5个前端练手项目(html css js canvas)

在这个项目中，在html中创立20个span标签

每个span标签设置style为–i:数字的样式用于

在css中动态分配圆圈分几份，transform: rotate(calc(18deg*var(–i)))

利用filter属性结合关键帧动态切换颜色。同时设置每一个span标签进行

旋转

1.3源码

2.彩虹爱心

2.1效果图

2.2思路解析

搭建基本的html结构，采用的svg技术，

通过js动态改变颜色，以及动态实现切换图形

2.3源码




const colors = ["#e03776","#8f3e98","#4687bf","#3bab6f","#f9c25e","#f47274"];
const SVG_NS = 'http://www.w3.org/2000/svg';
const SVG_XLINK = "http://www.w3.org/1999/xlink";

let heartsRy = []

function useTheHeart(n){
  let use = document.createElementNS(SVG_NS, 'use');
  use.n = n;
  use.setAttributeNS(SVG_XLINK, 'xlink:href', '#heart');
  use.setAttributeNS(null, 'transform', `scale(${use.n})`);
  use.setAttributeNS(null, 'fill', colors[n%colors.length]);
  use.setAttributeNS(null, 'x', -69);
  use.setAttributeNS(null, 'y', -69);
  use.setAttributeNS(null, 'width', 138);
  use.setAttributeNS(null, 'height', 138);
  
  heartsRy.push(use)
  hearts.appendChild(use);
}

for(let n = 18; n >= 0; n--){useTheHeart(n)}

function Frame(){
  window.requestAnimationFrame(Frame);
  for(let i = 0; i < heartsRy.length; i++){
    if(heartsRy[i].n < 18){heartsRy[i].n +=.01
     }else{
     heartsRy[i].n = 0;
     hearts.appendChild(heartsRy[i])
    }
    heartsRy[i].setAttributeNS(null, 'transform', `scale(${heartsRy[i].n})`);
  }
}

Frame()
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53

3.闹钟

3.1效果图

3.2思路解析

搭建基本的html结构，动态得到实时的时，分，秒

通过Date()函数获得。将得到的数字根据逻辑，绑定

给各div结构，实行动态旋转。点击按钮，改变背景颜色

3.3源码

html：

css:

@import url('https://fonts.googleapis.com/css?family=Heebo:300&display=swap');

* {
  box-sizing: border-box;
}

:root {
  --primary-color: #000;
  --secondary-color: #fff;
}

html {
  transition: all 0.5s ease-in;
}

html.dark {
  --primary-color: #fff;
  --secondary-color: #333;
}

html.dark {
  background-color: #111;
  color: var(--primary-color);
}

body {
  font-family: 'Heebo', sans-serif;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100vh;
  overflow: hidden;
  margin: 0;
}

.toggle {
  cursor: pointer;
  background-color: var(--primary-color);
  color: var(--secondary-color);
  border: 0;
  border-radius: 4px;
  padding: 8px 12px;
  position: absolute;
  top: 100px;
}

.toggle:focus {
  outline: none;
}

.clock-container {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: center;
}

.clock {
  position: relative;
  width: 200px;
  height: 200px;
}

.needle {
  background-color: var(--primary-color);
  position: absolute;
  top: 50%;
  left: 50%;
  height: 65px;
  width: 3px;
  transform-origin: bottom center;
  transition: all 0.5s ease-in;
}

.needle.hour {
  transform: translate(-50%, -100%) rotate(0deg);
}

.needle.minute {
  transform: translate(-50%, -100%) rotate(0deg);
  height: 100px;
}

.needle.second {
  transform: translate(-50%, -100%) rotate(0deg);
  height: 100px;
  background-color: #e74c3c;
}

.center-point {
  background-color: #e74c3c;
  width: 10px;
  height: 10px;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  border-radius: 50%;
}

.center-point::after {
  content: '';
  background-color: var(--primary-color);
  width: 5px;
  height: 5px;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  border-radius: 50%;
}

.time {
  font-size: 60px;
}

.date {
  color: #aaa;
  font-size: 14px;
  letter-spacing: 0.3px;
  text-transform: uppercase;
}

