Generate diagrams from text input.

Dimagram (the name will change at some point) is a tool to create diagrams from text input. All you have to do is write a text file with markup in a super simple markup language and compile this file to an image.

• Supports for ER diagrams in Chen notation
• Generates diagrams with evenly spaces nodes
• Renders diagrams from markup language

• Graphs induced by diagrams by conform to planarity, i.e. there's gotta be a way to draw it without edges crossing. If you try to compile a graph that does not conform to planarity compiler will give you an error.
• Diagrams must not be disconnected, i.e. there must be a path from one node to the other by links.
• Only ER diagrams are supported so far.
• No labels on the edges or near terminals of nodes.
• No key attributes out of the box
• No associative entities out of the box
• No weak entities out of the box
• Nodes are rendered in raster mode

Some node types are not supported out of the box. But you can use your own image of the node.

• igraph
• cairo
• make
• gcc
• libunwind-ptrace (for testing to print out backtraces)
• Unix like OS

To build in release mode

make build-release

To build in test mode (the compiled program might not output file correctly, idk why)

make build-test

Dimagram supports ER diagrams in Chen's notation.

You have to mark your diagram up in a text file using a special markup language.

Simple markup language which we shall call elementary graphics language (EGL) has the following notation

• To define an entity you use this notation

entity <identifier> "<label>"

• To define a relationship you use this notatation

relationship <identifier> "<label>"

• To define an attribute you you this notation

attribute <identifier> "<label>"

• To define any other node with you own image

node <identifier> "<filename>"

Each type of node requires identifier and label to be specified. Identifier can be any alphanumeric sequence of characters. Label is put in quotation marks. Importing images as nodes requires input images to be in raster format e.g. png, jpeg. After marking the diagram up the diagram needs to be compiled.

• To compile the file you use

<path to dimagram> -i <input> -o <output>

for example

dimagram -i diagram.txt -o diagram.svg

• Or you could run it like this

<path to dimagram> < <input> > <output>

for example

dimagram < diagram.txt > diagram.svg

entity student "Student"
entity course "Course"
relationship student_enrolls_course "Student enrolls in course"
link student and student_enrolls_course
link student_enrolls_course and course

entity lector "Lecturer"
relationship lector_makes_course "Lecturer creates course"
link lector and lector_makes_course
link lector_makes_course and course

entity lection "Lecture"
relationship lector_makes_lection "Lecturer creates lecture"
link lection and lector_makes_lection
link lector_makes_lection and lector

entity homework "Homework"
relationship lection_contains_homework "Lecture contains homework"
link lection_contains_homework and lection
link lection_contains_homework and homework

entity student "student"
entity book "book"
entity car "car"
link book and student
link car and student

This code was generated using glazer

• Graphviz
• PlantUML

• Log.c - logging library for C
• igraph - Graph library for C
• Cairo - Graphics library for C
• zhash-c - Hashmap implementation for C
• Boyer-Myrvold Planarity Tester - Original Boyer-Myrvold implementation by the authors of the original paper. (I tried to write my own one, but it was too hard)
• arena - Arena allocator for C

• Harel, D., Sardas, M. An Algorithm for Straight-Line Drawing of Planar Graphs . Algorithmica 20, 119–135 (1998). https://doi.org/10.1007/PL00009189
• Boyer, J., & Myrvold, W. (2004). On the Cutting Edge: Simplified O(n) Planarity by Edge Addition. Journal of Graph Algorithms and Applications, 8(3), 241–273. https://doi.org/10.7155/jgaa.00091
• Chen's notation Wikipedia. https://en.wikipedia.org/wiki/Entity%E2%80%93relationship_model