5  Examples

This page provides practical examples demonstrating various use cases for the cvd package.

5.1 Basic Usage

5.1.1 Quick Check for Deuteranopia

The simplest way to check your document for the most common form of color blindness:

\documentclass{article}
\usepackage[deuteranopia]{cvd}
\usepackage{xcolor}

\begin{document}

This document simulates deuteranopia (green-blind) color vision.

\textcolor{red}{Red text} \textcolor{green}{Green text} \textcolor{blue}{Blue text}

\end{document}

5.1.2 Comparing Multiple CVD Types

Create a comparison document showing how colors appear with different CVD types:

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

\begin{document}

\section{Normal Vision}
\cvddisable
\textcolor{red}{Red} \textcolor{green}{Green} \textcolor{blue}{Blue}

\section{Protanopia (Red-blind)}
\cvdenable
\cvdtype{protanopia}
\cvdseverity{1.0}
\textcolor{red}{Red} \textcolor{green}{Green} \textcolor{blue}{Blue}

\section{Deuteranopia (Green-blind)}
\cvdtype{deuteranopia}
\cvdseverity{1.0}
\textcolor{red}{Red} \textcolor{green}{Green} \textcolor{blue}{Blue}

\section{Tritanopia (Blue-blind)}
\cvdtype{tritanopia}
\cvdseverity{1.0}
\textcolor{red}{Red} \textcolor{green}{Green} \textcolor{blue}{Blue}

\end{document}

5.2 Scientific Papers and Charts

5.2.1 Color-Coded Data

When presenting color-coded data, check that your color scheme is accessible:

\documentclass{article}
\usepackage{pgfplots}
\usepackage[deuteranopia]{cvd}
\pgfplotsset{compat=1.18}

\begin{document}

\begin{tikzpicture}
\begin{axis}[xlabel=X, ylabel=Y]
  \addplot[red, mark=*] coordinates {(0,0) (1,1) (2,2)};
  \addplot[green, mark=square*] coordinates {(0,1) (1,0) (2,1)};
  \addplot[blue, mark=triangle*] coordinates {(0,2) (1,1) (2,0)};
\end{axis}
\end{tikzpicture}

\end{document}

If the colors become hard to distinguish, consider changing them until they can also be distinguished under the CVD simulation.

5.2.2 Multiple Charts with Different CVD Types

\documentclass{article}
\usepackage{pgfplots}
\usepackage{cvd}
\pgfplotsset{compat=1.18}

\begin{document}

% Define CVD-transformed colors for each type
\cvddefinecolor[type=protanopia]{red}{red-p}
\cvddefinecolor[type=protanopia]{green}{green-p}
\cvddefinecolor[type=protanopia]{blue}{blue-p}

\cvddefinecolor[type=deuteranopia]{red}{red-d}
\cvddefinecolor[type=deuteranopia]{green}{green-d}
\cvddefinecolor[type=deuteranopia]{blue}{blue-d}

\begin{tikzpicture}
\begin{axis}[xlabel=X, ylabel=Y, title=Protanopia]
  \addplot[red-p, mark=*] coordinates {(0,0) (1,1) (2,2)};
  \addplot[green-p, mark=square*] coordinates {(0,1) (1,0) (2,1)};
\end{axis}
\end{tikzpicture}

\begin{tikzpicture}
\begin{axis}[xlabel=X, ylabel=Y, title=Deuteranopia]
  \addplot[red-d, mark=*] coordinates {(0,0) (1,1) (2,2)};
  \addplot[green-d, mark=square*] coordinates {(0,1) (1,0) (2,1)};
\end{axis}
\end{tikzpicture}

\end{document}

5.3 Maps and Color-Coded Regions

5.3.1 Simple Color-Coded Map

\documentclass{article}
\usepackage{tikz}
\usepackage[deuteranomaly]{cvd}

\begin{document}

\begin{tikzpicture}
  % Draw a simple map with color-coded regions
  \fill[red!30] (0,0) rectangle (2,2);
  \fill[green!30] (2,0) rectangle (4,2);
  \fill[blue!30] (4,0) rectangle (6,2);
  
  \node at (1,1) {Region A};
  \node at (3,1) {Region B};
  \node at (5,1) {Region C};
\end{tikzpicture}

\end{document}

5.4 Shadings and Gradients

5.4.1 Basic Gradient with CVD

\documentclass{article}
\usepackage{tikz}
\usepackage[deuteranopia]{cvd}

\begin{document}

\begin{tikzpicture}
  % This gradient will be transformed with deuteranopia
  \shade[left color=red, right color=blue] (0,0) rectangle (6,2);
  \node at (3,1) {Deuteranopia Gradient};
\end{tikzpicture}

\end{document}

5.4.2 Multiple Gradients with Different CVD Types

See Chapter 6 for detailed examples on handling shadings with different CVD types, including the caching workaround.

5.5 Raster Images

5.5.1 Transforming a Photo

\documentclass{article}
\usepackage[graphics convert=true]{cvd}
\cvdtype{protanopia}

\begin{document}

% Requires --shell-escape and ImageMagick
\includegraphics[width=\textwidth]{my-photo.jpg}

\end{document}

Compile with:

lualatex --shell-escape mydocument.tex

5.5.2 Transforming Specific Images Only

\documentclass{article}
\usepackage[protanopia, graphics convert=false]{cvd}
% CVD simulation is disabled globally

\begin{document}

% This image is NOT transformed
\includegraphics[width=0.5\textwidth]{normal-image.png}

% This specific image IS transformed using \cvdincludegraphics
\cvdincludegraphics[width=0.5\textwidth]{cvd-image.png}

\end{document}