.date .circle {
  background-color: var(--primary-color);
  color: var(--secondary-color);
  border-radius: 50%;
  height: 18px;
  width: 18px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  line-height: 18px;
  transition: all 0.5s ease-in;
  font-size: 12px;
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136

js:

const hourEl = document.querySelector('.hour')
const minuteEl = document.querySelector('.minute')
const secondEl = document.querySelector('.second')
const timeEl = document.querySelector('.time')
const dateEl = document.querySelector('.date')
const toggle = document.querySelector('.toggle')

const days = ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"];
const months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];

toggle.addEventListener('click', (e) => {
    const html = document.querySelector('html')
    if (html.classList.contains('dark')) {
        html.classList.remove('dark')
        e.target.innerHTML = 'Dark mode'
    } else {
        html.classList.add('dark')
        e.target.innerHTML = 'Light mode'
    }
})

function setTime() {
    const time = new Date();
    const month = time.getMonth()
    const day = time.getDay()
    const date = time.getDate()
    const hours = time.getHours()
    const hoursForClock = hours >= 13 ? hours % 12 : hours;
    const minutes = time.getMinutes()
    const seconds = time.getSeconds()
    const ampm = hours >= 12 ? 'PM' : 'AM'

    hourEl.style.transform = `translate(-50%, -100%) rotate(${scale(hoursForClock, 0, 12, 0, 360)}deg)`
    minuteEl.style.transform = `translate(-50%, -100%) rotate(${scale(minutes, 0, 60, 0, 360)}deg)`
    secondEl.style.transform = `translate(-50%, -100%) rotate(${scale(seconds, 0, 60, 0, 360)}deg)`

    timeEl.innerHTML = `${hoursForClock}:${minutes < 10 ? `0${minutes}` : minutes} ${ampm}`
    dateEl.innerHTML = `${days[day]}, ${months[month]} ${date}`
}

// StackOverflow https://stackoverflow.com/questions/10756313/javascript-jquery-map-a-range-of-numbers-to-another-range-of-numbers
const scale = (num, in_min, in_max, out_min, out_max) => {
    return (num - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}

setTime()

setInterval(setTime, 1000)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48

4.自制笔记本

4.1效果展示

4.2思路解析

通过js实现动态添加DOM结构，绑定创建出DOM结构的

添加，删除按钮。实现监听事件。实现动态改变DOM结构

其他的就是设置css的相关属性，

4.3源码

html：

css：

@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@200;400&display=swap');

* {
  box-sizing: border-box;
  outline: none;
}

body {
  background-color: #7bdaf3;
  font-family: 'Poppins', sans-serif;
  display: flex;
  flex-wrap: wrap;
  margin: 0;
  padding-top: 3rem;
}

.add {
  position: fixed;
  top: 1rem;
  right: 1rem;
  background-color: #9ec862;
  color: #fff;
  border: none;
  border-radius: 3px;
  padding: 0.5rem 1rem;
  cursor: pointer;
}

.add:active {
  transform: scale(0.98);
}

.note {
  background-color: #fff;
  box-shadow: 0 0 10px 4px rgba(0, 0, 0, 0.1);
  margin: 30px 20px;
  height: 400px;
  width: 400px;
  overflow-y: scroll;
}

.note .tools {
  background-color: #9ec862;
  display: flex;
  justify-content: flex-end;
  padding: 0.5rem;
}

.note .tools button {
  background-color: transparent;
  border: none;
  color: #fff;
  cursor: pointer;
  font-size: 1rem;
  margin-left: 0.5rem;
}

.note textarea {
  outline: none;
  font-family: inherit;
  font-size: 1.2rem;
  border: none;
  height: 400px;
  width: 100%;
  padding: 20px;
}

.main {
  padding: 20px;
}

.hidden {
  display: none;
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74

js：

const addBtn = document.getElementById('add')

const notes = JSON.parse(localStorage.getItem('notes'))

if(notes) {
    notes.forEach(note => addNewNote(note))
}

addBtn.addEventListener('click', () => addNewNote())

function addNewNote(text = '') {
    const note = document.createElement('div')
    note.classList.add('note')

    note.innerHTML = `
    
        
        
    

    
    
    `

    const editBtn = note.querySelector('.edit')
    const deleteBtn = note.querySelector('.delete')
    const main = note.querySelector('.main')
    const textArea = note.querySelector('textarea')

    textArea.value = text
    main.innerHTML = marked(text)

    deleteBtn.addEventListener('click', () => {
        note.remove()

        updateLS()
    })

    editBtn.addEventListener('click', () => {
        main.classList.toggle('hidden')
        textArea.classList.toggle('hidden')
    })

    textArea.addEventListener('input', (e) => {
        const { value } = e.target

        main.innerHTML = marked(value)

        updateLS()
    })

    document.body.appendChild(note)
}

function updateLS() {
    const notesText = document.querySelectorAll('textarea')

    const notes = []

    notesText.forEach(note => notes.push(note.value))

    localStorage.setItem('notes', JSON.stringify(notes))
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63

