feat: canvas 更新

feat: 添加 canvas imageData

feat: 完善 canvas api

fix: canvas example api

update: canvas

fix: fillText

feat: add createImage

feat: drawImage createPattern 调整

feat: rotate update

feat: color update

feat: update canvas prop
master
wuzhihao 2021-12-07 10:34:32 +08:00
parent b4cb3134af
commit 697515df27
5 changed files with 728 additions and 154 deletions

View File

@ -1,5 +1,14 @@
const example = require('./example.js')
function randomHexColor() {
var r = Math.floor(Math.random() * 256); //随机生成256以内r值
var g = Math.floor(Math.random() * 256); //随机生成256以内g值
var b = Math.floor(Math.random() * 256); //随机生成256以内b值
var alpha = Math.random() * 0.4 + 0.6; //随机生成1以内a值
return `rgba(${r},${g},${b},${alpha})`; //返回rgba(r,g,b,a)格式颜色
}
Page({
onShareAppMessage() {
return {
@ -8,53 +17,165 @@ Page({
}
},
log1(e) {
console.log('ctx1:', e.type, e)
},
log2(e) {
console.log('ctx2:', e.type, e)
},
onLoad() {
this.context = wx.createContext()
console.log('wx.createContext', this.context);
const methods = Object.keys(example)
console.log(methods);
this.setData({
methods
})
// 旧获取 canvas 方式
const ctx1 = wx.createCanvasContext('canvas1');
console.log('ctx1', ctx1)
// 新获取 canvas 方式
let ctx2
let canvas2
const query = wx.createSelectorQuery()
query.select('#canvas2').fields({ node: true, size: true }).exec((res) => {
canvas2 = res[0].node
ctx2 = canvas2.getContext('2d')
// 可以设置 dpr 的值,绘制高分辨率的图
const dpr = 1 || wx.getSystemInfoSync().pixelRatio
canvas2.width = res[0].width * dpr
canvas2.height = res[0].height * dpr
console.log('ctx2', ctx2)
})
// fino 基础库兼容新旧写法,两者均可获取到同样的 context
// 当 canvas 带 native 时,表示用原生组件
// 原生组件下,仅 putImageData 和 getImageData api 会有区别
const that = this
methods.forEach(function (method) {
that[method] = function () {
// 写法1 官方文档有描述的写法, 微信基础库支持,我们不支持
//
console.log('call action', method)
const ctx = wx.createCanvasContext('canvas');
example[method](ctx)
ctx.draw(false, (res) => { console.log(res) });
const actions = that.context.getActions()
console.log('that.context.getActions()', actions, ctx);
console.log("run:", method)
let color = null
if (method === 'setRandom') {
color = randomHexColor()
}
example[method](ctx1, true, color)
// 旧版需要调用 draw 接口
ctx1.draw(true, (res) => { console.log('ctx1 draw finish:', res) });
// 写法2 更旧版本的写法 微信支持fino基础库不支持
// wx.createContext 和 wx.drawCanvas 疑似已经被从官方基础库文档中移除,但是官方基础库依旧支持
// example[method](that.context)
// const actions = that.context.getActions()
// wx.drawCanvas({
// canvasId: 'canvas',
// actions
// })
// 写法3 同层渲染的原生canvas 就没实现
example[method](ctx2, false, color, canvas2)
try {
// 微信新的 canvas 没有 draw 方法,加个报错兼容
ctx2.draw(true, (res) => { console.log('ctx2 draw finish:', res) })
} catch (err) {
}
}
})
},
toTempFilePath() {
wx.canvasToTempFilePath({
canvasId: 'canvas',
canvasId: 'canvas1',
success(res) {
console.log(res)
console.log('canvas1', res)
},
fail(res) {
console.log('canvas1', res)
}
})
const query = wx.createSelectorQuery()
query.select('#canvas2').fields({ node: true, size: true }).exec((res) => {
const canvas = res[0].node
wx.canvasToTempFilePath({
canvas,
success(res) {
console.log('canvas2', res)
},
fail(res) {
console.log('canvas2', res)
}
})
})
},
imageData() {
// 旧版
// 整一个绿色方块
const arr = new Array(100 * 100 * 4);
for (var i = 0; i < arr.length; i += 4) {
arr[i + 0] = 0;
arr[i + 1] = 255;
arr[i + 2] = 0;
arr[i + 3] = 255;
}
// 把绿色方块画到 0 0 坐标
wx.canvasPutImageData({
canvasId: 'canvas1',
x: 0,
y: 0,
width: 100,
height: 100,
data: new Uint8ClampedArray(arr),
success(res) {
console.log(res)
}
})
},
fail: console.log
})
// 获取 0 0 坐标100 * 100 的图
wx.canvasGetImageData({
canvasId: 'canvas1',
x: 50,
y: 50,
width: 100,
height: 100,
success(res) {
console.log(res)
// 把获取到的,画到 200 0 坐标上
// 会出现两个绿色方块
wx.canvasPutImageData({
canvasId: 'canvas1',
x: 200,
y: 0,
width: 100,
height: 100,
data: res.data,
success(res) {
console.log(res)
},
fail: console.log
})
},
fail: console.log
})
// 新版
const query = wx.createSelectorQuery()
query.select('#canvas2').fields({ node: true, size: true }).exec((res) => {
const canvas = res[0].node
const context = canvas.getContext('2d')
// 一个绿色方块数据
const imgData = context.createImageData(100, 100);
for (var i = 0; i < imgData.data.length; i += 4) {
imgData.data[i + 0] = 0;
imgData.data[i + 1] = 255;
imgData.data[i + 2] = 0;
imgData.data[i + 3] = 255;
}
context.putImageData(imgData, 0, 0, 20, 20, 100, 100)
const image = context.getImageData(50, 50, 100, 100)
context.putImageData(image, 200, 0, 20, 20, 100, 100)
})
}
})

