mjhjmtu

I'm trying to include a scaled graph into another picture (yes I need to use nested tikz pictures, but I can't find any better way), and the problem is that the arrow heads are not scaled properly, so the scaled graph looks weird. Any idea to scale properly a graph?

I tried scalebox.6... which works great for tikzpicture alone, but in nested tikzpicture, the bounding box used is as if the graph wouldn't have been scaled, which makes the positionning ugly.

Also, I could generate first a pdf and include it, but it's not really practical because I want to use it in a beamer slide and I need to include some onslide<...> command inside, so it means that I would need to create one tex/pdf for each slide...

Bonus: you get a bonus if the method also allow links to nested tikzpicture with remember options.

MWE:

documentclass[a4paper]article

usepackagetikz

begindocument
Not scaled:
begintikzpicture[
 qubit/.style=draw, circle, color=black, anchor=center,
 fill=rgb,255:red,143;green,146;blue,237,
 inner sep=0pt,minimum width=5mm
 ]
 node[qubit] (q1) at (0,0);
 draw[red,-stealth] (q1.center) -- (q1.north);
endtikzpicture


Scaled:
begintikzpicture[scale=.5, every node/.style=scale=.5,
 qubit/.style=draw, circle, color=black, anchor=center,
 fill=rgb,255:red,143;green,146;blue,237,
 inner sep=0pt,minimum width=5mm
 ]
 node[qubit] (q1) at (0,0);
 draw[red,-stealth] (q1.center) -- (q1.north);
endtikzpicture
enddocument

-- EDIT --
Here is a MWE with the included nested tikzpicture:

documentclassarticle

usepackagetikz
usetikzlibrarycalc,positioning

begindocument
Not scaled:
begintikzpicture[
 qubit/.style=draw, circle, color=black, anchor=center,
 fill=rgb,255:red,143;green,146;blue,237,
 inner sep=0pt,minimum width=5mm
 ]
 node[qubit] (q1) at (0,0);
 node[qubit,right=of q1] (q2) ;
 draw[-] (q1) -- (q2);
 draw[red,-stealth] (q1.center) -- (q1.north);
endtikzpicture

Scale + transform shape:\
begintikzpicture
 node[circle,draw,fill=green] (A) A;
 node[circle,draw,fill=green,right=of A] (B) B;
 node[circle,draw,fill=green,above=of A] (C) C;
 node[above=of B.center,anchor=south east] (graph) 
 begintikzpicture[scale=0.5, every node/.style=transform shape,
 qubit/.style=draw, circle, color=black, anchor=center,
 fill=rgb,255:red,143;green,146;blue,237,
 inner sep=0pt,minimum width=5mm
 ]
 node[qubit] (q1) at (0,0);
 node[qubit,right=of q1] (q2) ;
 draw[-] (q1) -- (q2);
 draw[red,-stealth] (q1.center) -- (q1.north);
 endtikzpicture
 ;
 node[fill=green,inner sep=0pt,minimum size=3pt] at (graph.north east) ;
 node[fill=red,inner sep=0pt,minimum size=3pt] at (graph.north west) ;
 node[fill=yellow,inner sep=0pt,minimum size=3pt] at (graph.south east) ;
 node[fill=orange,inner sep=0pt,minimum size=3pt] at (graph.south west) ;
endtikzpicture

transform canvas, good arrow size, bad position:\
begintikzpicture
 node[circle,draw,fill=green] (A) A;
 node[circle,draw,fill=green,right=of A] (B) B;
 node[circle,draw,fill=green,above=of A] (C) C;
 node[above=of B.center,anchor=south east] (graph2) 
 begintikzpicture[transform canvas=scale=0.5,
 qubit/.style=draw, circle, color=black, anchor=center,
 fill=rgb,255:red,143;green,146;blue,237,
 inner sep=0pt,minimum width=5mm
 ]
 node[qubit] (q3) at (0,0);
 node[qubit,right=of q3] (q4) ;
 draw[-] (q3) -- (q4);
 draw[red,-stealth] (q3.center) -- (q3.north);
 endtikzpicture
 ;
 node[fill=green,inner sep=0pt,minimum size=3pt] at (graph2.north east) ;
 node[fill=red,inner sep=0pt,minimum size=3pt] at (graph2.north west) ;
 node[fill=yellow,inner sep=0pt,minimum size=3pt] at (graph2.south east) ;
 node[fill=orange,inner sep=0pt,minimum size=3pt] at (graph2.south west) ;
endtikzpicture

enddocument

-- EDIT 2 --
I tried with xsavebox as proposed in comments, and it works pretty well, except that it does not deal with beamer overlay, which is quite a big issue in my case...

