• refactor: refactor offset of controller

• feature: Add @idraw/renderer to replace opts.onlyRender
• refactor: split engine from mixin/event for @idraw/core
• refactor: Deprecate opts.onlyRender

• feat: add toDataURL to idraw
• feat: add helperContext to @idraw/board
• refactor: add Context render to @idraw/renderer
• refactor: rename getDisplayContext2D and getOriginContext2D

• refactor: separate @idraw/renderer from @idraw/core

• fix: scroll to the y-end and unlock the wheel event
• refactor: refactor drawing circle
• build: output *.global.min.js

• feat: add operation.disableScale and operation.disableRotate to Element
• refactor: rename dot to controller

• fix: board event in iframes

fix: eliminate interference when other elements are invisible

• feat: add stroke to text-element
• feat: add textShadow and shadow to element-text
• feat: add shadow to element-rect
• feat: add shadow to element-circle
• fixbug: click block area twice to cancel selected-element

fix: click block area twice to cancel selected-element