samcarter
I stumbled over this while working on transparent shadows for the [smoothbars outer beamer theme](https://github.com/josephwright/beamer/issues/717) and am wondering why does the fading in the following MWE only stretch over half the space? If I change the scaling factor to `2` it will exactly fill it, but why is this necessary?
```
\documentclass{standalone}
\usepackage{tikz}
\pgfdeclareverticalshading{myshade}{3cm}{%
color(0ex)=(pgftransparent!100);%
color(1ex)=(pgftransparent!0)
}
\pgfdeclarefading{mymask}{\pgfuseshading{myshade}}
\begin{document}
\fbox{\begin{pgfpicture}
\pgfsetfillcolor{red}%
\pgfpathrectangle{\pgfpoint{0pt}{-1ex}}{\pgfpoint{3cm}{1.2ex}}%
\pgfsetfading{mymask}{\pgftransformscale{1}}%
\pgfusepath{fill}%
\end{pgfpicture}}
\end{document}
```
Top Answer
samcarter
I think the behaviour is explained in this comment by @muzimuzhi
> Since `fit fading=false` is set, the fading area is not shifted nor scaled to fit the current path. It is just centered at `(0,0)`. Manually adding the needed shifting `fading transform={xshift=-.5,yshift=.5}` seems to fix the problem.
>
> But I don't understand the behavior when `fit fading=false` is removed.
(form https://github.com/pgf-tikz/pgf/issues/978#issuecomment-757384587 )
So in reality my fading is scaled perfectly, I just choose my coordinates in such an unfortunate way that half the shape was cut off. Modifying my code to show a larger section shows that the shading is indeed perfectly positioned at (0,0) and does has the correct size of 3 cm times 1 ex:
```
\documentclass{standalone}
\usepackage{tikz}
\pgfdeclareverticalshading{myshade}{3cm}{%
color(0bp)=(pgftransparent!100);%
color(1ex)=(pgftransparent!0)
}
\pgfdeclarefading{mymask}{\pgfuseshading{myshade}}
\begin{document}
\begin{pgfpicture}
\pgfsetfillcolor{red}%
\pgfpathrectangle{\pgfpoint{-3cm}{-1ex}}{\pgfpoint{6cm}{2ex}}%
\pgfsetfading{mymask}{\pgftransformscale{1}}%
\pgfusepath{fill}%
\end{pgfpicture}
\end{document}
```
