[Tex/LaTex] TikZ Fading Speed

tikz-pgf

In the fading example at
TikZ examples

I would like to change the "speed" at which fade occurs. In fact I would like it to be very "sharp" so that in the square examples you basically will see about half a square because it fades out so quick.

Any ideas how to achieve that? (basically I want to overlay two squares with different colors and end up seeing half a square of one color and the other half the other color but with a sort of quick fade between the two in the center(instead of the gradual fade that the default tikz setup gives)

Best Answer

By default, there's no option for setting the transition speed between the colors of a linear shading. You can relatively easily add it, though. Here's a new style fading speed=<0..100> that allow setting the transition speed for the standard axis shading.

enter image description here

\documentclass{standalone}
\usepackage{tikz}
\begin{document}


\makeatletter
\tikzset{
    fading speed/.code={
        \pgfmathtruncatemacro\tikz@startshading{50-(100-#1)*0.25}
        \pgfmathtruncatemacro\tikz@endshading{50+(100-#1)*0.25}
        \pgfdeclareverticalshading[%
            tikz@axis@top,tikz@axis@middle,tikz@axis@bottom%
        ]{axis#1}{100bp}{%
            color(0bp)=(tikz@axis@bottom);
            color(\tikz@startshading)=(tikz@axis@bottom);
            color(50bp)=(tikz@axis@middle);
            color(\tikz@endshading)=(tikz@axis@top);
            color(100bp)=(tikz@axis@top)
        }
        \tikzset{shading=axis#1}
    }
}
\makeatother

\begin{tikzpicture}[top color=blue, bottom color=yellow]

\foreach \speed [count=\count] in {0,25,...,100}{
    \fill [fading speed=\speed] (\count,0) rectangle +(1,2);
    \path (\count,0) +(0.5,2) node [text=white,anchor=north] {\speed};
}
\end{tikzpicture}
\end{document}

Related Solutions

[Tex/LaTex] Faded drop-shadow using tikz-based rounded rectangle

You could use the pgf-blur package, which gives you this:

a rounded rectangle node with faded drop shadow

In fact, it can add a "faded" drop shadow to pretty much anything:

a slightly rounded tape node with faded drop shadow

The shadow fading is not continuous, like in the previously accepted answer. It fades in a number of discrete steps, but that number can be changed, see the documentation.

Here's the code for the examples:

\documentclass{article}
\usepackage{tikz}

\usetikzlibrary{shadows.blur}
\usetikzlibrary{shapes.symbols}

\begin{document}


\begin{center}
  \begin{tikzpicture}
    \node[draw=none,shade,
      top color=blue!40,
      bottom color=blue!5,
      rounded corners=6pt,
      blur shadow={shadow blur steps=5}
    ] {\sffamily\bfseries\large A pretty box};

    \node[tape,draw=none,shade,
      top color=blue!40,
      bottom color=blue!5,
      rounded corners=1pt,
      blur shadow={shadow blur steps=5,shadow blur extra rounding=1.3pt}
    ] at (5,0){\sffamily\bfseries\large Another pretty box};
  \end{tikzpicture}
\end{center}

\end{document}

Edit

Sometimes, PDF renderers will show a dark line in the center of the shadow. This is due to the way they handle anti-aliasing and clipping. To avoid this:

Use pgf-blur v1.01, which tries hard to hide this artefact
In Acrobat, turn off the "Page Display" preference "Enhance thin lines". These shadows consist of many thin lines, and they won't look good if Acrobat changes their width
Don't use too many blur shadow steps. It looks best if you have about two pixels per step at viewing resolution.

[Tex/LaTex] Overlapping tikz nodes with background fadings

Not very sophisticated … (but then: Why so tight ticks? Why not pgfplots?)

Code (the `scope`)

\begin{scope}[ticklabel/.style={fill=white,path fading=fade out,text opacity=1.0}]
    \foreach \x in {-4,-3,-2,-1,1,2,3,4}{
        \node[below,ticklabel] at (\x,0) {$\phantom{\x}$};
        \node[left,ticklabel] at (0,\x) {$\phantom{\x}$};
    }
    \foreach \x in {-4,-3,-2,-1,1,2,3,4}{
        \node[below] at (\x,0) {$\x$};
        \node[left] at (0,\x) {$\x$};
    }
\end{scope}

Output