diagramstikz-pgfvector
I'm been using Inkscape for the entire time, and it was just too much time consuming to resize the box, creating the arrow and placing the block etc…
I've noticed about tikz in latex, and wonder if I could create diagrams like this without so much hassle. (e.g manual positioning). The ideal scenario is to just define a block, place some code in, and define the links.
That doesn't look like it was created with a 3D-aware drawing tool - the sheets look like they were meant to be sections from a cylinder that didn't quite come out right, and it has that freehand look about it. I guess it wasn't created using Word's Drawing Tool: building up pictures by joining together curves is brutal in that environment, but Visio would be a good bet.
If you want a Tex-aware GUI drawing tool, people speak highly of Inkscape, which is a serious 2D drafting tool with support for ensuring lines are in proportion, to help avoid the freehand look. Inkscape supports export to embedded PS/ PDF, as well as to Xfig, allowing you to use the Xfig export function. Additionally, it supports export to SVG, which is used by the inkscape2tikz program. I can't say more, since I haven't seriously used Inkscape.
Xfig gives you less sophisticated drawing support, but better integration with Tex: it allows limited export to both the Latex picture environment and full export to Metapost. It is pleasant enough to use, but the results do look hand drawn.
Or finally, the figures do not look so difficult to draw algorithmically either using Metapost or Tikz. Metapost is very nice for computing complex figures using line intersections, which would be useful for the example diagrams.
It's because when you clear the text of the initial node you don't actually decrease the node size. I've added a draw to the node options to make it obvious that your guess is correct:
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{automata}
\tikzset{initial text={}}
\makeatletter
\tikzstyle{initial by arrow}= [after node path=
{
{
[to path=
{
[->,double=none,every initial by arrow]
([shift=(\tikz@initial@angle:\tikz@initial@distance)]\tikztostart.\tikz@initial@angle)
node [shape=rectangle,anchor=\tikz@initial@anchor,draw] {\tikz@initial@text}
-- (\tikztostart)}]
edge ()
}
}]
\makeatother
\begin{document}
\begin{tikzpicture}
\node[state, initial] {};
\draw[red, dashed] (current bounding box.south west) rectangle (current bounding box.north east);
\end{tikzpicture}
\end{document}
Instead of draw you can put an inner sep=0 which is a good approximation, or delete the node or add overlay to keep the node but not include it in the bounding box.
Best Answer
Now with texts.
I think that it is fair to say that the basics are not too difficult to learn. The problem everyone has is that the pgfmanual has more than 1000 pages, so any answer can be repeated in countless different flavors. Here you could choose another way to bend the path, could use a matrix of nodes and many other things. Your question is about the "Simplest way to draw a control flow graph similar like this?". I do not claim that this is the simplest way, but it is a possible way, which is IMHO rather straightforward.