View File

@ -2,16 +2,47 @@
<import src="../../common/foot.wxml" />
<view class="container">
<template is="head" data="{{title: 'createContext'}}"/>
<view>本demo使用官方文档中的CanvasContext的调用方式</view>
<template is="head"
data="{{title: 'createContext'}}" />
<view class="page-body">
<view class="page-section">
<canvas class="canvas-element" canvas-id="canvas"></canvas>
<scroll-view class="canvas-buttons" scroll-y="true">
<button class="canvas-button" bindtap="toTempFilePath">toTempFilePath</button>
<block wx:for="{{methods}}" wx:for-item="method">
<button class="canvas-button" bindtap="{{method}}" >{{method}}</button>
<!-- 旧 canvas 写法 -->
<canvas class="canvas-element"
style="border: 1rpx solid green;"
disable-scroll="{{true}}"
bindtouchstart="log1"
bindtouchmove="log1"
bindtouchend="log1"
bindtouchcancel="log1"
bindlongtap="log1"
binderror="log1"
canvas-id="canvas1"></canvas>
<!-- 新 canvas 写法 -->
<canvas native
class="canvas-element"
style="border: 1rpx solid rosybrown;"
id="canvas2"
disable-scroll="{{true}}"
bindtouchstart="log2"
bindtouchmove="log2"
bindtouchend="log2"
bindtouchcancel="log2"
bindlongtap="log2"
binderror="log2"
type="2d"></canvas>
<scroll-view class="canvas-buttons"
scroll-y="true">
<view class="canvas-button-box">
<button class="canvas-button"
bindtap="toTempFilePath">toTempFilePath</button>
<button class="canvas-button"
bindtap="imageData">imageData</button>
<block wx:for="{{methods}}"
wx:for-item="method">
<button class="canvas-button"
bindtap="{{method}}">{{method}}</button>
</block>
</view>
</scroll-view>
</view>
</view>

View File

@ -2,20 +2,32 @@
display: block;
margin-bottom: 50px;
}
.canvas-element {
width: 100%;
height: 250px;
height: 200px;
background-color: #ffffff;
}
.canvas-buttons {
padding: 15px 25px 5px;
width: 100%;
height: 330px;
box-sizing: border-box;
}
.canvas-button {
float: left;
line-height: 2;
width: 150px;
margin: 8px 11px;
.canvas-buttons {
padding: 5px;
width: 100%;
height: 450px;
box-sizing: border-box;
}
.canvas-button-box {
display: flex;
flex-direction: row;
flex-wrap: wrap;
}
.canvas-button {
flex: 0 1 45% !important;
width: 45% !important;
line-height: 2;
padding: 4rpx;
margin: 0 4rpx 4rpx 0 !important;
border: 1rpx solid #666;
}

