feat: sliding up player support

lib/components/player/player_overlay.dart

@@ -5,13 +5,15 @@ import 'package:flutter_hooks/flutter_hooks.dart';
 import 'package:go_router/go_router.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
 
-import 'package:spotube/collections/spotube_icons.dart';
 import 'package:spotube/components/player/player_track_details.dart';
+import 'package:spotube/components/root/spotube_navigation_bar.dart';
+import 'package:spotube/components/shared/panels/sliding_up_panel.dart';
+import 'package:spotube/collections/spotube_icons.dart';
 import 'package:spotube/collections/intents.dart';
 import 'package:spotube/hooks/use_progress.dart';
+import 'package:spotube/pages/player/player.dart';
 import 'package:spotube/provider/proxy_playlist/proxy_playlist_provider.dart';
 import 'package:spotube/services/audio_player/audio_player.dart';
-import 'package:spotube/utils/service_utils.dart';
 
 class PlayerOverlay extends HookConsumerWidget {
   final String albumArt;
@@ -39,22 +41,31 @@ class PlayerOverlay extends HookConsumerWidget {
       topRight: Radius.circular(10),
     );
 
-    return GestureDetector(
-      onVerticalDragEnd: (details) {
-        int sensitivity = 8;
-        if (details.primaryVelocity != null &&
-            details.primaryVelocity! < -sensitivity) {
-          ServiceUtils.push(context, "/player");
-        }
+    final mediaQuery = MediaQuery.of(context);
+
+    final panelController = useMemoized(() => PanelController(), []);
+
+    useEffect(() {
+      return () {
+        panelController.dispose();
+      };
+    }, []);
+
+    return SlidingUpPanel(
+      maxHeight: mediaQuery.size.height - mediaQuery.padding.top,
+      backdropEnabled: false,
+      minHeight: canShow ? 53 : 0,
+      onPanelSlide: (position) {
+        final invertedPosition = 1 - position;
+        ref.read(navigationPanelHeight.notifier).state = 50 * invertedPosition;
       },
-      child: ClipRRect(
+      collapsed: ClipRRect(
         borderRadius: radius,
         child: BackdropFilter(
           filter: ImageFilter.blur(sigmaX: 15, sigmaY: 15),
           child: AnimatedContainer(
             duration: const Duration(milliseconds: 250),
-            width: MediaQuery.of(context).size.width,
-            height: canShow ? 53 : 0,
+            width: mediaQuery.size.width,
             decoration: BoxDecoration(
               color: theme.colorScheme.secondaryContainer.withOpacity(.8),
               borderRadius: radius,
@@ -165,6 +176,19 @@ class PlayerOverlay extends HookConsumerWidget {
           ),
         ),
       ),
+      panelBuilder: (position) {
+        final navigationHeight = ref.watch(navigationPanelHeight);
+        if (navigationHeight == 50) return const SizedBox();
+
+        return AnimatedContainer(
+          clipBehavior: Clip.antiAlias,
+          duration: const Duration(milliseconds: 250),
+          decoration: navigationHeight == 0
+              ? const BoxDecoration(borderRadius: BorderRadius.zero)
+              : const BoxDecoration(borderRadius: radius),
+          child: const PlayerView(),
+        );
+      },
     );
   }
 }

lib/components/root/spotube_navigation_bar.dart

@@ -13,6 +13,8 @@ import 'package:spotube/hooks/use_brightness_value.dart';
 import 'package:spotube/provider/download_manager_provider.dart';
 import 'package:spotube/provider/user_preferences_provider.dart';
 
+final navigationPanelHeight = StateProvider<double>((ref) => 50);
+
 class SpotubeNavigationBar extends HookConsumerWidget {
   final int selectedIndex;
   final void Function(int) onSelectedIndexChanged;
@@ -41,6 +43,8 @@ class SpotubeNavigationBar extends HookConsumerWidget {
     final navbarTileList =
         useMemoized(() => getNavbarTileList(context.l10n), [context.l10n]);
 
+    final panelHeight = ref.watch(navigationPanelHeight);
+
     useEffect(() {
       insideSelectedIndex.value = selectedIndex;
       return null;
@@ -51,7 +55,10 @@ class SpotubeNavigationBar extends HookConsumerWidget {
       return const SizedBox();
     }
 
