# Tikzpicture: Strechting a specified interval (axis) of a diagram

In a collaboration I managed to create the following diagram. The last modification I need is ti emphazise that point B is located right to A (regarding the x-axis). Therefore I want to stretch the x-axis, but only in the interval of let's say 1.5 to 2.5 to let's say twice its current length. In other words: The distances from unit 1.5-2.5 should be twice as big as from 0.5-1.5 or 2.5-3.5 (difference betweens units and centimeters, or pixel).

Is this possible? \documentclass[15pt,a4paper,headinclude, totoc]{scrartcl}

\usepackage[usenames,dvipsnames]{xcolor}
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{compat=1.12}
\usetikzlibrary{angles,calc,intersections,quotes,positioning,shapes}

\begin{document}
\begin{center}
\begin{tikzpicture}[scale=1.5,
my angle/.style args = {#1/#2}{draw,<->,
angle eccentricity=#2,
} % angle label position!
]
\pgfplotsset{ticks=none}
\begin{axis}[axis lines=middle,xmin=-0.2,xmax=4.5,ymin=-0.5,ymax=15, ultra thick,
xlabel=$C_t$,
ylabel=$C_{t+1}$,
x label style={at={(1,-0.01)},anchor=north},
y label style={at={(-0.15,1)},anchor=west},
no marks,
samples=100
]
\coordinate (O) at (0,0);
\coordinate (a1) at (0,29.12722);
\coordinate (a2) at (3.0138,0);
\pic [my angle=12mm/1.2, "$\alpha$",blue] {angle = a1--a2--O};
\coordinate (b1) at (0,20.15286);
\coordinate (b2) at (2.08522,0);
\pic [my angle=19mm/1.15, "$\beta$",red] {angle = b1--b2--O};

\addplot+[gray,domain=1.2:4,thick] {(13.06666)/(0.8*x-0.4) -0.83333} node[right]{\footnotesize $U^0$};
\addplot+[gray,domain=0.8:4,thick] {(5.4)/(0.8*x-0.4) -0.83333 } node[right]{\footnotesize $U^1$};

\fill (1.8,11.73094) circle (2pt) node[right]{\tiny \textbf{A}};
\draw[gray, dash pattern=on 6pt off 3pt] (1.8,0) -- (1.8,11.73094);
\draw[gray, dash pattern=on 6pt off 3pt] (0,011.73094) -- (1.8,11.73094);

\fill[black] (1.8533,4.15433) circle (2pt) node[right]{\tiny \textbf{B}};
\fill (1.3357,7.2435) circle (2pt) node[right]{\tiny \textbf{C}};
\end{axis}
\end{tikzpicture}
\end{center}
\end{document}


It is not yet a complete answer, but it is way to long to put in a comment.

Inspired bij this: Plot with magnifying glass, with a different plot in it

May be you can do something with this:

 \documentclass[15pt,a4paper,headinclude, totoc]{scrartcl}

\usepackage[usenames,dvipsnames]{xcolor}
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{compat=1.12}
\usetikzlibrary{angles,calc,intersections,quotes,positioning,shapes}

%%% this part is for what's in the box
\newsavebox\plotbox
\begin{lrbox}{\plotbox}
\begin{tikzpicture}
\begin{axis}[
axis lines=none,
width=3cm,
height=3cm
]
\addplot[smooth,blue, very thick] coordinates {(0,0) (1,0.25) (1.5, 0.5) (2,1)};
\end{axis}
\end{tikzpicture}%
\end{lrbox}

\begin{document}
\begin{center}
\begin{tikzpicture}[scale=1.5, my angle/.style args = {#1/#2}{draw,<->, angle radius=#1, angle eccentricity=#2,
} % angle label position!
]
\pgfplotsset{ticks=none}
\begin{axis}[axis lines=middle,xmin=-0.2,xmax=4.5,ymin=-0.5,ymax=15, ultra thick,
xlabel=$C_t$,
ylabel=$C_{t+1}$,
x label style={at={(1,-0.01)},anchor=north},
y label style={at={(-0.15,1)},anchor=west},
no marks,
samples=100
]
\coordinate (O) at (0,0);
\coordinate (a1) at (0,29.12722);
\coordinate (a2) at (3.0138,0);
\pic [my angle=12mm/1.2, "$\alpha$",blue] {angle = a1--a2--O};
\coordinate (b1) at (0,20.15286);
\coordinate (b2) at (2.08522,0);
\pic [my angle=19mm/1.15, "$\beta$",red] {angle = b1--b2--O};

\addplot+[gray,domain=1.2:4,thick] {(13.06666)/(0.8*x-0.4) -0.83333} node[right]{\footnotesize $U^0$};
\addplot+[gray,domain=0.8:4,thick] {(5.4)/(0.8*x-0.4) -0.83333 } node[right]{\footnotesize $U^1$};

\fill (1.8,11.73094) circle (2pt) node[right]{\tiny \textbf{A}};
\draw[gray, dash pattern=on 6pt off 3pt] (1.8,0) -- (1.8,11.73094);
\draw[gray, dash pattern=on 6pt off 3pt] (0,011.73094) -- (1.8,11.73094);

\fill[black] (1.8533,4.15433) circle (2pt) node[right]{\tiny \textbf{B}};
\fill (1.3357,7.2435) circle (2pt) node[right]{\tiny \textbf{C}};
\end{axis}

%%%%
\coordinate (spyanchor) at (2,0.4);
\node[circle,draw,inner sep=0pt,red,fill=white] at (5,4)
(spyplot)
{\usebox\plotbox};
\node[green,circle,draw,inner sep=10pt] at (spyanchor) (spynode) {};
\draw[green] (spyplot) -- (spynode);

\end{tikzpicture}
\end{center}
\end{document} It looks like you magnify a part of your drawing...

• Why are you drawing the spy manually? :P This can be done (more) automatically. Jan 24, 2016 at 11:20
• I am looking for a kind of magnification. But my emphasize lies on an interval on the x-axis, that's why I'm not sure if the glass is suited. To be very precise I want to hightlight the horizontal distance between A and B (x-coordinates: 1.8 and 1.8533)
– Mac
Jan 24, 2016 at 11:24
• @Alenanno because that's the only thing I know for the moment. I would be happy to learn it, if there is an other possibility Jan 24, 2016 at 12:29
• @Arne There is a spy library in TikZ Feb 23, 2016 at 12:36