QT learning 07 coordinate system in QT

Qt Study 07 Qt The coordinate system in

Coordinate system

• GUI Each operating system has a specific Coordinate system

• Graphical interface program Locate windows and components in the coordinate system

• Location type

  • Positioning of the top-level widget
  • Positioning of internal parts of the window
  • The size of the widget

• Qt Use A unified coordinate system To locate a widget Location and size

• Qt Parts supply Member functions Positioning in a coordinate system

• QWidget class Provide The required for the widget Coordinate system member functions

remarks ：

• The upper left corner of the screen is black (0, 0) The window is positioned in the display 0 coordinate ;

• The upper left corner of the window is green (0, 0) It is located in the customer area 0 coordinate .

Coordinate system related member functions

• QWidget Coordinate system member functions in class

remarks ：

• QWidget Of x(),y() Is the position of the entire window in the display ,width(),height() Is the width and height of the client area in the window
• geometry() Of x(),y(),width(),height() Is the location and size of the client area inside the window , Does not include title blocks and borders ,geometry() Of width(),height() and QWidget Medium width(),height() It's the same
• frameGeometry() Of x(),y() and QWidget Of x(),y() It's the same , Indicates the position of the window in the display ,frameGeometry() Of width(),height() Is the width and height of the entire window including the title bar and border .

Qt Why provide 3 A coordinate system ？ In order to solve the problem of cross platform , Cross operating system

matters needing attention

geometry() and frameGeometry() The geometric data in must be in show() Only valid after calling ！！！

The size and position of the widget

• QWidget Class provides Member functions ：

  • Change the size of the widget

    void resize(int w, int h)

    void resize(const QSize &)

  • Change the position of the widget

    void move(int x, int y)

    void move(const QPoint &)

QPushButton Components

• QPushButton be used for Accept user click events
• QPushButton can Display the prompt string
• QPushButton yes Functional components , The parent component is required as the container
• QPushButton can Locate in the parent component

QWidget w;				//  Generate QWidget object , Top level components 
QPushButton b(&w);		//  Generate QPushButton object , Its parent component is QWidget
b.setText("Button");	//  Set the displayed string 
b.move(10, 10);			//  Move to coordinates (10, 10)
b.resize(100, 25);		//  Set size width=100, height=25

Summary

• Qt The geometric coordinates in The upper left corner is the origin

  • Level is x Axis , From left to right is positive
  • Vertical is y Axis , From top to bottom

• Qt Medium GUI Components Position in the upper left corner

• Qt The geometric coordinates in The upper left corner is the origin

  • Level is x Axis , From left to right is positive
  • Vertical is y Axis , From top to bottom

• Qt Medium GUI Components Position in the upper left corner

• Qt Of GUI Components can Set the size in the coordinate system