update.js
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import {
getNewScale
} from './core/scale'
export default function update () {
const self = this
if (!self.src) return
self.__oneTouchStart = (touch) => {
self.touchX0 = Math.round(touch.x)
self.touchY0 = Math.round(touch.y)
}
self.__oneTouchMove = (touch) => {
let xMove, yMove
// 计算单指移动的距离
if (self.touchended) {
return self.updateCanvas()
}
xMove = Math.round(touch.x - self.touchX0)
yMove = Math.round(touch.y - self.touchY0)
const imgLeft = Math.round(self.rectX + xMove)
const imgTop = Math.round(self.rectY + yMove)
self.outsideBound(imgLeft, imgTop)
self.updateCanvas()
}
self.__twoTouchStart = (touch0, touch1) => {
let xMove, yMove, oldDistance
self.touchX1 = Math.round(self.rectX + self.scaleWidth / 2)
self.touchY1 = Math.round(self.rectY + self.scaleHeight / 2)
// 计算两指距离
xMove = Math.round(touch1.x - touch0.x)
yMove = Math.round(touch1.y - touch0.y)
oldDistance = Math.round(Math.sqrt(xMove * xMove + yMove * yMove))
self.oldDistance = oldDistance
}
self.__twoTouchMove = (touch0, touch1) => {
const { oldScale, oldDistance, scale, zoom } = self
self.newScale = getNewScale(oldScale, oldDistance, zoom, touch0, touch1)
// 设定缩放范围
self.newScale <= 1 && (self.newScale = 1)
self.newScale >= scale && (self.newScale = scale)
self.scaleWidth = Math.round(self.newScale * self.baseWidth)
self.scaleHeight = Math.round(self.newScale * self.baseHeight)
const imgLeft = Math.round(self.touchX1 - self.scaleWidth / 2)
const imgTop = Math.round(self.touchY1 - self.scaleHeight / 2)
self.outsideBound(imgLeft, imgTop)
self.updateCanvas()
}
self.__xtouchEnd = () => {
self.oldScale = self.newScale
self.rectX = self.imgLeft
self.rectY = self.imgTop
}
}