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WebPadOnline! Draw on Websites! Take Notes! Doodle!

Allows drawing on websites when the control key and mouse button are pressed. Includes settings for color, line width, opacity, eraser tool, circle distance, softness, and shadow. Also includes undo, redo, clear all, save color, and clear color history buttons.

当前为 2024-02-08 提交的版本，查看 最新版本。

// ==UserScript==
// @name     WebPadOnline! Draw on Websites! Take Notes! Doodle!
// @namespace  https://greasyfork.org/en/scripts/486818-webpadonline-draw-on-websites-take-notes-doodle
// @version   0.8
// @description Allows drawing on websites when the control key and mouse button are pressed. Includes settings for color, line width, opacity, eraser tool, circle distance, softness, and shadow. Also includes undo, redo, clear all, save color, and clear color history buttons.
// @author    Heptatron
// @license MIT
// @match    *://*/*
// @grant    GM_setValue
// @grant    GM_getValue
// ==/UserScript==

(function() {
  'use strict';

  let canvas, ctx;
  let isDrawing = false;
  let lastX = 0;
  let lastY = 0;
  let history = [];
  let historyIndex = -1;
  let showControls = false;
  let colorHistory = [];

  // Default settings
  let settings = {
    color: 'black',
    lineWidth: 2,
    eraser: false,
    circleDistance: 2,
    opacity: 1,
    softness: 5,
    shadow: false
  };

  function createCanvas() {
    canvas = document.createElement('canvas');
    canvas.style.position = 'fixed';
    canvas.style.top = '0';
    canvas.style.left = '0';
    canvas.style.pointerEvents = 'none'; // To allow clicking through canvas
    canvas.style.zIndex = '9999'; // Ensure canvas is on top
    canvas.width = window.innerWidth;
    canvas.height = window.innerHeight;
    document.body.appendChild(canvas);
    ctx = canvas.getContext('2d');
  }

  function createOverlay() {
    const overlay = document.createElement('div');
    overlay.id = 'overlay';
    overlay.style.position = 'fixed';
    overlay.style.top = '0';
    overlay.style.left = '0';
    overlay.style.width = '100%';
    overlay.style.height = '100%';
    overlay.style.backgroundColor = 'rgba(0, 0, 0, 0)';
    overlay.style.zIndex = '9998'; // Below canvas, but above everything else
    overlay.style.display = 'none'; // Initially hidden
    document.body.appendChild(overlay);
  }

  function showOverlay() {
    const overlay = document.getElementById('overlay');
    overlay.style.display = 'block';
  }

  function hideOverlay() {
    const overlay = document.getElementById('overlay');
    overlay.style.display = 'none';
  }

  function startDrawing(e) {
    if ((e.ctrlKey && e.button === 0) || (e.ctrlKey && e.button === 2)) {
      isDrawing = true;
      [lastX, lastY] = [e.clientX, e.clientY];
      if (!settings.eraser) {
        addToHistory();
      }
    }
  }

  function draw(e) {
    if (!isDrawing) return;
    if (settings.eraser) {
        ctx.globalCompositeOperation = 'destination-out'; // Set the composite operation to erase
    } else {
        ctx.globalCompositeOperation = 'source-over'; // Set the composite operation to draw
    }
    // Use the same drawing logic as before
    const deltaX = e.clientX - lastX;
    const deltaY = e.clientY - lastY;
    const distance = Math.sqrt(deltaX * deltaX + deltaY * deltaY);
    const angle = Math.atan2(deltaY, deltaX);

    for (let i = 0; i < distance; i += settings.circleDistance) {
        const x = lastX + Math.cos(angle) * i;
        const y = lastY + Math.sin(angle) * i;
        ctx.beginPath();
        ctx.arc(x, y, settings.lineWidth / 2, 0, Math.PI * 2);
        ctx.fillStyle = settings.color;
        ctx.globalAlpha = settings.opacity;

        if (settings.shadow) {
            ctx.shadowColor = settings.color;
            ctx.shadowBlur = settings.lineWidth / 2;
        } else {
            ctx.shadowColor = 'transparent';
            ctx.shadowBlur = 0;
        }

        ctx.fill();
    }

    [lastX, lastY] = [e.clientX, e.clientY];
  }


  function stopDrawing() {
    isDrawing = false;
  }

  function init() {
    createCanvas();
    createOverlay(); // Add overlay initialization
    document.addEventListener('mousedown', startDrawing);
    document.addEventListener('mousemove', draw);
    document.addEventListener('mouseup', stopDrawing);
    createSettingsMenu();
    createButtons();
    document.addEventListener('keydown', handleKeyPress);
    document.addEventListener('keydown', toggleControls);
    document.addEventListener('keyup', toggleControls);
    loadSettings(); // Call loadSettings after all DOM manipulation is complete
    loadColorHistory();
  }

