CS 511-Web Engineering
Week 3
Topic 30-32
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| CS 511-Week 3: Topic 30-32 |
Topic 30:
The Box Model:
In CSS, the box model is a fundamental concept that describes how elements are rendered on a web page. It defines the rectangular box that surrounds every HTML element, including its content, padding, border, and margin.
The background properties in CSS allow you to control the background appearance of an element within its box. Here are some commonly used background properties:
- background-color
- background-image
- background-position
- background-size
- background-repeat
- background-origin
- background-clip
- background-attachment
By using these background properties, you can customize the background appearance of HTML elements and create visually appealing designs on your web pages.
As for the CSS TRBL (top, right, bottom, left) shortcut, it is used to set border colors for individual sides of an element. You can specify the color for each side separately using properties like border-top-color, border-right-color, border-bottom-color, and border-left-color. Alternatively, you can use the border-color property to set all four sides at once, either with a single color or by providing multiple colors in the order of top, right, bottom, and left.
Collapsing margins, on the other hand, refer to the behavior where the vertical margins of adjacent elements collapse into each other, resulting in a single margin. This occurs when the top and bottom margins of two or more elements meet. The collapsed margin will be equal to the larger of the two adjacent margins, effectively combining them. However, horizontal margins and margins of elements with certain properties (e.g., floated or absolutely positioned) do not collapse.
Understanding the box model, background properties, border shortcuts, and collapsing margins is essential for working with CSS and creating well-designed and visually appealing web pages.
Topic 31:
Box Dimensions:
In CSS, the box dimensions refer to the width and height of an element's box. There are two commonly used box dimension models: content-box and border-box.
- Content-box: The content-box model is the default box dimension model for most elements. When you specify the width and height of an element using the content-box model, the dimensions apply only to the content area inside the element. The borders and padding are added on top of the specified dimensions, which means they are counted separately. Margins are also calculated separately from the width and height.
- Border-box: The border-box model is an alternative box dimension model. When you use the border-box model, the specified width and height values include both the content area and any borders and padding. In other words, the dimensions represent the total size of the box, including its content, borders, and padding. Margins, however, are still calculated separately from the overall box size.
Limitations of Height Property: For block-level elements like <p> and <div>, there are limitations to what the height property can do. While you can shrink the width of these elements, the height property may be ignored by the browser if the content inside the element needs to be displayed. This means that even if you set a specific height value, the element's height may automatically adjust to accommodate its content.
Overflow Property: The overflow property allows you to control how the content within an element is displayed if it exceeds the dimensions of the element's box. By using the overflow property, you can specify whether the content should be clipped and hidden ("hidden"), displayed with scrollbars ("scroll"), automatically expanded to fit the content ("auto"), or displayed with scrollbars only when necessary ("auto"). This property provides control over how overflowing content is handled within the box.
Box Sizing Using Percentages: When specifying dimensions using percentages, the size of the box is calculated relative to the size of its parent container. For example, setting a width of 50% on an element will make it occupy half of its parent's width. This allows for flexible and responsive designs where elements adjust their size based on the size of their container.
Box Sizing Using Pixels: Alternatively, you can also specify box dimensions using fixed values in pixels. This means that the width and height values are set to specific pixel measurements. This approach provides more precise control over the size of the box, but it may not adapt as well to different screen sizes or dynamic content.
Understanding box dimensions, the content-box and border-box models, limitations of the height property, the overflow property, and the use of percentages or pixels for box sizing is crucial for effectively controlling the layout and appearance of elements in CSS.
Topic 32:
CSS Text Styling:
In CSS, there are two types of properties that affect text: font properties and paragraph properties. Font properties specifically target the font and its appearance, while paragraph properties affect the text in a similar way regardless of the font being used.
Font Properties:
- The "font" property is a shorthand property that allows you to set the font family, style, weight, variant, and size in one declaration.
- The "font-family" property specifies the typeface or font to be used, and you can specify multiple fonts as fallback options.
- The "font-size" property sets the size of the font using measurement units.
- The "font-style" property specifies whether the text should be displayed in italic, oblique, or normal.
- The "font-variant" property in CSS determines whether the text should be rendered in small capitals (small-caps) or the default normal format.
- The "font-weight" property determines the thickness or boldness of the text, with options like normal, bold, bolder, lighter, or numeric values between 100 and 900.
Specifying the Font Family:
- The "font-family" property allows you to specify the preferred font family for the text. You can provide multiple font names as fallback options to ensure that if the first font is not available, the browser can use the next available font.
Font Sizes:
- Setting font sizes can be challenging, especially when dealing with different devices and screen resolutions. Absolute units like points and inches may not translate well to pixel-based devices. The correlation between CSS pixels and device pixels can vary, especially with high pixel density screens on mobile devices.
Embedding Fonts:
- To overcome limitations and enhance typography on the web, embedding custom fonts has gained popularity. The "@font-face" rule allows you to specify and use custom fonts on your web page. Services like Google Web Fonts and Font Squirrel provide a wide range of open-source fonts that can be easily integrated using the "@font-face" rule.
Paragraph Properties:
- letter-spacing
- line-height
- text-indent
- white-space
- word-spacing
- text-shadow
In summary, CSS provides a range of font and paragraph properties that allow you to customize and style text on web pages. Understanding and utilizing these properties effectively can greatly enhance the appearance and readability of text content.
Assessment:
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| CS 511-Week 3: Topic 30-32 |
The CSS TRBL shortcut is used for setting:
What is the default box dimension model for most elements in CSS?
The "overflow" property in CSS is used to control:
Which CSS property allows you to specify the font family for text?
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