The Histogram View displays the trace events distribution with respect to time. When streaming a trace, this view is dynamically updated as the events are received.
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[[Image:images/HistogramView.png]]
The '''Hide Lost Events''' toggle button [[Image:images/hide_lost_events.gif]] in the local toolbar allows to hide the bars of lost events. When the button is selected it can be toggled again to show the lost events.
-On the top left, there are two data controls:
+On the top left, there are three text controls:
+
+* '''Selection Start''': Displays the start time of the current selection
+* '''Selection End''': Displays the end time of the current selection
+* '''Window Span''': Displays the current zoom window size in seconds
+
+The controls can be used to modify their respective value. After validation, the other controls and views will be synchronized and updated accordingly. To modify both selection times simultaneously, press the link icon [[Image:images/link.gif]] which disables the '''Selection End''' control input.
+
+The large (full) histogram, at the bottom, shows the event distribution over the whole trace or set of traces. It also has a smaller semi-transparent orange window, with a cross-hair, that shows the current zoom window.
+
+The smaller (zoom) histogram, on top right, corresponds to the current zoom window, a sub-range of the event set.
+
+The x-axis of each histogram corresponds to the event timestamps. The start time and end time of the histogram range is displayed. The y-axis shows the maximum number of events in the corresponding histogram bars.
-* '''Current Event (sec)''': Displays the current time or selected time range begin time
-* '''Window Span (sec)''': Displays the current time range window size
+The vertical blue line(s) show the current selection time (or range). If applicable, the region in the selection range will be shaded.
-Both control can be used to modify their respective value. After validation, the other controls and views will be synchronized and updated accordingly.
+The mouse can be used to control the histogram:
-The large histogram, at the bottom, shows the event distribution over the whole trace or set of traces. It also has a smaller semi-transparent window, with a cross-hair, that shows the currently selected time range window. The time range window can be zoomed in/out by using the mouse wheel. It can also be selected by the mouse and dragged to another region of the trace.
+* '''Left-click''': Set a selection time
+* '''Left-drag''': Set a selection range
+* '''Shift-left-click or drag''': Extend or shrink the selection range
-The smaller histogram, on top right, corresponds to the currently selected time range window, a sub-range of the event set. Its size can also be zoomed in/out using the mouse wheel.
+* '''Middle-click or Ctrl-left-click''': Center the zoom window on mouse (full histogram only)
+* '''Middle-drag or Ctrl-left-drag''': Move the zoom window
-The x-axis of each histogram corresponds to the events timestamps. The timestamp of the first and the last event of the respective ranges is displayed. The y-axis of each histogram shows the minimum/maximum number of events in the corresponding histogram bars.
+* '''Right-drag''': Set the zoom window
+* '''Shift-right-click or drag''': Extend or shrink the zoom window (full histogram only)
-The dashed vertical magenta bar, on the right, shows the position of the last event. The vertical blue bar shows the currently selected time. The current time can be changed by clicking on the histogram. Shift-clicking the histogram will select a time range, in which case there will be vertical blue bars at the begin and end time and the region in between will be shaded.
+* '''Mouse wheel up''': Zoom in
+* '''Mouse wheel down''': Zoom out
-Hovering the mouse over an histogram bar pops up an information window that displays the start/end time of the corresponding bar as well as the number of events it represents.
+Hovering the mouse over an histogram bar pops up an information window that displays the start/end time of the corresponding bar, as well as the number of events (and lost events) it represents. If the mouse is over the selection range, the selection span in seconds is displayed.
In each histogram, the following keys are handled:
-* '''Left''': Moves the current event to the previous non-empty bar
-* '''Right''': Moves the current event to the next non-empty bar
-* '''Home''': Sets the current time to the first histogram bar
+* '''Left Arrow''': Moves the current event to the previous non-empty bar
+* '''Right Arrow''': Moves the current event to the next non-empty bar
+* '''Home''': Sets the current time to the first non-empty bar
* '''End''': Sets the current time to the last non-empty histogram bar
== Statistics View ==