4  Output Formats

CCVisu produces two kinds of results: co-change graphs, when used as a pure extractor of co-change relations from the CVS repository, or graph layouts in different formats (text format LAY, VRML, SVG, and directly drawn on the screen).

4.1  Graph (RSF)

When used as a co-change graph extractor only, CCVisu stores the graph in RSF format for further use (the RSF format is described in Section 3.3).

4.2  Layout (LAY)

CCVisu can save layouts in its own text format, either by specifying LAY as output format or by pressing the save-button while viewing a screen layout using the DISP output format. The tool can produce all other provided layout formats from the LAY format.

Each line contains the data needed to represent a single vertex. For example, the line

LAY  -126.0  -72.0  0.0  32  src/Makefile  255  false

represents a vertex with name src/Makefile at coordinates x=-126.0, y=-72.0, z=0.0, edge degree 32, drawn in color 255 (which is blue, in usual 3 byte RGB code), and the name is by default not annotated (false). (’LAY’ is the name of the relation if the file is interpreted in RSF format.)

4.3  Displaying the Layout

This section describes common features of the different possibilities for actually viewing the computed layout. The vertices are drawn as filled circles in the visualizations. Edges are always omitted. The area of the filled circles is proportional to the degree of the corresponding vertex.

All three output options support the following mouse feature to show the names of vertices:

• If the mouse pointer is moved on a vertex, the name annotation is shown. After the mouse pointer leave the vertex, the annotation is removed.
• If the mouse pointer points to a vertex and the mouse button is clicked, the name annotation is permanently added to the vertex. Clicking again on a vertex removes the annotation.

4.3.1  Layout (VRML)

CCVisu supports the VRML graphics format as output format
(cf. http://tecfa.unige.ch/guides/vrml/vrml97/spec/
or http://tecfa.unige.ch/guides/vrml/pointers.html ).

For VRML viewers we refer to the VRML Viewers, Browsers and Plug-ins web page of the Web 3D Consortium (http://www.web3d.org/x3d/vrml/tools/viewers_and_browsers/), or, e.g., directly to the Cortona VRML Client (http://www.parallelgraphics.com/products/cortona/), which is a plug-in for some standard web browsers.

However, VRML viewers are not appropriate for viewing large layouts (thousands of vertices).

4.3.2  Layout (SVG)

CCVisu supports the SVG graphics format as output format
(cf. http://www.w3.org/TR/SVG/ or http://www.w3.org/Graphics/SVG/ ).

For SVG viewers we refer to the SVG Implementations web page of the World Wide Web Consortium
(http://www.w3.org/Graphics/SVG/SVG-Implementations), or, e.g., directly to the Adobe SVG Viewer
(http://www.adobe.com/svg/), which is a plug-in for some standard web browsers.

4.3.3  Layout on Screen (DISP)

The output-format option DISP provides the display of layouts without any additional viewer software, and at the same time this is the only possibility for viewing layouts up to a million vertices (where even an SVG viewer breaks down).

In difference to the above mentioned viewing techniques, the direct display annotates the vertex name (if mouse pointer moves on a vertex) in a separate frame to avoid repainting the layout. The separate frame also contains a SAVE button to save the layout using the LAY output format.