paper-pen

$3

> canvas、 annotation、annotate、Rect、Polygon、Line、Dot、Text、Matrix.

- Quick start

> npm i paper-pen --save

>

online example

- features (待实现)

- mask 超像素标注
- group 编组
- text editor

- demo

``js
//demo.html
;
// demo.js
import { Canvas } from "paper-pen";
let paperPen = new Canvas(
"#c", // id 、class string (#c, .c)| HTMLCanvasElement
{
// options
width: 1600, // canvas width
height: 700, // canvas height
preventDefault: true, // prevent right click
selection: true, // can or not renderTop
skipFindTarget: false, // skip find target， default false
}
);
paperPen.setBackground("Your Image Url"); // set background
paperPen.on("img:load", () => {
// do anything
});
`

> Now you hava a 1600 * 700 canvas and set a background image for it.

- 是否开启滚轮缩放 (Whether to enable wheel scaling)

> wheel: {scale: true}

`js
import { Canvas } from 'paper-pen'
let canvas = new Canvas({
'#c',
{
wheel: {
scale: true, // 开启此项，会使滚轮支持画布缩放
scroll: true, // 开启此项，会使鼠标滚轮在画布中禁用滚动条
}
}
})

`

- 是否开启鼠标右键拖动画布(Do you want to enable the right mouse button to drag the canvas)

> rightMove: true

`js
import { Canvas } from 'paper-pen'
let canvas = new Canvas({
'#c',
{
rightMove: true
}
})
`

- How to draw other shape(Rect、Polygon、Line、Point、and so on.)

- For example --- Rect

`js
import { Rect, Polygon } from "paper-pen";
let rect = new Rect({
left: 300,
top: 300,
width: 100,
height: 100,
stroke: "#000",
opacity: 0.5,
});
paperPen.add(rect);

let poly = new Polygon({
points: [
{ x: 100, y: 100 },
{ x: 200, y: 100 },
{ x: 150, y: 350 },
],
stroke: "#0f0",
opacity: 0.5,
fill: "#00f",
lineWidth: 5,
});
paperPen.add(poly);
`

> Now you get a Rect

this Library provide (Rect、Polygon、Line、Point、CrossLine、Text、Ruler、Arrow), Of course you can custom other Shapes by this Library.

#### API

- class
> need to call with 'new' new Rect() new Line()...

| name | description |
| :-------- | :----------------------- |
| Canvas | Canvas Instance |
| Rect | draw Rectangle, Instance |
| Polygon | draw Polygon, Instance |
| Point | draw Point, Instance |
| Line | draw Line, Instance |
| CrossLine | draw CrossLine, Instance |
| Text | draw Text, Instance |
| Ruler | draw Ruler, Instance |
| Arrow | draw Arrow, Instance |
| Matrix | Matrix transform |

- Canvas properties

| name | type | description |
| :-------------- | :------ | :--------------------------------------- |
| width | number | canvas width |
| height | number | canvas height |
| skipFindTarget | boolean | skip find element |
| preventDefault | boolean | prevent right click |
| selection | boolean | can or not renderTop |
| transformMatrix | object | matrix {a,b,c,d,e,f} |
| \_objects | array | [shape, shape] |
| imageFillMode | string | 'contain'、'cover',针对 backgroundImage |
| wheel | object | 鼠标滚轮相关 |
| wheel.scale | boolean | 是否开启滚轮缩放，default false |
| wheel.scroll | boolean | 是否缩放时禁用浏览器滚动条 default false |
| wheel.max | number | 缩放最大范围 |
| wheel.min | number | 缩放最小范围 |
| rightMove | boolean | 右键移动画布 default false |

- shape common properties

| name | type | description |
| :---------------- | :------ | :------------------------------------ | ------- |
| stroke | string | canvas strokeStyle |
| fill | string | canvas fillStyle |
| lineWidth | number | lineWidth |
| opacity | number | 0-1 globalAlpha |
| cornerSize | number |
| cornerStyle | string | 'square | circle' |
| cornerBorderColor | string | color |
| cornerColor | string |
| cornerOpacity | number | 0 - 1 |
| lockMove | boolean |
| displayGraph | boolean | 用来决定是否显示当前图形 default true |
| needControl | boolean | 是否显示控制点 default true |

- shape common methods

| name | type | description |
| :-------------- | :--- | :----------------- |
| getBoundingBox | | 获取包围盒 |
| getCommonConfig | | 获取控制点默认配置 |

- rect properties

| name | type | description |
| :----- | :----- | :---------- |
| left | number | |
| top | number | |
| width | number | width |
| height | number | height |

