Google Chart Tools / Image Charts
http://code.google.com/intl/zh-CN/apis/chart/faq.html
matplotlib
http://matplotlib.sourceforge.net/
网站有很好的文档
matplotlib is a python 2D plotting library which produces publication quality figures in a variety of hardcopy formats and interactive environments across platforms. matplotlib can be used in python scripts, the python and ipython shell (ala MATLAB®* or Mathematica®†),
web application servers, and six graphical user interface toolkits.
matplotlib tries to make easy things easy and hard things possible. You can generate plots, histograms, power spectra, bar charts, errorcharts, scatterplots, etc, with just a few lines of code. For a sampling, see the http://matplotlib.sourceforge.net/users/screenshots.html
ChartDirector
http://www.advsofteng.com/finance_demo.html
有已破解的软件（已下载）
Pychart
http://home.gna.org/pychart/
PyChart is a Python library for creating high quality Encapsulated Postscript, PDF, PNG, or SVG charts. It currently supports line plots, bar plots, range-fill plots, and pie charts. Because it is based on Python, you can make full use of Python's scripting
power. See some examples.
Gnuplot
Gnuplot is a portable command-line driven graphing utility for linux, OS/2, MS Windows, OSX, VMS, and many other platforms. The source code is copyrighted but freely distributed (i.e., you don't have to pay for it). It was originally created to allow scientists
and students to visualize mathematical functions and data interactively, but has grown to support many non-interactive uses such as web scripting. It is also used as a plotting engine by third-party applications like Octave. Gnuplot has been supported and
under active development since 1986.
k线图的例子
http://gnuplot.sourceforge.net/demo_4.2/finance.html
Gnuplot.py
http://gnuplot-py.sourceforge.net/
Gnuplot.py is a Python package that interfaces to gnuplot, the popular open-source plotting program. It allows you to use gnuplot from within Python to plot arrays of data from memory, data files, or mathematical functions. If you use Python to perform computations
or as 'glue' for numerical programs, you can use this package to plot data on the fly as they are computed. And the combination with Python makes it is easy to automate things, including to create crude 'animations' by plotting different datasets one after
another.
Commands are communicated to gnuplot through a pipe and data either through the same pipe (as "inline" data), through FIFOs (named pipes), or through temporary files. It has been developed under Unix and is known to work under various forms of Unix (including
Linux), MS Windows, MacOS, and Mac OS X. There is now also preliminary support for running Gnuplot.py under Jython/Java.
This package has an object-oriented design that allows the user flexibility to set plot options and to run multiple gnuplot sessions simultaneously. If you are more ambitious, it is not difficult to add entirely new types of plottable items by deriving from
the 'PlotItem' class.
The package includes a demonstration that can be run by typing 'python demo.py'.
Google Chart Tools
http://code.google.com/intl/zh-CN/apis/charttools/index.html
python-graph
python-graph is a library for working with graphs in Python.
This software provides ?a suitable data structure for representing graphs and a whole set of important algorithms.
What is graph-tool?
graph-tool is an efficient python module for manipulation and statistical analysis of graphs (a.k.a. networks). With graph-tool you can do the following:
NetworkX
http://networkx.lanl.gov/#
NetworkX is a Python package for the creation, manipulation, and study of the structure, dynamics, and functions of complex networks.
igraph
http://cneurocvs.rmki.kfki.hu/igraph/
igraph is a free software package for creating and manipulating undirected and directed graphs. It includes implementations for classic graph theory problems like minimum spanning trees and network flow, and also implements algorithms for some recent network
analysis methods, like community structure search.
GDCHART
http://www.fred.net/brv/chart/
Easy to use C API, high performance library
Create charts and graphs in PNG, GIF and WBMP format
PyGDChart2 is a comprehensive set of Python bindings for the GDChart graphing library. It features a full OO interface, an extensive manual, and support for the latest 0.11.x versions of GDChart
Creating a financial open-high-low-close (OHLC) chart in a high level language like Ruby or Python?
You can use matplotlib and the the optional bottom parameter of matplotlib.pyplot.bar.
Have you considered using R and the quantmod package?
You can use Pylab (matplotlib.finance) with Python. Here are some examples: http://matplotlib.sourceforge.net/examples/pylab_examples/plotfile_demo.html . There is some good material specifically on this problem in Beginning Python Visualization.
Update: I think you can use matplotlib.finance.candlestick for the Japanese candlestick effect.
JFreeChart
using Jython would give him access to Java classes, so he could use JFreeChart