时间戳

首页 > 解决方案 > JS 自定义颜色选择器

javascript - JS 自定义颜色选择器

问题描述

基本上大声笑不能在这里添加视频，但是使用默认的 html 颜色选择器，如果鼠标从颜色框边界向下移动并且它再次移动到边界的边缘，您可以移动颜色选择器点，但是对于我的它只是停止移动并且没有做好我快速移动鼠标。

我正在尝试创建一个自定义颜色选择器，其中您有一个颜色滑块，然后您选择了颜色框，您可以在此处更改它的白度和暗度（如 adobe xdcc 颜色选择器）： Adobe xdcc 颜色选择器示例

[下面的代码在此处创建][2] 您可以拖动小颜色选择器圆圈并更改所选颜色，但是当使用画布时，当鼠标离开画布时，我不必在边缘移动颜色选择器圆圈，我想改变。

HTML：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="style.css">
    <script src="app.js" defer></script>
</head>
<body>
    <h2>Let's Create a Color Picker</h2>
<div class="container">
  <canvas id="color-picker"></canvas>
  <div class="info">
    <h3>Selected Color</h3> 
    <div class="selected"></div>
  </div>
</div>
</body>
</html>

CSS：

    html, body {
        width: 100%;
        height: 100%;
        font-family: Oxygen, sans-serif;
        text-align: center;   }
         .container {
        width: 100%;
        height: 100%;
        display: flex;
        justify-content: center;
        align-items: center;   }
         #color-picker {
        border: .5px solid rgba(15, 15, 15, 0.2);   }
         .info {
        width: 12em;
        display: flex;
        margin-left: 4em;
        flex-direction: row;
        justify-content: space-between;   }
         .selected {
        width: 50px;
        height: 50px;
        border-radius: 100%;
        border: 2px solid rgba(15, 15, 15, 0.2);   }

JS：

    class Picker {
        constructor(target, width, height) {
          this.target = target;
          this.width = width;
          this.height = height;
          this.target.width = width;
          this.target.height = height;
          // Get context 
          this.context = this.target.getContext("2d");
          // Circle 
          this.pickerCircle = { x: 10, y: 10, width: 10, height: 10 };
          
          this.listenForEvents();
        }
        
        draw() {
        }
        
        build() {
          let gradient = this.context.createLinearGradient(0, 0, this.width, 0);
      
          //Color Stops
          gradient.addColorStop(0, "rgb(255, 0, 0)");
          gradient.addColorStop(0.15, "rgb(255, 0, 255)");
          gradient.addColorStop(0.33, "rgb(0, 0, 255)");
          gradient.addColorStop(0.49, "rgb(0, 255, 255)");
          gradient.addColorStop(0.67, "rgb(0, 255, 0)");
          gradient.addColorStop(0.84, "rgb(255, 255, 0)");
          gradient.addColorStop(1, "rgb(255, 0, 0)");
          //Fill it
          this.context.fillStyle = gradient;
          this.context.fillRect(0, 0, this.width, this.height);
          
          //Apply black and white 
              gradient = this.context.createLinearGradient(0, 0, 0,          this.height);
          gradient.addColorStop(0, "rgba(255, 255, 255, 1)");
          gradient.addColorStop(0.5, "rgba(255, 255, 255, 0)");
          gradient.addColorStop(0.5, "rgba(0, 0, 0, 0)");
          gradient.addColorStop(1, "rgba(0, 0, 0, 1)");
          this.context.fillStyle = gradient;
          this.context.fillRect(0, 0, this.width, this.height);
          
          //Circle 
          this.context.beginPath();
          this.context.arc(this.pickerCircle.x, this.pickerCircle.y, this.pickerCircle.width, 0, Math.PI * 2);
          this.context.strokeStyle = "black";
          this.context.stroke();
          this.context.closePath();
          
        }
        
        listenForEvents() {
          let isMouseDown = false;
          const onMouseDown = (e) => {
              this.build();
              let currentX = e.clientX - this.target.offsetLeft;
            let currentY = e.clientY - this.target.offsetTop;
              this.pickerCircle.x = currentX;
              this.pickerCircle.y = currentY;
              isMouseDown = true;
            }
          
          const onMouseMove = (e) => {
            if(isMouseDown) {
              this.build();
              let currentX = e.clientX - this.target.offsetLeft;
             let currentY = e.clientY - this.target.offsetTop;
              this.pickerCircle.x = currentX;
              this.pickerCircle.y = currentY;
            }
          }
          
          const onMouseUp = () => {
            isMouseDown = false;
          }
          
          //Register 
          this.target.addEventListener("mousedown", onMouseDown);
          this.target.addEventListener("mousemove", onMouseMove);
          this.target.addEventListener("mousemove", () => this.onChangeCallback(this.getPickedColor()));
      
          
          document.addEventListener("mouseup", onMouseUp);
        }
        
        getPickedColor() {
          let imageData = this.context.getImageData(this.pickerCircle.x, this.pickerCircle.y, 1, 1);
          return { r: imageData.data[0], g: imageData.data[1], b: imageData.data[2] };
        }
        
        onChange(callback) {
          this.onChangeCallback = callback;
        }
        
           }
         let picker = new Picker(document.getElementById("color-picker"), 250, 220);    picker.build();
    
      picker.onChange((color) => {
         let selected = document.getElementsByClassName("selected")[0];
        selected.style.backgroundColor = `rgb(${color.r}, ${color.g}, ${color.b})`;   });


