Understanding Camera Histograms While Shooting
Summary： We have two previous articles on the impact of shutter speed, aperture and sensitivity on photo exposure： 【Notes】 Grasp the three elements of exposure （up ）：shutter, aperture, ISO 【Notes】Three elements of exposure （ Application of Aperture and Sensitivity Through those two articles，We know how to achieve normal exposure by adjusting the shutter, aperture and sensitivity under overexposure or underexposure. So how do we judge whether a photo is properly exposed when shooting?? You can see it through the histogram. This article will talk about the use of the histogram in the early stage of shooting. 1. The concept of histogram Histogram in digital photography 中 is a very useful tool，you can clearly see the brightness information on the photo through the histogram，and then judge whether the photo is underexposed or overexposed，that is to say， After a photo ， check the histogram in time， can effectively judge the exposure of the photo. We can see the photo histogram through the camera display screen, LR, ACR, PS, mobile phone APP and so on. The picture is an example of a histogram： The picture below is the histogram we can see in the camera，We can directly view the histogram information when shooting…
Hivemysql metadata, error Specifiedkeywastoolong;maxkeylengththis767bytes
Specified key was too long; max key length is 767 bytes This error is hive metadata mysql character set encoding problem such as show create table PARTITIONS ; utf-8 will Report the above error. Change CHARSET=utf-8 to CHARSET=latin1; alter table PARTITIONS convert to character set latin1; So do a good job of setting the character set encoding at the beginning of hive database construction alter database hivedb character set latin1; In this way, everything will be fine, and then start the hive metastore service. All tables are encoded in latin1.
Comparison of Vue2.0 and Vue3.0DomDiff
In increasingly complex front-end applications, state management is a topic that is often mentioned. From the early slash-and-burn era to jQuery, and then to the current popular MVVM era, the form of state management has undergone earth-shaking changes. There is no need to maintain a large number of event callbacks and listeners to update the view. Instead, use two-way data binding. You only need to maintain the corresponding data state to automatically update the view, which greatly improves development efficiency. However, two-way data binding is not the only way. There is also a very rough and effective way: once the data changes, redraw the entire view, that is, reset Click on innerHTML. This approach is indeed simple, brutal, and effective, but if the entire view is updated only because of a small local data change, the cost-effectiveness is too low. Moreover, events, input boxes that acquire focus, etc., all need to be reprocessed. Therefore, for small applications or local small views, it is completely possible to do this, but it is not advisable for complex large-scale applications. In order to solve the problem that the view can be updated reasonably and efficiently under large and frequent data updates, Vue introduced…
Regular expression functions in php There are two sets of regular expression function libraries in php. One is, PHP regular expression function library (two sets)…
$string = “April 15, 2003”; $pattern = “/(\w+) (\d+), (\d+), (\d+ 43;)/i”; $replacement = “\${1}1,\$3”; print preg_replace($pattern, $replacement, $string ); preg_match_all() for global regular expression matching Grammar format ： preg_match_all (“|]+>(. *)[^>]+>|U”, “example: this is a test”, $out, PREG_PATTERN_ORDER) ; print $out[0][0].”, “.$out[0][1].” “; print $ out[1][0].”, “.$out[1][1].” “; Output result ：example: , this is a test example: , this is a test Original ：http://www.jb51.net/article/20400.htm
mysql redo log _mysql8.0 source code introduction of lock-free redo log
InnoDB, like most storage engines, uses WAL to write data. All data is first written to the redolog, and then flushed from the bufferpool to the data page or when the backup is restored. Restoring from redolog to bufferpoll, and then flushing dirty data pages, it is very important for WAL to convert random writes into sequential writes. Therefore, in the era of mechanical disks, the performance of sequential writes is far greater than that of random writes. Make full use of It improves the performance of the disk. But it also brings a problem, that is, any write operation must be locked for access to ensure that the next write operation can only be performed after the previous write operation is completed. This is also implemented in the early versions of InnoDB, but With the increase of the number of CPU cores, such frequent locking will not be able to exert multi-core performance, so in InnoDB8.0 it has been changed to lock-free implementation. This is the official introduction: https://mysqlserverteam.com/mysql-8-0 -new-lock-free-scalable-wal-design Version 5.6 implementation There are two operations that need to obtain the global mutex, log_sys_t::mutex, log_sys_t::flush_order_mutex Each user connection has a thread. Before writing data, log_sys_t::mutex must be obtained…
How to partition Lenovo Xiaoxinchao 7000i7 notebook disk?
