feat(slider): reimplement natively without bits-ui

src/shared/ui/Slider/Slider.svelte

@@ -1,13 +1,16 @@
 <!--
     Component: Slider
-    Single-value slider using bits-ui Slider primitive.
+    Single-value slider built on a native role="slider" element (no bits-ui).
+    Supports pointer drag, click-to-seek, touch, and full keyboard nav.
     Swiss design: 1px track, diamond thumb (rotate-45), brand accent.
 -->
 <script lang="ts">
 import {
-    type Orientation,
+    pointerToValue,
-    Slider,
+    snapToStep,
-} from 'bits-ui';
+} from './slider-math';
+
+type Orientation = 'horizontal' | 'vertical';
 
 interface Props {
     /**
@@ -67,8 +70,106 @@ let {
     class: className,
 }: Props = $props();
 
+/**
+ * PageUp/PageDown move by this multiple of `step`.
+ */
+const LARGE_STEP_MULTIPLIER = 10;
+
 const isVertical = $derived(orientation === 'vertical');
 
+/**
+ * Thumb/range offset as a clamped percentage of the track.
+ */
+const percent = $derived.by(() => {
+    if (max <= min) {
+        return 0;
+    }
+    return Math.min(Math.max(((value - min) / (max - min)) * 100, 0), 100);
+});
+
+let trackEl: HTMLElement | undefined;
+let dragging = $state(false);
+
+/**
+ * Apply a candidate value: snap, clamp, store, and notify only on change.
+ */
+function commit(raw: number): void {
+    const next = snapToStep(raw, { min, max, step });
+    if (next !== value) {
+        value = next;
+        onValueChange?.(next);
+    }
+}
+
+/**
+ * Resolve a pointer event to a value using the live track rect.
+ */
+function seek(event: PointerEvent): void {
+    if (!trackEl) {
+        return;
+    }
+    const rect = trackEl.getBoundingClientRect();
+    commit(pointerToValue(event, rect, { min, max, step, orientation }));
+}
+
+function handlePointerDown(event: PointerEvent): void {
+    if (disabled) {
+        return;
+    }
+    dragging = true;
+    (event.currentTarget as HTMLElement).setPointerCapture?.(event.pointerId);
+    seek(event);
+}
+
+function handlePointerMove(event: PointerEvent): void {
+    if (!dragging || disabled) {
+        return;
+    }
+    seek(event);
+}
+
+function handlePointerUp(event: PointerEvent): void {
+    if (!dragging) {
+        return;
+    }
+    dragging = false;
+    (event.currentTarget as HTMLElement).releasePointerCapture?.(event.pointerId);
+}
+
+function handleKeyDown(event: KeyboardEvent): void {
+    if (disabled) {
+        return;
+    }
+    const large = step * LARGE_STEP_MULTIPLIER;
+    let next: number | undefined;
+    switch (event.key) {
+        case 'ArrowRight':
+        case 'ArrowUp':
+            next = value + step;
+            break;
+        case 'ArrowLeft':
+        case 'ArrowDown':
+            next = value - step;
+            break;
+        case 'PageUp':
+            next = value + large;
+            break;
+        case 'PageDown':
+            next = value - large;
+            break;
+        case 'Home':
+            next = min;
+            break;
+        case 'End':
+            next = max;
+            break;
+        default:
+            return;
+    }
+    event.preventDefault();
+    commit(next);
+}
+
 const labelClasses = `font-mono text-2xs tabular-nums shrink-0
     text-subtle
     group-hover:text-neutral-700 dark:group-hover:text-neutral-300
@@ -91,22 +192,21 @@ const thumbClasses = `block w-2.5 h-2.5 bg-brand
             {format(value)}
         </span>
 
