Creating a UI

In this guide, we’ll build a simple user interface that lets users upload an image for optimization. The interface allows users to select an image, adjust the quality slider, and submit the file for processing to an API endpoint. This tutorial uses React for the front-end development.

Initializing the React Application

Begin by setting up your React application. The code below imports the required modules and renders the root component:

import { StrictMode } from 'react';
import { createRoot } from 'react-dom/client';
import App from './App.jsx';

createRoot(document.getElementById('root')).render(
  <StrictMode>
    <App />
  </StrictMode>
);

After launching the development server, you should observe output similar to the following in your console:

VITE v5.4.11  ready in 105 ms

Local:   http://localhost:5173/
Network: use --host to expose
press h  to show help

Setting Up Global Styles

Your application’s base styles are defined in the index.css file. These styles provide a foundational design for fonts, links, and backgrounds:

/* index.css */
:root {
  font-family: Inter, system-ui, Avenir, Helvetica, Arial, sans-serif;
  line-height: 1.5;
  font-weight: 400;
  color: scheme(light dark);
  background-color: rgba(255, 255, 255, 0.87);
}

a {
  font-synthesis: none;
  color: #646cff;
  text-decoration: inherit;
}

a:hover {
  color: #353bfa;
}

body {
}

The development server output might update as seen here:

VITE v5.4.11  ready in 185 ms

Local:   http://localhost:5173/
Network: use --host to expose
press h  enter to show help

At this point, the basic HTML structure is visible, featuring a heading for the image optimizer and a file input element. The next step is to implement the upload functionality in App.jsx.

Building the Image Optimizer Component

Start by creating a basic component in App.jsx that displays a heading and a file input field:

import React, { useState } from 'react';
import reactLogo from '/assets/react.svg';
import './App.css';

function App() {
  const [count, setCount] = useState(0);

  return (
    <>
      <h1>Image Optimizer</h1>
      <input type="file" />
    </>
  );
}

export default App;

After saving your file, you should see a console message similar to:

1:41:38 PM [vite] hmr update /src/App.jsx

This confirms that App.jsx is correctly integrated into your project.

Handling Image Uploads and Form Submission

Next, enhance the component by adding image upload handling and form submission. This version introduces state management for the selected image and builds a form that submits the image to your API endpoint. A callout alerts users if no image is selected:

import React, { useState } from 'react';
import reactLogo from './assets/react.svg';
import './App.css';

function App() {
  const [selectedImage, setSelectedImage] = useState(null);

  const handleSubmit = async (e) => {
    e.preventDefault();

    if (!selectedImage) {
      alert('Please select an image first');
      return;
    }

    const formData = new FormData();
    formData.append('image', selectedImage);

    try {
      const response = await fetch('YOUR_API_ENDPOINT', {
        method: 'POST',
        body: formData,
      });

      if (response.ok) {
        const data = await response.json();
        console.log('Upload successful:', data);
      } else {
        console.error('Upload failed');
      }
    } catch (error) {
      console.error('Error uploading image:', error);
    }
  };

  return (
    <div>
      <h1>Image Optimizer</h1>
      <form onSubmit={handleSubmit} className="upload-form">
        <input
          type="file"
          accept="image/*"
          onChange={(e) => setSelectedImage(e.target.files[0])}
        />
        <button type="submit">Upload</button>
      </form>
    </div>
  );
}

export default App;

Make sure to replace 'YOUR_API_ENDPOINT' with your actual endpoint before deploying the application.

Adding a Quality Slider

To further enhance the user experience, add a slider to control the quality parameter for image compression. The slider ranges from 0 to 100. The following code updates the form to include the quality slider and passes the slider value to the API:

import React, { useState } from 'react';
import reactLogo from './assets/react.svg';
import './App.css';

function App() {
  const [selectedImage, setSelectedImage] = useState(null);
  const [quality, setQuality] = useState(80); // Default quality value

  const handleSubmit = async (e) => {
    e.preventDefault();

    if (!selectedImage) {
      alert('Please select an image first');
      return;
    }

    const formData = new FormData();
    formData.append('image', selectedImage);
    formData.append('quality', quality);

    try {
      const response = await fetch('YOUR_API_ENDPOINT', {
        method: 'POST',
        body: formData,
      });

      if (response.ok) {
        const data = await response.json();
        console.log('Upload successful:', data);
      } else {
        console.error('Upload failed');
      }
    } catch (error) {
      console.error('Error uploading image:', error);
    }
  };

  return (
    <div>
      <h1>Image Optimizer</h1>
      <form onSubmit={handleSubmit} className="upload-form">
        <input
          type="file"
          accept="image/*"
          onChange={(e) => setSelectedImage(e.target.files[0])}
        />
        <div className="quality-control">
          <label htmlFor="quality">Quality:</label>
          <input
            type="range"
            id="quality"
            min="0"
            max="100"
            value={quality}
            onChange={(e) => setQuality(parseInt(e.target.value))}
          />
        </div>
        <button type="submit">Optimize Image</button>
      </form>
    </div>
  );
}

export default App;

This update introduces the quality slider just above the submit button and ensures that if no image is selected, a prompt will alert the user accordingly.

