feat: add dropzone, update tool page

docs/plan-redesign.md

@@ -331,7 +331,7 @@ src/routes/preview/tools/[id]/+page.svelte
       подключим на C12).
 - [x] **[C11]** `/preview/demo` — зеркало воркспейса (4 шага + панель превью), статичный приёмочный стенд.
 - [x] **[C12]** `/preview/tools/[id]` — data-driven settings-panel + preview-panel (gradient live, остальные — плейсхолдер); `NumberField`, `entries()` для prerender, ToolCard-ссылки подключены.
-- [ ] **[C13]** `/preview/tools/[id]` — раскладка background-remover (comparison-grid).
+- [x] **[C13]** `/preview/tools/[id]` — comparison-grid для file-source инструментов (`Dropzone` + before/after `CheckerCanvas`, `result-meta`); охватывает background-remover и прочие.
 - [ ] **[C14]** step-cards для chain в tool-page.
 
 ### Шаг 4. Переключатель и проверка

web/src/lib/components/kit/Dropzone.svelte

@@ -0,0 +1,94 @@
+<script lang="ts">
+	import { Upload } from "@lucide/svelte";
+
+	interface Props {
+		accept?: string;
+		onfile?: (file: File) => void;
+	}
+	let { accept = "image/*", onfile }: Props = $props();
+
+	let dragging = $state(false);
+	let input = $state<HTMLInputElement | null>(null);
+
+	function handleFiles(files: FileList | null | undefined) {
+		const file = files?.[0];
+		if (file) onfile?.(file);
+	}
+
+	function onDrop(e: DragEvent) {
+		e.preventDefault();
+		dragging = false;
+		handleFiles(e.dataTransfer?.files);
+	}
+
+	function open() {
+		input?.click();
+	}
+</script>
+
+<div
+	class="dropzone"
+	class:dragging
+	role="button"
+	tabindex="0"
+	ondragover={(e) => {
+		e.preventDefault();
+		dragging = true;
+	}}
+	ondragleave={() => (dragging = false)}
+	ondrop={onDrop}
+	onclick={open}
+	onkeydown={(e) => {
+		if (e.key === "Enter" || e.key === " ") {
+			e.preventDefault();
+			open();
+		}
+	}}
+>
+	<input
+		bind:this={input}
+		type="file"
+		{accept}
+		hidden
+		onchange={(e) => handleFiles((e.target as HTMLInputElement).files)}
+	/>
+	<Upload size={22} />
+	<span class="dz-title">Drop a PNG here</span>
+	<span class="dz-sub">or click to browse — processed locally</span>
+</div>
+
+<style>
+	.dropzone {
+		display: flex;
+		flex-direction: column;
+		align-items: center;
+		justify-content: center;
+		gap: 0.5rem;
+		min-height: 220px;
+		padding: 2rem;
+		border: 1px dashed var(--line);
+		border-radius: var(--radius);
+		color: var(--muted);
+		background: var(--background);
+		cursor: pointer;
+		text-align: center;
+		transition:
+			border-color 0.15s ease,
+			background 0.15s ease;
+	}
+	.dropzone:hover,
+	.dropzone:focus-visible,
+	.dropzone.dragging {
+		border-color: var(--blue);
+		color: var(--foreground);
+		outline: none;
+	}
+	.dz-title {
+		font: 600 0.9rem var(--font-mono);
+		color: var(--foreground);
+	}
+	.dz-sub {
+		font: 10px var(--font-mono);
+		letter-spacing: 0.04em;
+	}
+</style>