documentclassbeamer
usepackagexsavebox
usepackagetikz
usetikzlibrarycalc,positioning

begindocument

beginframe
Not scaled:
begintikzpicture[
 qubit/.style=draw, circle, color=black, anchor=center,
 fill=rgb,255:red,143;green,146;blue,237,
 inner sep=0pt,minimum width=5mm
 ]
 node[qubit] (q1) at (0,0);
 node[qubit,right=of q1] (q2) ;
 draw[-] (q1) -- (q2);
 draw[red,-stealth] (q1.center) -- (q1.north);
endtikzpicture
endframe

beginframe
Scale + transform shape, good position, bad arrow size:\
begintikzpicture
 node[circle,draw,fill=green] (A) A;
 node[circle,draw,fill=green,right=of A] (B) B;
 node[circle,draw,fill=green,above=of A] (C) C;
 node[above=of B.center,anchor=south east] (graph) 
 begintikzpicture[scale=0.5, every node/.style=transform shape,
 qubit/.style=draw, circle, color=black, anchor=center,
 fill=rgb,255:red,143;green,146;blue,237,
 inner sep=0pt,minimum width=5mm
 ]
 node[qubit] (q1) at (0,0);
 node[qubit,right=of q1] (q2) ;
 draw[-] (q1) -- (q2);
 draw[red,-stealth] (q1.center) -- (q1.north);
 node<2>[qubit,above=of q2] (q2bis) ;
 endtikzpicture
 ;
 node[fill=green,inner sep=0pt,minimum size=3pt] at (graph.north east) ;
 node[fill=red,inner sep=0pt,minimum size=3pt] at (graph.north west) ;
 node[fill=yellow,inner sep=0pt,minimum size=3pt] at (graph.south east) ;
 node[fill=orange,inner sep=0pt,minimum size=3pt] at (graph.south west) ;
endtikzpicture
endframe

beginframe
 transform canvas, good arrow size, bad position:\
 begintikzpicture
 node[circle,draw,fill=green] (A) A;
 node[circle,draw,fill=green,right=of A] (B) B;
 node[circle,draw,fill=green,above=of A] (C) C;
 node[above=of B.center,anchor=south east] (graph2) 
 begintikzpicture[transform canvas=scale=0.5,
 qubit/.style=draw, circle, color=black, anchor=center,
 fill=rgb,255:red,143;green,146;blue,237,
 inner sep=0pt,minimum width=5mm
 ]
 node[qubit] (q3) at (0,0);
 node[qubit,right=of q3] (q4) ;
 draw[-] (q3) -- (q4);
 draw[red,-stealth] (q3.center) -- (q3.north);
 node<2>[qubit,above=of q4] (q5) ;
 endtikzpicture
 ;
 node[fill=green,inner sep=0pt,minimum size=3pt] at (graph2.north east) ;
 node[fill=red,inner sep=0pt,minimum size=3pt] at (graph2.north west) ;
 node[fill=yellow,inner sep=0pt,minimum size=3pt] at (graph2.south east) ;
 node[fill=orange,inner sep=0pt,minimum size=3pt] at (graph2.south west) ;
 endtikzpicture
endframe


beginxlrboxmybox
 begintikzpicture[
 qubit/.style=draw, circle, color=black, anchor=center,
 fill=rgb,255:red,143;green,146;blue,237,
 inner sep=0pt,minimum width=5mm
 ]
 node[qubit] (q3) at (0,0);
 node[qubit,right=of q3] (q4) ;
 draw[-] (q3) -- (q4);
 draw[red,-stealth] (q3.center) -- (q3.north);
 node<2>[qubit,above=of q4] (q5) ;
 endtikzpicture
endxlrbox

beginframe
xlrbox, good resize, no beamer overlay:\
begintikzpicture
 node[circle,draw,fill=green] (A) A;
 node[circle,draw,fill=green,right=of A] (B) B;
 node[circle,draw,fill=green,above=of A] (C) C;
 node[above=of B.center,anchor=south east] (graph2) scalebox0.5themybox;
 node[fill=green,inner sep=0pt,minimum size=3pt] at (graph2.north east) ;
 node[fill=red,inner sep=0pt,minimum size=3pt] at (graph2.north west) ;
 node[fill=yellow,inner sep=0pt,minimum size=3pt] at (graph2.south east) ;
 node[fill=orange,inner sep=0pt,minimum size=3pt] at (graph2.south west) ;
endtikzpicture
endframe