Improving Layout with a Grid System

A clean, responsive layout enhances usability. Use a grid layout to neatly arrange your components. First, update your component structure in App.jsx:

import React, { useState } from 'react';
import reactLogo from './assets/react.svg';
import './App.css';

function App() {
  const [selectedImage, setSelectedImage] = useState(null);
  const [quality, setQuality] = useState(80); // Default quality value

  const handleSubmit = async (e) => {
    e.preventDefault();

    if (!selectedImage) {
      alert('Please select an image first');
      return;
    }

    const formData = new FormData();
    formData.append('image', selectedImage);
    formData.append('quality', quality);

    try {
      const response = await fetch('YOUR_API_ENDPOINT', {
        method: 'POST',
        body: formData,
      });
      if (response.ok) {
        const data = await response.json();
        console.log('Upload successful:', data);
      } else {
        console.error('Upload failed');
      }
    } catch (error) {
      console.error('Error uploading image:', error);
    }
  };

  return (
    <div className="container">
      <header className="header">
        <h1>Image Optimizer</h1>
      </header>
      <main className="main-content">
        <form onSubmit={handleSubmit} className="upload-form">
          <div className="upload-section">
            <label htmlFor="image-upload">Upload Image:</label>
            <input
              id="image-upload"
              type="file"
              accept="image/*"
              onChange={(e) => setSelectedImage(e.target.files[0])}
            />
          </div>

          <div className="quality-section">
            <label htmlFor="quality">Quality: {quality}%</label>
            <input
              type="range"
              id="quality"
              min="0"
              max="100"
              value={quality}
              onChange={(e) => setQuality(parseInt(e.target.value))}
            />
          </div>

          <div className="button-section">
            <button type="submit">Optimize Image</button>
          </div>
        </form>
      </main>
    </div>
  );
}

export default App;

Then, update your CSS (in App.css) to implement the grid layout:

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem;
}

.header {
  text-align: center;
  margin-bottom: 3rem;
}

.main-content {
  display: grid;
  place-items: center;
}

.upload-form {
  display: grid;
  gap: 2rem;
  max-width: 600px;
  padding: 2rem;
  background: #f5f5f5;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.upload-section,
.quality-section,
.button-section {
  display: grid;
  gap: 0.5rem;
  width: 100%;
}

.upload-section input[type="file"] {
  box-sizing: border-box;
  padding: 0.5rem;
  border: 2px dashed #ccc;
  border-radius: 4px;
  width: 100%;
  cursor: pointer;
}

.quality-section input[type="range"] {
  width: 100%;
}

button {
  background: #646cff;
  color: white;
  padding: 0.8rem 1.5rem;
  border: none;
  border-radius: 4px;
}

/* Optional: Ensure a consistent box-sizing across elements */
*, *::before, *::after {
  box-sizing: border-box;
}

@media (prefers-reduced-motion: no-preference) {
  .card {
    padding: 2em;
  }

  .read-the-docs {
    color: #888;
  }
}

The CSS above creates a responsive grid layout where the upload section, quality control, and button are evenly spaced and centered.

The image shows a web application interface for an "Image Optimizer" with options to upload an image, adjust quality, and optimize it. The background displays a code editor with a project directory and code files.

Notice that the dashed border around the file input has been adjusted using padding and box-sizing properties. The button styling was also refined for better consistency.

Refining the Page Background

To further improve the overall look, set a background color for the page. The CSS below ensures that both the body and the root container have a clean and consistent background:

body {
  background-color: #ffffff; /* Adjust this color as needed */
}

#root {
  background-color: #ffffff;
  max-width: 1280px;
  margin: 0 auto;
  padding: 2rem;
  text-align: center;
}

After applying these changes, your final design will feature a responsive layout with a clean background and centered form elements, ensuring a user-friendly experience.

At this stage, the interface includes all required features: selecting a file, adjusting the quality parameter via a slider, and optimizing the image using a neatly arranged grid layout.

In the next article, we will cover how to integrate the backend and process the image through the API endpoint.

For more information on related topics, check out these resources:

Course Introduction

Introduction to AI-Assisted Development

Planning Phase

Development Phase - Backend

Development Phase - Frontend

Project Completion

Initializing the React Application

Setting Up Global Styles

Building the Image Optimizer Component

Handling Image Uploads and Form Submission

Adding a Quality Slider

Improving Layout with a Grid System

Refining the Page Background

Watch Video

​Initializing the React Application

​Setting Up Global Styles

​Building the Image Optimizer Component

​Handling Image Uploads and Form Submission

​Adding a Quality Slider

​Improving Layout with a Grid System

​Refining the Page Background

Watch Video

Initializing the React Application

Setting Up Global Styles

Building the Image Optimizer Component

Handling Image Uploads and Form Submission

Adding a Quality Slider

Improving Layout with a Grid System

Refining the Page Background