paint-ui/tools/pencil-tool.ts

import { BaseTool } from './base-tool';
import type { PointerState, ToolSettings } from '@/types';

/**
 * Pencil tool - 1px drawing
 */
export class PencilTool extends BaseTool {
  constructor() {
    super('Pencil');
  }

  onPointerDown(
    pointer: PointerState,
    ctx: CanvasRenderingContext2D,
    settings: ToolSettings
  ): void {
    this.isDrawing = true;

    ctx.strokeStyle = settings.color;
    ctx.lineWidth = 1;
    ctx.lineCap = 'round';
    ctx.lineJoin = 'round';
    ctx.globalAlpha = settings.opacity;

    ctx.beginPath();
    ctx.moveTo(pointer.x, pointer.y);
  }

  onPointerMove(
    pointer: PointerState,
    ctx: CanvasRenderingContext2D,
    settings: ToolSettings
  ): void {
    if (!this.isDrawing) return;

    ctx.lineTo(pointer.x, pointer.y);
    ctx.stroke();
  }

  onPointerUp(
    pointer: PointerState,
    ctx: CanvasRenderingContext2D,
    settings: ToolSettings
  ): void {
    if (!this.isDrawing) return;

    this.isDrawing = false;
    ctx.globalAlpha = 1;
  }
}