[Tex/LaTex] How to fill a specified area using TikZ

path-clippingtikz-pgf

I want to fill some regions which are only parts of a shape in a TikZ drawing (marked as "Here" in the following drawings):

\documentclass{standalone}
\usepackage[tikz]{bclogo}
\usetikzlibrary{arrows,shapes,backgrounds,calc,arrows}
\begin{document}
    \begin{tikzpicture}[axis/.style={very thick, ->, >=stealth'}]
    % axis
        \draw[axis] (9,2.5)  -- (13.5,2.5) node(xline)[right]
            {$x_N$};
        \draw[axis] (11.25,0.5) -- (11.25,4.5) node(yline)[above] {$\hat{x}_N$};
         
    \draw[->, ultra thick](7,2.5) -- (8.5,2.5);    
    \draw [very thick] plot [smooth cycle] coordinates {(2,4) (5,3) (2,0.5) (1,1.75) (1,4) };
    %\draw[very thick] (0.5,3) to [ curve through ={(5.5,2) . . ( 3,0.25) . . (1,0.25) }]( 0.5,3 ) ;
    
    \draw[dashed, very thick] (11.25,2.5) ellipse (1cm and 1.5cm);
    \draw[dashed, very thick] (5,3) ellipse (1.5cm and 1cm);
    \draw[step=0.25cm,gray,very thin] (0,0) grid (15,5);
    \node (a) at (4,3) {Here};
    \node (b) at (11.7,3) {Here};
    \node (a) at (11.7,2) {Here};
    
    \end{tikzpicture}
\end{document}

enter image description here

How can I achieve that?

Best Answer

Is this what you seek? Here scope environment is used. Be aware that clip command must be contained in the scope environment to limit the effect of clipping. Without scope environment, the clipping effect will continue to the end of the code.

enter image description here

Code

\documentclass{standalone}
\usepackage[tikz]{bclogo}
\usetikzlibrary{arrows,shapes,backgrounds,calc,arrows,patterns}
\begin{document}
    \begin{tikzpicture}[axis/.style={very thick, ->, >=stealth'}]
    % axis
        \draw[axis] (9,2.5)  -- (13.5,2.5) node(xline)[right]
            {$x_N$};
        \draw[axis] (11.25,0.5) -- (11.25,4.5) node(yline)[above] {$\hat{x}_N$};
    \draw[->, ultra thick](7,2.5) -- (8.5,2.5);  
\begin{scope}
\draw [very thick] plot [smooth cycle] coordinates {(2,4) (5,3) (2,0.5) (1,1.75) (1,4) }; 
\clip (5,3) ellipse (1.5cm and 1cm);
 \draw [fill=red,very thick] plot [smooth cycle] coordinates {(2,4) (5,3) (2,0.5) (1,1.75) (1,4) };
\end{scope}
\begin{scope}
\draw [dashed,very thick] (11.25,2.5) ellipse (1cm and 1.5cm);
\clip (11.25,2.5) ellipse (1cm and 1.5cm);
\fill [red] (11.25,0) rectangle (15,5);
\end{scope}
    \draw[dashed, very thick] (5,3) ellipse (1.5cm and 1cm);
    \draw[step=0.25cm,gray,very thin] (0,0) grid (15,5);
    \node (a) at (4,3) {Here};
    \node (b) at (11.7,3) {Here};
    \node (a) at (11.7,2) {Here};
    \end{tikzpicture}
\end{document}

Edit: With patterns from tikzlibrary, and put pattern=crosshatch dots in the fill/draw options, one gets

enter image description here

Related Solutions

[Tex/LaTex] How to define the default vertical distance between nodes

I don't really get the question so I hope this is what you wanted. If you include a full document (such that we copy paste and see the problem on our systems) things are much more easier.

Here, you can change the default setting within a scope but your block style had a node distance which was resetting every time it is issued. I've made it 2mm such that we can see the difference easier.