web/src/routes/preview/tools/[id]/+page.svelte

@@ -2,7 +2,8 @@
 	import { browser } from "$app/environment";
 	import { untrack } from "svelte";
 	import { getTool, defaultParams } from "$lib/registry";
-	import { encode, downloadBlob, toDataUrl } from "$lib/core/io";
+	import { encode, downloadBlob, toDataUrl, decodeBytes } from "$lib/core/io";
+	import type { PixelImage } from "$lib/core/types";
 	import Panel from "$lib/components/kit/Panel.svelte";
 	import PanelHeading from "$lib/components/kit/PanelHeading.svelte";
 	import SettingsFooter from "$lib/components/kit/SettingsFooter.svelte";
@@ -12,13 +13,14 @@
 	import Toggle from "$lib/components/kit/Toggle.svelte";
 	import TextField from "$lib/components/kit/TextField.svelte";
 	import NumberField from "$lib/components/kit/NumberField.svelte";
-	import PreviewTile from "$lib/components/kit/PreviewTile.svelte";
 	import CheckerCanvas from "$lib/components/kit/CheckerCanvas.svelte";
 	import MetaList from "$lib/components/kit/MetaList.svelte";
 	import DownloadButton from "$lib/components/kit/DownloadButton.svelte";
 	import Badge from "$lib/components/kit/Badge.svelte";
 	import StatusLine from "$lib/components/kit/StatusLine.svelte";
 	import EmptyState from "$lib/components/kit/EmptyState.svelte";
+	import Button from "$lib/components/kit/Button.svelte";
+	import Dropzone from "$lib/components/kit/Dropzone.svelte";
 	import { SlidersHorizontal as ToolIcon } from "@lucide/svelte";
 
 	type ParamValue = string | number | boolean;
@@ -37,6 +39,13 @@
 	let previewUrl = $state("");
 	let previewError = $state("");
 
+	let sourceImg = $state<PixelImage | null>(null);
+	let sourceUrl = $state("");
+	let sourceName = $state("");
+	let resultImg = $state<PixelImage | null>(null);
+	let resultUrl = $state("");
+	let showMask = $state(false);
+
 	const tool = $derived(getTool(data.id));
 
 	$effect(() => {
@@ -71,6 +80,57 @@
 		}
 	});
 
+	$effect(() => {
+		const src = sourceImg;
+		if (!tool || !tool.run || !src) {
+			resultImg = null;
+			resultUrl = "";
+			return;
+		}
+		if (!browser) return;
+		const snapshot = { ...params };
+		const mask = showMask && !!tool.preview;
+		try {
+			const base = mask
+				? tool.preview!(src, snapshot)
+				: tool.run(src, snapshot);
+			const apply = (img: PixelImage) => {
+				resultImg = img;
+				resultUrl = toDataUrl(img);
+				previewError = "";
+			};
+			if (base instanceof Promise) {
+				base.then(apply).catch((e) => (previewError = String(e)));
+			} else {
+				apply(base);
+			}
+		} catch (e) {
+			previewError = String(e);
+		}
+	});
+
+	async function onFile(file: File) {
+		if (!browser) return;
+		try {
+			const bytes = new Uint8Array(await file.arrayBuffer());
+			const img = await decodeBytes(bytes);
+			sourceImg = img;
+			sourceName = file.name;
+			sourceUrl = toDataUrl(img);
+			previewError = "";
+		} catch (e) {
+			previewError = String(e);
+		}
+	}
+
+	function clearSource() {
+		sourceImg = null;
+		sourceUrl = "";
+		sourceName = "";
+		resultImg = null;
+		resultUrl = "";
+	}
+
 	async function download() {
 		if (!tool?.generate) return;
 		const result = tool.generate({ ...params });
@@ -79,10 +139,21 @@
 		downloadBlob(blob, `${tool.id}.png`);
 	}
 
+	async function downloadResult() {
+		if (!resultImg || !tool) return;
+		const blob = await encode(resultImg, "image/png");
+		const base = sourceName.replace(/\.[^.]+$/, "");
+		downloadBlob(blob, `${base}-${tool.id}.png`);
+	}
+
 	function setParam(id: string, value: ParamValue) {
 		params[id] = value;
 	}
 
