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  ./demo/canvas-001.js ./demo/canvas-002.js ./demo/canvas-003.js ./demo/canvas-004.js ./demo/canvas-005.js ./demo/canvas-006.js ./demo/canvas-007.js ./demo/canvas-008.js ./demo/canvas-009.js ./demo/canvas-010.js ./demo/canvas-011.js ./demo/canvas-012.js ./demo/canvas-013.js ./demo/canvas-014.js ./demo/canvas-015.js ./demo/canvas-015a.js ./demo/canvas-016.js ./demo/canvas-017.js ./demo/canvas-018.js ./demo/canvas-019.js ./demo/canvas-019a.js ./demo/canvas-020.js ./demo/canvas-021.js ./demo/canvas-022.js ./demo/canvas-023.js ./demo/canvas-024.js ./demo/canvas-025.js ./demo/canvas-026.js ./demo/canvas-027.js ./demo/canvas-028.js ./demo/canvas-029.js ./demo/canvas-030.js ./demo/canvas-031.js ./demo/canvas-032.js ./demo/canvas-033.js ./demo/canvas-034.js ./demo/canvas-035.js ./demo/canvas-036.js ./demo/canvas-037.js ./demo/canvas-038.js ./demo/canvas-039.js ./demo/canvas-040.js ./demo/canvas-041.js ./demo/canvas-042.js ./demo/canvas-043.js ./demo/canvas-044.js ./demo/canvas-045.js ./demo/canvas-046.js ./demo/canvas-047.js ./demo/canvas-048.js ./demo/canvas-049.js ./demo/canvas-050.js ./demo/canvas-051.js ./demo/canvas-052.js ./demo/canvas-053.js ./demo/canvas-054.js ./demo/canvas-055.js ./demo/canvas-056.js ./demo/canvas-058.js ./demo/canvas-059.js ./demo/canvas-060.js ./demo/canvas-061.js ./demo/canvas-062.js ./demo/canvas-063.js ./demo/canvas-064.js ./demo/core-001.js ./demo/delaunator-001.js ./demo/delaunator-002.js ./demo/dom-001.js ./demo/dom-002.js ./demo/dom-003.js ./demo/dom-004.js ./demo/dom-005.js ./demo/dom-006.js ./demo/dom-007.js ./demo/dom-008.js ./demo/dom-009.js ./demo/dom-010.js ./demo/dom-011.js ./demo/dom-012.js ./demo/dom-013.js ./demo/dom-015.js ./demo/dom-016.js ./demo/dom-017.js ./demo/dom-018.js ./demo/filters-001.js ./demo/filters-002.js ./demo/filters-002a.js ./demo/filters-003.js ./demo/filters-004.js ./demo/filters-005.js ./demo/filters-006.js ./demo/filters-007.js ./demo/filters-008.js ./demo/filters-009.js ./demo/filters-010.js ./demo/filters-011.js ./demo/filters-012.js ./demo/filters-013.js ./demo/filters-014.js ./demo/filters-015.js ./demo/filters-016.js ./demo/filters-017.js ./demo/filters-018.js ./demo/filters-019.js ./demo/filters-020.js ./demo/filters-021.js ./demo/filters-022.js ./demo/filters-023.js ./demo/filters-024.js ./demo/filters-025.js ./demo/filters-026.js ./demo/filters-027.js ./demo/filters-028.js ./demo/filters-101.js ./demo/filters-102.js ./demo/filters-103.js ./demo/filters-104.js ./demo/filters-105.js ./demo/filters-501.js ./demo/filters-502.js ./demo/filters-503.js ./demo/filters-504.js ./demo/filters-505.js ./demo/mediapipe-001.js ./demo/mediapipe-002.js ./demo/mediapipe-003.js ./demo/modules-001.js ./demo/modules-002.js ./demo/modules-003.js ./demo/modules-004.js ./demo/modules-005.js ./demo/modules-006.js ./demo/packets-001.js ./demo/packets-002.js ./demo/particles-001.js ./demo/particles-002.js ./demo/particles-003.js ./demo/particles-004.js ./demo/particles-005.js ./demo/particles-006.js ./demo/particles-007.js ./demo/particles-008.js ./demo/particles-009.js ./demo/particles-010.js ./demo/particles-011.js ./demo/particles-012.js ./demo/particles-013.js ./demo/particles-014.js ./demo/particles-015.js ./demo/particles-016.js ./demo/rapier-001.js ./demo/snippets-001.js ./demo/snippets-002.js ./demo/snippets-003.js ./demo/snippets-004.js ./demo/snippets-005.js ./demo/snippets-006.js ./demo/tensorflow-001.js ./demo/tensorflow-002.js ./demo/utilities.js