  [1]: https://i.stack.imgur.com/MQsjs.png
  [2]: https://i.stack.imgur.com/krEYa.png

提前致谢！

标签： javascripthtmlcss

解决方案

解决方案很简单，不要使用if(isMouseDown){..}，因为这会使您的代码非常无响应，所以我所做的是我let i = 0;在 上声明了一个变量onMouseDown，每当调用该函数时，它都会增加 of 的值，i并且我将onMouseMovefrom更改if(isMouseDown){..}为if(i % 2 === 0){..}这是我的解决方案：

class Picker {
        constructor(target, width, height) {
          this.target = target;
          this.width = width;
          this.height = height;
          this.target.width = width;
          this.target.height = height;
          //Get context
          this.context = this.target.getContext("2d");
          //Circle
          this.pickerCircle = { x: 10, y: 10, width: 10, height: 10 };
          
          this.listenForEvents();
        }
        
        draw() {
        }
        
        build() {
          let gradient = this.context.createLinearGradient(0, 0, this.width, 0);
      
          //Color Stops
          gradient.addColorStop(0, "rgb(255, 0, 0)");
          gradient.addColorStop(0.15, "rgb(255, 0, 255)");
          gradient.addColorStop(0.33, "rgb(0, 0, 255)");
          gradient.addColorStop(0.49, "rgb(0, 255, 255)");
          gradient.addColorStop(0.67, "rgb(0, 255, 0)");
          gradient.addColorStop(0.84, "rgb(255, 255, 0)");
          gradient.addColorStop(1, "rgb(255, 0, 0)");
          //Fill it
          this.context.fillStyle = gradient;
          this.context.fillRect(0, 0, this.width, this.height);
          
          //Apply black and white
              gradient = this.context.createLinearGradient(0, 0, 0,          this.height);
          gradient.addColorStop(0, "rgba(255, 255, 255, 1)");
          gradient.addColorStop(0.5, "rgba(255, 255, 255, 0)");
          gradient.addColorStop(0.5, "rgba(0, 0, 0, 0)");
          gradient.addColorStop(1, "rgba(0, 0, 0, 1)");
          this.context.fillStyle = gradient;
          this.context.fillRect(0, 0, this.width, this.height);
          
          //Circle
          this.context.beginPath();
          this.context.arc(this.pickerCircle.x, this.pickerCircle.y, this.pickerCircle.width, 0, Math.PI * 2);
          this.context.strokeStyle = "black";
          this.context.stroke();
          this.context.closePath();
          
        }
        
        listenForEvents() {
          let isMouseDown = true;
          let i =0;
          const onMouseDown = (e) => {
              this.build();
              isMouseDown = true
              i++
              let currentX = e.clientX - this.target.offsetLeft;
            let currentY = e.clientY - this.target.offsetTop;
              this.pickerCircle.x = currentX;
              this.pickerCircle.y = currentY;
             
            }
          
          const onMouseMove = (e) => {
            if(i%2 == 0) {
              this.build();
              let currentX = e.clientX - this.target.offsetLeft;
             let currentY = e.clientY - this.target.offsetTop;
              this.pickerCircle.x = currentX;
              this.pickerCircle.y = currentY;
            }
          }
          
          const onMouseUp = () => {
            
                isMouseDown = false;


            
          }
          
          //Register
          this.target.addEventListener("mousedown", onMouseDown);
          this.target.addEventListener("mousemove", onMouseMove);
          this.target.addEventListener("mousemove", () => this.onChangeCallback(this.getPickedColor()));
      
          
          document.addEventListener("mouseup", onMouseUp);
        }
        
        getPickedColor() {
          let imageData = this.context.getImageData(this.pickerCircle.x, this.pickerCircle.y, 1, 1);
          return { r: imageData.data[0], g: imageData.data[1], b: imageData.data[2] };
        }
        
        onChange(callback) {
          this.onChangeCallback = callback;
        }
        
           }
         let picker = new Picker(document.getElementById("color-picker"), 250, 220);    picker.build();
    
      picker.onChange((color) => {
         let selected = document.getElementsByClassName("selected")[0];
        selected.style.backgroundColor = `rgb(${color.r}, ${color.g}, ${color.b})`;   });
 html, body {
        width: 100%;
        height: 100%;
        font-family: Oxygen, sans-serif;
        text-align: center;   }
         .container {
        width: 100%;
        height: 100%;
        display: flex;
        justify-content: center;
        align-items: center;   }
         #color-picker {
        border: .5px solid rgba(15, 15, 15, 0.2);   }
         .info {
        width: 12em;
        display: flex;
        margin-left: 4em;
        flex-direction: row;
        justify-content: space-between;   }
         .selected {
        width: 50px;
        height: 50px;
        border-radius: 100%;
        border: 2px solid rgba(15, 15, 15, 0.2);   }
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="style.css">
    <script src="app.js" defer></script>
</head>
<body>
    <h2>Let's Create a Color Picker</h2>
<div class="container">
  <canvas id="color-picker"></canvas>
  <div class="info">
    <h3>Selected Color</h3>
    <div class="selected"></div>
  </div>
</div>
</body>
</html>

推荐阅读