+	const isFileTool = $derived(
+		tool ? tool.sourceMode === "file" || tool.sourceMode === undefined : false,
+	);
+
 	const meta = $derived(
 		tool
 			? [
@@ -108,26 +179,16 @@
 	<meta name="robots" content="noindex, nofollow" />
 </svelte:head>
 
-{#if !tool}
+{#snippet settingsPanel()}
-	<div class="tool-grid">
-		<EmptyState
-			title="Tool not found"
-			description="No tool is registered under “{data.id}”."
-			icon={ToolIcon}
-		/>
-	</div>
-{:else}
-	<div class="tool-grid">
-		<section class="settings-panel">
 	<Panel>
-				<PanelHeading title={tool.title} eyebrow={tool.category}>
+		<PanelHeading title={tool!.title} eyebrow={tool!.category}>
 			{#snippet actions()}
 				<Badge tone="accent">AUTO</Badge>
 			{/snippet}
 		</PanelHeading>
-				<p class="tool-desc">{tool.description}</p>
+		<p class="tool-desc">{tool!.description}</p>
 		<div class="settings-body">
-					{#each tool.params as p (p.id)}
+			{#each tool!.params as p (p.id)}
 				<div class="setting-row">
 					{#if p.type === "color"}
 						<ColorField
@@ -183,8 +244,19 @@
 			<StatusLine label="changes applied automatically" />
 		</SettingsFooter>
 	</Panel>
-		</section>
+{/snippet}
 
+{#if !tool}
+	<div class="tool-grid">
+		<EmptyState
+			title="Tool not found"
+			description="No tool is registered under “{data.id}”."
+			icon={ToolIcon}
+		/>
+	</div>
+{:else if tool.sourceMode === "none"}
+	<div class="tool-grid">
+		<section class="settings-panel">{@render settingsPanel()}</section>
 		<section class="preview-panel">
 			<Panel>
 				<PanelHeading title="Preview" eyebrow="OUTPUT">
@@ -196,11 +268,9 @@
 					{#if previewError}
 						<EmptyState title="Preview failed" description={previewError} />
 					{:else if previewUrl}
-						<PreviewTile label="RESULT">
 						<CheckerCanvas size="large">
 							<img class="result-img" src={previewUrl} alt="result" />
 						</CheckerCanvas>
-						</PreviewTile>
 					{:else if tool.generate}
 						<div class="preview-loading">
 							<StatusLine label="generating preview" />
@@ -208,7 +278,7 @@
 					{:else}
 						<EmptyState
 							title="No live preview"
-							description="This tool runs on an uploaded image. Source upload arrives in a later step."
+							description="This tool runs on an uploaded image."
 							icon={ToolIcon}
 						/>
 					{/if}
@@ -217,6 +287,89 @@
 			</Panel>
 		</section>
 	</div>
+{:else if isFileTool}
+	<div class="tool-grid remover-grid">
+		<section class="settings-panel">{@render settingsPanel()}</section>
+		<section class="preview-panel">
+			<Panel>
+				<PanelHeading title="Source / Result" eyebrow="OUTPUT">
+					{#snippet actions()}
+						{#if resultUrl}
+							<DownloadButton
+								label="Download result"
+								onclick={downloadResult}
+							/>
+						{/if}
+					{/snippet}
+				</PanelHeading>
+				<div class="preview-body">
+					{#if previewError}
+						<EmptyState title="Processing failed" description={previewError} />
+					{/if}
+					{#if !sourceImg}
+						<Dropzone onfile={onFile} />
+					{:else}
+						<div class="comparison-grid">
+							<div class="image-card">
+								<div class="image-label">
+									<span>SOURCE</span><b>{sourceName}</b>
+								</div>
+								<div class="remover-canvas">
+									<CheckerCanvas size="large">
+										<img class="cmp-img" src={sourceUrl} alt="source" />
+									</CheckerCanvas>
+									<span class="canvas-size"
+										>{sourceImg.width} × {sourceImg.height}</span
+									>
+								</div>
+							</div>
+							<div class="image-card">
+								<div class="image-label">
+									<span>RESULT</span><b>{sourceName}</b>
+								</div>
+								<div class="remover-canvas">
+									{#if resultUrl}
+										<CheckerCanvas size="large">
+											<img class="cmp-img" src={resultUrl} alt="result" />
+										</CheckerCanvas>
+									{/if}
+									<span class="canvas-size"
+										>{resultImg
+											? `${resultImg.width} × ${resultImg.height}`
+											: "—"}</span
+									>
+								</div>
+							</div>
+						</div>
+						<div class="result-meta">
+							<span>FORMAT <b>PNG-24</b></span>
+							<span>ALPHA <b>ENABLED</b></span>
+							<span>STATUS <b class="ok">PROCESSED</b></span>
+						</div>
+						<Button variant="ghost" onclick={clearSource}
+							>Change image</Button
+						>
+					{/if}
+				</div>
+			</Panel>
+		</section>
+	</div>
+{:else}
+	<div class="tool-grid">
+		<section class="settings-panel">{@render settingsPanel()}</section>
+		<section class="preview-panel">
+			<Panel>
+				<PanelHeading title="Preview" eyebrow="OUTPUT" />
+				<div class="preview-body">
+					<EmptyState
+						title="Text source"
+						description="Paste text on the left — arrives in a later step."
+						icon={ToolIcon}
+					/>
+				</div>
+			</Panel>
+		</section>
+	</div>
 {/if}
 
