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And the pen join defines how two lines join when multiple connected lines are drawn. The pen cap defines how the end points of lines are drawn. Setting the style to none ( Qt::NoPen) tells the painter to not draw lines or outlines. The default style is solid ( Qt::SolidLine). PenJoinLabel - >setBuddy(penJoinComboBox) PenJoinLabel = new QLabel(tr( "Pen &Join:")) PenJoinComboBox - >addItem(tr( "Round"), Qt ::RoundJoin) PenJoinComboBox - >addItem(tr( "Bevel"), Qt ::BevelJoin) PenJoinComboBox - >addItem(tr( "Miter"), Qt ::MiterJoin) PenCapLabel = new QLabel(tr( "Pen &Cap:")) PenCapComboBox - >addItem(tr( "Round"), Qt ::RoundCap) PenCapComboBox - >addItem(tr( "Square"), Qt ::SquareCap) PenCapComboBox - >addItem(tr( "Flat"), Qt ::FlatCap) PenStyleLabel - >setBuddy(penStyleComboBox) PenStyleLabel = new QLabel(tr( "&Pen Style:")) PenStyleComboBox - >addItem(tr( "None"), static_cast ( Qt ::NoPen)) PenStyleComboBox - >addItem(tr( "Dash Dot Dot"), static_cast ( Qt ::DashDotDotLine)) PenStyleComboBox - >addItem(tr( "Dash Dot"), static_cast ( Qt ::DashDotLine)) PenStyleComboBox - >addItem(tr( "Dot"), static_cast ( Qt ::DotLine)) PenStyleComboBox - >addItem(tr( "Dash"), static_cast ( Qt ::DashLine)) PenStyleComboBox - >addItem(tr( "Solid"), static_cast ( Qt ::SolidLine)) the different shapes a QPainter can draw). Then we create the Shape combobox, and add the associated items (i.e. ShapeComboBox - >addItem(tr( "Pixmap"), RenderArea ::Pixmap) įirst we create the RenderArea widget that will render the currently active shape. ShapeComboBox - >addItem(tr( "Text"), RenderArea ::Text)

ShapeComboBox - >addItem(tr( "Points"), RenderArea ::Points) ShapeComboBox - >addItem(tr( "Arc"), RenderArea ::Arc) ShapeComboBox - >addItem(tr( "Polyline"), RenderArea ::Polyline)

ShapeComboBox - >addItem(tr( "Line"), RenderArea ::Line) ShapeComboBox - >addItem(tr( "Path"), RenderArea ::Path) ShapeComboBox - >addItem(tr( "Chord"), RenderArea ::Chord) ShapeComboBox - >addItem(tr( "Pie"), RenderArea ::Pie) ShapeComboBox - >addItem(tr( "Ellipse"), RenderArea ::Ellipse) ShapeComboBox - >addItem(tr( "Rounded Rectangle"), RenderArea ::RoundedRect) ShapeComboBox - >addItem(tr( "Rectangle"), RenderArea ::Rect) ShapeComboBox - >addItem(tr( "Polygon"), RenderArea ::Polygon) In the constructor we create and initialize the various widgets appearing in the main application window. And the brushChanged() slot updates the RenderArea widget when the user changes the painter's brush style.

We call the penChanged() slot when either of the QPainter's pen parameters changes. We declare the various widgets, and three private slots updating the RenderArea widget: The shapeChanged() slot updates the RenderArea widget when the user changes the currently active shape. The Window class inherits QWidget, and is the application's main window displaying a RenderArea widget in addition to several parameter widgets.

Window is the application's main window displaying a RenderArea widget in addition to several parameter widgets.įirst we will review the Window class, then we will take a look at the RenderArea class.

RenderArea is a custom widget that renders multiple copies of the currently active shape.

The Basic Drawing example consists of two classes: In addition the user can rotate a shape ( Transformations) behind the scenes we use QPainter's ability to manipulate the coordinate system to perform the rotation. The example provides a render area, displaying the currently active shape, and lets the user manipulate the rendered shape and its appearance using the QPainter parameters: The user can change the active shape ( Shape), and modify the QPainter's pen ( Pen Width, Pen Style, Pen Cap, Pen Join), brush ( Brush Style) and render hints ( Antialiasing). Normally, it draws in a "natural" coordinate system, but it can in addition do view and world transformation. It can also draw aligned text and pixmaps. The class can draw everything from simple lines to complex shapes like pies and chords. QPainter performs low-level painting on widgets and other paint devices.