Web Front-end
HTML Tutorial
How to implement adaptive layout of Y-axis position in web annotation?
How to implement adaptive layout of Y-axis position in web annotation?
Apr 04, 2025 pm 11:30 PM
Detailed explanation of the Y-axis position adaptive algorithm for web page annotation
This article discusses how to build a web annotation function similar to Word documents, focusing on solving the problem of overlapping comments and realizing an adaptive layout of the Y-axis position of the annotation. Ideally, annotations should be closely arranged to avoid overlapping, while maintaining reasonable spacing between annotations.
The core challenge is to design an algorithm that automatically calculates its Y-axis position when adding new annotations. An effective solution is to use absolute positioning and combine data structures and algorithms to manage annotation locations.
Data structure:
We use an array to store the information for each annotation, each element containing top (initial top position) and height (height) properties. For example:
[
{ top: 100, height: 200 },
{ top: 800, height: 200 },
{ top: 820, height: 200 },
{ top: 1020, height: 200 },
]
Adaptive algorithm:
We use an algorithm similar to waterfall flow layout, use the reduce method to iterate the array, and calculate the final Y-axis position of each annotation ( currentTop ). The core of the algorithm is to compare the initial top value of the current annotation with the bottom position of the previous annotation, and select a larger value as the final currentTop of the current annotation, thereby avoiding overlap.
const arr = [
{ top: 100, height: 200 },
{ top: 800, height: 200 },
{ top: 820, height: 200 },
{ top: 1020, height: 200 },
{ top: 1430, height: 180 },
];
arr.reduce((s, n, i) => {
n.currentTop = Math.max(n.top, (s.currentTop || s.top) s.height);
return n;
});
console.log(arr);
Math.max(n.top, (s.currentTop || s.top) s.height) This line of code is the core of the algorithm. s.currentTop || s.top handles the case of the first annotation.
application:
The currentTop value calculated by this algorithm can be applied to the CSS style of the annotation element, such as top: ${currentTop}px; , thereby realizing the adaptive layout of the annotation, effectively solving the annotation overlap problem, and achieving an effect similar to the annotation spacing of Word documents. This algorithm ensures that the annotations are arranged closely, while avoiding mutual obstruction, achieving a smooth web annotation experience.
The above is the detailed content of How to implement adaptive layout of Y-axis position in web annotation?. For more information, please follow other related articles on the PHP Chinese website!
Hot AI Tools
Undress AI Tool
Undress images for free
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
Free Korean comics online viewing free comics entrance Free Korean comics online reading free pull-down
Jun 12, 2025 pm 08:03 PM
With the vigorous development of the Internet, Korean comics (Korean comics) have won the love of more and more readers around the world with their exquisite painting style, fascinating plots and rich and diverse themes. If you want to travel anywhere, in the exciting Korean comic world, it is crucial to find a stable, free and resource-rich online reading platform. This article will provide you with a detailed guide to watching Korean comics online for free comics, helping you easily start your Korean comic journey.
Which currencies can make investors profit in the short term? How to choose? Recommended short-term profitable currency in the currency circle
Jun 12, 2025 am 11:21 AM
Short-term crypto trading is risky, but it is one of the most favorable ways to make money. If you know how to apply the right strategy, the most important thing is to choose the right crypto assets, you can make a considerable profit, which is exactly what we are going to discuss today. Which currencies can make investors profit in the short term? How to choose? Recommended short-term profitable currencies in the currency circle How to choose short-term trading cryptocurrencies? Short-term transactions involve buying cryptocurrencies and holding them for a short period of time, ranging from minutes to days. This approach is both promising, risky and time-consuming as you need to constantly monitor the market. But that's not all; when choosing the right crypto assets, you should also pay attention to the following points:
What is 'render-blocking CSS'?
Jun 24, 2025 am 12:42 AM
CSS blocks page rendering because browsers view inline and external CSS as key resources by default, especially with imported stylesheets, header large amounts of inline CSS, and unoptimized media query styles. 1. Extract critical CSS and embed it into HTML; 2. Delay loading non-critical CSS through JavaScript; 3. Use media attributes to optimize loading such as print styles; 4. Compress and merge CSS to reduce requests. It is recommended to use tools to extract key CSS, combine rel="preload" asynchronous loading, and use media delayed loading reasonably to avoid excessive splitting and complex script control.
How can CSS be used to implement dark mode theming on a website?
Jun 19, 2025 am 12:51 AM
ToimplementdarkmodeinCSSeffectively,useCSSvariablesforthemecolors,detectsystempreferenceswithprefers-color-scheme,addamanualtogglebutton,andhandleimagesandbackgroundsthoughtfully.1.DefineCSSvariablesforlightanddarkthemestomanagecolorsefficiently.2.Us
Can you explain the difference between em, rem, px, and viewport units (vh, vw)?
Jun 19, 2025 am 12:51 AM
The topic differencebetweenem, Rem, PX, andViewportunits (VH, VW) LiesintheirreFerencepoint: PXISFixedandbasedonpixelvalues, emissrelative EtothefontsizeFheelementoritsparent, Remisrelelatotherootfontsize, AndVH/VwarebaseDontheviewporttimensions.1.PXoffersprecis
External vs. Internal CSS: What's the Best Approach?
Jun 20, 2025 am 12:45 AM
ThebestapproachforCSSdependsontheproject'sspecificneeds.Forlargerprojects,externalCSSisbetterduetomaintainabilityandreusability;forsmallerprojectsorsingle-pageapplications,internalCSSmightbemoresuitable.It'scrucialtobalanceprojectsize,performanceneed
Does my CSS must be on lower case?
Jun 19, 2025 am 12:29 AM
No,CSSdoesnothavetobeinlowercase.However,usinglowercaseisrecommendedfor:1)Consistencyandreadability,2)Avoidingerrorsinrelatedtechnologies,3)Potentialperformancebenefits,and4)Improvedcollaborationwithinteams.
What are the key differences between inline, block, inline-block, and flex display values?
Jun 20, 2025 am 01:01 AM
Choosing the correct display value in CSS is crucial because it controls the behavior of elements in the layout. 1.inline: Make elements flow like text, without occupying a single line, and cannot directly set width and height, suitable for elements in text, such as; 2.block: Make elements exclusively occupy one line and occupy all width, can set width and height and inner and outer margins, suitable for structured elements, such as; 3.inline-block: has both block characteristics and inline layout, can set size but still display in the same line, suitable for horizontal layouts that require consistent spacing; 4.flex: Modern layout mode, suitable for containers, easy to achieve alignment and distribution through justify-content, align-items and other attributes, yes