-    return ClipRect(
+    return AnimatedContainer(
+      duration: const Duration(milliseconds: 250),
+      height: panelHeight,
+      child: ClipRect(
         child: BackdropFilter(
           filter: ImageFilter.blur(sigmaX: 15, sigmaY: 15),
           child: CurvedNavigationBar(
@@ -59,7 +66,7 @@ class SpotubeNavigationBar extends HookConsumerWidget {
                 theme.colorScheme.secondaryContainer.withOpacity(0.72),
             buttonBackgroundColor: buttonColor,
             color: theme.colorScheme.background,
-          height: 50,
+            height: panelHeight,
             animationDuration: const Duration(milliseconds: 350),
             items: navbarTileList.map(
               (e) {
@@ -91,6 +98,7 @@ class SpotubeNavigationBar extends HookConsumerWidget {
             },
           ),
         ),
+      ),
     );
   }
 }

lib/components/shared/panels/controller.dart

@@ -0,0 +1,142 @@
+part of panels;
+
+class PanelController extends ChangeNotifier {
+  SlidingUpPanelState? _panelState;
+
+  void _addState(SlidingUpPanelState panelState) {
+    _panelState = panelState;
+    notifyListeners();
+  }
+
+  bool _forceScrollChange = false;
+
+  /// use this function when scroll change in func
+  /// Example:
+  /// panelController.forseScrollChange(scrollController.animateTo(100, duration: Duration(milliseconds: 400), curve: Curves.ease))
+  Future<void> forceScrollChange(Future func) async {
+    _forceScrollChange = true;
+    _panelState!._scrollingEnabled = true;
+    await func;
+    // if (_panelState!._sc.offset == 0) {
+    //   _panelState!._scrollingEnabled = true;
+    // }
+    if (panelPosition < 1) {
+      _panelState!._scMinOffset = _panelState!._scrollController.offset;
+    }
+    _forceScrollChange = false;
+  }
+
+  bool __nowTargetForceDraggable = false;
+
+  bool get _nowTargetForceDraggable => __nowTargetForceDraggable;
+
+  set _nowTargetForceDraggable(bool value) {
+    __nowTargetForceDraggable = value;
+    notifyListeners();
+  }
+
+  /// Determine if the panelController is attached to an instance
+  /// of the SlidingUpPanel (this property must return true before any other
+  /// functions can be used)
+  bool get isAttached => _panelState != null;
+
+  /// Closes the sliding panel to its collapsed state (i.e. to the  minHeight)
+  Future<void> close() {
+    assert(isAttached, "PanelController must be attached to a SlidingUpPanel");
+    return _panelState!._close();
+  }
+
+  /// Opens the sliding panel fully
+  /// (i.e. to the maxHeight)
+  Future<void> open() {
+    assert(isAttached, "PanelController must be attached to a SlidingUpPanel");
+    return _panelState!._open();
+  }
+
+  /// Hides the sliding panel (i.e. is invisible)
+  Future<void> hide() {
+    assert(isAttached, "PanelController must be attached to a SlidingUpPanel");
+    return _panelState!._hide();
+  }
+
+  /// Shows the sliding panel in its collapsed state
+  /// (i.e. "un-hide" the sliding panel)
+  Future<void> show() {
+    assert(isAttached, "PanelController must be attached to a SlidingUpPanel");
+    return _panelState!._show();
+  }
+
+  /// Animates the panel position to the value.
+  /// The value must between 0.0 and 1.0
+  /// where 0.0 is fully collapsed and 1.0 is completely open.
+  /// (optional) duration specifies the time for the animation to complete
+  /// (optional) curve specifies the easing behavior of the animation.
+  Future<void> animatePanelToPosition(double value,
+      {Duration? duration, Curve curve = Curves.linear}) {
+    assert(isAttached, "PanelController must be attached to a SlidingUpPanel");
+    assert(0.0 <= value && value <= 1.0);
+    return _panelState!
+        ._animatePanelToPosition(value, duration: duration, curve: curve);
+  }
+
+  /// Animates the panel position to the snap point
+  /// Requires that the SlidingUpPanel snapPoint property is not null
+  /// (optional) duration specifies the time for the animation to complete
+  /// (optional) curve specifies the easing behavior of the animation.
+  Future<void> animatePanelToSnapPoint(
+      {Duration? duration, Curve curve = Curves.linear}) {
+    assert(isAttached, "PanelController must be attached to a SlidingUpPanel");
+    assert(_panelState!.widget.snapPoint != null,
+        "SlidingUpPanel snapPoint property must not be null");
+    return _panelState!
+        ._animatePanelToSnapPoint(duration: duration, curve: curve);
+  }
+
+  /// Sets the panel position (without animation).
+  /// The value must between 0.0 and 1.0
+  /// where 0.0 is fully collapsed and 1.0 is completely open.
+  set panelPosition(double value) {
+    assert(isAttached, "PanelController must be attached to a SlidingUpPanel");
+    assert(0.0 <= value && value <= 1.0);
+    _panelState!._panelPosition = value;
+  }
+
+  /// Gets the current panel position.
+  /// Returns the % offset from collapsed state
+  /// to the open state
+  /// as a decimal between 0.0 and 1.0
+  /// where 0.0 is fully collapsed and
+  /// 1.0 is full open.
+  double get panelPosition {
+    assert(isAttached, "PanelController must be attached to a SlidingUpPanel");
+    return _panelState!._panelPosition;
+  }
+
+  /// Returns whether or not the panel is
+  /// currently animating.
+  bool get isPanelAnimating {
+    assert(isAttached, "PanelController must be attached to a SlidingUpPanel");
+    return _panelState!._isPanelAnimating;
+  }
+
+  /// Returns whether or not the
+  /// panel is open.
+  bool get isPanelOpen {
+    assert(isAttached, "PanelController must be attached to a SlidingUpPanel");
+    return _panelState!._isPanelOpen;
+  }
+
+  /// Returns whether or not the
+  /// panel is closed.
+  bool get isPanelClosed {
+    assert(isAttached, "PanelController must be attached to a SlidingUpPanel");
+    return _panelState!._isPanelClosed;
+  }
+
+  /// Returns whether or not the
+  /// panel is shown/hidden.
+  bool get isPanelShown {
+    assert(isAttached, "PanelController must be attached to a SlidingUpPanel");
+    return _panelState!._isPanelShown;
+  }
+}

