brighten

Brighten or darken colormap

Syntax

brighten(beta)

brighten(map,beta)

newmap = brighten(___)

brighten(f,beta)

Description

brighten(beta) shifts the intensities of all colors in the current colormap in the same direction. The colors brighten when beta is between 0 and 1, and they darken when beta is between -1 and 0. The magnitude of the change is proportional to the magnitude of beta. Use this syntax to adjust colors for all graphics objects in the current figure that use a colormap.

brighten(map,beta) shifts the intensities of the colormap specified as map.

newmap = brighten(___) returns the adjusted colormap for any of the input argument combinations in the previous syntaxes. When you specify the output argument, the current figure is not affected.

brighten(f,beta) shifts the intensities of the colormap assigned to figure f. The colors of other graphics objects are affected, such as the axes, axes labels, and ticks.

Examples

Brighten Current Colormap

Create a surface plot with the default colormap.

surf(peaks);

Brighten the colormap for current figure.

brighten(.8);

Darken Colormap for Specific Axes

Display two surface plots that use the summer colormap in a tiled chart layout.

t = tiledlayout(1,2);
ax1 = nexttile;
surf(ax1,peaks);
ax2 = nexttile;
surf(ax2,peaks);
colormap(summer)

Darken the summer colormap and apply it to the second surface.

newmap = brighten(summer,-.7);
colormap(ax2,newmap)

Input Arguments

beta — Brightness adjustment

numeric scalar value

Brightness adjustment parameter, specified as a numeric scalar value. The brighten function raises each value in the colormap to the power of γ, which is defined as:

$$\gamma =\{\begin{array}{cc}1-\beta ,& \beta >0\\ \frac{1}{1+\beta },& \beta \le 0\end{array}$$

Data Types: single | double

f — Figure

Figure object

Figure to adjust, specified as a Figure object. When you specify this argument, the colors of other graphics objects within the figure are affected in addition to the objects that use the colormap. For example, color of the axes, axes labels, and ticks changes.

map — Colormap

three-column matrix of RGB triplets

Colormap to adjust, specified as a three-column matrix of RGB triplets. An RGB triplet is a three-element row vector whose elements specify the intensities of the red, green, and blue components of a color. The intensities must be in the range [0, 1]. For example, here is a colormap that contains five colors:

map = [0.2 0.1 0.5
    0.1 0.5 0.8
    0.2 0.7 0.6
    0.8 0.7 0.3
    0.9 1 0];

This table lists the RGB triplet values for common colors.

Color	RGB Triplet
yellow	[1 1 0]
magenta	[1 0 1]
cyan	[0 1 1]
red	[1 0 0]
green	[0 1 0]
blue	[0 0 1]
white	[1 1 1]
black	[0 0 0]

Alternatively, you can create the matrix by calling one of the predefined colormap functions. Call the function as an input argument to the brighten function. For example, this command brightens the parula colormap.

brighten(parula,.8)

Data Types: double | single

Output Arguments

newmap — Adjusted colormap

three-column matrix of RGB triplets

Adjusted colormap, returned as a three-column matrix of RGB triplets.

Version History

Introduced before R2006a