canvas-drawing

a easy to use drawing board lib 🎨

• 0 dependencies
• Modern browser compatibility

Installing

Using npm:

npm install canvas-drawing

Using yarn:

yarn add canvas-drawing

Using script tag

<script src="your_path/dist/canvas-drawing.min.js"></script>

Play

live example

or

git clone this repository then open example/index.html in your browser

Usage

Initialize

<script type="text/javascript" src="//{you path to the dist file}/dist/canvas-drawing.min.js"></script>
<style>.container { width: 500px; height: 500px; }</style>
<div class="container"></div>

// More options are available in the following documents
const options = {
  container: document.getElementsByClassName('container')[0]
}
/*
  A canvas has 2 sizes, the dimension of the pixels in the canvas and the display size. 
  canvas's dimension of the pixels is (devicePixelRatio * canvas's display size) by default.
  canvas's display size equals container's size (width/height)
*/  
const draw = new canvasDrawing(options); 

Options

| Options | Type | Default value | Description | | :------------------ | :----------------: | :---------------------: | :-------------------------------------------- | | container | HtmlDom (required) | / | Container for canvas | | bgImg | String | Empty string | Canvas background Image's url, if you needed. | | canvasBgColor | String | #fff | Canvas background Color | | lineColor | String | #f00 | Color of brush | | lineWidth | String / Number | 1 | Width of brush | | arrowSize | String / Number | 15 | Size of arrows | | eraserSize | String / Number | 10 | Size of eraser | | textFontSize | String / Number | 16 | Font size of the textArea | | textLineHeight | String / Number | 20 | Font lineheight of the textArea | | textColor | String | #f00 | Font color of the textArea | | textareaPlaceholder | String | Type here... | Textarea's placeholder | | ratio | Nubmer | window.devicePixelRatio | Affects the quality of the picture |

APIs

| Method | Arguments | Description | | :--------------------: | :-------------------------------------------------------------------------------------------------------------------------------------------------- | :----------------------------------------- | | config( type,val ) | tpye's enum(lineColor, lineWidth, arrowSize, eraserSize, canvasBgColor, textFontSize, textLineHeight, textColor, bgImg, textareaPlaceholder, ratio) | Modifying the default configuration | | setMode( mode ) | mode's enum(pencil, straightLine, rect, circle, arrow, text, eraser) | Set current mode | | saveImg( [options] ) | default value { tpye: 'png', fileName: 'canvas_imgae' } | Save the canvas as an image, and download. | | generateBase64([type]) | default value "png" | Generate Base64 data | | undo() | / | Undo operation | | redo() | / | Redo operation | | clear() | / | Clear canvas |

Listeners

coords it will return canvas's coords (x, y) and Mouse's coords (clientX, clientY)

drawBegin

  import CanvasDrawing from 'canvas-drawing'
  const draw = new CanvasDrawing({container: Dom})
  draw.evt.on('drawBegin', function(coords) {
    console.log('begin', coords);  
  })

drawing

  draw.evt.on('drawing', function(coords) {
    console.log('drawing', coords);  
  })

drawEnd

  draw.evt.on('drawEnd', function(coords) {
    console.log('end', coords);
  })

removeListeners

  draw.evt.off('drawBegin');
  draw.evt.off('drawing');
  draw.evt.off('drawEnd');
  // or
  draw.evt.removeAllListeners();

Example

  // init
  import CanvasDrawing from 'canvas-drawing'
  const container = document.getElementsByClassName('container')[0]
  const draw = new CanvasDrawing({container: container})

  // methods
  draw.conifg('lineColor', '#FF1493')                         // Change the color of the brush.
  draw.setMode('rect')                                        // Now you can draw the rectangle.

  draw.generateBase64().then(data => console.log(data))       // generateBase64 method default is to export the PNG base64 data.                  
  draw.generateBase64('jpeg').then(data => console.log(data)) // get smaller data.              

  draw.saveImg()                                              // Save the canvas as an PNG images, and the file name is canvas_imgae.png.
  draw.saveImg({fileName: '233.png'})                         // Just Change of file name.
  draw.saveImg({tpye: 'jpeg', fileName: 'small.jpeg'})        // Sometimes we just need smaller pictures.

License

MIT