SEARCH KEYWORD -- Color


  Save QWidget as image

Qt library is an excellent GUI library for C++ programmers developed by Nokia and now is an open source project. Often, we may use QPainter to draw strings, lines or images on a QWidget. We can override the QWidget's paintEvent() method when we want to use QPianter object to draw something on a QWidget. If we want to save the items drawn on QWidget as image for later reference, what can we do? We can save a QWidget as an image. Here is the code for achieving this: QPixmap pixmap(this->size())...

   Qt,C++,QWidget,Image     2012-08-19 12:01:18

  Reproduce "MySQL server has gone away" in PHP

If you want to debug the issue of "MySQL server has gone away", you can reproduce it with below steps: Modify configuration file: sudo vi /etc/mysql/my.cnf  Make below changes: [mysqld]   wait_timeout = 30   interactive_timeout = 30  Restart the service: sudo /etc/init.d/mysql restart  Write below PHP codes: $link = mysql_connect('127.0.0.1', 'root', 'root');   if (!$link)&nbs...

   MySQL,debug,rMySQL server has gone away     2013-04-15 11:33:14

  Funny Linux commands

1. sl You will see a train moving from the right to left on the screen. Install : $ sudo apt-get install sl Run : $ sl It has options like -aiFe: -a An accident seems to happen. You'll feel pity for people who cry for help.-l shows little one.-F It flies.-e Allow interrupt by Ctrl+C. We can also make fun of other people by setting an alias like below: $alias ls=sl When the user types ls, he will see the train instead of the file list. 2. fortune Output one statement, it can be a joke, or famous...

   Linux,funny command,figlet,sl     2013-06-08 21:30:26

  Build route graph of Hurricane Sandy

Hurricane Sandy swept US east side and landed in New York, it killed 113 persons and incurred 50 billion US dollars economic loss. Sandy is also considered as the most expensive hurricane. We will now use matplotlib and basemap libraries in Python to build a route graph of Sandy. Below is the animated GIF. Shadow is added in the graph to show the time at night, we can see from the graph that Sandy stayed a while in Panama after emerging, then it went through Cuba and became Hurricane-2. Late...

   Hurricane Sandy,Route graph,Python     2012-11-17 07:58:13

  You can get properties of pseudo-element using JavaScript now

The pseudo-element6 in CSS is extremely useful, you can use it to create CSS triangles and lots of other elements without overuse many HTML elements. In the past, you cannot get the property value of pseudo-element in CSS using JavaScript. Now you can call a new method in JavaScript to get them easily. Assume you have below CSS codes: .element:before { content: 'NEW'; color: rgb(255, 0, 0); } To get the properties in .element:before, you can use below JavaScript method: var color = window.getC...

   pseudo-element,property,JavaScript     2014-04-05 20:58:25

  Speech balloon with pure CSS--One step further

Many of us want to add cool features to our websites to make our websites user friendly ad more attractive. Especially in Web2.0 era. Today we are talking about adding speech balloon feature to our webpage so that we can display beautiful help windows while users mouse over some help icons on our page. First, let me introduce one post written by Umar Ashfaq named "How to create a speech balloon with pure CSS". He also explains how this works. You can also refer Magic CSS shape for more informati...

   Speech balloon, Pure CSS,border     2013-03-16 04:11:58

  Android IDE gets Pie-Friendly Update

An integrated development environment (IDE) provides facilities to computer programmers for software development. It consists of a source code editor, builds automation tools, and a debugger. The aim of the IDE is to reduce the configuration necessary to piece together multiple development utilities.The android application development process has become easier with the advancement of the new technologies. There are many considerations that are taken into account before developing an application....

       2018-09-26 07:41:56

  Find the kth smallest number in an array

This is an classical question, the general solution to this question is first using sorting algorithm to sort the array, then get the kth number in the array, the complexity is O(nlogn), we can also use selective sort or head sort to, the complexity of selective sort is O(kn) and heap sort is O(nlogk). The better solution is to use quick sort to find the kth smallest number, the complexity is O(n), the worst case cost is O(n^2). But today we introduce one more solution which has the worst case c...

   Sort, Quick sort, Search,Smallest     2013-01-09 06:20:54

  Use cases of Java enumeration

JDK 1.5 introduces a new type -- enumeration. In Java, it's just a small feature, but it can bring us much convenience.Here we summarize some use cases of Java enumeration. 1. Constant Prior to JDK 1.5, we can define constant as public static final..., now we can use enumeration to group all constants in one enum variable and it also provides some useful functions. public enum Color {     RED, GREEN, BLANK, YELLOW   }  2.In Swit...

   Java, Enum,enumeration     2013-01-05 09:15:30

  Reasons to use blue in design

Blue color is used in many product designs and logo designs such as Facebook, Microsoft, Twitter and our site. Why do companies choose blue color in their design? It's not a coincidence for them to choose blue. One saying is the color blue is associated with trust, efficiency, clarity and simplicity. Beside this reason, are there other reasons? From an interface design standpoint, blue is an incredibly useful color. Among the dark colors designers have in their toolbox, red, orange and green al...

   Design,Blue     2013-12-13 07:13:22

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