GridFlow 0.7.7 - introduction
The philosophy that guides PureData is a simple but powerful one: the software must first provide the user with generic tools rather than imposing pre-cooked effects. In other words the user should have total freedom.
GridFlow follows that philosophy: it first defines elementary mathematical operations. Those can in turn be used as simple visual effects or be combined to produce more complex effects.
The strategy followed by most video plugins for PureData, jMax, and MAX/MSP, is to provide the user first with constructs for manipulating video streams at a fairly high level. The strategy put forward by GridFlow is different.
It can be said that in all those video plugins there are three layers: the first, the low level, is not accessible to non-programmers (and fairly difficult of access even to programmers); the second, mathematical, where one needs not to be a C++ programmer, but still requires a good understanding of how numbers and pixels and colours and geometry work; and a third level that looks more like the software an artist would like to use.
In other video plugins there is a fairly low emphasis on the second layer. In GridFlow that layer is very strong and opens many possibilities. Even though the third layer in GridFlow is not as developed as it could, the second layer may be used to produce third-layer object classes much more quickly.
GridFlow provides a unifying view of multimedia information. Several kinds of data -- raster graphics in any number of channels, coordinate transforms, matrices, vectors -- may all be represented by Grids (also known as multi-dimensional arrays). Grids exist in several ways: they are usually streamed from object to object, but they can also be stored in memory, stored into a file, sent through the network.
The new GridFlow (0.6) also provides scripting, which inserts itself between the first and second layer to provide additional functionality. The language that has been chosen is Ruby, designed by Yukihiro Matsumoto during the 90's. This new layer is used for portability between host software (PureData vs jMax), for portability between platforms (Windows/Mac versions do not exist but would be farther ahead if it wasn't for Ruby), for independency from host software (GridFlow can be tested and used independently of PureData/jMax), for quick extensibility (you can create PureData/jMax object classes directly in GridFlow's configuration file), and so on.
In short, GridFlow is a whole new world of possibilities for the multimedia artist and programmer.
- matju
Here is an example of how things work in GridFlow. (if you want more information, consult the rest of this manual)
A picture is a three-dimensional Grid:
0 : rows
1 : columns
2 : channels
Pictures come in all sorts of heights and widths. The channels, however, are more limited in number. Usually it's three: Red, Green, Blue.
A coordinate transform, when specified pixel by pixel, may be a three-dimensional Grid in which the two "channels" are Y and X, representing row-and-column positions in a separate picture.
Other shapes of grids could be designed to represent various things; for example, configuration for blur effects. Grids could be useful for things not directly related to raster pictures (e.g. sound recordings). Those are all kinds of things you could actually develop within the PureData / GridFlow framework. You don't need to wait for me.
GridFlow 0.7.7 Documentation
by Mathieu Bouchard matju@sympatico.ca
and
Alexandre Castonguay acastonguay@artengine.ca