After the Lenovo Xiaoxinchao 7000i7 notebook is bought, there are generally only two partitions. For some users, it is impossible to classify the files well. What should I do if I want to partition the notebook? Woolen cloth? Let’s take a look at the detailed tutorial below. 1. First Right-click “This PC” or “Computer” click “Manage“ 2. After popping up the “Computer Management” page, click “Disk Management” 3. If you want to partition the “d” drive, right click“d drive” strong> icon, click “Compressed Volume” 4. If you want to allocate 1g, we enter 1024(1gb=1024mb) in the third column to And so on. Note: After the compression is completed, no partition has been formed, and we need to create a new volume. 5. Right click on the green piece “Available Space”, click “New Simple Volume” and click “Next” All the way on the pop-up page, A partition of 1g is created. 6. This is also the method of dividing into 2 or 3 areas, starting from step 3 Just repeat The above is the tutorial of Lenovo Xiaoxinchao 7000i7 notebook disk partition, I hope you like it, please continue to pay attention to Qijiutui.
Door opener and door closer string C language, door opener and door closer
Description Every day, the first person to come to the computer room should open the door & # xff0c; the last person to leave should close the door. There are a bunch of messy computer room sign-in and sign-out records，Please find out who opened and closed the door on the day according to the records. Enter The first line of the test input gives the total number of days N of the record ( 0 The record of each day gives the number of recorded entries in the first line M ( 0 Certificate number Sign-in time Sign-out time The time is given in “hour: minute: second” (each takes 2 digits) ，The document number is A character string whose length does not exceed 15. Output For each day’s record, output 1 line ， that is, the ID number of the person who opened and closed the door on that day， in the middle 1 space separated. Note ：In the referee’s standard test input ，All records are guaranteed to be complete ，Everyone’s check-in time is before the check-out time，and There is no situation where multiple people sign in or sign out at the same time. Sample input 1 1 3 CS2322231…
How to set up 2 routers?
“I am yoyohoushuo Technology, focusing on data network answers, welcome to exchange data network questions with me” As in the title, if two routers want to surf the Internet at the same time, there are two ways to do it One is a wired connection; the other is a wireless bridge How to set up multiple routers. The following is a detailed introduction to the specific operation steps of the two methods: 1. Wired connection. a. Router 1 is normally connected and configured, and the WAN port of Router 2 is connected to the LAN port of Router 1. b. Configure the LAN port address of router 2. It should be noted that the LAN port address of router 2 is different from the LAN port address of router 1. c. Configure the wireless password of router 2 and set your own wireless password. It is recommended to use a combination of numbers + letters + symbols to prevent others from cracking it easily. Second, wireless bridging. a. First, confirm the wireless name, wireless password, wireless channel, and LAN port address of router 1. b. Adjust the LAN port address of router 2 to the same network segment as the…
【Certification】【DVB】DBook Certification Introduction and Summary
D-Book certification introduction and summary Summary ： due to D-book covers everything & # xff0c; equivalent to the “constitution” of DVB broadcasting business standards & # xff0c; has undergone more than ten years of revision & # xff0c; can not introduce everything & # xff0c; This article only summarizes the work based on my own experience The problems and needs encountered in the European standardization certification process， and how to deal with them. Specifically, each country has more detailed requirements for certification ， will be detailed in other articles later. D-book is the UK European standard broadcast standard certification organization （DTG） ; Official document drafted in 1996 for pan-European broadcast certification. Testing to this standard must be met prior to TV internationalization certification and product launch in order to be available in the region. This is also the threshold that must be passed in the TV product development process. D-Book is mainly British dominated ，is British digital terrestrial television （Freeview and Freeview HD） Technical Specifications，Standards cover the standards of each major country and operator in the mainstream EU. It is of great significance to the digital TV development and standard formulation of other countries in the world. Many business logics…
Android development learns to use XmlPullParser to parse xml files
There are three main ways to parse XML in Android: sax, dom and pull. For its content, please refer to: http://blog.csdn.net/liuhe688/article/details/6415593 This article will mainly introduce the pull parser to parse xml files, the environment is ubuntu 12.04+ intelij 13.1 + android sdk 2.1 1. Create an XML project, the steps are as follows: 2. Parse an xml file: assets/person.xml <?xml version=”1.0″ encoding=”UTF-8″?> persons person id=”1101″ nameamos</name age30</age </person person id=”1102″ nametom</name age18</age </person </persons com/amos/xml/domain/Person.java package com.amos.xml.domain; /** * Created by amosli on 14-6-3. */ public class Person { private String name; private Integer age; private Integer id; public Integer getAge() { return age; } public void setAge(Integer age) { if (age 100) { this.age = 0; } else { this.age = age; } } public Integer getId() { returnid; } public void setId(Integer id) { this.id =id; } public String getName() { returnname; } public void setName(String name) { this.name =name; } } com/amos/xml/service/PersonService.java package com.amos.xml.service; import android.content.Context; import android.content.res.AssetManager; import android.util.Log; import android.util.Xml; import com.amos.xml.domain.Person; import org.xmlpull.v1.XmlPullParser; importjava.io.InputStream; import java.util.ArrayList; importjava.util.List; /** * Created by amosli on 14-6-3. */ public class PersonService { private Context context; public PersonService(Context context) { this.cOntext= context; } /** * Convert the…
