The QTPlgGraphicsContext class provides a convenient, general purpose, container to deal with parameters that define a series of graphics transformation to apply to some visual data; using instances of this class allows to implement a simple and unique interface to provide and/or retrieve parameters that affect how data will be displayed or drawed somewhere by other plugin classes.
Since version 6.7 of the plugin this class can be used in Console Applications
The QTPlgGraphicsContext class constructors are called when you create a new instance of the class, while the ˜QTPlgGraphicsContext class destructor, is called automatically when the class is no more in use. Also, you can invoke the class destructor by setting the instance of the class to nil.
Once a new class instance is returned, it is good practice to check the class property to be sure that the new object can be used. A QTPlgGraphicsContext object is always valid.
The class implements the following initializer methods:
()
This is the default constructor. All of the class properties are initialized in such a way to define no
tranformation at all.
(other as QTPlgGraphicsContext)
This is the copy constructor. The properties of the object to be copied will be used to initialize the new class instance
properties
(srcRect as ,
dstRect as )
use this constructor version to define a region of interest to apply to the source of visual data
(the srcRect ) and a destination area (the dstRect )
in which the visual data will be displayed after any
specified transformation has been applied to them. You can modify both these rectangles anytime by using the
appropriate
identifies the source rectangle
identifies the destination rectangle
specifies a mask region to apply to the resulting image
determines if the resulting image will be inverted
specifies if any color information has to be discarded from the resulting image
specifies if the resulting image must be flipped horizontally
specifies if the resulting image must be flipped vertically
specifies the graphics mode to associate with the current drawing operation; you can use one of
the
defined by the plugin
[Deprecated]: since version 6.5 of the plugin this property is deprecated
and will be removed from a future plugin version; use the
class property instead
specifies the color for use in blending and transparent operations
[Deprecated]: since version 6.5 of the plugin this property is deprecated
and will be removed from a future plugin version; use the
class property instead
specifies the color for use in blending and transparent operations and the graphics mode to associate with the
current drawing operation
determines the amount of rotation, expresses as degrees, to apply to the resulting image; a
value of 0° means no rotation. The anchor point of the rotation
will be always the center of the
specifies the amount of horizontal translation, expresses in pixels, to apply to the resulting image; a value
of 0 means no horizontal translation.
The anchor point of the translation will be always the center of the
specifies the amount of vertical translation, expresses in pixels, to apply to the resulting image; a value
of 0 means no vertical translation.
The anchor point of the translation will be always the center of the
determines the scale to apply to the images before being displayed; a
value of 1.0 means no zoom. The anchor point of the zoom will be always the center of the
returns the matrix resulting from the application of the graphical transformations specified by the following class
properties (displayed in order of application):
- scaling and translating from to
- flipping along x () and y ()
- scaling according to
- translating according to and
- rotating according to
determines the amount of gamma correction that will be applied to the data before displaying them; a
value of 1.0 causes no gamma correction to be applied.
()
use this method to ensure that the
coincides with the
; any previously defined
clipping region will be discarded
(gc as QTPlgGraphicsContext)
this function allows you to assign the values of the properties of the object specified by the gc parameter
to the current graphics context; before copying, the properties of the class will be re–initialized to their default values
()
using this function clears at one go all of the changes previously done, restoring the default values of the class properties
() as
this operator allows you to use a QTPlgGraphicsContext object whenever the QTPlugin requires the usage of a
object
[Removed]: since version 6.5 of the plugin these constants have been removed; use the
of the plugin
module instead