\documentclass[tikz]{standalone}
\usetikzlibrary{arrows,shapes.geometric,positioning}

\begin{document}
\begin{tikzpicture}[decision/.style={diamond, draw, text width=4.5em, text badly centered, node distance=3.5cm, inner sep=0pt},
                    block/.style   ={rectangle, draw, text width=6em, text centered, rounded corners, minimum height=4em, minimum height=2em},
                    cloud/.style   ={draw, ellipse, minimum height=2em},
                    line/.style    ={draw,-latex'},
                    node distance = 1cm, 
                    auto]
    \node [block] (1st) {1st};
    \node [block, right= of 1st]  (2nd1) {2nd1};
\begin{scope}[node distance=2mm and 10mm]%Here we change it for everything inside this scope
    \node [block, above= of 2nd1] (2nd2) {2nd2};
    \node [block, below= of 2nd1] (2nd3) {2nd3};
    \node [block, right= of 2nd1] (3rd1) {3rd1};
    \node [block, above= of 3rd1] (3rd2) {3rd2};
    \node [block, above= of 3rd2] (3rd3) {3rd3};
\end{scope}
    \node [block, below= of 3rd1] (3rd4) {3rd4};
    \node [block, below= of 3rd4] (3rd5) {3rd5};

    \path [line] (1st) -- (2nd1);
    \path [line] (2nd1) -- (2nd2);
    \path [line] (2nd1) -- (2nd3);
    \path [line] (2nd2) -- (3rd3);
    \path [line] (2nd1) -- (3rd1);
    \path [line] (1st) -- (2nd1);
\end{tikzpicture}
\end{document}

enter image description here

[Tex/LaTex] Tikz-picture – Fill area

Another way, especially in more complex cases in which you are not sure about angles, is to just put \path [clip] (-3,-5)--(5,3)--(-3,3)--cycle; in a new scope together with your statement (without any change) \path[fill=black,opacity=0.2] (2,0) -- plot[domain=2:0] (0,0) circle (2cm) -- (0,-2) -- cycle; as follows:

\documentclass[10pt]{article}
\usepackage{ngerman, longtable}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{fancyhdr}
\usepackage{pdflscape}
\usepackage{wasysym}
\usepackage{color}
\usepackage{longtable}
\pagestyle{fancy}
\usepackage{multirow}
\usepackage[pdftex]{graphicx}
\usepackage{array}
\usepackage{tikz}

\begin{document}
\begin{tikzpicture}[scale=0.6,domain=-3:5]

\begin{scope}
\path [clip] (-3,-5)--(5,3)--(-3,3)--cycle;
\path[fill=black,opacity=0.2] (2,0) -- plot[domain=2:0] (0,0) circle (2cm) -- (0,-2) -- cycle;
\end{scope}

%draw grid+axis afterwards
\draw[very thin, color=gray,opacity=0.2] (-5.0,-5.0) grid (5.0,5.0);
\draw[->,color=black] (-5.5,0) -- (5.5,0);
\foreach \x in {-5,-4,-3,-2,-1,1,2,3,4,5}
\draw[shift={(\x,0)},color=black] (0pt,2pt) -- (0pt,-2pt) node[below] {\footnotesize $\x$};
\draw[->,color=black] (0,-5.5) -- (0,5.5);
\draw (5.7,0.2) node[anchor=north west] {$x_1$};
\draw (-0.3,6.2) node[anchor=north west] {$x_2$};
\foreach \y in {-5,-4,-3,-2,-1,1,2,3,4,5}
\draw[shift={(0,\y)},color=black] (2pt,0pt) -- (-2pt,0pt) node[left] {\footnotesize $\y$};
\draw[color=black] (0pt,-10pt) node[right] {\footnotesize $0$};

%draw cirle + graph
\draw[color=black] plot (\x,{(\x-2)}) node[right] {};
\draw (0,0) circle (2cm);

\end{tikzpicture}
\end{document}

which gives the required picture:

enter image description here

Best Answer

Related Solutions

[Tex/LaTex] How to define the default vertical distance between nodes

[Tex/LaTex] Tikz-picture – Fill area

Related Question