enddocument

With the xsavebox package you can save the tikzpicture in a xlrbox, and scale it when using:

documentclass[a4paper]article

usepackagetikz
usepackagexsavebox

beginxlrboxmybox
begintikzpicture[
 qubit/.style=draw, circle, color=black, anchor=center,
 fill=rgb,255:red,143;green,146;blue,237,
 inner sep=0pt,minimum width=5mm
 ]
 node[qubit] (q1) at (0,0);
 draw[red,-stealth] (q1.center) -- (q1.north);
endtikzpicture%
endxlrbox

begindocument
Not scaled: themybox

Scaled: scalebox0.5themybox
enddocument

This also solves the nesting of tikzpictures.

EDIT (by marmot who is happy to take the blame for all errors;-): You should never nest tikzpictures. You can work with scopes, which you can assign name with the local bounding box trick, these scopes will then behave pretty much like nodes (as far as the remembering and placing stuff relative to them is concerned). Clearly, inside the scope you can work with all overlays in the usual way. The perhaps easiest way to go is to load the arrows.meta library and downscale the arrow. (pgflowlevelsynccm does not work here in a straightforward way because of the additional translations, otherwise it scales the arrow automatically to the right size, but this command should anyway be used with great care.)

documentclassbeamer
usepackagetikz
usetikzlibrarycalc,positioning,arrows.meta

begindocument


beginframe
Scale + transform shape, good position, bad arrow size:\
begintikzpicture
 node[circle,draw,fill=green] (A) A;
 node[circle,draw,fill=green,right=of A] (B) B;
 node[circle,draw,fill=green,above=of A] (C) C;
 coordinate[above=of B.center] (X);

 beginscope[shift=($(X)+(-1,0)$),
 transform shape,scale=0.5, 
 qubit/.style=draw, circle, color=black, anchor=center,
 fill=rgb,255:red,143;green,146;blue,237,
 inner sep=0pt,minimum width=5mm,local bounding box=graph]
 node[qubit] (q1) at (0,0);
 node[qubit,right=of q1] (q2) ;
 draw[-] (q1) -- (q2);
 node<2>[qubit,above=of q2] (q2bis) ;
 draw[red,-Stealth[scale=0.5]] (q1.center) -- (q1.north);
 endscope
 % comparison
 draw[red,-stealth] ([xshift=2mm,yshift=-1cm]q1.center) -- ([xshift=2mm]q1.north);
 node[fill=green,inner sep=0pt,minimum size=3pt] at (graph.north east) ;
 node[fill=red,inner sep=0pt,minimum size=3pt] at (graph.north west) ;
 node[fill=yellow,inner sep=0pt,minimum size=3pt] at (graph.south east) ;
 node[fill=orange,inner sep=0pt,minimum size=3pt] at (graph.south west) ;
endtikzpicture
endframe

enddocument

Arrowheads are scaled by the line width (more or less), which is not scaled. Mostly because very thin lines are hard to see.

documentclass[varwidth]standalone

usepackagetikz

begindocument
Not scaled:
begintikzpicture[
 qubit/.style=draw, circle, color=black, anchor=center,
 fill=rgb,255:red,143;green,146;blue,237,
 inner sep=0pt,minimum width=5mm,
 line width=pgflinewidth % default value
 ]
 node[qubit] (q1) at (0,0);
 draw[red,-stealth] (q1.center) -- (q1.north);
endtikzpicture


Scaled:
begintikzpicture[scale=.5, every node/.style=scale=.5,
 qubit/.style=draw, circle, color=black, anchor=center,
 fill=rgb,255:red,143;green,146;blue,237,
 inner sep=0pt,minimum width=5mm,
 line width=0.5pgflinewidth
 ]
 node[qubit] (q1) at (0,0);
 draw[red,-stealth] (q1.center) -- (q1.north);
endtikzpicture
enddocument

Defaults:

pgfdeclarearrow{
 name = Stealth,
 defaults = 
 length = +3pt 4.5 .8,
 width' = +0pt .75,
 inset' = +0pt 0.325,
 line width = +0pt 1 1,
 ,