Fix keepGoing when a work area is used.

Fixes an issue introduced here https://github.com/rive-app/rive/pull/5849 where we added some extra smarts to keepGoing which didn't take the work area into account.

Adds tests to both editor and runtime!

Diffs=
853ae7de1 Fix keepGoing when a work area is used. (#5939)

Co-authored-by: Luigi Rosso <luigi-rosso@users.noreply.github.com>

.rive_head

diff --git a/.rive_head b/.rive_head
index 6b700cd..290281e 100644
--- a/.rive_head
+++ b/.rive_head
@@ -1 +1 @@
-33aec1b20028fed8d1cf790378db26241212784f
+853ae7de1d020bc13e84359f816215764923215c

include/rive/animation/linear_animation_instance.hpp

diff --git a/include/rive/animation/linear_animation_instance.hpp b/include/rive/animation/linear_animation_instance.hpp
index 36656d5..d7f6b25 100644
--- a/include/rive/animation/linear_animation_instance.hpp
+++ b/include/rive/animation/linear_animation_instance.hpp
@@ -31,6 +31,9 @@
     // Returns the direction that we are currently playing in
     float direction() const { return m_direction; }
 
+    // Returns speed in the current direction of the animation.
+    float directedSpeed() const { return m_direction * speed(); }
+
     // Update the direction of the animation instance, positive value for
     // forwards Negative for backwards
     void direction(int direction)
@@ -60,8 +63,8 @@
     bool keepGoing() const
     {
         return this->loopValue() != static_cast<int>(rive::Loop::oneShot) ||
-               (m_direction > 0 && m_time < m_animation->durationSeconds()) ||
-               (m_direction < 0 && m_time > 0);
+               (directedSpeed() > 0 && m_time < m_animation->endSeconds()) ||
+               (directedSpeed() < 0 && m_time > m_animation->startSeconds());
     }
 
     float totalTime() const { return m_totalTime; }

test/linear_animation_test.cpp

diff --git a/test/linear_animation_test.cpp b/test/linear_animation_test.cpp
index 8b073ce..fe59c28 100644
--- a/test/linear_animation_test.cpp
+++ b/test/linear_animation_test.cpp
@@ -1,5 +1,6 @@
 #include <rive/artboard.hpp>
 #include <rive/animation/linear_animation.hpp>
+#include <rive/animation/linear_animation_instance.hpp>
 #include "utils/no_op_factory.hpp"
 #include "rive_file_reader.hpp"
 #include "rive_testing.hpp"
@@ -79,4 +80,32 @@
     animation->quantize(false);
     animation->apply(artboard, 0.5f);
     REQUIRE(ellipse->x() == 200.0f);
+}
+
+TEST_CASE("LinearAnimation reports when to keep going correctly", "[animation]")
+{
+    rive::NoOpFactory emptyFactory;
+    // For each of these tests, we cons up a dummy artboard/instance
+    // just to make the animations happy.
+    rive::Artboard ab(&emptyFactory);
+    auto abi = ab.instance();
+
+    rive::LinearAnimation* linearAnimation = new rive::LinearAnimation();
+    linearAnimation->duration(60);
+    linearAnimation->fps(60);
+    linearAnimation->speed(1);
+    linearAnimation->enableWorkArea(true);
+    linearAnimation->workStart(30);
+    linearAnimation->workEnd(42);
+
+    auto animationInstance = rive::LinearAnimationInstance(linearAnimation, abi.get());
+
+    REQUIRE(animationInstance.advance(0.0f));
+    REQUIRE(animationInstance.time() == 0.5f);
+    REQUIRE(animationInstance.advance(0.1f));
+    REQUIRE(animationInstance.time() == 0.6f);
+    REQUIRE(!animationInstance.advance(0.2f));
+    REQUIRE(animationInstance.time() == 0.7f);
+
+    delete linearAnimation;
 }
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