dot graph viewer
Some plugins create graphical output in Graphviz DOT file format. The Dot Viewer widget provided by plugin dot_viewer provides not only a graphical viewer for these files but also an interactive interface which ties elements of the DOT graph to actions in Graph View.
The toolbar comprises these actions:
This action opens a file browser to select an existing .dot file. To setup interactive actions between DOT Viewer and Graph View the creator and the category of the graphics (e.g. visualizing state transitions, visualizing module connections, ...) must be known when loading the file into the viewer. Recent plugins write a comment into the file so the creator can be determined automatically. If the file was not created by HAL or by an older HAL version this information is missing. The DOT Viewer will then raise a popup where the plugin which created the file can be selected. If the default (none) gets chosen the file gets loaded into the viewer without enabling interactions.
This action toggled whether grid lines are drawn in the background of the DOT Viewer or not.
The color scheme in HAL gets determined by the selected style. This is "dark" on default but the user can switch to "light" e.g. for print outs. Color settings made within the .dot file very often create a very ugly if not unreadable graphic when combined with HAL color scheme. Therefore these settings get ignored by default and overwritten by the HAL style sheet. There is however the possibility that the color setting from .dot file provides important information like the power state of an edge. By invoking this action the user can decide to enforce color setting from .dot file either for edges or for nodes or for both.
Available interactions between DOT Viewer and Graph View depend of the category of the DOT graph. The category gets determined by the name of the plugin which created the graph file.
The Dataflow Analysis plugin creates a DOT graph which shows the identified modules as nodes and the connection between them as directed edges. A right click on an edge opens a context menu with the suggested action to isolate the shortest path between the modules connected by this edge into a new view.
When a module gets selected in Graph View the appropriate node in DOT Viewer gets selected as well and vice versa.
The Solve FSM plugin creates a DOT graph which shows the possible states of a final state machine as nodes. Directed edges between the nodes reflect transitions between the states. These transitions get triggered by a boolean expression which is shown as node label. A right click on an edge opens a context menu with the suggested action to solve the boolean expression and highlight the nets in the Graph View according to their state in the solution found.
When selecting a net in the Graph View every occurrence of the net in the boolean expression is highlighted, thus showing the impact of this net within the expression.