 <style>
@@ -229,6 +382,9 @@
 		margin: 0 auto;
 		padding: 48px clamp(24px, 4vw, 72px) 72px;
 	}
+	.remover-grid {
+		grid-template-columns: minmax(360px, 0.62fr) minmax(0, 1.38fr);
+	}
 	.tool-desc {
 		margin: 0;
 		padding: 0.85rem 1rem;
@@ -277,8 +433,69 @@
 		display: block;
 		border-radius: var(--radius);
 	}
+	.comparison-grid {
+		display: grid;
+		grid-template-columns: repeat(2, minmax(0, 1fr));
+		gap: 18px;
+	}
+	.image-card {
+		min-width: 0;
+	}
+	.image-label {
+		display: flex;
+		justify-content: space-between;
+		gap: 8px;
+		margin-bottom: 10px;
+		font: 10px var(--font-mono);
+		color: var(--muted);
+		letter-spacing: 0.08em;
+	}
+	.image-label span {
+		color: var(--blue);
+	}
+	.image-label b {
+		font-weight: 400;
+	}
+	.remover-canvas {
+		position: relative;
+		overflow: hidden;
+	}
+	.cmp-img {
+		max-width: 100%;
+		max-height: 420px;
+		display: block;
+	}
+	.canvas-size {
+		position: absolute;
+		bottom: 9px;
+		right: 10px;
+		font: 9px var(--font-mono);
+		color: var(--muted);
+		background: color-mix(in srgb, var(--panel) 70%, transparent);
+		padding: 2px 5px;
+		border-radius: var(--radius);
+	}
+	.result-meta {
+		display: flex;
+		flex-wrap: wrap;
+		gap: 18px;
+		padding-top: 14px;
+		border-top: 1px solid var(--line);
+		font: 10px var(--font-mono);
+		color: var(--muted);
+		letter-spacing: 0.08em;
+	}
+	.result-meta b {
+		margin-left: 6px;
+		color: var(--foreground);
+		font-weight: 600;
+	}
+	.result-meta b.ok {
+		color: var(--success);
+	}
 	@media (max-width: 900px) {
-		.tool-grid {
+		.tool-grid,
+		.remover-grid {
 			grid-template-columns: 1fr;
 			gap: 24px;
 			padding: 32px 16px 48px;
@@ -286,5 +503,8 @@
 		.preview-panel {
 			position: static;
 		}
+		.comparison-grid {
+			grid-template-columns: 1fr;
+		}
 	}
 </style>