View File

@ -1,18 +1,211 @@
const example = {}
example.measureText = function (context) {
example.setGreen = function (context, isOld) {
example.setRandom(context, isOld, 'green')
}
example.setRed = function (context, isOld) {
example.setRandom(context, isOld, 'red')
}
// 设置随机颜色
example.setRandom = function (context, isOld, color) {
if (isOld) {
context.setFillStyle(color)
context.setStrokeStyle(color)
context.setFontSize(10)
context.setShadow(10, 10, 30, color)
context.setLineCap('butt')
context.setLineJoin('miter')
context.setLineWidth(1)
context.setMiterLimit(10)
} else {
context.fillStyle = color
context.strokeStyle = color
context.fontSize = 10
context.shadowColor = color
context.shadowBlur = 30
context.shadowOffsetX = 10
context.shadowOffsetY = 10
context.lineCap = 'butt'
context.lineJoin = 'miter'
context.lineWidth = 1
context.miterLimit = 10
}
}
// 重置颜色
example.reset = function (context, isOld) {
context.beginPath()
if (isOld) {
context.setFillStyle('#000000')
context.setStrokeStyle('#000000')
context.setFontSize(10)
context.setShadow(0, 0, 0, 'rgba(0, 0, 0, 0)')
context.setLineCap('butt')
context.setLineJoin('miter')
context.setLineWidth(1)
context.setMiterLimit(10)
} else {
context.fillStyle = '#000000'
context.strokeStyle = '#000000'
context.fontSize = 10
context.shadowColor = 'rgba(0, 0, 0, 0)'
context.shadowBlur = 0
context.shadowOffsetX = 0
context.shadowOffsetY = 0
context.lineCap = 'butt'
context.lineJoin = 'miter'
context.lineWidth = 1
context.miterLimit = 10
}
}
example.transform = function (context, isOld) {
context.transform(1, 0, 0, 1, 30, 10)
}
example.measureText = function (context, isOld) {
const data = context.measureText('123')
console.log(`width: ${data.width}`)
}
example.rotate = function (context) {
example.arc = function (context, isOld) {
context.beginPath()
context.rotate(10 * Math.PI / 180)
context.rect(225, 75, 20, 10)
context.fill()
context.arc(75, 75, 50, 0, Math.PI * 2, true)
context.moveTo(110, 75)
context.arc(75, 75, 35, 0, Math.PI, false)
context.moveTo(65, 65)
context.arc(60, 65, 5, 0, Math.PI * 2, true)
context.moveTo(95, 65)
context.arc(90, 65, 5, 0, Math.PI * 2, true)
context.stroke()
}
example.scale = function (context) {
example.arcTo = function (context, isOld) {
context.beginPath();
context.moveTo(20, 20); // 创建开始点
context.lineTo(100, 20); // 创建水平线
context.arcTo(150, 20, 150, 70, 50); // 创建弧
context.lineTo(150, 120);
context.arcTo(200, 120, 200, 170, 20); // 创建弧
context.stroke();
}
example.beginPath = function (context, isOld) {
context.beginPath()
context.moveTo(20, 75)
context.lineTo(250, 75)
context.stroke()
context.beginPath()
context.moveTo(50, 20)
context.lineTo(150, 130)
context.stroke()
}
example.bezierCurveTo = function (context, isOld) {
context.beginPath()
context.moveTo(20, 20)
context.bezierCurveTo(20, 100, 200, 100, 200, 20)
context.stroke()
context.beginPath()
context.moveTo(60, 60)
context.bezierCurveTo(60, 100, 200, 100, 200, 60)
context.stroke()
}
example.clearRect = function (context, isOld) {
context.beginPath()
context.rect(0, 0, 300, 150)
context.fill()
context.clearRect(20, 20, 100, 50)
}
example.clip = function (context, isOld) {
// 剪切矩形区域
context.rect(50, 20, 200, 120)
context.stroke()
context.clip()
context.fillRect(0, 0, 150, 100)
}
example.closePath = function (context, isOld) {
context.beginPath()
context.moveTo(20, 20)
context.lineTo(20, 100)
context.lineTo(70, 100)
context.closePath()
context.stroke()
context.beginPath()
context.moveTo(100, 100)
context.lineTo(120, 120)
context.lineTo(100, 200)
context.closePath()
context.stroke()
}
example.rotate = function (context, isOld) {
context.beginPath()
context.rotate(10 * Math.PI / 180)
context.rect(225, 75, 50, 50)
context.fill()
context.strokeStyle = 'red'
context.rect(225, 75, 50, 50)
context.stroke()
}
example.createCircularGradient = function (context, isOld) {
if (isOld) {
const grd = context.createCircularGradient(75, 50, 50)
grd.addColorStop(0, 'red')
grd.addColorStop(1, 'green')
context.setFillStyle(grd)
context.fillRect(10, 10, 150, 80)
context.draw()
} else {
const grd = context.createRadialGradient(75, 50, 5, 20, 20, 20);
grd.addColorStop(0, "red")
grd.addColorStop(1, "green")
context.fillStyle = grd
context.fillRect(10, 10, 150, 80)
}
}
example.createLinearGradient = function (context, isOld) {
const grd = context.createLinearGradient(0, 0, 170, 0)
grd.addColorStop(0, "black")
grd.addColorStop(1, "white")
if (isOld) {
context.setFillStyle(grd)
} else {
context.fillStyle = grd
}
context.fillRect(20, 20, 150, 100)
}
example.createPattern = function (context, isOld, color, canvas) {
if (isOld) {
const pat = context.createPattern('../../../image/icon_cloud_HL.png', "repeat")
context.setFillStyle(pat)
context.rect(0, 0, 150, 100)
context.fill()
} else {
const img = canvas.createImage()
img.onload = () => {
const pat = context.createPattern(img, "repeat")
context.fillStyle = pat
context.rect(0, 0, 150, 100)
context.fill()
}
img.src = '../../../image/icon_cloud_HL.png'
}
}
example.scale = function (context, isOld) {
context.beginPath()
context.rect(25, 25, 50, 50)
context.stroke()
@ -22,50 +215,58 @@ example.scale = function (context) {
context.beginPath()
context.rect(25, 25, 50, 50)
context.stroke()
}
example.reset = function (context) {
context.scale(3, 3)
context.beginPath()
context.rect(40, 40, 50, 50)
context.stroke()
context.setFillStyle('#000000')
context.setStrokeStyle('#000000')
context.setFontSize(10)
context.setShadow(0, 0, 0, 'rgba(0, 0, 0, 0)')
context.scale(1, 1)
context.setLineCap('butt')
context.setLineJoin('miter')
context.setLineWidth(1)
context.setMiterLimit(10)
}
example.translate = function (context) {
example.translate = function (context, isOld) {
context.beginPath()
context.rect(10, 10, 100, 50)
context.fill()
context.translate(70, 70)
context.beginPath()
context.fill()
context.translate(120, 120)
context.beginPath()
context.fill()
}
example.save = function (context) {
example.save = function (context, isOld) {
context.beginPath()
if (isOld) {
context.setStrokeStyle('#00ff00')
} else {
context.strokeStyle = '#00ff00'
}
context.save()
context.scale(2, 2)
if (isOld) {
context.setStrokeStyle('#ff0000')
} else {
context.strokeStyle = '#ff0000'
}
context.rect(0, 0, 100, 100)
context.stroke()
context.restore()
context.rect(0, 0, 50, 50)
context.stroke()
context.scale(1, 1)
}
example.restore = function (context) {
example.restore = function (context, isOld) {
[3, 2, 1].forEach(function (item) {
context.beginPath()
context.save()
@ -76,27 +277,37 @@ example.restore = function (context) {
})
}
example.drawImage = function (context) {
example.drawImage = function (context, isOld, color, canvas) {
if (isOld) {
context.drawImage('/image/wechat.png', 0, 0)
} else {
const img = canvas.createImage()
img.onload = () => {
context.drawImage(img, 0, 0)
}
img.src = '/image/wechat.png'
}
}
example.fillText = function (context) {
context.setStrokeStyle('#ff0000')
example.fillText = function (context, isOld) {
context.beginPath()
context.moveTo(0, 10)
context.lineTo(300, 10)
context.stroke()
// context.save()
// context.scale(1.5, 1.5)
// context.translate(20, 20)
context.setFontSize(10)
context.fillText('Hello World', 0, 30)
context.setFontSize(20)
context.fillText('Hello World', 100, 30)
// context.restore()
if (isOld) {
context.setFontSize(10)
} else {
context.font = '10px arial'
}
context.fillText('Hello World', 0, 30)
