This post is about putting charts and formulas in your web pages, creating editable and scalable PNG files, and the need for a standard for embedded application data in image files.
Earlier today I looked at Google Charts, which allows you to ‘dynamically generate charts’. Send a Google a suitable GET request and you will get a pie chart, a bar chart or whatever, as specified in your query string. Their example is
http://chart.apis.google.com/chart?cht=p3&chd=s:hW&chs=250x100&chl=Hello|World
which will produce the chart
This is rather similar to MathTran, where are URL such as
http://www.mathtran.org/cgi-bin/mathtran?D=3;tex=1%20%2B%201%2F2%20%2B%201%2F4%20%2B%20%5Cldots%20%2B%201%2F2%5En
produces the image
Google Charts allows you to dynamically create graphs, and MathTran allows you to dynamically create rendered mathematical formulas. The Google API is rather better than MathTran’s, and it is certainly better documents. But MathTran has something that Google Charts doesn’t have … yet. The PNG’s returned by MathTran can be edited.