3  Commands

The cvd package provides several commands to control the CVD simulation at any point in your document. These commands allow you to enable, disable, and configure the simulation dynamically.

3.1 Simulation Control

3.1.1 Enable/Disable Simulation

Command	Description
\cvdenable	Enable color vision deficiency simulation
\cvddisable	Disable color vision deficiency simulation

When you disable the simulation using \cvddisable, the type and severity settings are stored in the background. A subsequent \cvdenable restores the original CVD simulation behavior.

\cvdenable   % Turn on CVD simulation
...          % Content with CVD applied
\cvddisable  % Turn off CVD simulation
...          % Content without CVD
\cvdenable   % Turn on CVD simulation again (restores previous settings)

3.2 Configuration Commands

3.2.1 Set CVD Type

\cvdtype{<type>}

Sets the type of color-vision deficiency. Possible values are: - protanopia — red-blind - deuteranopia — green-blind - tritanopia — blue-blind

Example:

\cvdtype{deuteranopia}

3.2.2 Set Severity

\cvdseverity{<value>}

Sets the severity level on a scale from 0 to 1. - 1 means maximum severity (full colorblindness of the given type) - 0 means completely normal vision

Example:

\cvdseverity{0.5}  % 50% severity

3.2.3 Set Multiple Options

\cvdset{<options>}

Set one or more CVD options at once using key-value syntax. All options available at package load time can be used here.

Example:

\cvdset{type=protanopia, severity=0.8, graphics hook=true}

3.3 Image Commands

3.3.1 Include Raster Image with CVD

\cvdincludegraphics[<options>]{<path>}

Include a raster image (PNG/JPG) with CVD transformation applied.

This macro behaves identically to \includegraphics when CVD simulation is enabled. However, when CVD simulation is disabled, this macro can be used to apply the CVD transformation to a single raster image.

Note: This macro has no effect for PDF images; PDF images are transformed according to the current state of the CVD simulation via the graphics hook option.

Example:

\cvdincludegraphics[width=0.5\textwidth]{example.png}

3.4 Color Commands

3.4.1 Define CVD Color

\cvddefinecolor[<options>]{<source color>}{<target color>}

Define a new color named <target color> by applying the current CVD transformation to the existing color <source color>.

The optional <options> argument can be used to override the current CVD settings (e.g., type, severity) for this specific color definition, using the same syntax as \cvdset.

This is particularly useful for creating pre-computed CVD colors that can be used consistently throughout your document, especially with shadings and gradients (see Chapter 6).

Example:

% Define a color that appears as blue would to someone with protanopia
\cvddefinecolor[protanopia, severity=0.5]{blue}{blue-cvd}

% Use the pre-computed color
\textcolor{blue-cvd}{This text uses the CVD-transformed blue color}

Example with multiple CVD variants:

\cvddefinecolor[protanopia]{red}{red-p}
\cvddefinecolor[deuteranopia]{red}{red-d}
\cvddefinecolor[tritanopia]{red}{red-t}

3.5 Complete Example

\documentclass{article}
\usepackage{xcolor}
\usepackage{cvd}

\begin{document}

% Start with normal vision
\cvddisable
Normal vision: \textcolor{red}{Red text} \textcolor{green}{Green text}

% Enable deuteranopia simulation
\cvdenable
\cvdtype{deuteranopia}
\cvdseverity{1.0}
\bigskip

Deuteranopia (severity 1.0): \textcolor{red}{Red text} \textcolor{green}{Green text}

% Try a different type
\cvdtype{protanopia}
\cvdseverity{0.5}
\bigskip

Protanopia (severity 0.5): \textcolor{red}{Red text} \textcolor{green}{Green text}

% Define and use pre-computed colors
\cvddisable
\cvddefinecolor[protanopia]{red}{red-p}
\cvddefinecolor[protanopia]{green}{green-p}
\bigskip

Pre-computed protanopia colors: \textcolor{red-p}{Red (as protanope)} \textcolor{green-p}{Green (as protanope)}

\end{document}