install Jpegoptim
Lossless JPEG image compression
In order to compress a pair of JPG images lossless, use:
The code is as follows:
$ Jpegoptim photo.jpg
Photo.jpg 2048x1536 24bit N ICC JFIF [OK] 882178--> 821064 bytes (6.93%), optimized.
Note that the original image will be overwritten by the compressed image.
If the Jpegoptim does not lossless the image, it will not be overwritten:
The code is as
First, briefZip is used to compress and decompress files. The classes used are: ZipEntry ZipoutputstreamSecond, the specific implementation of the CodePackage Com.joyplus.test;import Java.io.file;import java.io.fileinputstream;import Java.io.filenotfoundexception;import Java.io.fileoutputstream;import Java.io.ioexception;import Java.io.inputstream;import Java.util.arraylist;import Java.util.list;import Java.util.zip.zipentry;import Java.util.zip.ZipOu
Ijg JPEG function library: file listIjg JPEG function library: file list copyright (c) 1991-1996, Thomas G. Lane. This article is part of the independent JPEG group software. For how to distribute and use readme files, see the README files issued along with this database. Th
meaningsAn unlimited number of meaningless 0xFF fills can be added before each tag, and multiple 0xFF consecutive can be interpreted as a 0xFF and represent the beginning of a marker codeCommon Tag Code:
SOI 0xd8 Image Start
APP0 0xE0 Application Retention tag 0
APPn 0XE1–0XEF Application retention tag n (n=1~15)
DQT 0xDB Quantization table (Define quantization table)
SOF0 0xC0 Frame Start (start of frame)
DHT 0xc4 definition Huffman tables (Define Huffman table)
What file is JPEG?
JPEG compression technology is very advanced, and very flexible. JPEG format has the function of adjusting image quality, allowing compression of files with different compression ratios, supporting multiple compression levels, compression ratios usually between 10:1 and 40:1, compression ratio is la
Determine the end of a picture file, complete a. jpg,. jpeg,. png, or. gif
I try to save the picture locally from the network, and the file name retains the end of the original picture.
such as: Image.jpg, logo.png
But some picture files end up not. jpg,. jpeg,. png, or. gif, need to complement. jpg,.
Determine the end of a picture file, complete a. jpg,. jpeg,. png, or. gif
I try to save the picture locally from the network, and the file name retains the end of the original picture.
such as: Image.jpg, logo.png
But some picture files end up not. jpg,. jpeg,. png, or. gif, need to complement. jpg,.
/*Note: generate a watermark. You can generate a file based on the top left, bottom left, top right, bottom right, center, and transparency. This file is only valid for JPEG or JPG formats!Author: Blue. DreamDisclaimer: Recently, many websites have quoted my articles and omitted the author's information. Please refer to this article and do not omit the author's i
The JFIF file format uses the JPEG standard directly for many of the tags defined by the application, so the JFIF format becomes the de facto standard for JPEG file interchange formats. Each token of a JPEG is made up of 2 bytes, and the first byte is a fixed value of 0xFF.
will be prompted to gd.so the build directoryAfter adding gd.so under PHP.ini, restart the PHP restart Application server and it will be OK.Some machines may not work, so solveYum Install Libjpeg-devel freetype-devel libpng-develMake clean and then re-/configureMakemake InstallSee Phpinfo OK. support Version 2.0 Readsupport Create support Support Version support Version 1.2. Ten support enabled
GD Support
Enabled
GD Version
Bundled (2.0.34 compati
ImageMagick 'jpeg 'File Denial of Service Vulnerability
Release date:Updated on:
Affected Systems:ImageMagick 6.8.9-8Description:Bugtraq id: 70992
ImageMagick is an open-source image viewing and editing tool on Unix/Linux platforms.
ImageMagick 6.8.9-8 has a denial of service vulnerability in processing 'jpeg 'files. Attackers can exploit this vulnerability t
I 'd better take a look at my blog Simple Analysis of JPEG file formats> Article
JPEG files are divided into two parts: tag and compressed data.
The code stream formats are: soi, app0info, dqtinfo, driinfo, sofinfo, dhtinfo, sosinfo, and EOI. The specific structure is as follows:
# Define byte unsigned char# Define word unsigned short int
# Define SOI 0xffd8 // s
3. Output JPEG File
Because files in JPEG format are always saved and exported in 24-bit colors, they cannot be optimized by editing their palettes, as in GIF format. So when you select an image to output in JPEG format, the color table is empty. As shown in Figure 7-09.
Figure 7-09
Quality--Sets the output quality
Microsoft (r) cabinet maker-version 5.1.2600.2180
Copyright (c) Microsoft Corporation. All rights reserved ..
Makecab [/V [N] [/d Var = value...] [/L dir] source [destination]
Makecab [/V [N] [/d Var = value...]/F directive_file [...]
Source file to compress.
Destination File name to give compressed file. If
The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion;
products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the
content of the page makes you feel confusing, please write us an email, we will handle the problem
within 5 days after receiving your email.
If you find any instances of plagiarism from the community, please send an email to:
info-contact@alibabacloud.com
and provide relevant evidence. A staff member will contact you within 5 working days.