quick question:

\draw  (0,0) grid (4,2);
\fill[red] (canvas cs:x=1cm,y={sin(120)}) circle (2pt);
\fill[green] (canvas cs:x=2cm,y={sin(45)}) circle (2pt);
\fill[blue] (canvas cs:x=3cm,y=-{sin(30)}) circle (2pt);
\fill[black] (canvas cs:x=4cm,y=5mm+{sin(30)}) circle (2pt); << it does not work

How do I insert a trig function within a coordinate calculation, as above last line?

enter image description here

  • The nodes are exactly where they are supposed to be. e.g. sin(30) is 0.5, which would be 0.5cm, adding 5mm yields 1cm and that's where the black node is placed. – clocktown May 28 '17 at 9:04
  • @clocktown Forget my edit. How do I make tiles 1cmx1cm? – mario May 28 '17 at 10:29
\fill[black] (canvas cs:x=4cm,y={5mm+sin(30)}) circle (2pt);

You basically just have to move that one { to the left a bit. TikZ Syntax can be quite tricky sometimes.

The result of these sinus-calculations for y seem to be in a weird unit, at least not a metric one it seems. I always thought cm would be default, but that assumption seems to be wrong here. I'm guessing it's something like pt here. Thus I'd suggest:

\draw  (0,0) grid (4,2);
\fill[red] (canvas cs:x=1cm,y={1cm*sin(120)}) circle (2pt);
\fill[green] (canvas cs:x=2cm,y={1cm*sin(45)}) circle (2pt);
\fill[blue] (canvas cs:x=3cm,y=-{1cm*sin(30)}) circle (2pt);
\fill[black] (canvas cs:x=4cm,y={5mm+1cm*sin(30)}) circle (2pt);

1cm* converts it into cm, so you can change it to whatever unit you want.

  • @ clocktown Thks, look at it tomorrow. – mario May 25 '17 at 17:13
  • @ clocktown See new image, it seems that 1cm*sin(120) returns 1cm plus sin(120). Is that intended? – mario May 28 '17 at 8:52
  • It's most likely not a weird unit, but points (1 pt = 1/72.27 in). It appears that if no unit is given, then points are used, try for example \fill[red] (canvas cs:x=1cm,y=28.45) circle (2pt); \fill[green] (canvas cs:x=2cm,y=1cm) circle (2pt); (28.45pt is about 1cm) Also, read the description of the xyz coordinate system in the manual, especially the last two paragraphs, starting with Note and Note furthermore. – Torbjørn T. May 28 '17 at 9:45
  • That's what I assumed too. Points is a weird unit to me, anything non metric is for me ;) – clocktown May 28 '17 at 10:00

Package calculator seems to make things easier:



\draw[step=1cm,black!25,thin] (-1,-1) grid (5,2);
\fill[red] (canvas cs:x=0cm,y={1cm*sin(120)}) circle (2pt) 
node[label={[xshift=0.35cm]{\sol}}] {};

\fill[red] (canvas cs:x=0.2cm,y={1cm*\sol}) circle (2pt) 
node[label={[xshift=0.35cm, yshift=-0.65cm]{\sol}}] {};

\fill[red] (canvas cs:x=.4cm,y=0.86cm) circle (2pt);
\fill[purple] (canvas cs:x=1cm,y={1cm*sin(90)}) circle (2pt) 
node[label={[xshift=0.35cm]{\sol}}] {};

\fill[purple] (canvas cs:x=1.2cm,y={1cm*\sol}) circle (2pt) 
node[label={[xshift=0.35cm, yshift=-0.65cm]{\sol}}] {};

\fill[green] (canvas cs:x=2cm,y={1*sin(45)}) circle (2pt)
node[label={[xshift=0.35cm]{\sol}}] {};

% sin(30) = 0.5
\fill[blue] (canvas cs:x=3cm,y={1cm*sin(30)}) circle (2pt)
node[label={[xshift=-0.35cm, yshift=-0.65cm]{\sol}}] {};

\fill[black] (canvas cs:x=3cm,y={5mm+1*sin(30)}) circle (2pt)
node[label={[xshift=0.35cm]{\sol}}] {};

\fill[pink] (canvas cs:x=4cm,y={5mm+1*\sol}) circle (2pt)
node[label={[xshift=0.35cm]{\sol}}] {};

enter image description here

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