lib/components/shared/panels/helpers.dart

@@ -0,0 +1,96 @@
+part of panels;
+
+/// if you want to prevent the panel from being dragged using the widget,
+/// wrap the widget with this
+class IgnoreDraggableWidget extends SingleChildRenderObjectWidget {
+  const IgnoreDraggableWidget({
+    super.key,
+    required super.child,
+  });
+
+  @override
+  IgnoreDraggableWidgetWidgetRenderBox createRenderObject(
+    BuildContext context,
+  ) {
+    return IgnoreDraggableWidgetWidgetRenderBox();
+  }
+}
+
+class IgnoreDraggableWidgetWidgetRenderBox extends RenderPointerListener {
+  @override
+  HitTestBehavior get behavior => HitTestBehavior.opaque;
+}
+
+/// if you want to force the panel to be dragged using the widget,
+/// wrap the widget with this
+/// For example, use [Scrollable] inside to allow the panel to be dragged
+///  even if the scroll is not at position 0.
+class ForceDraggableWidget extends SingleChildRenderObjectWidget {
+  const ForceDraggableWidget({
+    super.key,
+    required super.child,
+  });
+
+  @override
+  ForceDraggableWidgetRenderBox createRenderObject(
+    BuildContext context,
+  ) {
+    return ForceDraggableWidgetRenderBox();
+  }
+}
+
+class ForceDraggableWidgetRenderBox extends RenderPointerListener {
+  @override
+  HitTestBehavior get behavior => HitTestBehavior.opaque;
+}
+
+/// To make [ForceDraggableWidget] work in [Scrollable] widgets
+class PanelScrollPhysics extends ScrollPhysics {
+  final PanelController controller;
+  const PanelScrollPhysics({required this.controller, ScrollPhysics? parent})
+      : super(parent: parent);
+  @override
+  PanelScrollPhysics applyTo(ScrollPhysics? ancestor) {
+    return PanelScrollPhysics(
+        controller: controller, parent: buildParent(ancestor));
+  }
+
+  @override
+  double applyPhysicsToUserOffset(ScrollMetrics position, double offset) {
+    if (controller._nowTargetForceDraggable) return 0.0;
+    return super.applyPhysicsToUserOffset(position, offset);
+  }
+
+  @override
+  Simulation? createBallisticSimulation(
+      ScrollMetrics position, double velocity) {
+    if (controller._nowTargetForceDraggable) {
+      return super.createBallisticSimulation(position, 0);
+    }
+    return super.createBallisticSimulation(position, velocity);
+  }
+
+  @override
+  bool get allowImplicitScrolling => false;
+}
+
+/// if you want to prevent unwanted panel dragging when scrolling widgets [Scrollable] with horizontal axis
+/// wrap the widget with this
+class HorizontalScrollableWidget extends SingleChildRenderObjectWidget {
+  const HorizontalScrollableWidget({
+    super.key,
+    required super.child,
+  });
+
+  @override
+  HorizontalScrollableWidgetRenderBox createRenderObject(
+    BuildContext context,
+  ) {
+    return HorizontalScrollableWidgetRenderBox();
+  }
+}
+
+class HorizontalScrollableWidgetRenderBox extends RenderPointerListener {
+  @override
+  HitTestBehavior get behavior => HitTestBehavior.opaque;
+}