if (isOld) {
context.setFontSize(20)
} else {
context.font = '20px arial'
}
context.fillText('Hello World', 100, 30)
context.beginPath()
context.moveTo(0, 30)
@ -104,160 +315,281 @@ example.fillText = function (context) {
context.stroke()
}
example.fill = function (context) {
example.fill = function (context, isOld) {
context.beginPath()
context.rect(20, 20, 150, 100)
context.setStrokeStyle('#00ff00')
context.fill()
}
example.stroke = function (context) {
example.stroke = function (context, isOld) {
context.beginPath()
context.moveTo(20, 20)
context.lineTo(20, 100)
context.lineTo(70, 100)
context.setStrokeStyle('#00ff00')
context.stroke()
}
example.clearRect = function (context) {
context.setFillStyle('#ff0000')
context.beginPath()
context.rect(0, 0, 300, 150)
context.fill()
context.clearRect(20, 20, 100, 50)
example.strokeRect = function (context, isOld) {
context.strokeRect(20, 20, 150, 100)
context.strokeRect(160, 180, 200, 200)
}
example.beginPath = function (context) {
context.beginPath()
context.setLineWidth(5)
context.setStrokeStyle('#ff0000')
context.moveTo(0, 75)
context.lineTo(250, 75)
context.stroke()
example.strokeText = function (context, isOld) {
context.font = "20px arial"
context.strokeText("Hello World!", 10, 50)
context.beginPath()
context.setStrokeStyle('#0000ff')
context.moveTo(50, 0)
context.lineTo(150, 130)
context.stroke()
context.font = "30px arial"
// 创建渐变
const gradient = context.createLinearGradient(0, 0, 200, 0)
gradient.addColorStop("0", "magenta")
gradient.addColorStop("0.5", "blue")
gradient.addColorStop("1.0", "red")
// 用渐变填色
if (isOld) {
context.setStrokeStyle(gradient)
} else {
context.strokeStyle = gradient
}
context.strokeText("finclip", 10, 90)
}
example.closePath = function (context) {
context.beginPath()
context.moveTo(20, 20)
context.lineTo(20, 100)
context.lineTo(70, 100)
context.closePath()
context.stroke()
}
example.moveTo = function (context) {
example.moveTo = function (context, isOld) {
context.beginPath()
context.moveTo(0, 0)
context.lineTo(300, 150)
context.stroke()
context.beginPath()
context.moveTo(40, 40)
context.lineTo(200, 180)
context.stroke()
}
example.lineTo = function (context) {
example.lineTo = function (context, isOld) {
context.beginPath()
context.moveTo(20, 20)
context.lineTo(20, 100)
context.lineTo(70, 100)
context.stroke()
context.beginPath()
context.moveTo(40, 40)
context.lineTo(200, 180)
context.lineTo(70, 100)
context.stroke()
}
example.rect = function (context) {
example.rect = function (context, isOld) {
context.beginPath()
context.rect(20, 20, 150, 100)
context.stroke()
}
example.arc = function (context) {
context.beginPath()
context.arc(75, 75, 50, 0, Math.PI * 2, true)
context.moveTo(110, 75)
context.arc(75, 75, 35, 0, Math.PI, false)
context.moveTo(65, 65)
context.arc(60, 65, 5, 0, Math.PI * 2, true)
context.moveTo(95, 65)
context.arc(90, 65, 5, 0, Math.PI * 2, true)
context.rect(40, 40, 180, 100)
context.stroke()
}
example.quadraticCurveTo = function (context) {
example.quadraticCurveTo = function (context, isOld) {
context.beginPath()
context.moveTo(20, 20)
context.quadraticCurveTo(20, 100, 200, 20)
context.stroke()
}
example.bezierCurveTo = function (context) {
context.beginPath()
context.moveTo(20, 20)
context.bezierCurveTo(20, 100, 200, 100, 200, 20)
context.moveTo(60, 60)
context.quadraticCurveTo(30, 130, 200, 20)
context.stroke()
}
example.setFillStyle = function (context) {
example.setFillStyle = function (context, isOld) {
['#fef957', 'rgb(242,159,63)', 'rgb(242,117,63)', '#e87e51'].forEach(function (item, index) {
if (isOld) {
context.setFillStyle(item)
} else {
context.fillStyle = item
}
context.beginPath()
context.rect(0 + 75 * index, 0, 50, 50)
