Diaaagram (a.k.a. react-diagram)

A diagram drawing application which is demonstrating how we can utilize React.js and HTML <canvas/> to create an interactive drawing.

Application URL

https://draw.crispyscript.com (works best in desktop)

Demo

Demo.mp4

Feature Roadmap

• Line drawing tool
• Rectangle drawing tool
• Pencil drawing tool(free-hand)
• Selection tool for moving and resizing a single element
• Undo/Redo/Clear
• Text tool
• Support deleting a selected element
• Arrow drawing tool
  • https://stackoverflow.com/a/26806316
  • https://codesandbox.io/s/magical-feynman-mtuziv?file=/src/index.js
• Pan
• Zoom
• CSS & Styling
• Mobile & Resizing friendly
• Multi-select elements
• Support uploading an image
• Duplicate elements
• Send to back/front
• Save the result to file / local storage (need to serialize the image)
• Limit max history stack to ~50 items
• Export canvas to png/jpeg
• Rotate
• Keyboard shortcut
• Setting stroke color
• Setting stroke width
• Filled rectangle
• Copy & Paste elements (upgrade "Duplicate" feature)

Developer Notes

Start the app locally

1. Run yarn to install all dependencies
2. Run yarn start to start the app locally

Steps for running visual tests

1. Run yarn visual:test to do regression test
2. If there is any failed test, investigate it one-by-one by going to ./cypress/snapshots/diff directory.
3. After a specific test file is fixed. To override all base screenshots of that file, run the following command.

   # We want to override ALL screenshots for test-file.spec.js file
   yarn cypress run --env type=base --config screenshotsFolder=cypress/snapshots/base,trashAssetsBeforeRuns=false --spec "cypress/integration/test-file.spec.js"

4. Repeat step 2-3 until yarn visual:test results all passed.
5. Only after all tests are passed, clean up all existing screenshots and re-create them from scratch by running yarn visual:dangerously-override-all-base. Note that, this command is dangerous since you will lose all existing screenshots.

Note: Tests may fail due to OS difference. All base screenshots are created on Macbook Pro 13".

More info: cypress-visual-regression Doc

Temporary functions for export/import diagram

The following functions are temporary. Mostly use for debugging. In the future, we will implement a proper export/import feature.

• exportSnapshot() to export the diagram (must not have any image element)
• importSnapshot(value) to import, value is the result of calling exportSnapshot() (must not have any image element)

Icons

https://phosphoricons.com/

Naming Confusion

• Most of x, y value are in scene coordinate (i.e. canvas coord, not viewport coord). They are inconsistency in naming. For example,

  // All of these variable names are in `scene` coord
  let sceneX, x1, x2, pointerX

• However, the viewport coordinate is more consistency in naming.

  // There always be `viewport` keyword in `viewport` coord
  let viewportX