-        <Slider.Root
+        <div
-            type="single"
+            bind:this={trackEl}
-            orientation="vertical"
+            role="presentation"
-            bind:value
+            onpointerdown={handlePointerDown}
-            {min}
+            onpointermove={handlePointerMove}
-            {max}
+            onpointerup={handlePointerUp}
-            {step}
+            onpointercancel={handlePointerUp}
-            {disabled}
-            onValueChange={(v => onValueChange?.(v))}
             class="
                 relative flex flex-col items-center select-none touch-none
                 w-5 h-full grow cursor-row-resize
                 disabled:opacity-50 disabled:cursor-not-allowed
             "
+            class:opacity-50={disabled}
+            class:cursor-not-allowed={disabled}
         >
-            {#snippet children({ thumbItems })}
             <span
                 class="
                     bg-neutral-200 dark:bg-neutral-800
@@ -115,37 +215,45 @@ const thumbClasses = `block w-2.5 h-2.5 bg-brand
                     transition-colors
                 "
             >
-                    <Slider.Range class="absolute bg-brand w-full" />
+                <span
+                    class="absolute bottom-0 left-0 bg-brand w-full"
+                    style="height: {percent}%"
+                ></span>
             </span>
 
-                {#each thumbItems as thumb (thumb)}
+            <span
-                    <Slider.Thumb
+                role="slider"
-                        index={thumb.index}
+                tabindex={disabled ? -1 : 0}
-                        class={thumbClasses}
                 aria-label="Value"
-                    />
+                aria-orientation="vertical"
-                {/each}
+                aria-valuemin={min}
-            {/snippet}
+                aria-valuemax={max}
-        </Slider.Root>
+                aria-valuenow={value}
+                aria-disabled={disabled ? 'true' : undefined}
+                data-active={dragging ? '' : undefined}
+                onkeydown={handleKeyDown}
+                class="{thumbClasses} absolute left-1/2 -translate-x-1/2 translate-y-1/2"
+                style="bottom: {percent}%"
+            ></span>
+        </div>
     </div>
 {:else}
     <div class="flex items-center gap-4 group w-full {className ?? ''}">
-        <Slider.Root
+        <div
-            type="single"
+            bind:this={trackEl}
-            orientation="horizontal"
+            role="presentation"
-            bind:value
+            onpointerdown={handlePointerDown}
-            {min}
+            onpointermove={handlePointerMove}
-            {max}
+            onpointerup={handlePointerUp}
-            {step}
+            onpointercancel={handlePointerUp}
-            {disabled}
-            onValueChange={(v => onValueChange?.(v))}
             class="
                 relative flex items-center select-none touch-none
                 w-full h-5 cursor-col-resize
                 disabled:opacity-50 disabled:cursor-not-allowed
             "
+            class:opacity-50={disabled}
+            class:cursor-not-allowed={disabled}
         >
-            {#snippet children({ thumbItems })}
             <span
                 class="
                     bg-neutral-200 dark:bg-neutral-800
@@ -154,18 +262,27 @@ const thumbClasses = `block w-2.5 h-2.5 bg-brand
                     transition-colors
                 "
             >
-                    <Slider.Range class="absolute bg-brand h-full" />
+                <span
+                    class="absolute top-0 left-0 bg-brand h-full"
+                    style="width: {percent}%"
+                ></span>
             </span>
 
-                {#each thumbItems as thumb (thumb)}
+            <span
-                    <Slider.Thumb
+                role="slider"
-                        index={thumb.index}
+                tabindex={disabled ? -1 : 0}
-                        class={thumbClasses}
                 aria-label="Value"
-                    />
+                aria-orientation="horizontal"
-                {/each}
+                aria-valuemin={min}
-            {/snippet}
+                aria-valuemax={max}
-        </Slider.Root>
+                aria-valuenow={value}
+                aria-disabled={disabled ? 'true' : undefined}
+                data-active={dragging ? '' : undefined}
+                onkeydown={handleKeyDown}
+                class="{thumbClasses} absolute top-1/2 -translate-y-1/2 -translate-x-1/2"
+                style="left: {percent}%"
+            ></span>
+        </div>
 
         <!-- Label: right of slider -->
         <span class="{labelClasses} w-12 text-right">