- §

  # Demo Canvas 032

  Freehand drawing

  - Note that the Polyline entity remains experimental technology and may be subject to breaking changes in future minor updates
- §

  Run code

      import * as scrawl from '../source/scrawl.js';

      import { reportSpeed } from './utilities.js';

- §

  #### Scene setup

      const canvas = scrawl.library.artefact.mycanvas,
          base = canvas.base;

- §

  Internal state variables

      const currentPins = [],
          lineHold = [],
          lineBin = [];

      let counter = 0,
          currentLine, lastX, lastY;

- §

  Use a color factory object to generate random colors within a restricted palette

      const myColorFactory = scrawl.makeColor({

          name: 'color-factory',
          minimumColor: 'red',
          maximumColor: 'green',
      });

- §

  Freehand line drawing functions, used by event listeners attached to the canvas element

      const startLine = function () {

          if (base.here.active) {

              const coord = base.here;

              if (coord) {

                  currentPins.push([coord.x, coord.y])

                  currentLine = scrawl.makePolyline({

                      name: `line-${counter}`,

                      pins: currentPins,
                      mapToPins: true,

                      tension: 0.3,

                      strokeStyle: myColorFactory.getRangeColor(Math.random()),
                      lineWidth: 4 + Math.floor(Math.random() * 20),

                      lineCap: 'round',
                      lineJoin: 'round',

                      method: 'draw',
                  });

                  counter++;
              }

          }
      };
      scrawl.addListener('down', startLine, canvas.domElement);

      const endLine = function () {

          if (currentLine) lineHold.push(currentLine);

          currentLine = false;
          currentPins.length = 0;
          lastX = lastY = -1;
      };
      scrawl.addListener(['up', 'leave'], endLine, canvas.domElement);

      const checkLine = function () {

          if (currentLine && base.here.active) {

              const coord = base.here;

              const x = coord.x,
                  y = coord.y;

              if (x === lastX && y === lastY) return false;

              currentPins.push([x, y]);

              currentLine.set({
                  pins: currentPins,
              });

              lastX = x;
              lastY = y;
          }
      };
      scrawl.addListener('move', checkLine, canvas.domElement);

- §

  #### Scene animation

  Function to display frames-per-second data, and other information relevant to the demo

      const report = reportSpeed('#reportmessage');

- §

  Create the Display cycle animation

      scrawl.makeRender({

          name: 'demo-animation',
          target: canvas,
          afterShow: report,
      });

- §

  #### User interaction

- §

  For this demo we will suppress touchmove functionality over the canvas

      scrawl.addNativeListener('touchmove', (e) => {

          e.preventDefault();
          e.returnValue = false;

      }, canvas.domElement);

- §

  Undo action

      scrawl.addNativeListener('click', () => {

          const line = lineHold.pop();

          if (line) {

              line.set({ visibility: false });
              lineBin.push(line);
          }

      }, '#undo-button');

- §

  Redo action

      scrawl.addNativeListener('click', () => {

          const line = lineBin.pop();

          if (line) {

              line.set({ visibility: true });
              lineHold.push(line);
          }

      }, '#redo-button');

- §

  Clear action

      scrawl.addNativeListener('click', () => {

          lineHold.forEach(line => line && line.kill());
          lineHold.length = 0;

          lineBin.forEach(line => line && line.kill());
          lineBin.length = 0;

      }, '#clear-button');

      console.log(scrawl.library);