# Difference between revisions of "DynamicImages2"

(changed init_graph command to take the form: init_graph(xmin,ymin,xmax,ymax,options) (was: init_graph(-1,4,-1,4,options) which gave a division by zero error upon cut and paste)) |
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Line 29: | Line 29: | ||

<pre> |
<pre> |
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# a graph object |
# a graph object |
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− | $gr = init_graph(-1 |
+ | $gr = init_graph(-1,-1,4,4,axes=>[0,0],grid=>[5,5]); |

# plot a function |
# plot a function |
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add_functions($gr, |
add_functions($gr, |

## Revision as of 14:40, 30 May 2008

## Adding Labels, Lines and Points to Dynamic Graphs: PG Code Snippet

*This code snippet shows the essential PG code to add labels, lines and points to dynamically generated graphs. Note that these are insertions, not a complete PG file. This code will have to be incorporated into the problem file on which you are working.*

PG problem file | Explanation |
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loadMacros("PGgraphmacros.pl"); |
We have no required additions to the tagging and description section of the file, and we obviously need to include |

# a graph object $gr = init_graph(-1,-1,4,4,axes=>[0,0],grid=>[5,5]); # plot a function add_functions($gr, "4-3*e^(-x) for x in <-1,4> using color:blue and weight:2"); # add a label $gr->lb( new Label(0.25,3.25,'(0,3)', 'black','center','center')); # a line $gr->moveTo(-1,1); $gr->lineTo(4,1,'black'); # and a point $gr->stamps( closed_circle(0,3,'blue') ); |
In the initialization part of the file, we define a [dynamically generated graph|DynamicImages]. Then we can add labels, lines and points to the graph.
To add labels, we use the Lines are added by moving the graph "cursor" to a point and then drawing a line to a new point.
And we add points by using the |

BEGIN_TEXT \{ image( insertGraph($gr) ) \} END_TEXT |
And the graph is inserted in the text portion of the problem as we'd expect any static or dynamic image to be. |

Note that there is a more complete list of the plotting options available in a graph object in the CVS documentation for WWPlot and PGgraphmacros.