0. Introduction

This project is focused on using STL containers in order to graph data on a one-dimensional and two-dimensional (and if time allows, 3D!) plot. The plot would be written in an svg image, compliant with the W3C standard. The goals of the project are as follows:

• To provide an easy syntax for graphing data
• To let users produce a simple plot with minimal intervention by using sane defaults
• To demonstrate how to incorporate SVG images into Boost documentation
• To allow users to easily customize graphs to their heart's content
• To allow the user to talk with the svg_graph class using coordinate units instead of pixels or other arbitrary measures

I have only a student's grasp of C++, so if you have a suggestion to help me with design or implementation, either leave them here or email me at jakevoytko [at] gmail [dot] com

This page will hold examples of what I have implemented thus far, and what my program will be capable of in the future. More complete documentation will be live in a few days on my personal website.

What can it do?

Example

vector<double> data1, data2;

// fill vectors

svg_plot my_plot("./image.svg");

my_plot << image_size(500, 200) << x_scale(-7, 9) << draw_axis()
        << plot_range(data1.begin(), data1.end(), blue)
        << plot_range(data2.begin(), data2.end(), green)
        << write();

produces the following output:

Using different STL containers

deque<double> data1;
vector<double> data2;

//fill vectors

svg_plot my_plot("./image.svg");

my_plot << image_size(500, 200) << x_scale(-7, 9) << draw_axis()
        << plot_range(data1.begin(), data1.end(), orange)
        << plot_range(data2.begin(), data2.end(), blue)
        << write();

produces the following output:

Using Boost.Array

boost::array<double, 10> arr;

// fill arr

my_plot << image_size(500, 200) << x_scale(-7, 9) << draw_axis()
        << plot_range(arr.begin(), arr.end(), orange)
        << write();

produces the following output:

To-Do List

For next week

• Create a more consistent internal name scheme (I'm starting to confuse myself)
• Accept generic STL containers, Boost.Array
• Begin to incorporate a key/legend into the graph
• Allow streams to be specified as output points
• Move files not to be consumed by users to "detail" folder

By July 2nd

• Expand workings of program to two dimensions

3. Suggestions (No ETA as of May 28)

By Matias Capeletto:

• Be able to choose a log scale for either the X or the Y axis
• Proposal to include a plugable extractor to plot_range()

In general, containers will store other things than double. Starting simple, I want to be able to plot std::vector<int>. This is very easy to support. Add a function:

template<class Iter, class DoubleExtractor >
plot& plot_range( Iter start, Iter end, DoubleExtractor double_extractor)
{
    return your_old_plot_range(
       boost::make_transform_iterator(start, double_extractor),
       boost::make_transform_iterator(end  , double_extractor)
    );
}

This have other implications, for example if we have list<Human> hl, and struct get_age_functor { ... }; We can:

svg << plot_range( hl.begin(), hl.end(), get_age_functor() ); // fun stuff :)

By Paul Bristow

• Customize background color of plot
• Customize the background border color
• Customize the "axis area" background color
• Title
  • Customize font
  • Customize font color
• Axis
  • Customize line colors
  • Customize line thickness
  • Define labels for axis
  • Major ticks width, length, color
  • Minor ticks width, length, color
  • Reasonable defaults for ticks
  • Axis marker labels
  • Consider the axis for data where the origin is not in the view window
  • Consider auto-scaling
  • Grid lines
• Data representation
  • Allow different data representation points
  • Allow appropriate customization of data points
  • Consider labels for data points (combined with exploration of hover-text features of SVG mentioned above)
  • Consider how to concisely represent the scale of data points
  • Multiple data series
• Legend
  • Border
  • color
  • position
  • border thickness
  • background colors
• Unicode strings

4. Bugs D:

• Changing or setting the x_scale after calling my_graph<<draw_axis() makes the axis not be drawn.
  • This is caused because I store points after setting the graph. I will fix this by storing infinity as +NaN in the point, and when outputting, writing it at a location far off the graph