  function createSettingsMenu() {
    const settingsMenu = document.createElement('div');
    settingsMenu.id = 'settingsMenu';
    settingsMenu.style.display = 'none';
    settingsMenu.style.position = 'fixed';
    settingsMenu.style.top = '10px';
    settingsMenu.style.left = '10px';
    // Background color with 70% opacity
    settingsMenu.style.backgroundColor = 'rgba(77, 77, 77, 0.7)';
    settingsMenu.style.padding = '10px';
    settingsMenu.style.borderRadius = '5px';
    settingsMenu.style.zIndex = '10000'; // Ensure menu is on top
    settingsMenu.innerHTML = `
      <h3>Settings</h3>
      <label for="color">Color:</label>
      <input type="color" id="color" value="${settings.color}">
      <button id="saveColor">Save Color</button>
      <br>
      <div id="colorHistoryContainer"></div>
      <button id="clearColorHistory">Clear Color History</button>
      <br>
      <label for="lineWidth">Line Width:</label>
      <input type="range" id="lineWidth" min="0.5" max="100" step="0.5" value="${settings.lineWidth}">
      <br>
      <label for="circleDistance">Circle Distance:</label>
      <input type="number" id="circleDistance" min="1" value="${settings.circleDistance}">
      <br>
      <label for="eraser">Eraser:</label>
      <input type="checkbox" id="eraser">
      <br>
      <label for="opacity">Opacity:</label>
      <input type="range" id="opacity" min="0" max=".5" step="0.01" value="${settings.opacity}">
      <br>
      <label for="softness">Softness:</label>
      <input type="number" id="softness" min="1" value="${settings.softness}">
      <br>
      <label for="shadow">Shadow:</label>
      <input type="checkbox" id="shadow">
    `;
    document.body.appendChild(settingsMenu);

    const colorInput = document.getElementById('color');
    colorInput.addEventListener('input', function() {
      settings.color = colorInput.value;
      GM_setValue('color', settings.color);
    });

    const lineWidthInput = document.getElementById('lineWidth');
    lineWidthInput.addEventListener('input', function() {
      settings.lineWidth = parseFloat(lineWidthInput.value);
      GM_setValue('lineWidth', settings.lineWidth);
    });

    const circleDistanceInput = document.getElementById('circleDistance');
    circleDistanceInput.addEventListener('input', function() {
      settings.circleDistance = parseInt(circleDistanceInput.value);
      GM_setValue('circleDistance', settings.circleDistance);
    });

    const eraserCheckbox = document.getElementById('eraser');
    eraserCheckbox.checked = settings.eraser;
    eraserCheckbox.addEventListener('change', function() {
      settings.eraser = eraserCheckbox.checked;
      GM_setValue('eraser', settings.eraser);
    });

    const opacityInput = document.getElementById('opacity');
    opacityInput.addEventListener('input', function() {
      settings.opacity = parseFloat(opacityInput.value);
      GM_setValue('opacity', settings.opacity);
      ctx.globalAlpha = settings.opacity;
    });

    const softnessInput = document.getElementById('softness');
    softnessInput.addEventListener('input', function() {
      settings.softness = parseInt(softnessInput.value);
      GM_setValue('softness', settings.softness);
    });

    const shadowCheckbox = document.getElementById('shadow');
    shadowCheckbox.checked = settings.shadow;
    shadowCheckbox.addEventListener('change', function() {
      settings.shadow = shadowCheckbox.checked;
      GM_setValue('shadow', settings.shadow);
    });

    const saveColorButton = document.getElementById('saveColor');
    saveColorButton.addEventListener('click', saveColor);

    const clearColorHistoryButton = document.getElementById('clearColorHistory');
    clearColorHistoryButton.addEventListener('click', clearColorHistory);
  }

  function createButtons() {
    const buttonsContainer = document.createElement('div');
    buttonsContainer.id = 'buttonsContainer';
    buttonsContainer.style.display = 'none';
    buttonsContainer.style.position = 'fixed';
    buttonsContainer.style.top = '10px';
    buttonsContainer.style.right = '10px';
    buttonsContainer.style.zIndex = '10000'; // Ensure buttons are on top

    const undoButton = document.createElement('button');
    undoButton.textContent = 'Undo (Ctrl + Z)';
    undoButton.addEventListener('click', undo);
    buttonsContainer.appendChild(undoButton);

    const redoButton = document.createElement('button');
    redoButton.textContent = 'Redo (Ctrl + Shift + Z)';
    redoButton.addEventListener('click', redo);
    buttonsContainer.appendChild(redoButton);

