search
HomeWeb Front-endHTML TutorialProblems with canvas and drawImage, experts can quickly learn_html/css_WEB-ITnose

代码如下:

html>




<script></script>
<script> <br /> jQuery(function ($) { <br /> $("img").load(function () { <br /> var w = $(this).width(), <br /> h = $(this).height(); <br /> $(this).after($("<canvas>").css({"width": w, "height": h, "backgroundColor": "blue"})); <br /> var ctx = $(this).next("canvas")[0].getContext("2d"); <br /> ctx.drawImage($(this)[0], 0, 0, w, h); <br /> }); <br /> }); <br /> </script>


Problems with canvas and drawImage, experts can quickly learn_html/css_WEB-ITnose



drawImage出来的图片尺寸变形,不是原来图片的形状,会看到canvas背景蓝色。

回复讨论(解决方案)

请问你用的是什么浏览器呀???我用的chrome opera ie9貌似都没有你说的问题

.after($("")


canvas的实际宽高(canvas代码种实际参考的大小) 要这样设置  否则默认是 300-150
样式里面的 宽高 代表 渲染大小

实际宽高 和  样式 宽高 不一致  就会拉伸了

canvas画布的尺寸没问题,用drawImage画出来的图片与源img节点尺寸不一样

canvas里面的width和height跟css里面的width和height是不一样的,我以前就被坑过。。 统一用canvas.width比较好,画板的坐标神马的跟这个width是一样的,跟css里面的不一样

canvas画布的尺寸没问题,用drawImage画出来的图片与源img节点尺寸不一样
2楼已经和你说的很清楚了

谢了各位,解决了

怎么解决的呀,也碰到了同样的问题,望楼主告知下解决的方法哦!!

怎么解决的呀,也碰到了同样的问题,望楼主告知下解决的方法哦!!
canvas的width和height要设置成属性而不是样式
就是这种 
不是  和 canvas {width: 400px; height: 300px;}

原来如此。。。。 坑了我好久。。。。

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
What is the difference between an HTML tag and an HTML attribute?What is the difference between an HTML tag and an HTML attribute?May 14, 2025 am 12:01 AM

HTMLtagsdefinethestructureofawebpage,whileattributesaddfunctionalityanddetails.1)Tagslike,,andoutlinethecontent'splacement.2)Attributessuchassrc,class,andstyleenhancetagsbyspecifyingimagesources,styling,andmore,improvingfunctionalityandappearance.

The Future of HTML: Evolution and TrendsThe Future of HTML: Evolution and TrendsMay 13, 2025 am 12:01 AM

The future of HTML will develop in a more semantic, functional and modular direction. 1) Semanticization will make the tag describe the content more clearly, improving SEO and barrier-free access. 2) Functionalization will introduce new elements and attributes to meet user needs. 3) Modularity will support component development and improve code reusability.

Why are HTML attributes important for web development?Why are HTML attributes important for web development?May 12, 2025 am 12:01 AM

HTMLattributesarecrucialinwebdevelopmentforcontrollingbehavior,appearance,andfunctionality.Theyenhanceinteractivity,accessibility,andSEO.Forexample,thesrcattributeintagsimpactsSEO,whileonclickintagsaddsinteractivity.Touseattributeseffectively:1)Usese

What is the purpose of the alt attribute? Why is it important?What is the purpose of the alt attribute? Why is it important?May 11, 2025 am 12:01 AM

The alt attribute is an important part of the tag in HTML and is used to provide alternative text for images. 1. When the image cannot be loaded, the text in the alt attribute will be displayed to improve the user experience. 2. Screen readers use the alt attribute to help visually impaired users understand the content of the picture. 3. Search engines index text in the alt attribute to improve the SEO ranking of web pages.

HTML, CSS, and JavaScript: Examples and Practical ApplicationsHTML, CSS, and JavaScript: Examples and Practical ApplicationsMay 09, 2025 am 12:01 AM

The roles of HTML, CSS and JavaScript in web development are: 1. HTML is used to build web page structure; 2. CSS is used to beautify the appearance of web pages; 3. JavaScript is used to achieve dynamic interaction. Through tags, styles and scripts, these three together build the core functions of modern web pages.

How do you set the lang attribute on the  tag? Why is this important?How do you set the lang attribute on the tag? Why is this important?May 08, 2025 am 12:03 AM

Setting the lang attributes of a tag is a key step in optimizing web accessibility and SEO. 1) Set the lang attribute in the tag, such as. 2) In multilingual content, set lang attributes for different language parts, such as. 3) Use language codes that comply with ISO639-1 standards, such as "en", "fr", "zh", etc. Correctly setting the lang attribute can improve the accessibility of web pages and search engine rankings.

What is the purpose of HTML attributes?What is the purpose of HTML attributes?May 07, 2025 am 12:01 AM

HTMLattributesareessentialforenhancingwebelements'functionalityandappearance.Theyaddinformationtodefinebehavior,appearance,andinteraction,makingwebsitesinteractive,responsive,andvisuallyappealing.Attributeslikesrc,href,class,type,anddisabledtransform

How do you create a list in HTML?How do you create a list in HTML?May 06, 2025 am 12:01 AM

TocreatealistinHTML,useforunorderedlistsandfororderedlists:1)Forunorderedlists,wrapitemsinanduseforeachitem,renderingasabulletedlist.2)Fororderedlists,useandfornumberedlists,customizablewiththetypeattributefordifferentnumberingstyles.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

SublimeText3 English version

SublimeText3 English version

Recommended: Win version, supports code prompts!

MinGW - Minimalist GNU for Windows

MinGW - Minimalist GNU for Windows

This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.

ZendStudio 13.5.1 Mac

ZendStudio 13.5.1 Mac

Powerful PHP integrated development environment

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor