feat: add color picker

web/src/lib/components/ParamForm.svelte

@@ -9,12 +9,15 @@
 	interface Props {
 		params: ParamDef[];
 		values: Record<string, any>;
+		pipetteTargetId?: string | null;
+		onPipetteToggle?: (id: string) => void;
 	}
 
-	let { params, values = $bindable() }: Props = $props();
+	let { params, values = $bindable(), pipetteTargetId = null, onPipetteToggle }: Props = $props();
 </script>
 
 {#each params as param (param.id)}
+	<div class="field">
 		{#if param.type === 'checkbox'}
 			<CheckboxField id={param.id} label={param.label} bind:checked={values[param.id]} />
 		{:else if param.type === 'number'}
@@ -45,6 +48,13 @@
 				bind:value={values[param.id]}
 			/>
 		{:else if param.type === 'color'}
-		<ColorField id={param.id} label={param.label} bind:value={values[param.id]} />
+			<ColorField
+				id={param.id}
+				label={param.label}
+				bind:value={values[param.id]}
+				pipetteActive={pipetteTargetId === param.id}
+				onPipetteToggle={() => onPipetteToggle?.(param.id)}
+			/>
 		{/if}
+	</div>
 {/each}

web/src/lib/components/Preview.svelte

@@ -1,7 +1,14 @@
 <script lang="ts">
+	import { rgbToHex } from '$lib/core/color';
 	import type { PixelImage } from '$lib/core/types';
 
-	let { image }: { image: PixelImage | null } = $props();
+	interface Props {
+		image: PixelImage | null;
+		pipetteActive?: boolean;
+		onPickColor?: (hex: string) => void;
+	}
+
+	let { image, pipetteActive = false, onPickColor }: Props = $props();
 
 	let canvas = $state<HTMLCanvasElement | undefined>();
 
@@ -13,10 +20,29 @@
 		if (!ctx) return;
 		ctx.putImageData(new ImageData(image.data, image.width, image.height), 0, 0);
 	});
+
+	function pickColor(event: MouseEvent) {
+		if (!pipetteActive || !onPickColor || !canvas) return;
+		const rect = canvas.getBoundingClientRect();
+		if (rect.width === 0 || rect.height === 0) return;
+		const x = Math.floor((event.clientX - rect.left) * (canvas.width / rect.width));
+		const y = Math.floor((event.clientY - rect.top) * (canvas.height / rect.height));
+		if (x < 0 || y < 0 || x >= canvas.width || y >= canvas.height) return;
+		const ctx = canvas.getContext('2d');
+		if (!ctx) return;
+		const [r, g, b] = ctx.getImageData(x, y, 1, 1).data;
+		onPickColor(rgbToHex(r, g, b));
+	}
 </script>
 
 {#if image}
-	<canvas bind:this={canvas} title="{image.width} × {image.height}"></canvas>
+	<!-- svelte-ignore a11y_no_static_element_interactions -->
+	<canvas
+		bind:this={canvas}
+		title="{image.width} × {image.height}"
+		class:pipette={pipetteActive}
+		onclick={pickColor}
+	></canvas>
 	<p class="dims">{image.width} × {image.height} px</p>
 {/if}
 
@@ -32,9 +58,13 @@
 		border-radius: var(--radius-m);
 	}
 
+	canvas.pipette {
+		cursor: crosshair;
+	}
+
 	.dims {
 		margin-top: var(--space-1);
 		color: var(--text-muted);
-		font-size: 0.85rem;
+		font-size: var(--text-s);
 	}
 </style>

web/src/lib/components/ToolPage.svelte

@@ -26,6 +26,17 @@
 	let runToken = 0;
 	let lastRunSource: PixelImage | null = null;
 	let lastRunValuesJson = '';
+	let pipetteTargetId = $state<string | null>(null);
+
+	function handlePipetteToggle(id: string) {
+		pipetteTargetId = pipetteTargetId === id ? null : id;
+	}
+
+	function handlePickColor(hex: string) {
+		if (!pipetteTargetId) return;
+		values[pipetteTargetId] = hex;
+		pipetteTargetId = null;
+	}
 
 	async function handleFile(file: File) {
 		errorText = '';
@@ -36,6 +47,7 @@
 			result = null;
 			previewResult = null;
 			showMask = false;
+			pipetteTargetId = null;
 			info = isInfo ? imageInfo(source) : null;
 			if (isInfo) {
 				status = 'loaded';
@@ -90,6 +102,7 @@
 		result = null;
 		previewResult = null;
 		showMask = false;
+		pipetteTargetId = null;
 		info = null;
 		errorText = '';
 		status = 'idle';
@@ -132,6 +145,8 @@
 				onFile={handleFile}
 				onError={(message) => (errorText = message)}
 				onReset={reset}
+				pipetteActive={!!pipetteTargetId}
+				onPickColor={handlePickColor}
 			/>
 		</div>
 		<div class="cell">
@@ -151,7 +166,12 @@
 	</div>
 
 	{#if source && !isInfo}
-		<ParamsCard params={tool.params} bind:values />
+		<ParamsCard
+			params={tool.params}
+			bind:values
+			{pipetteTargetId}
+			onPipetteToggle={handlePipetteToggle}
+		/>
 	{/if}
 </section>
 

web/src/lib/components/tool/ParamsCard.svelte

@@ -5,15 +5,17 @@
 	interface Props {
 		params: ParamDef[];
 		values: Record<string, any>;
+		pipetteTargetId?: string | null;
+		onPipetteToggle?: (id: string) => void;
 	}
 
-	let { params, values = $bindable() }: Props = $props();
+	let { params, values = $bindable(), pipetteTargetId = null, onPipetteToggle }: Props = $props();
 </script>
 
 <div class="panel root">
 	<h2 class="heading-section">Параметры</h2>
 	{#if params.length > 0}
-		<ParamForm {params} bind:values />
+		<ParamForm {params} bind:values {pipetteTargetId} {onPipetteToggle} />
 	{:else}
 		<p class="hint text-caption text-muted">
 			У этого инструмента нет параметров — результат уже готов.

web/src/lib/components/tool/SourceCard.svelte

@@ -10,9 +10,11 @@
 		onFile: (file: File) => void;
 		onError: (message: string) => void;
 		onReset: () => void;
+		pipetteActive?: boolean;
+		onPickColor?: (hex: string) => void;
 	}
 
-	let { source, onFile, onError, onReset }: Props = $props();
+	let { source, onFile, onError, onReset, pipetteActive = false, onPickColor }: Props = $props();
 </script>
 
 <div class="container">
@@ -22,7 +24,7 @@
 	{:else}
 		<DropOverlay {onFile} {onError}>
 			<div class="media">
-				<Preview image={source} />
+				<Preview image={source} pipetteActive={pipetteActive} onPickColor={onPickColor} />
 			</div>
 			<Button variant="secondary" onclick={onReset}>Заменить изображение</Button>
 		</DropOverlay>

web/src/lib/components/ui/ColorField.svelte

@@ -6,20 +6,75 @@
 		label: string;
 		value?: string;
 		hint?: string;
+		pipetteActive?: boolean;
+		onPipetteToggle?: () => void;
 	}
 
-	let { id, label, value = $bindable('#000000'), hint }: Props = $props();
+	let { id, label, value = $bindable('#000000'), hint, pipetteActive = false, onPipetteToggle }:
+		Props = $props();
 </script>
 
 <Field {id} {label} {hint}>
+	<div class="row">
 		<input id={id} class="control swatch" type="color" bind:value />
+		{#if onPipetteToggle}
+			<button
+				type="button"
+				class="pipette"
+				aria-label="Пипетка"
+				aria-pressed={pipetteActive}
+				title="Пипетка"
+				onclick={onPipetteToggle}
+			>
+				◎
+			</button>
+		{/if}
+	</div>
 </Field>
 
 <style>
+	.row {
+		display: flex;
+		align-items: center;
+		gap: var(--space-1);
+	}
+
 	.swatch {
 		height: var(--control-height);
 		width: 3.5rem;
 		padding: 2px;
 		cursor: pointer;
 	}
+
+	.pipette {
+		flex: none;
+		width: var(--control-height);
+		height: var(--control-height);
+		display: inline-flex;
+		align-items: center;
+		justify-content: center;
+		padding: 0;
+		border: 1px solid var(--border);
+		border-radius: var(--radius-s);
+		background: var(--surface);
+		color: var(--text-muted);
+		font-size: 1.1rem;
+		line-height: 1;
+		cursor: pointer;
+		transition:
+			border-color var(--transition-fast),
+			color var(--transition-fast),
+			background var(--transition-fast);
+	}
+
+	.pipette:hover {
+		border-color: var(--accent);
+		color: var(--accent);
+	}
+
+	.pipette[aria-pressed='true'] {
+		border-color: var(--accent);
+		color: var(--accent);
+		background: color-mix(in srgb, var(--accent) 10%, var(--surface));
+	}
 </style>