5.自定义写字台（也可自定义字的样式）

5.1效果展示

5.2思路解析

搭建html结构,创建canvas标签，

绑定设置的结构比如+，-，颜色改变

动态设置并获取他的值，然后将这些值动态的

设置为canvas语法中设置渲染的宽度，以及设置

颜色的属性

5.3源码

html:

css:

@import url('https://fonts.googleapis.com/css2?family=Roboto:wght@400;700&display=swap');

* {
  box-sizing: border-box;
}

body {
  background-color: #f5f5f5;
  font-family: 'Roboto', sans-serif;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100vh;
  margin: 0;
}

canvas {
  border: 2px solid steelblue;
}

.toolbox {
  background-color: steelblue;
  border: 1px solid slateblue;
  display: flex;
  width: 804px;
  padding: 1rem;
}

.toolbox > * {
  background-color: #fff;
  border: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  height: 50px;
  width: 50px;
  margin: 0.25rem;
  padding: 0.25rem;
  cursor: pointer;
}

.toolbox > *:last-child {
  margin-left: auto;
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46

js:

const canvas = document.getElementById('canvas');
const increaseBtn = document.getElementById('increase');
const decreaseBtn = document.getElementById('decrease');
const sizeEL = document.getElementById('size');
const colorEl = document.getElementById('color');
const clearEl = document.getElementById('clear');

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

let size = 10
let isPressed = false
colorEl.value = 'black'
let color = colorEl.value
let x
let y

canvas.addEventListener('mousedown', (e) => {
    isPressed = true

    x = e.offsetX
    y = e.offsetY
})

document.addEventListener('mouseup', (e) => {
    isPressed = false

    x = undefined
    y = undefined
})

canvas.addEventListener('mousemove', (e) => {
    if(isPressed) {
        const x2 = e.offsetX
        const y2 = e.offsetY

        drawCircle(x2, y2)
        drawLine(x, y, x2, y2)

        x = x2
        y = y2
    }
})

function drawCircle(x, y) {
    ctx.beginPath();
    ctx.arc(x, y, size, 0, Math.PI * 2)
    ctx.fillStyle = color
    ctx.fill()
}

function drawLine(x1, y1, x2, y2) {
    ctx.beginPath()
    ctx.moveTo(x1, y1)
    ctx.lineTo(x2, y2)
    ctx.strokeStyle = color
    ctx.lineWidth = size * 2
    ctx.stroke()
}

function updateSizeOnScreen() {
    sizeEL.innerText = size
}

increaseBtn.addEventListener('click', () => {
    size += 5

    if(size > 50) {
        size = 50
    }

    updateSizeOnScreen()
})

decreaseBtn.addEventListener('click', () => {
    size -= 5

    if(size < 5) {
        size = 5
    }

    updateSizeOnScreen()
})

colorEl.addEventListener('change', (e) => color = e.target.value)

clearEl.addEventListener('click', () => ctx.clearRect(0,0, canvas.width, canvas.height))
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86

在最后，如果觉得博主写的还行，期待??点赞 ??评论 ??收藏

先自我介绍一下，小编13年上师交大毕业，曾经在小公司待过，去过华为OPPO等大厂，18年进入阿里，直到现在。深知大多数初中级java工程师，想要升技能，往往是需要自己摸索成长或是报班学习，但对于培训机构动则近万元的学费，着实压力不小。自己不成体系的自学效率很低又漫长，而且容易碰到天花板技术停止不前。因此我收集了一份《java开发全套学习资料》送给大家，初衷也很简单，就是希望帮助到想自学又不知道该从何学起的朋友，同时减轻大家的负担。添加下方名片，即可获取全套学习资料哦

相关阅读:
LightDB数据库中的模式
 027、工具_redis-benchmark
hiveSql 相互关注问题
 解析小结—自用
 在亚马逊云科技控制台上创建 Amazon Cognito 用户池
 使用HBuilderX将vue或H5项目打包app
奥斯卡·王尔德
 CSS 常用样式之字体属性
 【毕业设计】基于STM32的天气预报盒子 - 嵌入式单片机物联网
 一文总结现代 C++ 中的初始化
原文地址：https://blog.csdn.net/drnrrwfs/article/details/126098070