From a48c96559d18643bcce13435a2b4df738a456d45 Mon Sep 17 00:00:00 2001
From: Matthias Metelka <62722460+kleinerpirat@users.noreply.github.com>
Date: Thu, 1 Dec 2022 06:45:52 +0100
Subject: [PATCH] Fix glitchy animation of floating elements (#2224)

* Set max-height of 400px to scrollable Popover

* Pass computed placement to user components

to set different animation directions when the placement changes.

* Move elevation effect from WithFloating/WithOverlay to Popover

* Apply same changes as in WithFloating to WithOverlay

* Adjust FloatingArrow CSS to Popover

* Run eslint and formatter
---
 ts/components/FloatingArrow.svelte            |   9 +-
 ts/components/Popover.svelte                  | 101 +++++++++++++-----
 ts/components/WithFloating.svelte             |  29 ++---
 ts/components/WithOverlay.svelte              |  37 ++++---
 ts/components/context-keys.ts                 |   2 +
 ts/sveltelib/position/position-algorithm.d.ts |   4 +-
 ts/sveltelib/position/position-floating.ts    |  10 +-
 ts/sveltelib/position/position-overlay.ts     |   8 +-
 8 files changed, 131 insertions(+), 69 deletions(-)

diff --git a/ts/components/FloatingArrow.svelte b/ts/components/FloatingArrow.svelte
index b9754857f..356329cc1 100644
--- a/ts/components/FloatingArrow.svelte
+++ b/ts/components/FloatingArrow.svelte
@@ -18,19 +18,12 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
         z-index: 60;
 
         /* outer border */
-        border: 1px solid #b6b6b6;
-
-        &.dark {
-            border-color: #060606;
-        }
+        border: 1px solid var(--border-subtle);
 
         /* Rotate the box to indicate the different directions */
         border-right: none;
         border-bottom: none;
 
-        /* inner border */
-        box-shadow: inset 1px 1px 0 0 #eeeeee;
-
         &.dark {
             box-shadow: inset 1px 1px 0 0 #565656;
         }
diff --git a/ts/components/Popover.svelte b/ts/components/Popover.svelte
index 31615d331..4cd182852 100644
--- a/ts/components/Popover.svelte
+++ b/ts/components/Popover.svelte
@@ -3,52 +3,101 @@ Copyright: Ankitects Pty Ltd and contributors
 License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 -->
 <script lang="ts">
+    import type { Placement } from "@floating-ui/dom";
+    import { getContext, onMount } from "svelte";
+    import { create_in_transition } from "svelte/internal";
+    import type { Writable } from "svelte/store";
     import { slide } from "svelte/transition";
 
-    import { pageTheme } from "../sveltelib/theme";
+    import { floatingKey } from "./context-keys";
 
     export let scrollable = false;
+    let element: HTMLDivElement;
+    let wrapper: HTMLDivElement;
+    let hidden = true;
+    let minHeight = 0;
+
+    let placement: Placement;
+
+    const placementStore = getContext<Writable<Promise<Placement>>>(floatingKey);
+
+    /* await computed placement of floating element to determine animation direction */
+    $: if ($placementStore !== undefined) {
+        $placementStore.then((computedPlacement) => {
+            if (placement != computedPlacement) {
+                placement = computedPlacement;
+                /* use internal function to animate popover */
+                create_in_transition(element, slide, { duration: 200 }).start();
+                hidden = false;
+            }
+        });
+    }
+
+    onMount(async () => {
+        /* set min-height on wrapper to ensure correct
+           popover placement at animation start */
+        minHeight = wrapper.offsetHeight;
+    });
 </script>
 
 <div
-    class="popover"
-    class:scrollable
-    class:dark={$pageTheme.isDark}
-    transition:slide={{ duration: 200 }}
+    class="popover-wrapper d-flex"
+    style:--min-height="{minHeight}px"
+    bind:this={wrapper}
 >
-    <slot />
+    <div
+        class="popover"
+        class:scrollable
+        class:hidden
+        class:top={placement === "top"}
+        class:right={placement === "right"}
+        class:bottom={placement === "bottom"}
+        class:left={placement === "left"}
+        bind:this={element}
+    >
+        <slot />
+    </div>
 </div>
 
