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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 041

  Access and use a canvas context engine using the makeAnimation factory

- §

  Run code

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

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

- §

  Ignore pixel ratio considerations

  - Leads to issues when dragging the browser between screens with different pixel ratio densities

      scrawl.setIgnorePixelRatio(true);

- §

  #### Scene setup

      const canvas = scrawl.library.canvas.mycanvas;

      const boxes = [];

      const engine = {

          width: canvas.get("width"),
          height: canvas.get("height"),
          count: 1000,
      };

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  Setup the display canvas

      canvas.set({

          width: engine.width,
          height: engine.height,

      }).render();

- §

  Build and populate our cache Cell with pre-drawn boxes

      canvas.buildCell({

          name: 'cache',
          width: 50 * 40,
          height: 50,
          cleared: false,
          compiled: false,
          shown: false,
          willReadFrequently: false,
      });

      const source = scrawl.library.cell.cache.element;
      const sourceEngine = scrawl.library.cell.cache.engine;

      sourceEngine.fillStyle = 'white';
      sourceEngine.strokeStyle = 'black';
      sourceEngine.lineWidth = 1;

      for (let i = 0; i < 40; i++) {

          const size = 10 + i,
              delta = Math.floor(size / 2) + 0.5;

          sourceEngine.setTransform(1, 0, 0, 1, (50 * i) + 25, 25);
          sourceEngine.fillRect(-delta, -delta, size, size);
          sourceEngine.strokeRect(-delta, -delta, size, size);
      }

- §

  On start, and UI, create the required number of box objects

  - these are plain JS objects holding data for our box drawing routine

      const buildBoxes = function (boxesRequired) {

          const { width, height } = engine;
          let size, x, y, dx;

          boxes.length = 0;

          for (let i = 0; i < boxesRequired; i++) {

              size = 10 + Math.random() * 40;
              x = Math.floor(Math.random() * width);
              y = Math.floor(Math.random() * height);
              dx = -1 - Math.random();

              boxes.push([x, y, dx, Math.floor(size - 10)]);
          }
      };

- §

  Use the box data to draw the appropriate box images onto the screen at the required positions

      const drawBoxes = function () {

          const engineWidth = engine.width,
              ctx = canvas.base.engine;

          let box, x, y, deltaX, boxpos, width;

          return function () {

              ctx.setTransform(1, 0, 0, 1, 0, 0);

              for (let i = 0, iz = boxes.length; i < iz; i++) {

                  box = boxes[i];
                  [x, y, deltaX, boxpos] = box;
                  width = boxpos + 10

                  ctx.drawImage(source, ~~(boxpos * 50), 0, 50, 50, ~~(x - 25), ~~(y - 25), 50, 50);

                  x += deltaX;
                  if (x < -width) x += engineWidth + (width * 2);
                  box[0] = x;
              }
          }
      }();

- §

  Speed reporter

      const report = reportSpeed('#reportmessage', function () {

          return `Box count: ${boxes.length}`;
      });

- §

  The animation loop object

      scrawl.makeAnimation({

          name: 'demo-animation',

          fn: () => {

              if (boxes.length !== engine.count) buildBoxes(engine.count);

              canvas.clear();
              drawBoxes();
              canvas.show();
              report();
          },
      });

      scrawl.addListener("up", () => engine.count += 1000, canvas.domElement);

- §

  #### Development and testing

      console.log(scrawl.library);