Following some exchange off-list (trying to figure out how tikz under context got broken), the subject of understanding pgf/tikz with respect to metapost came up. I am posting a follow-up here as it may be of interest to others on the mailing list, those who know metapost very well as well as those, like myself, who are still learning how to use different graphics tools. On Sunday 26 October 2008 11:46:22 Mojca Miklavec wrote:
I am just starting to learn about metapost, and I can't judge yet what pgf/tikz has as advantages and disadvantages.
Advantages of TikZ: 1.) many many many many "libraries" that are ready-to-use. Just take a glimpse through the manual and it will be evident to you in the first glimpse. If you want to draw a graph, you can do it with a few commands. (one command draws you axis, one for function, ...) You can achieve the same with metapost, but you need to do everything from scratch. However, it's really easy to write your own libraries. 2.) some special effects like smooth shading works in metapost only conditionally (does not work with XeTeX at the moment), and you have a wider range with TikZ
Advantages of metapost: 1.) rich mathematical machinery (you can write a set of equations and metapost will calculate your coordinates) 2.) easy to write your own macros
I thought that a major interest of pgf/tikz was the production of portable graphics (using many different motors).
I use metapost when I need to program something, and TikZ when I need to do something fancy very quickly. Another option is export to TikZ in Geogebra.
As an experiment, I did try comparing making a graph using pgfplot and metagraph, and I did *not* like the result of the second.
metagraph is old as earth.
graph.mp,v 1.2 2004/09/19 Current estimates place the age of the earth at around 4.6 billion years...
If I draw graphs is meapost, I do that manually. Or I use gnuplot module to draw graphs for me, but graph drawing is much easier & more flexible with TikZ if you have datapoints ready.
I myself find gnuplot to be fatally flawed and have never liked using it. (I still sometimes produce graphics using an old program written in K&R C that generates HPGL for pen plotters, with a filter that then creates postscript. Now THAT is almost stone age! But this program can also handle an arbitrary number of points VERY efficiently, only limited by the size of your storage device.)
If you need some complex curve, TikZ is improving in that area, but in metapost it's out-of-the-box to draw it.
Why did Till Tantau write pgf/tikz? Clearly he knew metapost, so another route could have been to develop a standard library of metapost macros. I'm asking these questions here as there seems to be a preference (or prejudice) towards metapost amongst the context community. Indeed, it appears pretty powerful. But as Mojca wrote about glimpsing at the pgf/tikz manual, it too is very rich and I have yet to learn about all of the new features that were introduced in pgf-2.0. Thus, I am trying to figure out where to invest my learning efforts. Do any other metapost and/or pgf-tikz experts have something to contribute to this query? -- Alan Braslau