 <style lang="scss">
-    @use "sass/vars" as *;
+    @use "sass/elevation" as elevation;
+
+    .popover-wrapper {
+        min-height: var(--min-height, 0);
+    }
+
     .popover {
-        border-radius: 5px;
-        background-color: color(canvas-elevated);
+        @include elevation.elevation(8);
+
+        align-self: flex-start;
+        border-radius: var(--border-radius);
+        background-color: var(--canvas-elevated);
+        border: 1px solid var(--border-subtle);
+
         min-width: var(--popover-width, 1rem);
         max-width: 95vw;
 
         /* Needs this much space for FloatingArrow to be positioned */
         padding: var(--popover-padding-block, 6px) var(--popover-padding-inline, 6px);
 
-        font-size: 1rem;
-        color: color(fg);
-
-        /* outer border */
-        border: 1px solid palette(lightgray, 6);
-
-        &.dark {
-            border-color: palette(darkgray, 9);
-        }
-
-        /* inner border */
-        box-shadow: inset 0 0 0 1px palette(lightgray, 3);
-
-        &.dark {
-            box-shadow: inset 0 0 0 1px palette(darkgray, 2);
-        }
         &.scrollable {
-            max-height: 80vh;
+            max-height: 400px;
             overflow: hidden auto;
         }
+
+        &.hidden {
+            width: 0;
+            visibility: hidden;
+        }
+
+        /* alignment determines slide animation direction */
+        &.top,
+        &.left {
+            align-self: flex-end;
+        }
+        &.bottom,
+        &.right {
+            align-self: flex-start;
+        }
     }
 </style>
diff --git a/ts/components/WithFloating.svelte b/ts/components/WithFloating.svelte
index fadaef32c..50773fb83 100644
--- a/ts/components/WithFloating.svelte
+++ b/ts/components/WithFloating.svelte
@@ -10,8 +10,9 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
     } from "@floating-ui/dom";
     import type { Callback } from "@tslib/typing";
     import { singleCallback } from "@tslib/typing";
-    import { createEventDispatcher, onDestroy } from "svelte";
+    import { createEventDispatcher, onDestroy, setContext } from "svelte";
     import type { ActionReturn } from "svelte/action";
+    import { writable } from "svelte/store";
 
     import isClosingClick from "../sveltelib/closing-click";
     import isClosingKeyup from "../sveltelib/closing-keyup";
@@ -23,12 +24,18 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
     import type { PositionAlgorithm } from "../sveltelib/position/position-algorithm";
     import positionFloating from "../sveltelib/position/position-floating";
     import subscribeToUpdates from "../sveltelib/subscribe-updates";
+    import { floatingKey } from "./context-keys";
     import FloatingArrow from "./FloatingArrow.svelte";
 
     export let portalTarget: HTMLElement | null = null;
 
     let placement: Placement = "bottom";
     export { placement as preferredPlacement };
+
+    /* Used by Popover to set animation direction depending on placement */
+    const placementPromise = writable(undefined as Promise<Placement> | undefined);
+    setContext(floatingKey, placementPromise);
+
     export let offset = 5;
     /* 30px box shadow from elevation(8) */
     export let shift = 30;
@@ -72,8 +79,10 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
         reference: ReferenceElement,
         floating: FloatingElement,
         position: PositionAlgorithm,
-    ): Promise<void> {
-        return position(reference, floating);
+    ): Promise<Placement> {
+        const promise = position(reference, floating);
+        $placementPromise = promise;
+        return promise;
     }
 
     async function position(
@@ -81,8 +90,8 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
             reference: ReferenceElement,
             floating: FloatingElement,
             position: PositionAlgorithm,
-        ) => Promise<void> = applyPosition,
-    ): Promise<void> {
+        ) => Promise<Placement> = applyPosition,
+    ): Promise<Placement | void> {
         if (reference && floating) {
             return callback(reference, floating, positionCurried);
         }
@@ -97,9 +106,9 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
         callback: PositioningCallback,
     ): Callback {
         const innerFloating = floating;
-        return callback(reference, innerFloating, () =>
-            positionCurried(reference, innerFloating),
-        );
+        return callback(reference, innerFloating, () => {
+            $placementPromise = positionCurried(reference, innerFloating);
+        });
     }
 
     let cleanup: Callback | null = null;
@@ -186,7 +195,6 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 </div>
 