lib/components/shared/panels/sliding_up_panel.dart

@@ -0,0 +1,683 @@
+/*
+Name: Zotov Vladimir
+Date: 18/06/22
+Purpose: Defines the package: sliding_up_panel2
+Copyright: © 2022, Zotov Vladimir. All rights reserved.
+Licensing: More information can be found here: https://github.com/Zotov-VD/sliding_up_panel/blob/master/LICENSE
+
+This product includes software developed by Akshath Jain (https://akshathjain.com)
+*/
+
+library panels;
+
+import 'dart:math';
+
+import 'package:flutter/gestures.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/physics.dart';
+import 'package:flutter/rendering.dart';
+
+part 'controller.dart';
+part 'helpers.dart';
+
+enum SlideDirection { up, down }
+
+enum PanelState { open, closed }
+
+class SlidingUpPanel extends StatefulWidget {
+  /// Returns the Widget that slides into view. When the
+  /// panel is collapsed and if [collapsed] is null,
+  /// then top portion of this Widget will be displayed;
+  /// otherwise, [collapsed] will be displayed overtop
+  /// of this Widget.
+  final Widget? Function(double position)? panelBuilder;
+
+  /// The Widget displayed overtop the [panel] when collapsed.
+  /// This fades out as the panel is opened.
+  final Widget? collapsed;
+
+  /// The Widget that lies underneath the sliding panel.
+  /// This Widget automatically sizes itself
+  /// to fill the screen.
+  final Widget? body;
+
+  /// Optional persistent widget that floats above the [panel] and attaches
+  /// to the top of the [panel]. Content at the top of the panel will be covered
+  /// by this widget. Add padding to the bottom of the `panel` to
+  /// avoid coverage.
+  final Widget? header;
+
+  /// Optional persistent widget that floats above the [panel] and
+  /// attaches to the bottom of the [panel]. Content at the bottom of the panel
+  /// will be covered by this widget. Add padding to the bottom of the `panel`
+  /// to avoid coverage.
+  final Widget? footer;
+
+  /// The height of the sliding panel when fully collapsed.
+  final double minHeight;
+
+  /// The height of the sliding panel when fully open.
+  final double maxHeight;
+
+  /// A point between [minHeight] and [maxHeight] that the panel snaps to
+  /// while animating. A fast swipe on the panel will disregard this point
+  /// and go directly to the open/close position. This value is represented as a
+  /// percentage of the total animation distance ([maxHeight] - [minHeight]),
+  /// so it must be between 0.0 and 1.0, exclusive.
+  final double? snapPoint;
+
+  /// The amount to inset the children of the sliding panel sheet.
+  final EdgeInsetsGeometry? padding;
+
+  /// Empty space surrounding the sliding panel sheet.
+  final EdgeInsetsGeometry? margin;
+
+  /// Set to false to disable the panel from snapping open or closed.
+  final bool panelSnapping;
+
+  /// Disable panel draggable on scrolling. Defaults to false.
+  final bool disableDraggableOnScrolling;
+
+  /// If non-null, this can be used to control the state of the panel.
+  final PanelController? controller;
+
+  /// If non-null, shows a darkening shadow over the [body] as the panel slides open.
+  final bool backdropEnabled;
+
+  /// Shows a darkening shadow of this [Color] over the [body] as the panel slides open.
+  final Color backdropColor;
+
+  /// The opacity of the backdrop when the panel is fully open.
+  /// This value can range from 0.0 to 1.0 where 0.0 is completely transparent
+  /// and 1.0 is completely opaque.
+  final double backdropOpacity;
+
+  /// Flag that indicates whether or not tapping the
+  /// backdrop closes the panel. Defaults to true.
+  final bool backdropTapClosesPanel;
+
+  /// If non-null, this callback
+  /// is called as the panel slides around with the
+  /// current position of the panel. The position is a double
+  /// between 0.0 and 1.0 where 0.0 is fully collapsed and 1.0 is fully open.
+  final void Function(double position)? onPanelSlide;
+
+  /// If non-null, this callback is called when the
+  /// panel is fully opened
+  final VoidCallback? onPanelOpened;
+
+  /// If non-null, this callback is called when the panel
+  /// is fully collapsed.
+  final VoidCallback? onPanelClosed;
+
+  /// If non-null and true, the SlidingUpPanel exhibits a
+  /// parallax effect as the panel slides up. Essentially,
+  /// the body slides up as the panel slides up.
+  final bool parallaxEnabled;
+
+  /// Allows for specifying the extent of the parallax effect in terms
+  /// of the percentage the panel has slid up/down. Recommended values are
+  /// within 0.0 and 1.0 where 0.0 is no parallax and 1.0 mimics a
+  /// one-to-one scrolling effect. Defaults to a 10% parallax.
+  final double parallaxOffset;
+
+  /// Allows toggling of the draggability of the SlidingUpPanel.
+  /// Set this to false to prevent the user from being able to drag
+  /// the panel up and down. Defaults to true.
+  final bool isDraggable;
+
+  /// Either SlideDirection.UP or SlideDirection.DOWN. Indicates which way
