How to use JS to rotate the preview of IOS photo taken by 90 degrees
Apr 17, 2018 pm 04:43 PM
This time I will show you how to use JS to rotate the preview of the IOS photo taken by 90 degrees, and how to use JS to process the preview of the IOS photo taken 90 degrees by rotating it 90 degrees. , let’s take a look. To solve this problem, you need to introduce a third-party JS library: exif.js Download address:
https://github.com/exif-js/exif-js Through exif.js we can obtain the meta information of the image , which includes the direction in which the photo was taken. The photo direction
attributegiven by exif.js is used in IOS to obtain the direction of the photographed picture through exif.js. The returned value is 6, which is the case of the leftmost F in the above picture. This is where our bug lies. Therefore, we perform corresponding processing by judging the value of the direction. If the value is 6, we perform rotation correction on the image. The specific code is as follows:
//獲取圖片方向
function?getPhotoOrientation(img)?{
???var?orient;
???EXIF.getData(img,?function?()?{
??????orient?=?EXIF.getTag(this,?'Orientation');
???});
???return?orient;
}
Next, we will modify the compression function in the previous article as follows:
//圖片壓縮
function?compress(img,?width,?height,?ratio)?{
???var?canvas,?ctx,?img64,?orient;
????
???//獲取圖片方向
???orient?=?getPhotoOrientation(img);
???canvas?=?document.createElement('canvas');
???canvas.width?=?width;
???canvas.height?=?height;
???ctx?=?canvas.getContext("2d");
???//如果圖片方向等于6?，則旋轉(zhuǎn)矯正，反之則不做處理
???if?(orient?==?6)?{
??????ctx.save();
??????ctx.translate(width?/?2,?height?/?2);
??????ctx.rotate(90?*?Math.PI?/?180);
??????ctx.drawImage(img,?0?-?height?/?2,?0?-?width?/?2,?height,?width);
??????ctx.restore();
???}?else?{
??????ctx.drawImage(img,?0,?0,?width,?height);
???}
???img64?=?canvas.toDataURL("image/jpeg",?ratio);
???return?img64;
}
I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the PHP Chinese website!
Recommended reading:
The above is the detailed content of How to use JS to rotate the preview of IOS photo taken by 90 degrees. 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
How to set up the keyboard boot function on a GIGABYTE motherboard (enable keyboard boot mode on GIGABYTE motherboard)
Dec 31, 2023 pm 05:15 PM
How to set up keyboard startup on Gigabyte's motherboard. First, if it needs to support keyboard startup, it must be a PS2 keyboard! ! The setting steps are as follows: Step 1: Press Del or F2 to enter the BIOS after booting, and go to the Advanced (Advanced) mode of the BIOS. Ordinary motherboards enter the EZ (Easy) mode of the motherboard by default. You need to press F7 to switch to the Advanced mode. ROG series motherboards enter the BIOS by default. Advanced mode (we use Simplified Chinese to demonstrate) Step 2: Select to - [Advanced] - [Advanced Power Management (APM)] Step 3: Find the option [Wake up by PS2 keyboard] Step 4: This option The default is Disabled. After pulling down, you can see three different setting options, namely press [space bar] to turn on the computer, press group
WebSocket and JavaScript: key technologies for implementing real-time monitoring systems
Dec 17, 2023 pm 05:30 PM
WebSocket and JavaScript: Key technologies for realizing real-time monitoring systems Introduction: With the rapid development of Internet technology, real-time monitoring systems have been widely used in various fields. One of the key technologies to achieve real-time monitoring is the combination of WebSocket and JavaScript. This article will introduce the application of WebSocket and JavaScript in real-time monitoring systems, give code examples, and explain their implementation principles in detail. 1. WebSocket technology
How to implement an online speech recognition system using WebSocket and JavaScript
Dec 17, 2023 pm 02:54 PM
How to use WebSocket and JavaScript to implement an online speech recognition system Introduction: With the continuous development of technology, speech recognition technology has become an important part of the field of artificial intelligence. The online speech recognition system based on WebSocket and JavaScript has the characteristics of low latency, real-time and cross-platform, and has become a widely used solution. This article will introduce how to use WebSocket and JavaScript to implement an online speech recognition system.
JavaScript and WebSocket: Building an efficient real-time weather forecasting system
Dec 17, 2023 pm 05:13 PM
JavaScript and WebSocket: Building an efficient real-time weather forecast system Introduction: Today, the accuracy of weather forecasts is of great significance to daily life and decision-making. As technology develops, we can provide more accurate and reliable weather forecasts by obtaining weather data in real time. In this article, we will learn how to use JavaScript and WebSocket technology to build an efficient real-time weather forecast system. This article will demonstrate the implementation process through specific code examples. We
Simple JavaScript Tutorial: How to Get HTTP Status Code
Jan 05, 2024 pm 06:08 PM
JavaScript tutorial: How to get HTTP status code, specific code examples are required. Preface: In web development, data interaction with the server is often involved. When communicating with the server, we often need to obtain the returned HTTP status code to determine whether the operation is successful, and perform corresponding processing based on different status codes. This article will teach you how to use JavaScript to obtain HTTP status codes and provide some practical code examples. Using XMLHttpRequest
How to identify genuine and fake shoe boxes of Nike shoes (master one trick to easily identify them)
Sep 02, 2024 pm 04:11 PM
As a world-renowned sports brand, Nike's shoes have attracted much attention. However, there are also a large number of counterfeit products on the market, including fake Nike shoe boxes. Distinguishing genuine shoe boxes from fake ones is crucial to protecting the rights and interests of consumers. This article will provide you with some simple and effective methods to help you distinguish between real and fake shoe boxes. 1: Outer packaging title By observing the outer packaging of Nike shoe boxes, you can find many subtle differences. Genuine Nike shoe boxes usually have high-quality paper materials that are smooth to the touch and have no obvious pungent smell. The fonts and logos on authentic shoe boxes are usually clear and detailed, and there are no blurs or color inconsistencies. 2: LOGO hot stamping title. The LOGO on Nike shoe boxes is usually hot stamping. The hot stamping part on the genuine shoe box will show
How to get HTTP status code in JavaScript the easy way
Jan 05, 2024 pm 01:37 PM
Introduction to the method of obtaining HTTP status code in JavaScript: In front-end development, we often need to deal with the interaction with the back-end interface, and HTTP status code is a very important part of it. Understanding and obtaining HTTP status codes helps us better handle the data returned by the interface. This article will introduce how to use JavaScript to obtain HTTP status codes and provide specific code examples. 1. What is HTTP status code? HTTP status code means that when the browser initiates a request to the server, the service
How to enable direct connection of independent graphics card on Shenzhou Xuanlong m7e8s3?
Jan 04, 2024 am 09:24 AM
How to enable the direct connection of the independent graphics card of the Shenzhou Xuanlong m7. To enable the direct connection function of the independent graphics card of the Shenzhou Xuanlong m7, you can follow the following steps: 1. First, make sure that you have installed the driver of the independent graphics card. You can go to the official Shenzhou website or the official website of the independent graphics card manufacturer to download and install the latest driver suitable for your graphics card model. 2. On the computer desktop, right-click a blank space and select "NVIDIA Control Panel" in the pop-up menu (if it is an AMD graphics card, select "AMDRadeon Settings"). 3. In the control panel, find "3D Settings" or a similarly named option and click to enter. 4. In "3D Settings" you need to find "Global Settings" or a similarly named option. Here you can specify the use of a unique
