<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head><meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>[269583] trunk/Source/WebCore</title>
</head>
<body>

<style type="text/css"><!--
#msg dl.meta { border: 1px #006 solid; background: #369; padding: 6px; color: #fff; }
#msg dl.meta dt { float: left; width: 6em; font-weight: bold; }
#msg dt:after { content:':';}
#msg dl, #msg dt, #msg ul, #msg li, #header, #footer, #logmsg { font-family: verdana,arial,helvetica,sans-serif; font-size: 10pt;  }
#msg dl a { font-weight: bold}
#msg dl a:link    { color:#fc3; }
#msg dl a:active  { color:#ff0; }
#msg dl a:visited { color:#cc6; }
h3 { font-family: verdana,arial,helvetica,sans-serif; font-size: 10pt; font-weight: bold; }
#msg pre { overflow: auto; background: #ffc; border: 1px #fa0 solid; padding: 6px; }
#logmsg { background: #ffc; border: 1px #fa0 solid; padding: 1em 1em 0 1em; }
#logmsg p, #logmsg pre, #logmsg blockquote { margin: 0 0 1em 0; }
#logmsg p, #logmsg li, #logmsg dt, #logmsg dd { line-height: 14pt; }
#logmsg h1, #logmsg h2, #logmsg h3, #logmsg h4, #logmsg h5, #logmsg h6 { margin: .5em 0; }
#logmsg h1:first-child, #logmsg h2:first-child, #logmsg h3:first-child, #logmsg h4:first-child, #logmsg h5:first-child, #logmsg h6:first-child { margin-top: 0; }
#logmsg ul, #logmsg ol { padding: 0; list-style-position: inside; margin: 0 0 0 1em; }
#logmsg ul { text-indent: -1em; padding-left: 1em; }#logmsg ol { text-indent: -1.5em; padding-left: 1.5em; }
#logmsg > ul, #logmsg > ol { margin: 0 0 1em 0; }
#logmsg pre { background: #eee; padding: 1em; }
#logmsg blockquote { border: 1px solid #fa0; border-left-width: 10px; padding: 1em 1em 0 1em; background: white;}
#logmsg dl { margin: 0; }
#logmsg dt { font-weight: bold; }
#logmsg dd { margin: 0; padding: 0 0 0.5em 0; }
#logmsg dd:before { content:'\00bb';}
#logmsg table { border-spacing: 0px; border-collapse: collapse; border-top: 4px solid #fa0; border-bottom: 1px solid #fa0; background: #fff; }
#logmsg table th { text-align: left; font-weight: normal; padding: 0.2em 0.5em; border-top: 1px dotted #fa0; }
#logmsg table td { text-align: right; border-top: 1px dotted #fa0; padding: 0.2em 0.5em; }
#logmsg table thead th { text-align: center; border-bottom: 1px solid #fa0; }
#logmsg table th.Corner { text-align: left; }
#logmsg hr { border: none 0; border-top: 2px dashed #fa0; height: 1px; }
#header, #footer { color: #fff; background: #636; border: 1px #300 solid; padding: 6px; }
#patch { width: 100%; }
#patch h4 {font-family: verdana,arial,helvetica,sans-serif;font-size:10pt;padding:8px;background:#369;color:#fff;margin:0;}
#patch .propset h4, #patch .binary h4 {margin:0;}
#patch pre {padding:0;line-height:1.2em;margin:0;}
#patch .diff {width:100%;background:#eee;padding: 0 0 10px 0;overflow:auto;}
#patch .propset .diff, #patch .binary .diff  {padding:10px 0;}
#patch span {display:block;padding:0 10px;}
#patch .modfile, #patch .addfile, #patch .delfile, #patch .propset, #patch .binary, #patch .copfile {border:1px solid #ccc;margin:10px 0;}
#patch ins {background:#dfd;text-decoration:none;display:block;padding:0 10px;}
#patch del {background:#fdd;text-decoration:none;display:block;padding:0 10px;}
#patch .lines, .info {color:#888;background:#fff;}
--></style>
<div id="msg">
<dl class="meta">
<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/269583">269583</a></dd>
<dt>Author</dt> <dd>clord@igalia.com</dd>
<dt>Date</dt> <dd>2020-11-09 09:55:07 -0800 (Mon, 09 Nov 2020)</dd>
</dl>

<h3>Log Message</h3>
<pre>[GTK] kinetic scroll speed should be cumulative
https://bugs.webkit.org/show_bug.cgi?id=203914

Reviewed by Carlos Garcia Campos.

Accumulate velocity in the same direction with ScrollAnimationKinetic.

* platform/ScrollAnimationKinetic.cpp:
(WebCore::ScrollAnimationKinetic::stop):
(WebCore::ScrollAnimationKinetic::start):
(WebCore::ScrollAnimationKinetic::animationTimerFired):
(WebCore::ScrollAnimationKinetic::deltaToNextFrame):
* platform/ScrollAnimationKinetic.h:</pre>

<h3>Modified Paths</h3>
<ul>
<li><a href="#trunkSourceWebCoreChangeLog">trunk/Source/WebCore/ChangeLog</a></li>
<li><a href="#trunkSourceWebCoreplatformScrollAnimationKineticcpp">trunk/Source/WebCore/platform/ScrollAnimationKinetic.cpp</a></li>
<li><a href="#trunkSourceWebCoreplatformScrollAnimationKinetich">trunk/Source/WebCore/platform/ScrollAnimationKinetic.h</a></li>
</ul>

</div>
<div id="patch">
<h3>Diff</h3>
<a id="trunkSourceWebCoreChangeLog"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/ChangeLog (269582 => 269583)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/ChangeLog   2020-11-09 17:26:43 UTC (rev 269582)
+++ trunk/Source/WebCore/ChangeLog      2020-11-09 17:55:07 UTC (rev 269583)
</span><span class="lines">@@ -1,3 +1,19 @@
</span><ins>+2020-11-09  Chris Lord  <clord@igalia.com>
+
+        [GTK] kinetic scroll speed should be cumulative
+        https://bugs.webkit.org/show_bug.cgi?id=203914
+
+        Reviewed by Carlos Garcia Campos.
+
+        Accumulate velocity in the same direction with ScrollAnimationKinetic.
+
+        * platform/ScrollAnimationKinetic.cpp:
+        (WebCore::ScrollAnimationKinetic::stop):
+        (WebCore::ScrollAnimationKinetic::start):
+        (WebCore::ScrollAnimationKinetic::animationTimerFired):
+        (WebCore::ScrollAnimationKinetic::deltaToNextFrame):
+        * platform/ScrollAnimationKinetic.h:
+
</ins><span class="cx"> 2020-11-09  Chris Dumez  <cdumez@apple.com>
</span><span class="cx"> 
</span><span class="cx">         Look at parents when event bubbles for input element activation behavior
</span></span></pre></div>
<a id="trunkSourceWebCoreplatformScrollAnimationKineticcpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/platform/ScrollAnimationKinetic.cpp (269582 => 269583)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/platform/ScrollAnimationKinetic.cpp 2020-11-09 17:26:43 UTC (rev 269582)
+++ trunk/Source/WebCore/platform/ScrollAnimationKinetic.cpp    2020-11-09 17:55:07 UTC (rev 269583)
</span><span class="lines">@@ -65,11 +65,14 @@
</span><span class="cx">  *   f2(x) = t exp(-mx / 2)
</span><span class="cx">  */
</span><span class="cx"> 
</span><del>-static const double decelFriction = 4;
-static const double frameRate = 60;
-static const Seconds tickTime = 1_s / frameRate;
-static const Seconds minimumTimerInterval { 1_ms };
-static const Seconds scrollCaptureThreshold { 150_ms };
</del><ins>+static constexpr double decelFriction = 4;
+static constexpr double frameRate = 60;
+static constexpr double velocityAccumulationFloor = 0.33;
+static constexpr double velocityAccumulationCeil = 1.0;
+static constexpr double velocityAccumulationMax = 6.0;
+static constexpr Seconds tickTime = 1_s / frameRate;
+static constexpr Seconds minimumTimerInterval { 1_ms };
+static constexpr Seconds scrollCaptureThreshold { 150_ms };
</ins><span class="cx"> 
</span><span class="cx"> namespace WebCore {
</span><span class="cx"> 
</span><span class="lines">@@ -124,8 +127,6 @@
</span><span class="cx"> void ScrollAnimationKinetic::stop()
</span><span class="cx"> {
</span><span class="cx">     m_animationTimer.stop();
</span><del>-    m_horizontalData = WTF::nullopt;
-    m_verticalData = WTF::nullopt;
</del><span class="cx"> }
</span><span class="cx"> 
</span><span class="cx"> bool ScrollAnimationKinetic::isActive() const
</span><span class="lines">@@ -171,23 +172,46 @@
</span><span class="cx"> {
</span><span class="cx">     stop();
</span><span class="cx"> 
</span><del>-    m_position = initialPosition;
-
-    if (!velocity.x() && !velocity.y())
</del><ins>+    if (!velocity.x() && !velocity.y()) {
+        m_position = initialPosition;
+        m_horizontalData = WTF::nullopt;
+        m_verticalData = WTF::nullopt;
</ins><span class="cx">         return;
</span><ins>+    }
</ins><span class="cx"> 
</span><ins>+    auto delta = deltaToNextFrame();
</ins><span class="cx">     auto extents = m_scrollExtentsFunction();
</span><ins>+
+    auto accumulateVelocity = [&](double velocity, Optional<PerAxisData> axisData) -> double {
+        if (axisData && axisData.value().animateScroll(delta)) {
+            double lastVelocity = axisData.value().velocity();
+            if ((std::signbit(lastVelocity) == std::signbit(velocity))
+                && (std::abs(velocity) >= std::abs(lastVelocity * velocityAccumulationFloor))) {
+                double minVelocity = lastVelocity * velocityAccumulationFloor;
+                double maxVelocity = lastVelocity * velocityAccumulationCeil;
+                double accumulationMultiplier = (velocity - minVelocity) / (maxVelocity - minVelocity);
+                velocity += lastVelocity * std::min(accumulationMultiplier, velocityAccumulationMax);
+            }
+        }
+
+        return velocity;
+    };
+
</ins><span class="cx">     if (mayHScroll) {
</span><span class="cx">         m_horizontalData = PerAxisData(extents.minimumScrollPosition.x(),
</span><span class="cx">             extents.maximumScrollPosition.x(),
</span><del>-            initialPosition.x(), velocity.x());
-    }
</del><ins>+            initialPosition.x(), accumulateVelocity(velocity.x(), m_horizontalData));
+    } else
+        m_horizontalData = WTF::nullopt;
+
</ins><span class="cx">     if (mayVScroll) {
</span><span class="cx">         m_verticalData = PerAxisData(extents.minimumScrollPosition.y(),
</span><span class="cx">             extents.maximumScrollPosition.y(),
</span><del>-            initialPosition.y(), velocity.y());
-    }
</del><ins>+            initialPosition.y(), accumulateVelocity(velocity.y(), m_verticalData));
+    } else
+        m_verticalData = WTF::nullopt;
</ins><span class="cx"> 
</span><ins>+    m_position = initialPosition;
</ins><span class="cx">     m_startTime = MonotonicTime::now() - tickTime / 2.;
</span><span class="cx">     animationTimerFired();
</span><span class="cx"> }
</span><span class="lines">@@ -194,18 +218,17 @@
</span><span class="cx"> 
</span><span class="cx"> void ScrollAnimationKinetic::animationTimerFired()
</span><span class="cx"> {
</span><del>-    MonotonicTime currentTime = MonotonicTime::now();
-    Seconds deltaToNextFrame = 1_s * ceil((currentTime - m_startTime).value() * frameRate) / frameRate - (currentTime - m_startTime);
</del><ins>+    auto delta = deltaToNextFrame();
</ins><span class="cx"> 
</span><del>-    if (m_horizontalData && !m_horizontalData.value().animateScroll(deltaToNextFrame))
</del><ins>+    if (m_horizontalData && !m_horizontalData.value().animateScroll(delta))
</ins><span class="cx">         m_horizontalData = WTF::nullopt;
</span><span class="cx"> 
</span><del>-    if (m_verticalData && !m_verticalData.value().animateScroll(deltaToNextFrame))
</del><ins>+    if (m_verticalData && !m_verticalData.value().animateScroll(delta))
</ins><span class="cx">         m_verticalData = WTF::nullopt;
</span><span class="cx"> 
</span><span class="cx">     // If one of the axes didn't finish its animation we must continue it.
</span><span class="cx">     if (m_horizontalData || m_verticalData)
</span><del>-        m_animationTimer.startOneShot(std::max(minimumTimerInterval, deltaToNextFrame));
</del><ins>+        m_animationTimer.startOneShot(std::max(minimumTimerInterval, delta));
</ins><span class="cx"> 
</span><span class="cx">     double x = m_horizontalData ? m_horizontalData.value().position() : m_position.x();
</span><span class="cx">     double y = m_verticalData ? m_verticalData.value().position() : m_position.y();
</span><span class="lines">@@ -213,4 +236,10 @@
</span><span class="cx">     m_notifyPositionChangedFunction(FloatPoint(m_position));
</span><span class="cx"> }
</span><span class="cx"> 
</span><ins>+Seconds ScrollAnimationKinetic::deltaToNextFrame()
+{
+    MonotonicTime currentTime = MonotonicTime::now();
+    return 1_s * ceil((currentTime - m_startTime).value() * frameRate) / frameRate - (currentTime - m_startTime);
+}
+
</ins><span class="cx"> } // namespace WebCore
</span></span></pre></div>
<a id="trunkSourceWebCoreplatformScrollAnimationKinetich"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/platform/ScrollAnimationKinetic.h (269582 => 269583)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/platform/ScrollAnimationKinetic.h   2020-11-09 17:26:43 UTC (rev 269582)
+++ trunk/Source/WebCore/platform/ScrollAnimationKinetic.h      2020-11-09 17:55:07 UTC (rev 269583)
</span><span class="lines">@@ -42,6 +42,7 @@
</span><span class="cx">         PerAxisData(double lower, double upper, double initialPosition, double initialVelocity);
</span><span class="cx"> 
</span><span class="cx">         double position() { return m_position; }
</span><ins>+        double velocity() { return m_velocity; }
</ins><span class="cx"> 
</span><span class="cx">         bool animateScroll(Seconds timeDelta);
</span><span class="cx"> 
</span><span class="lines">@@ -74,6 +75,7 @@
</span><span class="cx"> 
</span><span class="cx"> private:
</span><span class="cx">     void animationTimerFired();
</span><ins>+    Seconds deltaToNextFrame();
</ins><span class="cx"> 
</span><span class="cx">     ScrollExtentsCallback m_scrollExtentsFunction;
</span><span class="cx">     NotifyPositionChangedCallback m_notifyPositionChangedFunction;
</span></span></pre>
</div>
</div>

</body>
</html>