-polygon properties

| name | type | description |
| :----------------- | :---------------------------- | :--------------------------------------------------------------- |
| points | Array<{x: number, y: number}> | |
| needArrow | boolean | 是否需要起始箭头 |
| needCenterControl | boolean | 是否需要线段中点 |
| centerPointsStyle | string | 'square'\| 'circle' 中点样式 |
| centerPointsSize | number | 中点大小 |
| centerPointsStroke | string | 中点描边颜色 |
| centerPointsFill | string | 中点填充颜色 |
| isDouble | Array | 是否绘制双线, 传一个值，就是单线，两个就是双线,取值范围[0-1] |
| isDash | Array | 是否绘制虚线, 传一个值，就是单虚线，两个就是双虚线,取值范围[0-1] |
| doubleLineDistance | number | 两线间距离 |

- instance methods

| name | description | parameter | return |
| :------------------------- | :---------------------------------------------------------------------- | :-------------------------------------------------------- | :--------------------------------------------------------- |
| setBackground | set canvas background | imgUrl\|Image\|Video\|Canvas\|bitmap |
| getPointer | Obtain the coordinates of the mouse on the canvas | null | {x number, y:number} |
| add | Add elements to object list | DrawObject | |
| remove | remove elements from object list | DrawObject | |
| setActiveObject | set the current object to active | DrawObject | |
| setCursor | set the cursor of canvas | css cursor | |
| resetActive | Deactivate all objects | null | |
| toJSON | get all elements on the canvas | null | [{},{}] |
| requestRenderAll | clear all Objects on the canvas, draw all objects on the canvas | null |
| toDataUrl | 将画布转换为图片（Convert Canvas to Pictures） | null | {imgData, imgUrl} |
| toBitMap | 将画布转换为单通道位图（Convert the canvas to a single channel bitmap） | [{r:number,g: number,b:number,a?:number},...]\|null | new Promise (ImageBitmap) 不传参数，默认转为二值图（黑白） |
| off | 卸载指定事件 | (事件名称，回调函数) | |
| offAll | 卸载监听事件， 不传参，卸载所有实例监听事件 | 事件名称，如：'mouse:down',将会卸载所有的 mouse:down 事件 | |
| removeUpperCanvasMoveEvent | 卸载画布移动事件, 应用于鼠标在画布外时 | null |

- eventListener

| name | description | callback |
| :------------ | :------------------------------------------- | :------- |
| mouse:down | 鼠标按下事件 |
| mouse:move | 鼠标移动事件 |
| mouse:wheel | 鼠标滚轮事件 |
| mouse:up | 鼠标抬起事件 |
| img:load | 当背景图是在线地址时，等图片加载完成后的回调 |
| render:before | 画布元素渲染前 |
| render:after | 画布元素渲染后 |
| obj:add | 元素被添加到画布后 |
| obj:remove | 元素从画布中删除后 |
| obj:edit | 元素被编辑后 |
| obj:move | 元素被移动后 |

`js
// paper-pen为开发者提供了mouse:down 、mouse:move、mouse:up、img:load、after:render事件回调。
paperPen.on("mouse:down", (opt) => {
let pos = paperPen.getPointer(opt); // 获取鼠标按下的点映射到当前画布的真实坐标位置。
console.log(pos);
// 您能在此处做想要做的业务。
});
paperPen.off("mouse:down"); // 此方法会去掉画布上所有的mouse:down事件, 最好指定第二个参数来删除对应的事件。
paperPen.on("mouse:down", handleMouseDown);
paperPen.off("mouse:down", handleMouseDown);
`

- Matrix， Support chain operation（支持链式操作）

| name | decription | params | type |
| :----------- | :--------------------------------------------------- | :---------- | :----- |
| translate | translate matrix | x , y | number |
| scale | Multiples corresponding to x-axis and y-axis scaling | x, y | number |
| scaleU | scale Matrix | scaler | number |
| rotate | rotate matrix | radian | number |
| transform | transform matrix | a,b,c,d,e,f | number |
| applyToPoint | Apply the current matrix to point | x, y | number |

`js
import { Matrix } from "paper-pen";
let mat = new Matrix(); /*
默认生成单位矩阵
1, 0, 0,
0, 1, 0,
0, 0, 1
*/
mat.translate(10, 10); // (1, 0, 0, 1, 10, 10) 返回新的矩阵
mat.translate(100, 100).scale(1.5, 2); // 这里的换算都是用矩阵的叉乘。
``