A utility class for profiling regular updates. Times the length of each update as well as the idle periods between updates. For both, tracks the minimum, average and maximum times. All times are in milliseconds.
| Signature | Description |
|---|---|
| Seadragon.Profiler() | Creates a Profiler. |
| Name and Signature | Return Type | Description |
|---|---|---|
| isMidUpdate() | Boolean | Returns true if an update has begun but has not yet ended. |
| getNumUpdates() | Number | Returns the number of updates that have been profiled. |
| Name and Signature | Return Type | Description |
|---|---|---|
| getAvgUpdateTime() | Number | Returns the average length of each update. |
| getMinUpdateTime() | Number | Returns the length of the shortest update. |
| getMaxUpdateTime() | Number | Returns the length of the longest update. |
| Name and Signature | Return Type | Description |
|---|---|---|
| getAvgIdleTime() | Number | Returns the average length of each idle period between two updates. |
| getMinIdleTime() | Number | Returns the length of the shortest idle period between two updates. |
| getMaxIdleTime() | Number | Returns the length of the longest idle period between two updates. |
| Name and Signature | Return Type | Description |
|---|---|---|
| beginUpdate() | - | Signals to the Profiler that an update has begun. |
| endUpdate() | - | Signals to the Profiler that the last update has ended. |
| clearProfile() | - | Clears all previously tracked information. |
The following code profiles an update function. The function is run on a timer, and the average update time is shown when a button is clicked.
var profiler = new Seadragon.Profiler(); var button = document.getElementById("show_profile_button"); function update() { profiler.beginUpdate(); ... profiler.endUpdate(); } window.setInterval(update, 50); Seadragon.Utils.addEvent(button, "click", function() { alert("Average update time = " + profiler.getAvgUpdateTime()); });
The following code shows a computed updates per second value.
function showProfile(profiler) { var period = profiler.getAvgUpdateTime() + profiler.getAvgIdleTime(); var freq = 1000 / period; // 1000 milliseconds in 1 second alert("Averaging " + freq + " updates per second over " + profiler.getNumUpdates() + " updates."); }