Colors
"gem" — Light theme default Before R2025a: Most plots use these colors by default.
"glow" — Dark theme default

You can get the RGB triplets and hexadecimal color codes for these palettes using the orderedcolors and rgb2hex functions. For example, get the RGB triplets for the "gem" palette and convert them to hexadecimal color codes.

RGB = orderedcolors("gem");
H = rgb2hex(RGB);

Before R2023b: Get the RGB triplets using RGB = get(groot,"FactoryAxesColorOrder").

Before R2024a: Get the hexadecimal color codes using H = compose("#%02X%02X%02X",round(RGB*255)).

FaceAlpha — Face transparency

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

Face transparency, specified as one of these values:

• Scalar in range [0,1] — Use uniform transparency across all of the faces. A value of 1 is fully opaque and 0 is completely transparent. This option does not use the transparency values in the FaceVertexAlphaData property.

• 'flat' — Use a different transparency for each face based on the values in the FaceVertexAlphaData property. First you must specify the FaceVertexAlphaData property as a vector containing one transparency value per face or vertex. The transparency value at the first vertex determines the transparency for the entire face.

• 'interp' — Use interpolated transparency for each face based on the values in FaceVertexAlphaData property. First you must specify the FaceVertexAlphaData property as a vector containing one transparency value per vertex. The transparency varies across each face by interpolating the values at the vertices.

EdgeColor — Edge colors

'none' | 'flat' | 'interp' | RGB triplet | hexadecimal color code | 'r' | 'g' | 'b' | ...

Edge colors, specified as one of the values in this table. The default edge color is black with a value of [0 0 0]. If multiple polygons share an edge, then the first polygon drawn controls the displayed edge color.

Value	Description	Result
RGB triplet, hexadecimal color code, or color name	Single color for all of the edges. See the following table for more details.
'flat'	Different color for each edge. Use the vertex colors to set the color of the edge that follows it. You must first specify CData or FaceVertexCData as an array containing one color per vertex. The edge color depends on the order in which you specify the vertices.
'interp'	Interpolated edge color. You must first specify CData or FaceVertexCData as an array containing one color per vertex. Determine the edge color by linearly interpolating the values at the two bounding vertices.
'none'	No edges displayed.	No edges displayed.

RGB triplets and hexadecimal color codes are useful for specifying custom colors.

• 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 character vector or a string scalar 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. Thus, 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"

This table lists the default color palettes for plots in the light and dark themes.

Palette	Palette Colors
"gem" — Light theme default Before R2025a: Most plots use these colors by default.
"glow" — Dark theme default

You can get the RGB triplets and hexadecimal color codes for these palettes using the orderedcolors and rgb2hex functions. For example, get the RGB triplets for the "gem" palette and convert them to hexadecimal color codes.

RGB = orderedcolors("gem");
H = rgb2hex(RGB);

Before R2023b: Get the RGB triplets using RGB = get(groot,"FactoryAxesColorOrder").

Before R2024a: Get the hexadecimal color codes using H = compose("#%02X%02X%02X",round(RGB*255)).

LineStyle — Line style

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

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

Output Arguments

p — Displayed polygonal regions

Patch object | vector of Patch objects

Displayed polygonal regions, returned as a Patch object or vector of Patch objects. Each patch corresponds to a plotted region. Use p to query or change properties of a region after it is plotted.

Alternative Functionality

Several functions offer all of the functionality of fill as well as additional options for plotting, manipulating, and querying polygons. Use these functions in place of fill when appropriate:

• To create regular polygons, use nsidedpoly. This function simplifies creation of regular polygons and offers additional options for managing the position and dimensions of a plotted polygon.

  nsidedpoly creates a polyshape object, with additional options for altering the location, radius, and side length of the polyshape after its creation. A polyshape created with nsidedpoly can be manipulated using all properties of polyshape as well as the properties exclusive to nsidedpoly.

• To create irregular polygons, use polyshape. This function offers additional options for defining polygons.

  polyshape creates a polyshape object, which has additional properties and object functions for querying and altering a polygon after its creation. For a complete list, see polyshape.

• To create Patch objects as fill does, use patch. This function offers additional options for defining both 2-D and 3-D patches by their face and vertex data.

Extended Capabilities

GPU Arrays

Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™.

The fill function supports GPU array input with these usage notes and limitations:

• This function accepts GPU arrays, but does not run on a GPU.

For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).

Distributed Arrays

Partition large arrays across the combined memory of your cluster using Parallel Computing Toolbox™.

Usage notes and limitations:

• This function operates on distributed arrays, but executes in the client MATLAB.

For more information, see Run MATLAB Functions with Distributed Arrays (Parallel Computing Toolbox).

Version History

Introduced before R2006a

R2025a: Create filled patches in polar coordinates

Create filled patches in polar coordinates by specifying a PolarAxes object as the first argument.

R2021a: The XData, YData, and ZData properties on Patch objects created with the fill and fill3 functions return values of the original data type

The XData, YData, and ZData properties on a Patch object created by the fill or fill3 functions return the coordinates using the original input data type, rather than returning them as double values.

In previous releases, datetime, duration, and categorical coordinates are converted to double values when they are stored in the XData, YData, and ZData properties.

For example, this code creates a filled polygonal region with datetime x-coordinates. Then it calculates x2 using the values stored in the XData property. In R2020b, h.XData and x2 are double arrays. In R2021a, h.XData and x2 are datetime arrays.

x = datetime('01-Jan-2018') + days([0 1 1 0]);
y = [0 0 1 1];
h = fill(x,y,'red');
x2 = h.XData + 1;

To preserve the double values in your code, get the double values from the Vertices property of the Patch object. The x-, y-, and z-coordinates are stored as double values in the first, second, and third columns of the Vertices array.

x2 = h.Vertices(:,1) + 1;

Alternatively, use the ruler2num function. Pass the coordinate values and the corresponding axis ruler to the ruler2num function.

ax = gca;
x2 = ruler2num(h.XData,ax.XAxis) + 1;