CS 511-Week 5:Topic 54-56

     

CS 511-Web Engineering

Week 5

Topic 54-56

CS 511-Week 5:Topic 54-56

Topic 54:

Scaling Images

The process of scaling images for responsive designs step by step:

1. Begin with a liquid layout: A responsive design starts with a liquid layout, where elements on the web page have their widths specified as percentages rather than fixed pixel values. This allows the elements to adjust and scale according to the screen size or device used by the viewer.
2. Define the image scaling rule: To make images scale in size, we can use CSS rules. In this case, we'll use the following rule:

Image {

  width: 100%;

  max-width: 1024px;

}

This CSS rule is applied to the img or picture elements on the web page. It specifies that the width of the image should be 100% of its parent container's width, allowing it to fill the available space. However, the max-width property limits the image's width to a maximum of 1024 pixels, ensuring that it doesn't become too large on larger screens.

3. Implement the rule within the HTML structure: To apply this rule to an image, you can wrap it in a <picture> element or directly use the <img> tag. Here's an example of how it can be implemented within the HTML structure:

<picture>

  <img src="your-image.jpg" alt="Description of the image">

</picture>

The <picture> element is optional but useful when you need to provide multiple image sources for different screen resolutions or formats. If you only have a single image source, you can use the <img> tag directly.

By setting the CSS rule mentioned earlier, the image will automatically scale to fit the width of its parent container while maintaining its aspect ratio. The max-width property ensures that the image doesn't exceed 1024 pixels in width, regardless of the screen size.

Remember to replace "your-image.jpg" with the actual source URL or file path of your desired image, and provide a descriptive "Description of the image" for accessibility purposes.

This approach allows the images to adapt to different screen sizes and provides a responsive design that caters to various devices, ensuring a better user experience across platforms.

Topic 55:

CSS Frameworks & CSS Preprocessors:

CSS preprocessors are powerful tools that enhance the capabilities of CSS by introducing programming concepts such as variables, nesting, functions, and inheritance. They provide an additional layer of abstraction on top of CSS, allowing developers to write more efficient and maintainable stylesheets.

One of the key advantages of CSS preprocessors is the use of variables. Variables enable developers to store and reuse values throughout their stylesheets, making it easier to manage and update global styles. For example, instead of manually changing the color of multiple elements, you can define a variable for the color and update it in one place.

Nesting is another feature provided by CSS preprocessors, which allows you to nest selectors within one another. This nesting improves code organization and readability by reflecting the HTML structure. With nesting, you can target specific elements within their parent containers without the need for repetitive or complex selectors.

Functions and calculations are additional capabilities offered by CSS preprocessors. Functions allow you to define reusable pieces of code that can accept parameters and generate dynamic CSS properties. Calculations enable you to perform mathematical operations directly within the stylesheets, making it easier to create responsive designs or calculate values based on specific conditions.

CSS preprocessors also support the concept of inheritance. This means you can create reusable styles by extending or inheriting properties from existing classes or placeholders. Inheritance helps reduce code duplication and promotes a modular approach to stylesheet development.

Some popular CSS preprocessors include:

1. LESS (Leaner Style Sheets): It introduces features like variables, mixins (reusable code snippets), nested rules, and functions. LESS code is compiled into regular CSS.
2. SASS (Syntactically Awesome Style Sheets): SASS provides a more extensive set of features and options compared to LESS. It offers a syntax with both the indented format (SASS) and the more concise SCSS (Sassy CSS) syntax, which closely resembles CSS. SASS code is also compiled into regular CSS.
3. Stylus: Stylus is known for its minimalistic and expressive syntax. It offers a wide range of features and allows developers to omit semicolons and braces, resulting in more concise code. Stylus code is compiled into regular CSS.

These CSS preprocessors enable developers to write cleaner, more maintainable CSS code and provide additional functionalities not available in standard CSS. By using variables, nesting, functions, and inheritance, developers can streamline their stylesheet development process, reduce code duplication, and create more flexible and scalable stylesheets.

Topic 56:

Installing Bootstrap

Bootstrap has two parts:

1. CSS
2. JavaScript

Ways to get Bootstrap:

There are three main ways to get the bootstrap:

1. Content Delivery Network
2. Web server/local Machines
3. Package Managers

Bootstrap Requirements:

Require certain tags on the web page

<!DOCTYPE html>

<html lang="en">

  <head>

    <meta charset="utf-8">

<meta name="viewport" content="width=device-width, initial-scale=1">

  </head>

</html>

Revision:

CS 511-Week 5:Topic 54-56

Scaling Images (Topic 54):

Scaling images in responsive designs involves a step-by-step process. It begins with implementing a liquid layout, where elements on the web page have their widths specified as percentages rather than fixed pixels. This allows the elements to adjust and scale based on the screen size or device used.

Next, an image scaling rule is defined using CSS. This rule typically includes setting the width of the image to 100% of its parent container's width, allowing it to fill the available space. Additionally, a max-width property can be set to limit the image's width to a maximum value, ensuring it doesn't become too large on larger screens.

To apply the image scaling rule within the HTML structure, either the <picture> element or the <img> tag can be used. The <picture> element is useful when providing multiple image sources for different screen resolutions or formats, while the <img> tag can be used for a single image source. By applying the CSS rule to the image, it will automatically scale to fit the width of its parent container while maintaining its aspect ratio.

CSS Frameworks & CSS Preprocessors (Topic 55):

CSS preprocessors enhance CSS by introducing programming concepts such as variables, nesting, functions, and inheritance. Variables allow for easier management and updating of global styles, reducing repetition and ensuring consistency throughout the stylesheet.

Nesting improves code organization and readability by reflecting the HTML structure. Selectors can be nested within one another, eliminating the need for complex selectors and making the code more maintainable.

Functions and calculations enable the creation of dynamic CSS properties. Functions allow for reusable code snippets that accept parameters, while calculations facilitate mathematical operations directly within the stylesheets.

Inheritance reduces code duplication by extending or inheriting properties from existing classes or placeholders. This promotes a modular approach to stylesheet development and improves code reusability.

Popular CSS preprocessors like LESS, SASS, and Stylus offer these features. LESS and SASS provide variables, mixins, nesting, and functions. SASS offers both the indented and SCSS syntaxes. Stylus has a minimalistic syntax, allowing for concise code without semicolons and braces.

Using CSS preprocessors enhances productivity, enables cleaner and more maintainable code, and provides additional functionalities not available in standard CSS.

Installing Bootstrap (Topic 56):

Bootstrap, a popular CSS framework, can be obtained through different methods. It consists of CSS and JavaScript components that provide ready-to-use styles and components for web development.

There are three main ways to get Bootstrap. First, you can include the Bootstrap CSS and JavaScript files by linking to a Content Delivery Network (CDN). This allows you to access the latest version of Bootstrap hosted on a remote server.

Second, you can download the Bootstrap files and host them on your web server or local machine. This gives you direct control over the files and allows for customization.

Third, you can use package managers like npm or yarn to install Bootstrap as a dependency in your project. This simplifies the installation process and enables easy updates.

To use Bootstrap, certain tags are required on the web page, such as the doctype declaration, the <html> element with the lang attribute, and the <meta> tag for specifying the viewport.

Bootstrap provides a foundation for building responsive and visually appealing websites, offering a wide range of pre-designed styles and components that can be easily customized to suit specific project requirements.

THE END 😊