+  /// the panel should slide. Defaults to UP. If set to DOWN, the panel attaches
+  /// itself to the top of the screen and is fully opened when the user swipes
+  /// down on the panel.
+  final SlideDirection slideDirection;
+
+  /// The default state of the panel; either PanelState.OPEN or PanelState.CLOSED.
+  /// This value defaults to PanelState.CLOSED which indicates that the panel is
+  /// in the closed position and must be opened. PanelState.OPEN indicates that
+  /// by default the Panel is open and must be swiped closed by the user.
+  final PanelState defaultPanelState;
+
+  /// To attach to a [Scrollable] on a panel that
+  /// links the panel's position to the scroll position. Useful for implementing
+  /// infinite scroll behavior
+  final ScrollController? scrollController;
+
+  final BoxDecoration? panelDecoration;
+
+  const SlidingUpPanel(
+      {Key? key,
+      this.body,
+      this.collapsed,
+      this.minHeight = 100.0,
+      this.maxHeight = 500.0,
+      this.snapPoint,
+      this.padding,
+      this.margin,
+      this.panelDecoration,
+      this.panelSnapping = true,
+      this.disableDraggableOnScrolling = false,
+      this.controller,
+      this.backdropEnabled = false,
+      this.backdropColor = Colors.black,
+      this.backdropOpacity = 0.5,
+      this.backdropTapClosesPanel = true,
+      this.onPanelSlide,
+      this.onPanelOpened,
+      this.onPanelClosed,
+      this.parallaxEnabled = false,
+      this.parallaxOffset = 0.1,
+      this.isDraggable = true,
+      this.slideDirection = SlideDirection.up,
+      this.defaultPanelState = PanelState.closed,
+      this.header,
+      this.footer,
+      this.scrollController,
+      this.panelBuilder})
+      : assert(panelBuilder != null),
+        assert(0 <= backdropOpacity && backdropOpacity <= 1.0),
+        assert(snapPoint == null || 0 < snapPoint && snapPoint < 1.0),
+        super(key: key);
+
+  @override
+  SlidingUpPanelState createState() => SlidingUpPanelState();
+}
+
+class SlidingUpPanelState extends State<SlidingUpPanel>
+    with SingleTickerProviderStateMixin {
+  late AnimationController _animationController;
+  late final ScrollController _scrollController;
+
+  bool _scrollingEnabled = false;
+  final VelocityTracker _velocityTracker =
+      VelocityTracker.withKind(PointerDeviceKind.touch);
+
+  bool _isPanelVisible = true;
+
+  @override
+  void initState() {
+    super.initState();
+
+    _animationController = AnimationController(
+        vsync: this,
+        duration: const Duration(milliseconds: 300),
+        value: widget.defaultPanelState == PanelState.closed
+            ? 0.0
+            : 1.0 //set the default panel state (i.e. set initial value of _ac)
+        )
+      ..addListener(() {
+        if (widget.onPanelSlide != null) {
+          widget.onPanelSlide!(_animationController.value);
+        }
+
+        if (widget.onPanelOpened != null &&
+            (_animationController.value == 1.0 ||
+                _animationController.value == 0.0)) {
+          widget.onPanelOpened!();
+        }
+      });
+
+    // prevent the panel content from being scrolled only if the widget is
+    // draggable and panel scrolling is enabled
+    _scrollController = widget.scrollController ?? ScrollController();
+    _scrollController.addListener(() {
+      if (widget.isDraggable &&
+          !widget.disableDraggableOnScrolling &&
+          (!_scrollingEnabled || _panelPosition < 1) &&
+          widget.controller?._forceScrollChange != true) {
+        _scrollController.jumpTo(_scMinOffset);
+      }
+    });
+
+    widget.controller?._addState(this);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final mediaQuery = MediaQuery.of(context);
+
+    return Stack(
+      alignment: widget.slideDirection == SlideDirection.up
+          ? Alignment.bottomCenter
+          : Alignment.topCenter,
+      children: <Widget>[
+        //make the back widget take up the entire back side
+        if (widget.body != null)
+          AnimatedBuilder(
+            animation: _animationController,
+            builder: (context, child) {
+              return Positioned(
+                top: widget.parallaxEnabled ? _getParallax() : 0.0,
+                child: child ?? const SizedBox(),
+              );
+            },
+            child: SizedBox(
+              height: mediaQuery.size.height,
+              width: mediaQuery.size.width,
+              child: widget.body,
+            ),
+          ),
+
+        //the backdrop to overlay on the body
+        if (widget.backdropEnabled)
+          GestureDetector(
+            onVerticalDragEnd: widget.backdropTapClosesPanel
+                ? (DragEndDetails details) {
+                    // only trigger a close if the drag is towards panel close position
+                    if ((widget.slideDirection == SlideDirection.up ? 1 : -1) *
