viz

:Author: Jared Flatow http://jared.flatown.com :Copyright: 2009 Jared Flatow

What is viz?

viz is a utility for visualizing streams of data records, by applying a given paint function to each record in a stream. Although viz is designed to operate according to the UNIX philosophy, it is also intimately tied to Mac OS X. viz is tightly coupled to the OS X graphics layers, in order to provide high-quality visualization and interaction.

Building viz

xcodebuild install prefix=/usr/local

This will build viz.app and install the command line utility under prefix/bin, in this case /usr/local/bin. The viz.app will get built and installed under /tmp/viz.dst, the application can be copied from there to the Applications folder. To install viz.app to ~/Applications, set DSTROOT=/ as follows:

xcodebuild install prefix=/usr/local DSTROOT=/

For more information on building xcode products see: http://developer.apple.com/documentation/developertools/conceptual/XcodeProjectManagement/070-Building_Products/chapter_8_section_1.html

Invoking viz

viz can be invoked as a normal OS X application, using the Finder or the open utility. When viz is installed according to the instructions above, a command line utility is also installed. Invoking viz through the command line allows for specifying options at startup, as well as for reading input from stdin.

viz currently recognizes the following command line options:

Canvas options:

-CanvasWidth                The width of the canvas.
-CanvasHeight               The height of the canvas.

.. hint:: Use CanvasWidth and CanvasHeight to achieve a desired aspect ratio, since viz will enforce this ratio when resizing the window.

RecordStream options:

-CheckpointDistance         The distance between saved Checkpoints.
                            If set to zero or if SavesCheckpoints is set to NO, Checkpoints are not saved.
-FramesPerSecond            The number of frames per second when the animation is playing.
                            Upper limits on this parameter will depend on the host CPU and the paint function itself.
-RecordsPerFrame            The number of records to paint in each frame.
-RecordPainterClass         The name of the painter class to use for painting records.
                            Currently the default is WebScriptRecordPainter, which allows for paint functions written in Javascript.
                            Future support aims to include painter classes which allow for paint functions written in Python and Ruby.
-RecordParserClass          The name of the class to use for parsing records.
                            Currently the only class provided is the Record class itself, which allows for splitting records and fields on specific strings.
-SavesCheckpoints           Whether or not to save Checkpoints.
                            Without Checkpoints, it is not possible to reverse through a RecordStream, however memory usage will not increase with the number of records.

WebScriptRecordPainter options:

-PaintRecordScript          A string containing the paintRecord function.
-PaintRecordScriptFile      The name of a file containing the paintRecord function.
                            The file must contain a function with a particular signature, the default function is::

                                    function paintRecord(record, index, canvas) {
                                             canvas.setText_(index + '
' + record.fields.join('
'));
                                    }

Record parsing options:

-RecordSeparator            The string which separates records in the input.
                            Default is "
".
-FieldSeparator             The string which separates fields in the record.
                            Default is "	".

.. note:: Specifying separator strings which contain only whitespace (from the command line) can be tricky, due to shell expansions.

Miscellaneous:

-CommandLineInvocation      Flag to tell viz that it's being invoked from the command line.
                            If using the builtin command line utility, there is no need to specify this option.

Example::

    sort -k 3 recordsfile | viz -PaintRecordScriptFile paintRecord.js

License information

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program (see the file "COPYING"). If not, see http://www.gnu.org/licenses/.