OS X PAINTCODE MAC OS X
OS X PAINTCODE MAC OS
OS X PAINTCODE WINDOWS

One huge benefit from this is that we utilize the high performance of OpenGL for most drawing operations, such as transformations and pixmap drawing. It is now possible to open a QPainter on a QGLWidget as if it were a normal QWidget.

OS X PAINTCODE MAC OS

The code shown above produces the following output:Īlpha-blended drawing is supported on Windows, Mac OS X, and on X11 systems that have the X Render extension installed. For example: // Specfiy semi-transparent red The alpha channel specifies the transparency effect, 0 represents a fully transparent color, while 255 represents a fully opaque color. The alpha channel of a color is defined through QColor. With Qt 4 we support alpha-blended outlining and filling. Setting a conical brush is done by creating a QConicalGradient object and setting it as a brush. The code shown above produces a pattern as shown in the following pixmap:Ĭonical gradients are specified using a center and a start angle. Setting a radial brush is done by creating a QRadialGradient object and setting it as a brush. Radial gradients are specified using a center, a radius, and a focal point. The code shown above produces a pattern as show in the following pixmap: QLinearGradient gradient( 0, 0, 100, 100) Setting a linear gradient brush is done by creating a QLinearGradient object and setting it as a brush. Linear gradients are specified using two control points. Qt 4 supports linear, radial, and conical gradients. A gradient can span from one color to another or over a number of colors by specifying multiple colors at positions in the gradient area. A gradient in this case is used to describe the transition from one color at a given point to different color at another point. With Qt 4 it is possible to fill shapes using gradient brushes. New Features in the Qt 4 Paint System Gradient Brushes This means that adding support for new features and providing default implementations for unsupported ones has become much simpler.

The main benefit of this approach is that all painting follows the same painting pipeline. You also need to derive from QPaintDevice and reimplement the virtual function QPaintDevice::paintEngine() to tell QPainter which paint engine should be used to draw on this particular device. To implement support for a new backend, you must derive from QPaintEngine and reimplement its virtual functions. X11 and the X Render Extension on Linux and Unix systems.

OS X PAINTCODE MAC OS X

PostScript on Linux, Unix, and Mac OS X.

OS X PAINTCODE WINDOWS

A pixel-based engine for the Windows platform that is also used to draw onto QImages on all platforms.

Qt currently provides paint engines for the following platforms and APIs: The QPaintEngine class is only used internally by QPainter and QPaintDevice, and it is hidden from application programmers unless they reimplement their own device types for their own QPaintEngine subclasses. Implementations of this class provide the concrete functionality needed to draw to specific device types. In Qt 4 we have introduced the QPaintEngine abstract class. This has led us to devise a more convenient and intuitive API for Qt 4. Supporting multiple device backends, such as OpenGL, was therefore inconvenient and not very efficient. One of these is that an external device could not reuse any functionality implemented in QPainter since QPainter was tied to widget/pixmap painting on that platform. This allowed reimplementation of arbitrary devices, but the approach has some disadvantages which we have addressed in Qt 4. QPainter was capable of recognizing external devices and could serialize each paint operation to the reimplemented cmd() function. A reimplemented paint device was treated as an external device. (It could also be used to draw to printers on Windows and Mac OS X.) When other paint devices needed to be supported, such as QPrinter on X11, this was done by deriving from QPaintDevice and reimplementing the virtual function QPaintDevice::cmd(). In Qt 3, QPainter could be used to draw on widgets and pixmaps. QPaintEngine provides the interface that the painter uses to draw onto different types of devices. QPaintDevice represents a device that can be painted on using a QPainter both QWidget and QPixmap are QPaintDevices.

QPainter is the class used to perform drawing operations, such as drawLine() and drawRect(). The Qt 4 Paint System is primarily based on the classes QPainter, QPaintDevice, and QPaintEngine. This document describes Qt 4's painting system, providing a comparison between the approaches used by Qt when rendering graphics in Qt 3 and Qt 4.

Os x paintcode