    const clearButton = document.createElement('button');
    clearButton.textContent = 'Clear All';
    clearButton.addEventListener('click', clearCanvas);
    buttonsContainer.appendChild(clearButton);

    document.body.appendChild(buttonsContainer);
  }

  function handleKeyPress(e) {
    if (e.ctrlKey && e.key === 'z') {
      if (e.shiftKey) {
        redo();
      } else {
        undo();
      }
    }
  }

  function addToHistory() {
    if (historyIndex !== history.length - 1) {
      history = history.slice(0, historyIndex + 1);
    }
    const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
    history.push(imageData);
    historyIndex++;
  }

  function undo() {
    if (historyIndex > 0) {
      historyIndex--;
      ctx.putImageData(history[historyIndex], 0, 0);
    }
  }

  function redo() {
    if (historyIndex < history.length - 1) {
      historyIndex++;
      ctx.putImageData(history[historyIndex], 0, 0);
    }
  }

  function clearCanvas() {
    ctx.clearRect(0, 0, canvas.width, canvas.height);
    history = [];
    historyIndex = -1;
  }

  function loadSettings() {
    const savedColor = GM_getValue('color', settings.color);
    settings.color = savedColor;
    document.getElementById('color').value = savedColor;

    const savedLineWidth = parseFloat(GM_getValue('lineWidth', settings.lineWidth));
    settings.lineWidth = savedLineWidth;
    document.getElementById('lineWidth').value = savedLineWidth;

    const savedCircleDistance = parseInt(GM_getValue('circleDistance', settings.circleDistance));
    settings.circleDistance = savedCircleDistance;
    document.getElementById('circleDistance').value = savedCircleDistance;

    const savedEraser = GM_getValue('eraser', settings.eraser);
    settings.eraser = savedEraser;
    document.getElementById('eraser').checked = savedEraser;

    const savedOpacity = parseFloat(GM_getValue('opacity', settings.opacity));
    settings.opacity = savedOpacity;
    document.getElementById('opacity').value = savedOpacity;

    const savedSoftness = parseInt(GM_getValue('softness', settings.softness));
    settings.softness = savedSoftness;
    document.getElementById('softness').value = savedSoftness;

    const savedShadow = GM_getValue('shadow', settings.shadow);
    settings.shadow = savedShadow;
    document.getElementById('shadow').checked = savedShadow;
  }

  function toggleControls(e) {
    if (e.ctrlKey && e.altKey) {
      const settingsMenu = document.getElementById('settingsMenu');
      const buttonsContainer = document.getElementById('buttonsContainer');
      if (!showControls) {
        settingsMenu.style.display = 'block';
        buttonsContainer.style.display = 'block';
        showControls = true;
        showOverlay();
        createColorHistoryButtons();
      } else {
        settingsMenu.style.display = 'none';
        buttonsContainer.style.display = 'none';
        showControls = false;
        hideOverlay();
        clearColorHistoryButtons();
      }
    }
  }

  function createColorHistoryButtons() {
    const colorHistoryContainer = document.getElementById('colorHistoryContainer');
    colorHistoryContainer.innerHTML = '';
    let row;
    colorHistory.forEach((color, index) => {
      if (index % 10 === 0) {
        row = document.createElement('div');
        row.style.display = 'flex';
        row.style.flexWrap = 'wrap';
        colorHistoryContainer.appendChild(row);
      }
      const colorButton = document.createElement('button');
      colorButton.textContent = '';
      colorButton.style.width = '20px';
      colorButton.style.height = '20px';
      colorButton.style.backgroundColor = color;
      colorButton.style.marginRight = '5px';
      colorButton.style.marginBottom = '5px'; // Add bottom margin for better spacing
      colorButton.addEventListener('click', () => {
        settings.color = color;
        document.getElementById('color').value = color;
        GM_setValue('color', settings.color);
      });
      row.appendChild(colorButton);
    });
  }

  function clearColorHistoryButtons() {
    const colorHistoryContainer = document.getElementById('colorHistoryContainer');
    colorHistoryContainer.innerHTML = '';
  }

  function saveColor() {
    const colorInput = document.getElementById('color');
    const color = colorInput.value;
    if (!colorHistory.includes(color)) {
      colorHistory.push(color);
      GM_setValue('colorHistory', JSON.stringify(colorHistory));
      createColorHistoryButtons();
    }
  }

  function clearColorHistory() {
    colorHistory = [];
    GM_setValue('colorHistory', JSON.stringify(colorHistory));
    clearColorHistoryButtons();
  }

  function loadColorHistory() {
    const savedColorHistory = JSON.parse(GM_getValue('colorHistory', '[]'));
    colorHistory = savedColorHistory;
    createColorHistoryButtons();
  }

  init();

})();