TikZImages

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Graphic Images, TikZImages


This example shows how to create an image/plot using Tikz.

Problem Techniques Index

PG problem file Explanation
DOCUMENT();
loadMacros(
"PGstandard.pl",
"MathObjects.pl",
"PGML.pl",
"PGtikz.pl"
);
TEXT(beginproblem());

Initialization: It is important to include the PGtikz.pl macro.

$graph_image = createTikZImage();
$graph_image->tikzLibraries("arrows.meta");

$graph_image->BEGIN_TIKZ
\draw[<->,thick] (-11,0) -- (11,0) node[above left,outer sep=2pt]{\(x\)};
\draw[<->,thick] (0,-11) -- (0,11) node[below right,outer sep=2pt]{\(y\)};
\foreach \x in {-10,-8,...,-2,2,4,...,10} \draw[thin] (\x,5pt) -- (\x,-5pt) node[below]{\(\x\)};
\foreach \y in {-10,-8,...,-2,2,4,...,10} \draw[thin] (5pt,\y) -- (-5pt,\y) node[left]{\(\y\)};
\draw[<->,red] plot[domain={-3.2+$a}:{3.2+$a}] (\x,{pow(\x-$a,2)+$b});
END_TIKZ


Setup:

  • The createTikZImage() function creates an image to be built using tikz.
  • By default an 'svg' image will be generated, which will generally look better than a 'png image.
  • In certain cases the 'svg' creation methods do not give the correct output, and so in those cases a 'png' image may be generated instead by adding $graph_image->ext('png');.
  • The $graph_image->tikzLibraries("arrows.meta"); will load the arrows.meta Tikz library.
  • The actual tikz image is built between $graph_image->BEGIN_TIKZ and END_TIKZ
BEGIN_PGML

[@ image($graph_image, width => 300, tex_size => 1000) @]*

END_PGML

Main Text: This is how to insert the tikz image. Note the width and tex_size parameters can change the size of the image on the web and as hardcopy.

Note that you may want to call $image = image($graph_image, width => 300, tex_size => 1000) above and use [@ $image @]* here while developing the problem. If the image call occurs inside the BEGIN_PGML/END_PGML section, then you will not get the warnings from failed image generation. You will instead get no image, and no reason as to why.

ENDDOCUMENT();

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Problem Techniques Index