+                            details.velocity.pixelsPerSecond.dy >
+                        0) _close();
+                  }
+                : null,
+            onTap: widget.backdropTapClosesPanel ? () => _close() : null,
+            child: AnimatedBuilder(
+                animation: _animationController,
+                builder: (context, _) {
+                  return Container(
+                    height: mediaQuery.size.height,
+                    width: mediaQuery.size.width,
+
+                    //set color to null so that touch events pass through
+                    //to the body when the panel is closed, otherwise,
+                    //if a color exists, then touch events won't go through
+                    color: _animationController.value == 0.0
+                        ? null
+                        : widget.backdropColor.withOpacity(
+                            widget.backdropOpacity * _animationController.value,
+                          ),
+                  );
+                }),
+          ),
+
+        //the actual sliding part
+        if (_isPanelVisible)
+          _gestureHandler(
+            child: AnimatedBuilder(
+              animation: _animationController,
+              builder: (context, child) {
+                return Container(
+                  height: _animationController.value *
+                          (widget.maxHeight - widget.minHeight) +
+                      widget.minHeight,
+                  margin: widget.margin,
+                  padding: widget.padding,
+                  decoration: widget.panelDecoration,
+                  child: child,
+                );
+              },
+              child: Stack(
+                children: <Widget>[
+                  //open panel
+                  Positioned(
+                    top:
+                        widget.slideDirection == SlideDirection.up ? 0.0 : null,
+                    bottom: widget.slideDirection == SlideDirection.down
+                        ? 0.0
+                        : null,
+                    width: mediaQuery.size.width -
+                        (widget.margin != null
+                            ? widget.margin!.horizontal
+                            : 0) -
+                        (widget.padding != null
+                            ? widget.padding!.horizontal
+                            : 0),
+                    child: SizedBox(
+                      height: widget.maxHeight,
+                      child: widget.panelBuilder!(
+                        _animationController.value,
+                      ),
+                    ),
+                  ),
+
+                  // footer
+                  if (widget.footer != null)
+                    Positioned(
+                        top: widget.slideDirection == SlideDirection.up
+                            ? null
+                            : 0.0,
+                        bottom: widget.slideDirection == SlideDirection.down
+                            ? null
+                            : 0.0,
+                        child: widget.footer ?? const SizedBox()),
+
+                  // header
+                  if (widget.header != null)
+                    Positioned(
+                      top: widget.slideDirection == SlideDirection.up
+                          ? 0.0
+                          : null,
+                      bottom: widget.slideDirection == SlideDirection.down
+                          ? 0.0
+                          : null,
+                      child: widget.header ?? const SizedBox(),
+                    ),
+
+                  // collapsed panel
+                  Positioned(
+                    top:
+                        widget.slideDirection == SlideDirection.up ? 0.0 : null,
+                    bottom: widget.slideDirection == SlideDirection.down
+                        ? 0.0
+                        : null,
+                    width: mediaQuery.size.width -
+                        (widget.margin != null
+                            ? widget.margin!.horizontal
+                            : 0) -
+                        (widget.padding != null
+                            ? widget.padding!.horizontal
+                            : 0),
+                    child: AnimatedContainer(
+                      duration: const Duration(milliseconds: 250),
+                      height: widget.minHeight,
+                      child: widget.collapsed == null
+                          ? null
+                          : FadeTransition(
+                              opacity: Tween(begin: 1.0, end: 0.0)
+                                  .animate(_animationController),
+
+                              // if the panel is open ignore pointers (touch events) on the collapsed
+                              // child so that way touch events go through to whatever is underneath
+                              child: widget.collapsed,
