Graphics and media/Drawing graphs and diagrams/Flow charts

Context provides a charts module to create flow charts. The details are in the Charts uncovered manual by Pragma.

For example

• \usemodule[chart]
  \setupFLOWcharts[height=3\lineheight]
  
  \startFLOWchart[example]
  \startFLOWcell 
    \name {flow}
    \location {1,1}
    \text {Flow}
    \connection [rl] {chart}
  \stopFLOWcell
  \startFLOWcell
    \name {chart}
    \location{2,1}
    \text {Charts}
  \stopFLOWcell
  \stopFLOWchart
  \FLOWchart[example]
  

• 

The more sophisticated example:

• \usemodule[chart]
  \setuppapersize[A2]
  
  \setupFLOWcharts
  [nx=5,
  ny=3,
  dx=2\bodyfontsize,
  dy=2\bodyfontsize,
  maxwidth=\textwidth
  ]
  
  \setupFLOWshapes
  [framecolor=black,
  background=color,
  backgroundcolor=white,
  ]
  
  \startFLOWchart[DSP]
  
  	\startFLOWcell
  	\name{input}
  	\location{1,1}
  	\shape{44}
  	\connection[rl] {lowpass1}
  	\comment[t]{$x(t)$}
  	\comment[b]{$X(t)$}
  	\stopFLOWcell
  
  	\startFLOWcell
  	\name {lowpass1}
  	\location {2,1}
  	\text {Low Pass\crlf Filter}
  	\connection[bt] {adconv}
  	\comment[r]{$x_f(t)$}
  	\comment[l]{$X_f(t)$}
  	\stopFLOWcell
  
  	\startFLOWcell
  	\name{adconv}
  	\location{2,2}
  	\text{Analog/Digital\crlf conversion}
  	\connection[rl]{dsp}
  	\comment[t]{$x[n]$}
  	\comment[b]{$X(\Omega)$}
  	\stopFLOWcell
  
  	\startFLOWcell
  	\name{dsp}
  	\location{3,2}
  	\text{Digital Signal\crlf Processing}
  	\connection[rl]{daconv}
  	\comment[t]{$y[n]$}
  	\comment[b]{$Y(\Omega)$}
  	\stopFLOWcell
  
  	\startFLOWcell
  	\name{daconv}
  	\location{4,2}
  	\text{Digital/Analog\crlf Conversion}
  	\connection[bt]{lowpass2}
  	\comment[r]{$y_d(t)$}
  	\comment[l]{$Y_d(t)$}
  	\stopFLOWcell
  
  	\startFLOWcell
  	\name {lowpass2}
  	\location {4,3}
  	\text {Low Pass\crlf Filter}
  	\connection[rl]{output}
  	\comment[t]{$y_f(t)$}
  	\comment[b]{$Y_f(t)$}
  	\stopFLOWcell
  
  	\startFLOWcell
  	\name {output}
  	\location {5,3}
  	\shape{44}
  	\stopFLOWcell
  
  \stopFLOWchart
  
  \placefigure[here][fig:chart]{The path of signal in digital processing.}
  {
  	\FLOWchart[DSP]
  }
  

• 

Changing the appearance of cells (background color, rule thickness)

It is possible to have each cell with its own color and its own rule thickness. For example

• \usemodule[chart]
  \setupFLOWcharts[height=3\lineheight]
  
  \startFLOWchart[example-Cell]
  \startFLOWcell[background=color,backgroundcolor=yellow,rulethickness=5pt]
    \name {flow}
    \location {1,1}
    \text {Flow}
    \connection [rl] {chart}
  \stopFLOWcell
  \startFLOWcell[background=color,backgroundcolor=lightblue]
    \name {chart}
    \location{2,1}
    \text {Charts}
  \stopFLOWcell
  \stopFLOWchart
  \FLOWchart[example-Cell]
  

• 

As a matter of fact, there is no need for "background=color" because each cell already has a background color by default.

Syntax for \connection

\connection [<from><to>] {<FLOWcell>}

<from> and <to> are the points from which point to which point the connection should be drawn. The following graphic depicts the names of the points.

       -t    t    +t
     ---------------- 
 +l |                | +r
    |                |
  l |                |  r
    |                |
 -l |                | -r
    |                |
     ---------------- 
       -b    b    +b

Example

The following code draws a line from the left top point of the current cell to the right bottom point of cell foobar.

\connection [-t+b] {foobar}

The code for connections in the pdf manual, e.g.

\connection[nb,pt]{episode_02_title}

No longer works

Aligning text within the cell

To align left or right, use

\text[l]{left}
\text[r]{right}

Forcing a paragraph break with \par in a cell does not work...

\text[l]{firstline \par secondline}

Whereas using \\ does work, so:

\text[l]{firstline \\ secondline}

Further hints

• Charts uncovered manual
• There was a Flowchart creater to create flowchart code using javascript, but it disappeared.
• The nodes module covers even more applications of charts.