context.fill()
})
}
example.setStrokeStyle = function (context) {
example.setStrokeStyle = function (context, isOld) {
['#fef957', 'rgb(242,159,63)', 'rgb(242,117,63)', '#e87e51'].forEach(function (item, index) {
if (isOld) {
context.setStrokeStyle(item)
} else {
context.strokeStyle = item
}
context.beginPath()
context.rect(0 + 75 * index, 0, 50, 50)
context.stroke()
})
}
example.setGlobalAlpha = function (context) {
context.setFillStyle('#000000');
example.setTextAlign = function (context, isOld) {
// 在位置 150 创建蓝线
function setTextAlign(text) {
if (isOld) {
context.setTextAlign(text)
} else {
context.textAlign = text
}
}
context.moveTo(150, 20)
context.lineTo(150, 170)
context.stroke()
context.font = "15px Arial"
// 显示不同的 textAlign 值
setTextAlign("start")
context.fillText("textAlign=start", 150, 60)
setTextAlign("end")
context.fillText("textAlign=end", 150, 80)
setTextAlign("left")
context.fillText("textAlign=left", 150, 100)
setTextAlign("center")
context.fillText("textAlign=center", 150, 120)
setTextAlign("right")
context.fillText("textAlign=right", 150, 140)
}
example.setTextBaseline = function (context, isOld) {
// 在位置 150 创建蓝线
function setTextBaseline(text) {
if (isOld) {
context.setTextBaseline(text)
} else {
context.textBaseline = text
}
}
context.moveTo(5, 100)
context.lineTo(395, 100)
context.stroke()
context.font = "20px Arial"
// 显示不同的 textAlign 值
setTextBaseline("top")
context.fillText("Top", 5, 100)
setTextBaseline("bottom")
context.fillText("Bottom", 50, 100)
setTextBaseline("middle")
context.fillText("Middle", 120, 100)
setTextBaseline("alphabetic")
context.fillText("Alphabetic", 190, 100)
setTextBaseline("hanging")
context.fillText("Hanging", 290, 100)
}
example.setTransform = function (context, isOld) {
// 在位置 150 创建蓝线
context.fillRect(0, 0, 250, 100)
context.setTransform(1, 0.5, -0.5, 1, 30, 10)
if (isOld) {
context.setFillStyle('red')
} else {
context.fillStyle = 'red'
}
context.fillRect(0, 0, 250, 100);
context.setTransform(1, 0.5, -0.5, 1, 30, 10)
if (isOld) {
context.setFillStyle('blue')
} else {
context.fillStyle = 'blue'
}
context.fillRect(0, 0, 250, 100)
}
example.setGlobalAlpha = function (context, isOld) {
[1, 0.5, 0.1].forEach(function (item, index) {
try {
context.setGlobalAlpha(item)
} catch (e) {
context.globalAlpha = item
}
context.beginPath()
context.rect(0 + 75 * index, 0, 50, 50)
context.fill()
})
}
example.setShadow = function (context) {
example.setShadow = function (context, isOld) {
context.beginPath()
context.setShadow(10, 10, 10, 'rgba(0, 0, 0, 199)')
context.rect(10, 10, 100, 100)
context.fill()
context.beginPath()
context.rect(50, 50, 100, 100)
context.fill()
}
example.setFontSize = function (context) {
example.setFontSize = function (context, isOld) {
[10, 20, 30, 40].forEach(function (item, index) {
if (isOld) {
context.setFontSize(item)
} else {
context.font = item + 'px arial'
}
context.fillText('Hello, world', 20, 20 + 40 * index)
})
}
example.setLineCap = function (context) {
context.setLineWidth(10);
example.setLineCap = function (context, isOld) {
context.setLineWidth(10)
if (isOld) {
context.setLineWidth(10)
} else {
context.lineWidth = 10
}
['butt', 'round', 'square'].forEach(function (item, index) {
context.beginPath()
if (isOld) {
context.setLineCap(item)
} else {
context.lineCap = item
}
context.moveTo(20, 20 + 20 * index)
context.lineTo(100, 20 + 20 * index)
context.stroke()
})
}
example.setLineJoin = function (context) {
context.setLineWidth(10);
example.setLineDash = function (context, isOld) {
context.beginPath()
context.setLineDash([5, 15])
context.moveTo(0, 50)
context.lineTo(300, 50)
context.stroke()
// Solid line
context.beginPath()
context.setLineDash([])