 <style lang="scss">
-    @use "sass/elevation" as elevation;
     span.floating-reference {
         line-height: 1;
     }
@@ -195,9 +203,6 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
         border-radius: 5px;
 
         z-index: 890;
-        &.show {
-            @include elevation.elevation(8);
-        }
 
         &-arrow {
             position: absolute;
diff --git a/ts/components/WithOverlay.svelte b/ts/components/WithOverlay.svelte
index d50a8696c..ec5c50b9c 100644
--- a/ts/components/WithOverlay.svelte
+++ b/ts/components/WithOverlay.svelte
@@ -3,11 +3,16 @@ Copyright: Ankitects Pty Ltd and contributors
 License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 -->
 <script lang="ts">
-    import type { FloatingElement, ReferenceElement } from "@floating-ui/dom";
+    import type {
+        FloatingElement,
+        Placement,
+        ReferenceElement,
+    } from "@floating-ui/dom";
     import type { Callback } from "@tslib/typing";
     import { singleCallback } from "@tslib/typing";
-    import { createEventDispatcher } from "svelte";
+    import { createEventDispatcher, setContext } from "svelte";
     import type { ActionReturn } from "svelte/action";
+    import { writable } from "svelte/store";
 
     import isClosingClick from "../sveltelib/closing-click";
     import isClosingKeyup from "../sveltelib/closing-keyup";
@@ -18,6 +23,11 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
     import type { PositionAlgorithm } from "../sveltelib/position/position-algorithm";
     import positionOverlay from "../sveltelib/position/position-overlay";
     import subscribeToUpdates from "../sveltelib/subscribe-updates";
+    import { overlayKey } from "./context-keys";
+
+    /* Used by Popover to set animation direction depending on placement */
+    const placementPromise = writable(undefined as Promise<Placement> | undefined);
+    setContext(overlayKey, placementPromise);
 
     export let padding = 0;
     export let inline = false;
@@ -50,8 +60,10 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
         reference: HTMLElement,
         floating: FloatingElement,
         position: PositionAlgorithm,
-    ): Promise<void> {
-        return position(reference, floating);
+    ): Promise<Placement> {
+        const promise = position(reference, floating);
+        $placementPromise = promise;
+        return promise;
     }
 
     async function position(
@@ -59,8 +71,8 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
             reference: HTMLElement,
             floating: FloatingElement,
             position: PositionAlgorithm,
-        ) => Promise<void> = applyPosition,
-    ): Promise<void> {
+        ) => Promise<Placement> = applyPosition,
+    ): Promise<Placement | void> {
         if (reference && floating) {
             return callback(reference, floating, positionCurried);
         }
@@ -75,9 +87,9 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
         callback: PositioningCallback,
     ): Callback {
         const innerFloating = floating;
-        return callback(reference, innerFloating, () =>
-            positionCurried(reference, innerFloating),
-        );
+        return callback(reference, innerFloating, () => {
+            $placementPromise = positionCurried(reference, innerFloating);
+        });
     }
 
     let cleanup: Callback;
@@ -147,15 +159,10 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 </div>
 