+                            ),
+                    ),
+                  ),
+                ],
+              ),
+            ),
+          ),
+      ],
+    );
+  }
+
+  @override
+  void dispose() {
+    _animationController.dispose();
+    super.dispose();
+  }
+
+  double _getParallax() {
+    if (widget.slideDirection == SlideDirection.up) {
+      return -_animationController.value *
+          (widget.maxHeight - widget.minHeight) *
+          widget.parallaxOffset;
+    } else {
+      return _animationController.value *
+          (widget.maxHeight - widget.minHeight) *
+          widget.parallaxOffset;
+    }
+  }
+
+  bool _ignoreScrollable = false;
+  bool _isHorizontalScrollableWidget = false;
+  Axis? _scrollableAxis;
+
+  // returns a gesture detector if panel is used
+  // and a listener if panelBuilder is used.
+  // this is because the listener is designed only for use with linking the scrolling of
+  // panels and using it for panels that don't want to linked scrolling yields odd results
+  Widget _gestureHandler({required Widget child}) {
+    if (!widget.isDraggable) return child;
+
+    return Listener(
+      onPointerDown: (PointerDownEvent e) {
+        var rb = context.findRenderObject() as RenderBox;
+        var result = BoxHitTestResult();
+        rb.hitTest(result, position: e.position);
+
+        if (_panelPosition == 1) {
+          _scMinOffset = 0.0;
+        }
+        // if there any widget in the path that must force graggable,
+        // stop it right here
+        if (result.path.any((entry) =>
+            entry.target.runtimeType == ForceDraggableWidgetRenderBox)) {
+          widget.controller?._nowTargetForceDraggable = true;
+          _scMinOffset = _scrollController.offset;
+          _isHorizontalScrollableWidget = false;
+        } else if (result.path.any((entry) =>
+            entry.target.runtimeType == HorizontalScrollableWidgetRenderBox)) {
+          _isHorizontalScrollableWidget = true;
+          widget.controller?._nowTargetForceDraggable = false;
+        } else if (result.path.any((entry) =>
+            entry.target.runtimeType == IgnoreDraggableWidgetWidgetRenderBox)) {
+          _ignoreScrollable = true;
+          widget.controller?._nowTargetForceDraggable = false;
+          _isHorizontalScrollableWidget = false;
+          return;
+        } else {
+          widget.controller?._nowTargetForceDraggable = false;
+          _isHorizontalScrollableWidget = false;
+        }
+        _ignoreScrollable = false;
+        _velocityTracker.addPosition(e.timeStamp, e.position);
+      },
+      onPointerMove: (PointerMoveEvent e) {
+        if (_scrollableAxis == null) {
+          if (e.delta.dx.abs() > e.delta.dy.abs()) {
+            _scrollableAxis = Axis.horizontal;
+          } else {
+            _scrollableAxis = Axis.vertical;
+          }
+        }
+
+        if (_isHorizontalScrollableWidget &&
+            _scrollableAxis == Axis.horizontal) {
+          return;
+        }
+
+        if (_ignoreScrollable) return;
+        _velocityTracker.addPosition(
+          e.timeStamp,
+          e.position,
+        ); // add current position for velocity tracking
+        _onGestureSlide(e.delta.dy);
+      },
+      onPointerUp: (PointerUpEvent e) {
+        if (_ignoreScrollable) return;
+        _scrollableAxis = null;
+        _onGestureEnd(_velocityTracker.getVelocity());
+      },
+      child: child,
+    );
+  }
+
+  double _scMinOffset = 0.0;
+
+  // handles the sliding gesture
+  void _onGestureSlide(double dy) {
+    // only slide the panel if scrolling is not enabled
+    if (widget.controller?._nowTargetForceDraggable == false &&
+        widget.disableDraggableOnScrolling) {
+      return;
+    }
+    if ((!_scrollingEnabled) ||
+        _panelPosition < 1 ||
+        widget.controller?._nowTargetForceDraggable == true) {
+      if (widget.slideDirection == SlideDirection.up) {
+        _animationController.value -=
+            dy / (widget.maxHeight - widget.minHeight);
+      } else {
+        _animationController.value +=
+            dy / (widget.maxHeight - widget.minHeight);
+      }
+    }
+
+    // if the panel is open and the user hasn't scrolled, we need to determine
+    // whether to enable scrolling if the user swipes up, or disable closing and
+    // begin to close the panel if the user swipes down
+    if (_isPanelOpen &&
+        _scrollController.hasClients &&
+        _scrollController.offset <= _scMinOffset) {
+      setState(() {
+        if (dy < 0) {
+          _scrollingEnabled = true;
+        } else {
+          _scrollingEnabled = false;
+        }
+      });
+    }
+  }
+
+  // handles when user stops sliding
+  void _onGestureEnd(Velocity v) {
+    if (widget.controller?._nowTargetForceDraggable == false &&
+        widget.disableDraggableOnScrolling) {
+      return;
+    }
+    double minFlingVelocity = 365.0;
+    double kSnap = 8;
+
