DirectFB 两则技巧 DirectFB 的运行行为可以通过配置文件进行控制，可以从多个配置文件中读出配置信息，然后合并到一起，甚至可以对不同名称的应用程序指定不同的配置文件。其主配置文件为 /etc/direcfbrc ，它的内容影响所有用户的应用程序。 建立 PC 模拟
DirectFB两则技巧
DirectFB的运行行为可以通过配置文件进行控制，可以从多个配置文件中读出配置信息，然后合并到一起，甚至可以对不同名称的应用程序指定不同的配置文件。其主配置文件为/etc/direcfbrc，它的内容影响所有用户的应用程序。
建立PC模拟环境。
DirectFB和X Window都是独占显示设备的，在通常的情况下，DirectFB运行时，X Window就不能运行，反之亦然。当然，输入设备，如键盘、鼠标等也是独占设备，不能被DirectFB和X Window同时使用。
当我们用DirectFB开发嵌入式软件时，要使用X Window下的IDE的工具（如glade），同时又需要在PC模拟运行开发的程序。此时，由于X Window已经在运行，再运行DirectFB程序就会发生冲突。
怎么办呢？DirectFB的天才作者们早就想到这一点，DirectFB把后端（输入设备和显示设备）做了抽象，与DirectFB主体是分开的。DirectFB主体并不依赖于具体的物理设置，它可以利用SDL、X11、VNC等作为后端。
所以要建立PC模拟环境，是轻而易举的事情。我们可以利用X Window的输入事件作为输入设备，利用X Window的窗口作为显示设备。更进一步，可以利用Xnest(见笔者另外一篇文章)，这样就可以模拟不同屏幕大小的设备，看到比较真实的外观效果。选择X Window作为后端，可以使用下列参数：
system=x11
使用不同的窗口管理器。
DirectFB的窗口管理器做得比较弱，它毕竟是针对嵌入式设备的，我们没有必要苛求。它自带两种不同的窗口管理器，可以根据自己的需要选择。一个称为default，顾名思义，它是默认的窗口管理器，另外一个称为unique，功能更强一点。
Default只提供了最基本的窗口管理功能，如：
l 窗口栈管理，提供诸如向栈中插入窗口、删除栈中的窗口、调整窗口在栈的Z-Order位置等。
l 输入事件管理，根据输入事件，切换焦点窗口，把消息投递到对应的窗口等功能。
l 还提供了一些快捷操作方式，如关闭窗口，移动窗口等。
Unique 除了提供default具有的基本功能外，还提供了：
l 窗口装饰功能，可以显示窗口标题栏图片，四周边框、四角圆角化等，但不能显示标题本身（居然没有这个基本功能！）。
l 桌面背景图片/颜色，可以设置桌面的背景图片/颜色。这对于demo来说，会好看一点，但对于实际应用来说，作用不大。因为实际的桌面和DirectFB的桌面是两个不同的对象。
l 调试功能，如显示窗口栈中的窗口等。
l 更重要的是，它相当于一个框架，你可以在此基础上扩展其它自己需要的功能。
选择不同的窗口管理器，可以使用下列参数：
wm=default或者wm=unique
Explain the InnoDB Buffer Pool and its importance for performance.Apr 19, 2025 am 12:24 AMInnoDBBufferPool reduces disk I/O by caching data and indexing pages, improving database performance. Its working principle includes: 1. Data reading: Read data from BufferPool; 2. Data writing: After modifying the data, write to BufferPool and refresh it to disk regularly; 3. Cache management: Use the LRU algorithm to manage cache pages; 4. Reading mechanism: Load adjacent data pages in advance. By sizing the BufferPool and using multiple instances, database performance can be optimized.
MySQL vs. Other Programming Languages: A ComparisonApr 19, 2025 am 12:22 AMCompared with other programming languages, MySQL is mainly used to store and manage data, while other languages such as Python, Java, and C are used for logical processing and application development. MySQL is known for its high performance, scalability and cross-platform support, suitable for data management needs, while other languages have advantages in their respective fields such as data analytics, enterprise applications, and system programming.
Learning MySQL: A Step-by-Step Guide for New UsersApr 19, 2025 am 12:19 AMMySQL is worth learning because it is a powerful open source database management system suitable for data storage, management and analysis. 1) MySQL is a relational database that uses SQL to operate data and is suitable for structured data management. 2) The SQL language is the key to interacting with MySQL and supports CRUD operations. 3) The working principle of MySQL includes client/server architecture, storage engine and query optimizer. 4) Basic usage includes creating databases and tables, and advanced usage involves joining tables using JOIN. 5) Common errors include syntax errors and permission issues, and debugging skills include checking syntax and using EXPLAIN commands. 6) Performance optimization involves the use of indexes, optimization of SQL statements and regular maintenance of databases.
MySQL: Essential Skills for Beginners to MasterApr 18, 2025 am 12:24 AMMySQL is suitable for beginners to learn database skills. 1. Install MySQL server and client tools. 2. Understand basic SQL queries, such as SELECT. 3. Master data operations: create tables, insert, update, and delete data. 4. Learn advanced skills: subquery and window functions. 5. Debugging and optimization: Check syntax, use indexes, avoid SELECT*, and use LIMIT.
MySQL: Structured Data and Relational DatabasesApr 18, 2025 am 12:22 AMMySQL efficiently manages structured data through table structure and SQL query, and implements inter-table relationships through foreign keys. 1. Define the data format and type when creating a table. 2. Use foreign keys to establish relationships between tables. 3. Improve performance through indexing and query optimization. 4. Regularly backup and monitor databases to ensure data security and performance optimization.
MySQL: Key Features and Capabilities ExplainedApr 18, 2025 am 12:17 AMMySQL is an open source relational database management system that is widely used in Web development. Its key features include: 1. Supports multiple storage engines, such as InnoDB and MyISAM, suitable for different scenarios; 2. Provides master-slave replication functions to facilitate load balancing and data backup; 3. Improve query efficiency through query optimization and index use.
The Purpose of SQL: Interacting with MySQL DatabasesApr 18, 2025 am 12:12 AMSQL is used to interact with MySQL database to realize data addition, deletion, modification, inspection and database design. 1) SQL performs data operations through SELECT, INSERT, UPDATE, DELETE statements; 2) Use CREATE, ALTER, DROP statements for database design and management; 3) Complex queries and data analysis are implemented through SQL to improve business decision-making efficiency.
MySQL for Beginners: Getting Started with Database ManagementApr 18, 2025 am 12:10 AMThe basic operations of MySQL include creating databases, tables, and using SQL to perform CRUD operations on data. 1. Create a database: CREATEDATABASEmy_first_db; 2. Create a table: CREATETABLEbooks(idINTAUTO_INCREMENTPRIMARYKEY, titleVARCHAR(100)NOTNULL, authorVARCHAR(100)NOTNULL, published_yearINT); 3. Insert data: INSERTINTObooks(title, author, published_year)VA
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
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
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.
WebStorm Mac version
Useful JavaScript development tools
mPDF
mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),
DVWA
Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software
SecLists
SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.
