Implement chat filter design feedback.

app/src/main/java/org/thoughtcrime/securesms/conversationlist/ConversationListFragment.java

@@ -115,6 +115,7 @@ import org.thoughtcrime.securesms.contacts.sync.CdsPermanentErrorBottomSheet;
 import org.thoughtcrime.securesms.contacts.sync.CdsTemporaryErrorBottomSheet;
 import org.thoughtcrime.securesms.conversation.ConversationFragment;
 import org.thoughtcrime.securesms.conversationlist.chatfilter.ConversationListFilterPullView;
+import org.thoughtcrime.securesms.conversationlist.chatfilter.FilterLerp;
 import org.thoughtcrime.securesms.conversationlist.model.Conversation;
 import org.thoughtcrime.securesms.conversationlist.model.UnreadPayments;
 import org.thoughtcrime.securesms.database.MessageTable.MarkedMessageInfo;
@@ -280,7 +281,7 @@ public class ConversationListFragment extends MainFragment implements ActionMode
     cameraFab.setVisibility(View.VISIBLE);
 
     CollapsingToolbarLayout collapsingToolbarLayout = view.findViewById(R.id.collapsing_toolbar);
-    int                     minHeight               = (int) DimensionUnit.DP.toPixels(52);
+    int                     openHeight              = (int) DimensionUnit.DP.toPixels(FilterLerp.FILTER_OPEN_HEIGHT);
 
     pullView.setOnFilterStateChanged(state -> {
       switch (state) {
@@ -291,7 +292,7 @@ public class ConversationListFragment extends MainFragment implements ActionMode
           viewModel.setFiltered(true);
           break;
         case OPEN_APEX:
-          ViewUtil.setMinimumHeight(collapsingToolbarLayout, minHeight);
+          ViewUtil.setMinimumHeight(collapsingToolbarLayout, openHeight);
           break;
         case CLOSE_APEX:
           ViewUtil.setMinimumHeight(collapsingToolbarLayout, 0);

app/src/main/java/org/thoughtcrime/securesms/conversationlist/chatfilter/ConversationListFilterPullView.kt

@@ -7,9 +7,9 @@ import android.content.Context
 import android.util.AttributeSet
 import android.widget.FrameLayout
 import androidx.core.animation.doOnEnd
-import org.signal.core.util.dp
 import org.thoughtcrime.securesms.R
 import org.thoughtcrime.securesms.databinding.ConversationListFilterPullViewBinding
+import org.thoughtcrime.securesms.util.VibrateUtil
 
 /**
  * Encapsulates the push / pull latch for enabling and disabling
@@ -51,13 +51,14 @@ class ConversationListFilterPullView @JvmOverloads constructor(
       setState(FilterPullState.CLOSED)
     } else if (state == FilterPullState.CLOSED && progress >= 1f) {
       setState(FilterPullState.OPEN_APEX)
+      vibrate()
     } else if (state == FilterPullState.OPEN && progress >= 1f) {
       setState(FilterPullState.CLOSE_APEX)
+      vibrate()
     }
 
-    // If we are pulling toward the open apex
-    if (state == FilterPullState.OPEN || state == FilterPullState.CLOSE_APEX || state == FilterPullState.CLOSING) {
-      binding.filterText.translationY = EVAL.evaluate(progress, 26.dp, -24.dp.toFloat())
+    if (state == FilterPullState.OPEN || state == FilterPullState.OPEN_APEX || state == FilterPullState.CLOSE_APEX || state == FilterPullState.CLOSING) {
+      binding.filterText.translationY = FilterLerp.getPillLerp(progress)
     } else {
       binding.filterText.translationY = 0f
     }
@@ -130,6 +131,12 @@ class ConversationListFilterPullView @JvmOverloads constructor(
     onFilterStateChanged?.newState(state)
   }
 
+  private fun vibrate() {
+    if (VibrateUtil.isHapticFeedbackEnabled(context)) {
+      VibrateUtil.vibrateTick(context)
+    }
+  }
+
   interface OnFilterStateChanged {
     fun newState(state: FilterPullState)
   }

app/src/main/java/org/thoughtcrime/securesms/conversationlist/chatfilter/FilterCircleView.kt

@@ -175,8 +175,8 @@ class FilterCircleView @JvmOverloads constructor(
 
   private fun evaluateBottomOffset(progress: Float, state: FilterPullState): Float {
     return when (state) {
-      FilterPullState.OPEN_APEX, FilterPullState.OPENING, FilterPullState.OPEN, FilterPullState.CLOSE_APEX -> CIRCLE_Y_EVALUATOR.evaluate(progress, (-46).dp, 55.dp)
-      FilterPullState.CLOSED, FilterPullState.CLOSING -> CIRCLE_Y_EVALUATOR.evaluate(progress, 0.dp, 55.dp)
+      FilterPullState.OPEN_APEX, FilterPullState.OPENING, FilterPullState.OPEN, FilterPullState.CLOSE_APEX -> FilterLerp.getOpenCircleBottomPadLerp(progress)
+      FilterPullState.CLOSED, FilterPullState.CLOSING -> FilterLerp.getClosedCircleBottomPadLerp(progress)
     }
   }
 

app/src/main/java/org/thoughtcrime/securesms/conversationlist/chatfilter/FilterLerp.kt