context.moveTo(0, 100)
context.lineTo(300, 100)
context.stroke()
}
example.setLineJoin = function (context, isOld) {
if (isOld) {
context.setLineWidth(10)
} else {
context.lineWidth = 10
}
['bevel', 'round', 'miter'].forEach(function (item, index) {
context.beginPath()
if (isOld) {
context.setLineJoin(item)
} else {
context.lineJoin = item
}
context.moveTo(20 + 80 * index, 20)
context.lineTo(100 + 80 * index, 50)
context.lineTo(20 + 80 * index, 100)
@ -265,22 +597,34 @@ example.setLineJoin = function (context) {
})
}
example.setLineWidth = function (context) {
example.setLineWidth = function (context, isOld) {
[2, 4, 6, 8, 10].forEach(function (item, index) {
context.beginPath()
if (isOld) {
context.setLineWidth(item)
} else {
context.lineWidth = item
}
context.moveTo(20, 20 + 20 * index)
context.lineTo(100, 20 + 20 * index)
context.stroke()
})
}
example.setMiterLimit = function (context) {
context.setLineWidth(4);
example.setMiterLimit = function (context, isOld) {
if (isOld) {
context.setLineWidth(4)
} else {
context.lineWidth = 4
}
[2, 4, 6, 8, 10].forEach(function (item, index) {
context.beginPath()
if (isOld) {
context.setMiterLimit(item)
} else {
context.miterLimit = item
}
context.moveTo(20 + 80 * index, 20)
context.lineTo(100 + 80 * index, 50)
context.lineTo(20 + 80 * index, 100)
@ -288,4 +632,67 @@ example.setMiterLimit = function (context) {
})
}
example.globalCompositeOperation = function (context, isOld) {
if (isOld) {
context.setFillStyle('red')
} else {
context.fillStyle = 'red'
}
context.fillRect(20, 20, 75, 50)
context.globalCompositeOperation = "source-over"
if (isOld) {
context.setFillStyle('blue')
} else {
context.fillStyle = 'blue'
}
context.fillRect(50, 50, 75, 50)
if (isOld) {
context.setFillStyle('red')
} else {
context.fillStyle = 'red'
}
context.fillRect(150, 20, 75, 50)
context.globalCompositeOperation = "destination-over"
if (isOld) {
context.setFillStyle('blue')
} else {
context.fillStyle = 'blue'
}
context.fillRect(180, 50, 75, 50)
}
example.createImage = function (context, isOld, color, canvas) {
if (isOld) {
context.fillText('createImage 不会生效', 20, 20)
} else {
// 本地路径 1
const img = canvas.createImage()
img.src = '../../../image/wechat.png'
img.onload = () => {
context.drawImage(img, 0, 0, 100, 100)
}
wx.getImageInfo({
src: 'http://img.daimg.com/uploads/allimg/210526/3-2105261P1490-L.jpg',
success(res) {
const img = canvas.createImage()
img.src = res.path
// finfile
img.onload = () => {
context.drawImage(img, 120, 0, 100, 100)
}
}
})
// 网络路径
const img2 = canvas.createImage()
img2.src = 'http://img.daimg.com/uploads/allimg/211113/3-2111131612510-L.jpg'
img2.onload = () => {
context.drawImage(img2, 240, 0, 100, 100)
}
}
}
module.exports = example

View File

@ -2,32 +2,35 @@
<import src="../../common/foot.wxml" />
<view class="container">
<template is="head" data="{{title: 'canvas'}}"/>
<template is="head"
data="{{title: 'canvas'}}" />
<view class="page-body">
<view class="page-section page-section-gap">
<view class="page-section-title">绘制</view>
<view class="body-view">
<canvas canvas-id="canvas" class="canvas"></canvas>
<canvas canvas-id="canvas"
class="canvas"></canvas>
</view>
</view>
<view class="page-section page-section-gap">
<view class="page-section-title">绘制图片</view>
<view class="body-view">
<canvas canvas-id="canvas2" class="canvas"></canvas>
<canvas canvas-id="canvas2"
class="canvas"></canvas>
</view>
</view>
<view class="page-section page-section-gap">
<view class="page-section-title">绘制图片-高清</view>
<view class="body-view">
<canvas canvas-id="canvas3" class="canvas" hidpi></canvas>
<canvas canvas-id="canvas3"
class="canvas"
hidpi></canvas>
</view>
</view>
</view>
<template is="foot" />
</view>