 <style lang="scss">
-    @use "sass/elevation" as elevation;
-
     .overlay {
         position: absolute;
-        border-radius: 5px;
+        border-radius: var(--border-radius);
 
         z-index: 40;
-        &.show {
-            @include elevation.elevation(5);
-        }
     }
 </style>
diff --git a/ts/components/context-keys.ts b/ts/components/context-keys.ts
index a093c3b52..27803547c 100644
--- a/ts/components/context-keys.ts
+++ b/ts/components/context-keys.ts
@@ -6,3 +6,5 @@ export const sectionKey = Symbol("section");
 export const buttonGroupKey = Symbol("buttonGroup");
 export const dropdownKey = Symbol("dropdown");
 export const modalsKey = Symbol("modals");
+export const floatingKey = Symbol("floating");
+export const overlayKey = Symbol("overlay");
diff --git a/ts/sveltelib/position/position-algorithm.d.ts b/ts/sveltelib/position/position-algorithm.d.ts
index c48ddd852..d088702b9 100644
--- a/ts/sveltelib/position/position-algorithm.d.ts
+++ b/ts/sveltelib/position/position-algorithm.d.ts
@@ -1,7 +1,7 @@
 // Copyright: Ankitects Pty Ltd and contributors
 // License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 
-import type { FloatingElement, ReferenceElement } from "@floating-ui/dom";
+import type { FloatingElement, Placement, ReferenceElement } from "@floating-ui/dom";
 
 /**
  * The interface of a function that calls `computePosition` of floating-ui.
@@ -9,4 +9,4 @@ import type { FloatingElement, ReferenceElement } from "@floating-ui/dom";
 export type PositionAlgorithm = (
     reference: ReferenceElement,
     floating: FloatingElement,
-) => Promise<void>;
+) => Promise<Placement>;
diff --git a/ts/sveltelib/position/position-floating.ts b/ts/sveltelib/position/position-floating.ts
index e834cf724..44016889a 100644
--- a/ts/sveltelib/position/position-floating.ts
+++ b/ts/sveltelib/position/position-floating.ts
@@ -30,7 +30,7 @@ function positionFloating({
     return async function(
         reference: ReferenceElement,
         floating: FloatingElement,
-    ): Promise<void> {
+    ): Promise<Placement> {
         const middleware: Middleware[] = [
             flip(),
             offset(offsetArg),
@@ -63,11 +63,13 @@ function positionFloating({
         } = await computePosition(reference, floating, computeArgs);
 
         if (middlewareData.hide?.escaped) {
-            return hideCallback("escaped");
+            hideCallback("escaped");
+            return computedPlacement;
         }
 
         if (middlewareData.hide?.referenceHidden) {
-            return hideCallback("referenceHidden");
+            hideCallback("referenceHidden");
+            return computedPlacement;
         }
 
         Object.assign(floating.style, {
@@ -102,6 +104,8 @@ function positionFloating({
             top: arrowY ? `${arrowY}px` : "",
             transform: `rotate(${rotation}deg)`,
         });
+
+        return computedPlacement;
     };
 }
 
diff --git a/ts/sveltelib/position/position-overlay.ts b/ts/sveltelib/position/position-overlay.ts
index 8660cbb18..86dc26e18 100644
--- a/ts/sveltelib/position/position-overlay.ts
+++ b/ts/sveltelib/position/position-overlay.ts
@@ -1,7 +1,7 @@
 // Copyright: Ankitects Pty Ltd and contributors
 // License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 
-import type { ComputePositionConfig, FloatingElement, Middleware, ReferenceElement } from "@floating-ui/dom";
+import type { ComputePositionConfig, FloatingElement, Middleware, Placement, ReferenceElement } from "@floating-ui/dom";
 import { computePosition, inline, offset } from "@floating-ui/dom";
 
 import type { PositionAlgorithm } from "./position-algorithm";
@@ -20,7 +20,7 @@ function positionOverlay({
     return async function(
         reference: ReferenceElement,
         floating: FloatingElement,
-    ): Promise<void> {
+    ): Promise<Placement> {
         const middleware: Middleware[] = inlineArg ? [inline()] : [];
 
         const { width, height } = reference.getBoundingClientRect();
@@ -35,7 +35,7 @@ function positionOverlay({
             middleware,
         };
 
-        const { x, y, middlewareData } = await computePosition(
+        const { x, y, middlewareData, placement } = await computePosition(
             reference,
             floating,
             computeArgs,
@@ -57,6 +57,8 @@ function positionOverlay({
             width: `${width + 2 * padding}px`,
             height: `${height + 2 * padding}px`,
         });
+
+        return placement;
     };
 }