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NAME
GraphicView, GraphicViews - base classes for graphical component views
SYNOPSIS
#include <Unidraw/Components/grview.h>
DESCRIPTION
GraphicView is an abstract base class for graphical views of GraphicComp objects.
GraphicView is derived from ComponentView and adds operations for manipulating its
graphical attributes. GraphicViews is a non-abstract subclass of GraphicView for
composite graphical component views.
GRAPHICVIEW PUBLIC OPERATIONS
virtual void Interpret(Command*)
virtual void Uninterpret(Command*)
GraphicView objects can (un)interpret the following command:
AlignToGridCmd aligns the graphical component to the grid that affects the view.
Interpret uses AlignToGridCmd::Align to carry out the alignment, while Uninterpret
uses AlignToGridCmd::Unalign to reverse Interpret's effects.
virtual void DrawHandles()
virtual void RedrawHandles()
virtual void InitHandles()
virtual void EraseHandles()
Operations for displaying and hiding the view's selection handles. All use
CreateHandles (described below) to create component-specific rubberbands that draw
the handles if they do not already exist. The rubberband is stored in the _handles
protected member. DrawHandles makes the handles visible if they are not already
visible. RedrawHandles forces the handles to draw themselves even if they are
already drawn, which may make them disappear if the rubberband draws them in XOR
mode. InitHandles deletes and recreates the rubberband defining the handles if it
existed when InitHandles was called. EraseHandles erases the handles and deletes
the rubberband.
virtual Manipulator* CreateManipulator(
Viewer*, Event&, Transformer*, Tool*
)
virtual void InterpretManipulator(Manipulator*)
Operations that define how the GraphicView reacts when it is manipulated by a tool
and how the tool affects that component following manipulation. They effectively
override the tool's default behavior if the tool defers manipulator creation and
interpretation to the view. This allows the same tool to behave differently
depending on the component it manipulates.
CreateManipulator creates a manipulator that is appropriate for the given tool. It
receives the viewer in which the manipulation will take place, an event with which
to initialize the manipulator if necessary, and the coordinate transformation that
maps canvas coordinates into the subject's coordinate space. InterpretManipulator
is called following manipulation and defines how to construct a command that
carries out the manipulation's desired effect. GraphicView objects create and
interpret manipulators for the following tools:
GraphicCompTool will let the user position a fixed-sized outline reflecting the
view's bounding box on the screen. Interpretation will produce a command that
inserts a copy of the subject into the editor's component at the specified
position. Placement will be constrained by gravity, if active.
MoveTool will let the user move a fixed-sized outline reflecting the view's
bounding box on the screen. Interpretation will produce a command that moves the
subject to the specified position. Holding down the Shift key will constrain the
movement to purely horizontal or vertical, and movement will be constrained by
gravity.
ScaleTool will let the user drag a scaling rectangular outline corresponding to the
view's scale following manipulation with the tool. Scaling will be constrained by
gravity.
StretchTool will let the user drag a variable-sized rectangular outline
corresponding to a two-dimensional stretch that the component will undergo
following manipulation. Holding the Shift key down will constrain the stretch to
one dimension. Stretching will be constrained by gravity.
RotateTool will let the user rotate a fixed-sized rectangular outline reflecting
the view's bounding box. The rotation of the outline corresponds to the rotation
that the component will undergo following manipulation. Rotation will be
constrained by gravity.
virtual Graphic* GetGraphic()
Return the graphic that defines the GraphicView's appearance. Often this graphic
is a copy of that in the subject, but it needn't be.
virtual Viewer* GetViewer()
Return the viewer (if any) that displays the view.
GraphicComp* GetGraphicComp()
Return the view's subject.
boolean Includes(GraphicView*)
A convenience function that returns whether or not the GraphicView includes the
given view, that is, whether the view is a child of this.
GraphicView* GetGraphicView(Component*)
A convenience function that returns the view of the given component (if any) that
appears in the same viewer as this.
GraphicView* GetView(Iterator)
void SetView(GraphicView*, Iterator&)
These operations do nothing by default. Subclasses that contain children should
redefine them as follows: GetView should return the GraphicView to which an
iterator points. SetView should initialize the iterator to point to a particular
GraphicView in the list of children; it should initialize the iterator to point to
a nil instance if the given GraphicView is not a child.
virtual Selection* SelectAll()
virtual Selection* ViewContaining(Coord, Coord)
virtual Selection* ViewsContaining(Coord, Coord)
virtual Selection* ViewIntersecting(Coord, Coord, Coord, Coord)
virtual Selection* ViewsIntersecting(Coord, Coord, Coord, Coord)
virtual Selection* ViewsWithin(Coord, Coord, Coord, Coord)
virtual ConnectorView* ConnectorIntersecting(
Coord, Coord, Coord, Coord
)
These convenience operations do nothing by default. Subclasses containing children
should redefine them to do the following: SelectAll should return a selection
object containing (pointers to) all its children; ViewContaining should return the
last (visibly topmost) child view containing the given point, while ViewsContaining
should return all children containing the point; ViewIntersecting should return the
last (visibly topmost) child view intersecting a rectangular area, while
ViewsIntersecting should return all such children; ViewsWithin should return all
the child views falling strictly within a rectangular area; and
ConnectorIntersecting should return the child ConnectorView (if any) that
intersects a rectangular area.
