Driven class of unary_function can be used to check a single element based on special condition.Programmer can regard it as some algorithms’ parameter, such as count_if, find_if, and find_if_not.The following code shows how to write a customized unray class and use it. C++ struct Widget Read more…
We need not sort all elements sometimes. Here are a few simple examples of STL algorithms partial_sort, nth_element, and partition. partial_sort For example, find the 5 biggest ones in 10 random numbers. #include <iostream> #include <vector> #include <cstdlib> #include <ctime> Read more…
We need a flexible compare way for our objects in some situations, so it’s necessary to write our own compare class. The article has an example which puts all widgets in a multiset container, the widgets should be sort by Read more…
vtkReverseSense can help us to reverse the direction of point normals and cell normals. The following code shows a simple example which display vertexes’ normals by cones in a sphere. Here is its original geometric states. #include <iostream> #include <vtkSmartPointer.h> Read more…
Draw geometric curve of Quadratic equation Here is a simple quadratic equation: Draw its geometric curve by wolfram. We can use Table to calculate all discrete values in special range. Table[2*x^2 + 1, {x, -10, 10}] {201, 163, Read more…
Sometimes we need to check character encoding for special word, or by contrast, to input some special words according to character encoding. The article will show you how to handle the two situations. Find the character encoding for special world Read more…
Open multiple files Open multiple files on the horizontal direction: vim -o file1 file2 file3 ….Switch edit file：ctrl + ww.Close all opened files without saving operation：qa.Multiple fails in the vertical direction: vim -O file1 file2 file3 ….Add a number n after -o, we can open Read more…
Borderless window: setWindowFlags( Qt::FramelessWindowHint ); Set background color: QPalette pal = mainWin->Getui().qvtkWidget->palette(); pal.setColor( QPalette::Background, Qt::black ); setAutoFillBackground( true ); this->setPalette( pal ); Make window stay on the top level: setWindowFlags(Qt::WindowStaysOnTopHint) Remove maximize button in widget： setWindowFlags( this->windowFlags() & ~Qt::WindowMaximizeButtonHint ); Read more…
The interfaces can imitate users’ operations. QTest::keyClick QTest::keyPress QTest::mouseClick QSignalSpy listens for signal emission, it is a list of QVariant lists. It will not shield off signal to make slot invalid. QCheckBox *box = …; QSignalSpy spy(box, SIGNAL(clicked(bool))); //… QList Read more…