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// index.js
// 获取应用实例
const app = getApp()

Page({
data: {
canvas: {
size: {
width: 300,
height: 200,
}
}
},

onReady() {
let that = this
const query = wx.createSelectorQuery()
query.select('#myCanvas')
.fields({ node: true, size: true })
.exec((res) => {

    const canvas = res[0].node

    let globalData = app.globalData        


    that.initCanvas(canvas, globalData)

    const ctx = canvas.getContext('2d')

    ctx.fillStyle = "#f3f2f7"
    ctx.fillRect(0, 0, globalData.windowWidth, globalData.windowHeight)

    ctx.fillStyle = "#fff"

    let main_block_horizontal_margin = 27
    let main_block_vertical_margin = 80
    let main_block_width = globalData.windowWidth - main_block_horizontal_margin * 2
    let main_block_height = globalData.windowHeight - main_block_vertical_margin * 2


    ctx.fillRect(main_block_horizontal_margin, main_block_vertical_margin, main_block_width, main_block_height); 

    that.drawLogo(canvas, ctx, globalData, {
      main_block_horizontal_margin,
      main_block_vertical_margin,
      main_block_width,
      main_block_height
    })
    
  })

},

initCanvas(canvas, globalData) {

let canvas_data = this.data.canvas
canvas_data.size.width = globalData.windowWidth
canvas_data.size.height = globalData.windowHeight

this.setData({
  canvas: canvas_data
})

canvas.width = globalData.windowWidth
canvas.height = globalData.windowHeight

},

drawLogo(canvas, ctx, globalData, main_block) {
let image = canvas.createImage()
image.src = 'https://asset.gign.xyz/logo.png'

image.onload  = () => {

  let image_drawing_width = 200
  let image_drawing_height = 200

  let logo_block_horizontal_margin = (globalData.windowWidth - main_block.main_block_horizontal_margin * 2) / 2
  let logo_block_vertical_margin = (globalData.windowHeight - main_block.main_block_vertical_margin * 2) / 2

  let logo_margin = 

  ctx.drawImage(image, canvas.width / 2 - image_drawing_width / 2, 100, image_drawing_width, image_drawing_height)

}

},

onLoad() {

},

})