GRAPHICVIEW PROTECTED OPERATIONS
GraphicView(GraphicComp* = nil)
The constructor is protected to guard against instantiation. It takes the view's
subject as an optional argument, passing it to the ComponentView constructor.
virtual void SetGraphic(Graphic*)
Set the GraphicView's graphic to the given one, and store this in the graphic using
Graphic::SetTag. This makes it possible to obtain the GraphicView that owns the
graphic from the graphic itself, e.g., after hit detection.
virtual void CreateHandles()
Initialize the _handles member with a rubberband that will draw the appropriate
handles. By default, CreateHandles creates a RubberHandles object with eight
handles around the periphery of the view's bounding box.
virtual int ClosestPoint(
Coord x[], Coord y[], int n, Coord px, Coord py
)
A convenience function that returns the index of the point closest to (px, py) in
an array of n points.
GraphicView* View(UList*)
GraphicView* GetGraphicView(Graphic*)
Convenience functions that return the GraphicView in a UList element and the
GraphicView associated with a graphic, respectively.
Manipulator* CreateGraphicCompManip(
Viewer*, Event&, Transformer*, Tool*
)
Manipulator* CreateStretchManip(
Viewer*, Event&, Transformer*, Tool*
)
Command* InterpretGraphicCompManip(Manipulator*)
Command* InterpretStretchManip(Manipulator*)
Helper functions used by CreateManipulator and InterpretManipulator to create and
interpret the manipulators associated with GraphicCompTool and StretchTool.
void AddDamage(Graphic*)
void IncurDamage(Graphic*)
GraphicViews should incur damage in response to a change in their appearance, which
generally happens in their Update function. AddDamage and IncurDamage produce
damage by calling the related operations on the enclosing viewer's damage object.
Subclasses can use these functions for convenience to avoid accessing the enclosing
viewer's damage object directly.
void Unselect(GraphicView*)
A convenience function that unselects the given view, which entails erasing its
handles and removing it from the enclosing editor's selection object.
virtual void Add(GraphicView*)
virtual void Append(GraphicView*)
virtual void InsertBefore(Iterator, GraphicView*)
virtual void Remove(Iterator&)
virtual void DeleteView(Iterator&)
Unimplemented operations that composite subclasses should redefine for modifying
the their (conceptual) list of children. Note that subclasses needn't necessarily
store their children in a list data structure, but a list maps closely to the
semantics of these operations. These operations are not public because only the
view itself knows how to keep its structure consistent with that of the subject
and/or its semantics.
Add adds a GraphicView to the end of the list of children. InsertBefore inserts a
GraphicView before the GraphicView pointed to by the iterator. Remove removes a
view to which the given iterator refers from the list without deleting it, while
DeleteView removes it and deletes it. Remove and DeleteView should advance the
iterator to point to the following view as a side effect.
GRAPHICVIEWS PUBLIC OPERATIONS
GraphicViews(GraphicComps* = nil)
virtual ~GraphicViews()
The constructor creates a GraphicViews, optionally supplying the subject. The
destructor deletes the GraphicViews' children.
virtual void Interpret(Command*)
GraphicViews objects interpret the following command:
AlignToGridCmd aligns the graphical component to the grid that affects the view.
The overall alignment is based on how the first leaf subcomponent aligns itself:
Interpret aligns the first leaf subcomponent to the grid and then moves all other
subcomponents by the amount that the leaf moved.
virtual void Update()
Automatically update the GraphicViews' state and structure to match the subject's.
Update will not necessarily detect restructurings or state modifications made to
the subject's children more than one level deep. Update uses GVUpdater to do its
work.
virtual Graphic* GetGraphic()
Return the GraphicViews' graphic, which (like its subject's graphic) is a Picture.
GraphicComps* GetGraphicComps()
Return the subject.
GRAPHICVIEWS PROTECTED OPERATIONS
UList* Elem(Iterator)
A convenience function for extracting a UList from an iterator.
SEE ALSO
Command(3U), ComponentView(3U), Connector(3U), Damage(3U), GVUpdater(3U), GraphicComp(3U),
GraphicCompTool(3U), Grid(3U), Event(3I), Manipulator(3U), MoveTool(3U), Picture(3U),
RotateTool(3U), Rubband(3I), ScaleTool(3U), Selection(3U), StretchTool(3U),
Transformer(3I), Viewer(3U), align(3U)