+    //let the current animation finish before starting a new one
+    if (_animationController.isAnimating) return;
+
+    // if scrolling is allowed and the panel is open, we don't want to close
+    // the panel if they swipe up on the scrollable
+    if (_isPanelOpen && _scrollingEnabled) return;
+
+    //check if the velocity is sufficient to constitute fling to end
+    double visualVelocity =
+        -v.pixelsPerSecond.dy / (widget.maxHeight - widget.minHeight);
+
+    // reverse visual velocity to account for slide direction
+    if (widget.slideDirection == SlideDirection.down) {
+      visualVelocity = -visualVelocity;
+    }
+
+    // get minimum distances to figure out where the panel is at
+    double d2Close = _animationController.value;
+    double d2Open = 1 - _animationController.value;
+    double d2Snap = ((widget.snapPoint ?? 3) - _animationController.value)
+        .abs(); // large value if null results in not every being the min
+    double minDistance = min(d2Close, min(d2Snap, d2Open));
+
+    // check if velocity is sufficient for a fling
+    if (v.pixelsPerSecond.dy.abs() >= minFlingVelocity) {
+      // snapPoint exists
+      if (widget.panelSnapping && widget.snapPoint != null) {
+        if (v.pixelsPerSecond.dy.abs() >= kSnap * minFlingVelocity ||
+            minDistance == d2Snap) {
+          _animationController.fling(velocity: visualVelocity);
+        } else {
+          _flingPanelToPosition(widget.snapPoint!, visualVelocity);
+        }
+
+        // no snap point exists
+      } else if (widget.panelSnapping) {
+        _animationController.fling(velocity: visualVelocity);
+
+        // panel snapping disabled
+      } else {
+        _animationController.animateTo(
+          _animationController.value + visualVelocity * 0.16,
+          duration: const Duration(milliseconds: 410),
+          curve: Curves.decelerate,
+        );
+      }
+
+      return;
+    }
+
+    // check if the controller is already halfway there
+    if (widget.panelSnapping) {
+      if (minDistance == d2Close) {
+        _close();
+      } else if (minDistance == d2Snap) {
+        _flingPanelToPosition(widget.snapPoint!, visualVelocity);
+      } else {
+        _open();
+      }
+    }
+  }
+
+  void _flingPanelToPosition(double targetPos, double velocity) {
+    final Simulation simulation = SpringSimulation(
+        SpringDescription.withDampingRatio(
+          mass: 1.0,
+          stiffness: 500.0,
+          ratio: 1.0,
+        ),
+        _animationController.value,
+        targetPos,
+        velocity);
+
+    _animationController.animateWith(simulation);
+  }
+
+  //---------------------------------
+  //PanelController related functions
+  //---------------------------------
+
+  //close the panel
+  Future<void> _close() {
+    return _animationController.fling(velocity: -1.0);
+  }
+
+  //open the panel
+  Future<void> _open() {
+    return _animationController.fling(velocity: 1.0);
+  }
+
+  //hide the panel (completely offscreen)
+  Future<void> _hide() {
+    return _animationController.fling(velocity: -1.0).then((x) {
+      setState(() {
+        _isPanelVisible = false;
+      });
+    });
+  }
+
+  //show the panel (in collapsed mode)
+  Future<void> _show() {
+    return _animationController.fling(velocity: -1.0).then((x) {
+      setState(() {
+        _isPanelVisible = true;
+      });
+    });
+  }
+
+  //animate the panel position to value - must
+  //be between 0.0 and 1.0
+  Future<void> _animatePanelToPosition(double value,
+      {Duration? duration, Curve curve = Curves.linear}) {
+    assert(0.0 <= value && value <= 1.0);
+    return _animationController.animateTo(value,
+        duration: duration, curve: curve);
+  }
+
+  //animate the panel position to the snap point
+  //REQUIRES that widget.snapPoint != null
+  Future<void> _animatePanelToSnapPoint(
+      {Duration? duration, Curve curve = Curves.linear}) {
+    assert(widget.snapPoint != null);
+    return _animationController.animateTo(widget.snapPoint!,
+        duration: duration, curve: curve);
+  }
+
+  //set the panel position to value - must
+  //be between 0.0 and 1.0
+  set _panelPosition(double value) {
+    assert(0.0 <= value && value <= 1.0);
+    _animationController.value = value;
+  }
+
+  //get the current panel position
+  //returns the % offset from collapsed state
+  //as a decimal between 0.0 and 1.0
+  double get _panelPosition => _animationController.value;
+
+  //returns whether or not
+  //the panel is still animating
+  bool get _isPanelAnimating => _animationController.isAnimating;
+
+  //returns whether or not the
+  //panel is open
+  bool get _isPanelOpen => _animationController.value == 1.0;
+
+  //returns whether or not the
+  //panel is closed
+  bool get _isPanelClosed => _animationController.value == 0.0;
+
+  //returns whether or not the
+  //panel is shown/hidden
+  bool get _isPanelShown => _isPanelVisible;
+}