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| <html><head><title>Python: module telemetry.web_perf.metrics.smoothness</title> |
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| <td valign=bottom> <br> |
| <font color="#ffffff" face="helvetica, arial"> <br><big><big><strong><a href="telemetry.html"><font color="#ffffff">telemetry</font></a>.<a href="telemetry.web_perf.html"><font color="#ffffff">web_perf</font></a>.<a href="telemetry.web_perf.metrics.html"><font color="#ffffff">metrics</font></a>.smoothness</strong></big></big></font></td |
| ><td align=right valign=bottom |
| ><font color="#ffffff" face="helvetica, arial"><a href=".">index</a><br><a href="../telemetry/web_perf/metrics/smoothness.py">telemetry/web_perf/metrics/smoothness.py</a></font></td></tr></table> |
| <p><tt># Copyright 2014 The Chromium Authors. All rights reserved.<br> |
| # Use of this source code is governed by a BSD-style license that can be<br> |
| # found in the LICENSE file.</tt></p> |
| <p> |
| <table width="100%" cellspacing=0 cellpadding=2 border=0 summary="section"> |
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| <font color="#ffffff" face="helvetica, arial"><big><strong>Modules</strong></big></font></td></tr> |
| |
| <tr><td bgcolor="#aa55cc"><tt> </tt></td><td> </td> |
| <td width="100%"><table width="100%" summary="list"><tr><td width="25%" valign=top><a href="telemetry.value.improvement_direction.html">telemetry.value.improvement_direction</a><br> |
| <a href="telemetry.value.list_of_scalar_values.html">telemetry.value.list_of_scalar_values</a><br> |
| </td><td width="25%" valign=top><a href="logging.html">logging</a><br> |
| <a href="telemetry.util.perf_tests_helper.html">telemetry.util.perf_tests_helper</a><br> |
| </td><td width="25%" valign=top><a href="telemetry.web_perf.metrics.rendering_stats.html">telemetry.web_perf.metrics.rendering_stats</a><br> |
| <a href="telemetry.value.scalar.html">telemetry.value.scalar</a><br> |
| </td><td width="25%" valign=top><a href="telemetry.util.statistics.html">telemetry.util.statistics</a><br> |
| <a href="telemetry.web_perf.metrics.timeline_based_metric.html">telemetry.web_perf.metrics.timeline_based_metric</a><br> |
| </td></tr></table></td></tr></table><p> |
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| <font color="#ffffff" face="helvetica, arial"><big><strong>Classes</strong></big></font></td></tr> |
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| <tr><td bgcolor="#ee77aa"><tt> </tt></td><td> </td> |
| <td width="100%"><dl> |
| <dt><font face="helvetica, arial"><a href="telemetry.web_perf.metrics.timeline_based_metric.html#TimelineBasedMetric">telemetry.web_perf.metrics.timeline_based_metric.TimelineBasedMetric</a>(<a href="__builtin__.html#object">__builtin__.object</a>) |
| </font></dt><dd> |
| <dl> |
| <dt><font face="helvetica, arial"><a href="telemetry.web_perf.metrics.smoothness.html#SmoothnessMetric">SmoothnessMetric</a> |
| </font></dt></dl> |
| </dd> |
| </dl> |
| <p> |
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| <font color="#000000" face="helvetica, arial"><a name="SmoothnessMetric">class <strong>SmoothnessMetric</strong></a>(<a href="telemetry.web_perf.metrics.timeline_based_metric.html#TimelineBasedMetric">telemetry.web_perf.metrics.timeline_based_metric.TimelineBasedMetric</a>)</font></td></tr> |
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| <tr bgcolor="#ffc8d8"><td rowspan=2><tt> </tt></td> |
| <td colspan=2><tt>Computes metrics that measure smoothness of animations over given ranges.<br> |
| <br> |
| Animations are typically considered smooth if the frame rates are close to<br> |
| 60 frames per second (fps) and uniformly distributed over the sequence. To<br> |
