Detailed Description
The QCanvasSprite class provides an animated canvas item on a QCanvas.
A canvas sprite is an object which can contain any number of images
(referred to as frames), only one of which is current, i.e.
displayed, at any one time. The images can be passed in the
constructor or set or changed later with setSequence(). If you
subclass QCanvasSprite you can change the frame that is displayed
periodically, e.g. whenever QCanvasItem::advance(1) is called to
create the effect of animation.
The current frame can be set with setFrame() or with move(). The
number of frames available is given by frameCount(). The bounding
rectangle of the current frame is returned by boundingRect().
The current frame's image can be retrieved with image(); use
imageAdvanced() to retrieve the image for the frame that will be
shown after advance(1) is called. Use the image() overload passing
it an integer index to retrieve a particular image from the list of
frames.
Use width() and height() to retrieve the dimensions of the current
frame.
Use leftEdge() and rightEdge() to retrieve the current frame's
left-hand and right-hand x-coordinates respectively. Use
bottomEdge() and topEdge() to retrieve the current frame's bottom
and top y-coordinates respectively. These functions have an overload
which will accept an integer frame number to retrieve the
coordinates of a particular frame.
QCanvasSprite draws very quickly, at the expense of memory.
The current frame's image can be drawn on a painter with draw().
Like any other canvas item, canvas sprites can be moved with
move() which sets the x and y coordinates and the frame number, as
well as with QCanvasItem::move() and QCanvasItem::moveBy(), or by
setting coordinates with QCanvasItem::setX(), QCanvasItem::setY()
and QCanvasItem::setZ().
See also Graphics Classes and Image Processing Classes.
Member Type Documentation
QCanvasSprite::FrameAnimationType
This enum is used to identify the different types of frame
animation offered by QCanvasSprite.
- QCanvasSprite::Cycle - at each advance the frame number will be incremented by
1 (modulo the frame count).
- QCanvasSprite::Oscillate - at each advance the frame number will be
incremented by 1 up to the frame count then decremented to by 1 to
0, repeating this sequence forever.
Member Function Documentation
Constructs a QCanvasSprite which uses images from the
QCanvasPixmapArray a.
The sprite in initially positioned at (0, 0) on canvas, using
frame 0.
QCanvasSprite::~QCanvasSprite () [virtual]
Destroys the sprite and removes it from the canvas. Does not
delete the images.
void QCanvasSprite::advance ( int phase ) [virtual]
Extends the default QCanvasItem implementation to provide the
functionality of setFrameAnimation().
The phase is 0 or 1: see QCanvasItem::advance() for details.
See also QCanvasItem::advance() and setVelocity().
Example: canvas/canvas.cpp.
Reimplemented from QCanvasItem.
int QCanvasSprite::bottomEdge () const
Returns the y-coordinate of the current bottom edge of the sprite.
(This may change as the sprite animates since different frames may
have different bottom edges.)
See also leftEdge(), rightEdge(), and topEdge().
int QCanvasSprite::bottomEdge ( int ny ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns what the y-coordinate of the top edge of the sprite would
be if the sprite (actually its hotspot) were moved to y-position
ny.
See also leftEdge(), rightEdge(), and topEdge().
QRect QCanvasSprite::boundingRect () const [virtual]
Returns the bounding rectangle for the image in the sprite's
current frame. This assumes that the images are tightly cropped
(i.e. do not have transparent pixels all along a side).
Reimplemented from QCanvasItem.
void QCanvasSprite::draw ( QPainter & painter ) [virtual]
Draws the current frame's image at the sprite's current position
on painter painter.
Reimplemented from QCanvasItem.
int QCanvasSprite::frame () const
Returns the index of the current animation frame in the
QCanvasSprite's QCanvasPixmapArray.
See also setFrame() and move().
int QCanvasSprite::frameCount () const
Returns the number of frames in the QCanvasSprite's
QCanvasPixmapArray.
int QCanvasSprite::height () const
The height of the sprite for the current frame's image.
See also frame().
QCanvasPixmap * QCanvasSprite::image () const
Returns the current frame's image.
See also frame() and setFrame().
QCanvasPixmap * QCanvasSprite::image ( int f ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns the image for frame f. Does not do any bounds checking on f.
QCanvasPixmap * QCanvasSprite::imageAdvanced () const [virtual]
Returns the image the sprite will have after advance(1) is
called. By default this is the same as image().
int QCanvasSprite::leftEdge () const
Returns the x-coordinate of the current left edge of the sprite.
(This may change as the sprite animates since different frames may
have different left edges.)
See also rightEdge(), bottomEdge(), and topEdge().
int QCanvasSprite::leftEdge ( int nx ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns what the x-coordinate of the left edge of the sprite would
be if the sprite (actually its hotspot) were moved to x-position
nx.
See also rightEdge(), bottomEdge(), and topEdge().
void QCanvasSprite::move ( double nx, double ny, int nf ) [virtual]
Set the position of the sprite to nx, ny and the current
frame to nf. nf will be ignored if it is larger than
frameCount() or smaller than 0.
int QCanvasSprite::rightEdge () const
Returns the x-coordinate of the current right edge of the sprite.
(This may change as the sprite animates since different frames may
have different right edges.)
See also leftEdge(), bottomEdge(), and topEdge().
int QCanvasSprite::rightEdge ( int nx ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns what the x-coordinate of the right edge of the sprite
would be if the sprite (actually its hotspot) were moved to
x-position nx.
See also leftEdge(), bottomEdge(), and topEdge().
int QCanvasSprite::rtti () const [virtual]
Returns 1 (QCanvasItem::Rtti_Sprite).
See also QCanvasItem::rtti().
Example: canvas/canvas.cpp.
Reimplemented from QCanvasItem.
void QCanvasSprite::setFrame ( int f )
Sets the animation frame used for displaying the sprite to f,
an index into the QCanvasSprite's QCanvasPixmapArray. The call
will be ignored if f is larger than frameCount() or smaller
than 0.
See also frame() and move().
void QCanvasSprite::setFrameAnimation ( FrameAnimationType type = Cycle, int step = 1, int state = 0 ) [virtual]
Sets the animation characteristics for the sprite.
For type == Cycle, the frames will increase by step
at each advance, modulo the frameCount().
For type == Oscillate, the frames will increase by step
at each advance, up to the frameCount(), then decrease by step
back to 0, repeating forever.
The state parameter is for internal use.
void QCanvasSprite::setSequence ( QCanvasPixmapArray * a )
Set the array of images used for displaying the sprite to the
QCanvasPixmapArray a.
If the current frame() is larger than the number of images in a, the current frame will be reset to 0.
int QCanvasSprite::topEdge () const
Returns the y-coordinate of the top edge of the sprite. (This may
change as the sprite animates since different frames may have
different top edges.)
See also leftEdge(), rightEdge(), and bottomEdge().
int QCanvasSprite::topEdge ( int ny ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns what the y-coordinate of the top edge of the sprite would
be if the sprite (actually its hotspot) were moved to y-position
ny.
See also leftEdge(), rightEdge(), and bottomEdge().
int QCanvasSprite::width () const
The width of the sprite for the current frame's image.
See also frame().
This file is part of the Qt toolkit.
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