@@ -0,0 +1,107 @@
+package org.thoughtcrime.securesms.conversationlist.chatfilter
+
+import android.animation.FloatEvaluator
+import org.signal.core.util.dp
+
+/**
+ * Centralized location for filter view linear interpolations.
+ */
+object FilterLerp {
+
+  /**
+   * The minimum height of the filter pull when the filter is open.
+   */
+  const val FILTER_OPEN_HEIGHT = 52f
+
+  /**
+   * The maximum height of the filter pull. Note that this should match
+   * whatever value is set to in XML.
+   */
+  private const val FILTER_APEX = 130f
+
+  private val EVAL = FloatEvaluator()
+
+  private val PILL_LERP = getFn(
+    Point(FILTER_OPEN_HEIGHT / FILTER_APEX, 0f),
+    Point(1f, ((FILTER_OPEN_HEIGHT - FILTER_APEX) / 2))
+  )
+
+  private val OPEN_CIRCLE_BOTTOM_PAD_LERP = getFn(
+    Point(FILTER_OPEN_HEIGHT / FILTER_APEX, 8f),
+    Point(1f, FILTER_APEX * 0.55f)
+  )
+
+  private val CLOSED_CIRCLE_BOTTOM_PAD_LERP = getFn(
+    Point(0f, 0f),
+    Point(1f, FILTER_APEX * 0.55f)
+  )
+
+  /**
+   * Get the LERP for the "Filter enabled" pill.
+   */
+  fun getPillLerp(fraction: Float): Float {
+    return getLerp(fraction, PILL_LERP)
+  }
+
+  /**
+   * Get the LERP for the padding below the filter circle when the filter is open
+   */
+  fun getOpenCircleBottomPadLerp(fraction: Float): Float {
+    return getLerp(fraction, OPEN_CIRCLE_BOTTOM_PAD_LERP)
+  }
+
+  /**
+   * Get the LERP for the padding below the filter circle when the filter is closed
+   */
+  fun getClosedCircleBottomPadLerp(fraction: Float): Float {
+    return getLerp(fraction, CLOSED_CIRCLE_BOTTOM_PAD_LERP)
+  }
+
+  private fun getLerp(fraction: Float, fn: Fn): Float {
+    return EVAL.evaluate(fraction, fn(0f), fn(1f)).dp
+  }
+
+  /**
+   * Gets the linear slope between two points using:
+   *
+   * m = (y2 - y1) / (x2 - x1)
+   */
+  private fun getSlope(
+    a: Point,
+    b: Point
+  ): Float = (b.y - a.y) / (b.x - a.x)
+
+  /**
+   * Gets the y-intercept between two points using:
+   *
+   * b = y - mx
+   */
+  private fun getYIntercept(
+    a: Point,
+    b: Point
+  ): Float = a.y - getSlope(a, b) * a.x
+
+  /**
+   * For a given set of points, generates a function in the form
+   *
+   * y = mx + b
+   */
+  private fun getFn(
+    a: Point,
+    b: Point
+  ): Fn = Fn(getSlope(a, b), getYIntercept(a, b))
+
+  /**
+   * 2D cartesian coordinate.
+   */
+  data class Point(val x: Float, val y: Float)
+
+  /**
+   * LERP function defined as y = mx + b
+   */
+  data class Fn(val m: Float, val b: Float) {
+    operator fun invoke(x: Float): Float {
+      return m * x + b
+    }
+  }
+}

app/src/main/java/org/thoughtcrime/securesms/util/VibrateUtil.java

@@ -4,6 +4,7 @@ import android.content.Context;
 import android.os.Build;
 import android.os.VibrationEffect;
 import android.os.Vibrator;
+import android.provider.Settings;
 
 import androidx.annotation.NonNull;
 
@@ -27,4 +28,10 @@ public final class VibrateUtil {
       vibrator.vibrate(duration);
     }
   }
+
+  public static boolean isHapticFeedbackEnabled(@NonNull Context context) {
+      int enabled = Settings.System.getInt(context.getContentResolver(),
+                                           android.provider.Settings.System.HAPTIC_FEEDBACK_ENABLED, 0);
+      return enabled != 0;
+  }
 }

app/src/main/res/layout/conversation_list_fragment.xml

@@ -63,7 +63,7 @@
                 <org.thoughtcrime.securesms.conversationlist.chatfilter.ConversationListFilterPullView
                     android:id="@+id/pull_view"
                     android:layout_width="match_parent"
-                    android:layout_height="100dp"
+                    android:layout_height="130dp"
                     android:background="@color/signal_colorBackground"
                     app:layout_scrollInterpolator="@android:anim/linear_interpolator" />