| determine if a timeline range contains a smooth animation, we update the<br> |
| results object with several representative metrics:<br> |
| <br> |
| frame_times: A list of raw frame times<br> |
| mean_frame_time: The arithmetic mean of frame times<br> |
| percentage_smooth: Percentage of frames that were hitting 60 FPS.<br> |
| frame_time_discrepancy: The absolute discrepancy of frame timestamps<br> |
| mean_pixels_approximated: The mean percentage of pixels approximated<br> |
| queueing_durations: The queueing delay between compositor & main threads<br> |
| <br> |
| Note that if any of the interaction records provided to AddResults have less<br> |
| than 2 frames, we will return telemetry values with None values for each of<br> |
| the smoothness metrics. Similarly, older browsers without support for<br> |
| tracking the BeginMainFrame events will report a ListOfScalarValues with a<br> |
| None value for the queueing duration metric.<br> </tt></td></tr> |
| <tr><td> </td> |
| <td width="100%"><dl><dt>Method resolution order:</dt> |
| <dd><a href="telemetry.web_perf.metrics.smoothness.html#SmoothnessMetric">SmoothnessMetric</a></dd> |
| <dd><a href="telemetry.web_perf.metrics.timeline_based_metric.html#TimelineBasedMetric">telemetry.web_perf.metrics.timeline_based_metric.TimelineBasedMetric</a></dd> |
| <dd><a href="__builtin__.html#object">__builtin__.object</a></dd> |
| </dl> |
| <hr> |
| Methods defined here:<br> |
| <dl><dt><a name="SmoothnessMetric-AddResults"><strong>AddResults</strong></a>(self, model, renderer_thread, interaction_records, results)</dt></dl> |
| |
| <dl><dt><a name="SmoothnessMetric-__init__"><strong>__init__</strong></a>(self)</dt></dl> |
| |
| <hr> |
| Methods inherited from <a href="telemetry.web_perf.metrics.timeline_based_metric.html#TimelineBasedMetric">telemetry.web_perf.metrics.timeline_based_metric.TimelineBasedMetric</a>:<br> |
| <dl><dt><a name="SmoothnessMetric-AddWholeTraceResults"><strong>AddWholeTraceResults</strong></a>(self, model, results)</dt><dd><tt>Computes and adds metrics corresponding to the entire trace.<br> |
| <br> |
| Override this method to compute results that correspond to the whole trace.<br> |
| <br> |
| Args:<br> |
| model: An instance of telemetry.timeline.model.TimelineModel.<br> |
| results: An instance of page.PageTestResults.</tt></dd></dl> |
| |
| <dl><dt><a name="SmoothnessMetric-VerifyNonOverlappedRecords"><strong>VerifyNonOverlappedRecords</strong></a>(self, interaction_records)</dt><dd><tt>This raises exceptions if interaction_records contain overlapped ranges.</tt></dd></dl> |
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| <hr> |
| Data descriptors inherited from <a href="telemetry.web_perf.metrics.timeline_based_metric.html#TimelineBasedMetric">telemetry.web_perf.metrics.timeline_based_metric.TimelineBasedMetric</a>:<br> |
| <dl><dt><strong>__dict__</strong></dt> |
| <dd><tt>dictionary for instance variables (if defined)</tt></dd> |
| </dl> |
| <dl><dt><strong>__weakref__</strong></dt> |
| <dd><tt>list of weak references to the object (if defined)</tt></dd> |
| </dl> |
| </td></tr></table></td></tr></table><p> |
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| <font color="#ffffff" face="helvetica, arial"><big><strong>Data</strong></big></font></td></tr> |
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| <tr><td bgcolor="#55aa55"><tt> </tt></td><td> </td> |
| <td width="100%"><strong>NOT_ENOUGH_FRAMES_MESSAGE</strong> = "Not enough frames for smoothness metrics (at lea...der extremely slow<font color="#c040c0">\n</font>- Pages that can't be scrolled"</td></tr></table> |
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