Does \pgflowlevel{\pgftransformscale{}} do the same as normal tikz scale?

Question

I am wondering the following.

Somebody made a complicated tikz figure (our university logo). Now I am having troubles, because the width and height latex is reporting are not the 'real' width and height, a very small box instead.

The beginning of the tikzpicture environment looks like this:

\begin{tikzpicture}%

\pgflowlevel{\pgftransformscale{#1}}%

\pgftransformscale{0.1}%

% Scaled smaller from the large logo
\begin{pgfscope}%

The culprit seems to be in the \pgflowlevel{} line. When I replace this line with a normal scale, like this:

\begin{tikzpicture}[scale=#1]%

\pgftransformscale{0.1}%

% Scaled smaller from the large logo
\begin{pgfscope}%

the logo seems to be rendered the same, except that the width and height are now ok.

What is the difference between the lowlevel command and the tikz scale command, except for messing up the reported dimensions? If none, why would somebody want to use the lowlevel command?

Answer 1

\pgflowlevel applies the transformation you feed it to the entire canvas instead of just the coordinates. That means everything (including text and line widths) are scaled without further ado, when applying the transformation to coordinates text remains the same and line widths are taken care of such that they are scaled uniformly.

Examples of this behaviour can be found in Section 52.4 of the PGF/TikZ manual, version 2.0.

As to why the creator of the logo uses this: he wanted to resize line thickness and text size uniformly, so the logo looks the same for all scale factors. What I don't understand is the presence of \pgftransformscale{0.1} in both code snippets and the fact that the logo is rendered the same. Maybe there's no text or fiddling with line thickness in it.