NAME¶
Rubband - rubberbanding graphical objects
SYNOPSIS¶
#include <InterViews/rubband.h>
#include <InterViews/rubcurve.h>
#include <InterViews/rubgroup.h>
#include <InterViews/rubline.h>
#include <InterViews/rubrect.h>
#include <InterViews/rubverts.h>
DESCRIPTION¶
Rubband is the base class for a set of classes that provide graphical
feedback to a user during an interactive operation such as sizing a rectangle.
A rubberband varies in appearance as its
tracking point changes. A
rubberband is
not an interactor itself; interactors use rubberbands to
provide animated effects. Because rubberbands are not interactors, rubberband
constructors must be passed the painter and canvas to use for drawing.
PUBLIC OPERATIONS¶
- RubberLine(
- Painter*, Canvas*, Coord fx, fy, mx, my, offx = 0, offy
= 0
- )
-
A rubber line stretches to follow the tracking point while its other
endpoint stays tied down.
- RubberAxis(
- Painter*, Canvas*, Coord fx, fy, mx, my, offx = 0, offy
= 0
- )
-
A rubber axis stretches either horizontally or vertically to follow the
tracking point while its other endpoint stays tied down. One endpoint
stays fixed while the other moves along either the horizontal or vertical
axis, whichever is closer to the tracking point.
- SlidingLine(
- Painter*, Canvas*, Coord x0, y0, x1, y1, rfx,
rfy,
- Coord offx = 0, offy = 0
- )
-
A sliding line slides around without changing its length or angle as the
tracking point moves around a reference point.
- RotatingLine(
- Painter*, Canvas*, Coord x0, y0, x1, y1, rfx,
rfy,
- Coord offx = 0, offy = 0
- )
-
A rotating line rotates around ( cx, cy) based on the
angle between the radius from ( cx, cy) to
(rfx, rfy) and the radius from (
cx, cy) to the tracking point.
- RubberRect(
- Painter*, Canvas*, Coord fx, fy, mx, my, offx = 0, offy
= 0
- )
-
A rubber rectangle stretches to follow the tacking point while its opposite
corner stays tied down.
- SlidingRect(
- Painter*, Canvas*, Coord x1, y1, x2, y2, rfx,
rfy,
- Coord offx = 0, offy = 0
- )
-
A sliding rectangle slides around the screen without changing its side or
orientation as the tracking point moves around a reference point.
- ScalingRect(
- Painter*, Canvas*, Coord x1, y1, x2, y2, cx,
cy,
- Coord offx = 0, offy = 0
- )
-
A scaling rectangle scales equally in both dimensions about (
cx, cy) to keep one edge intersecting the tracking
point.
- RotatingRect(
- Painter*, Canvas*, Coord x1, y1, x2, y2, cx, cy, rfx,
rfy,
- Coord offx = 0, offy = 0
- )
-
A rotating rectangle rotates about ( cx, cy) based on the
radius from ( cx, cy) to (rfx, rfy)
and the radius from ( cx, cy) to the tracking
point.
- StretchingRect(
- Painter*, Canvas*, Coord x1, y1, x2, y2, Side
ts,
- Coord offx = 0, offy = 0
- )
-
A stretching rectangle's tracking side follows the tracking point while the
opposite side stays fixed. The side can be one of LeftSide,
RightSide, BottomSide, or TopSide.
- RubberCircle(
- Painter*, Canvas*, Coord cx, cy, rx, ry, offx = 0, offy
= 0
- )
-
A rubber circle's radius varies with the magnitude of the tracking point's
distance from ( cx, cy).
- RubberEllipse(
- Painter*, Canvas*, Coord cx, cy, rx, ry, offx = 0, offy
= 0
- )
-
A rubber ellipse's horizontal and vertical radii vary with the magnitude of
the tracking point's distance from ( cx, cy).
- RubberSpline(
- Painter*, Canvas*, Coord x[], y[], int n, pt,
- Coord offx = 0, offy = 0
- )
-
- RubberClosedSpline(
- Painter*, Canvas*, Coord x[], y[], int n, pt,
- Coord offx = 0, offy = 0
- )
-
A rubber spline is the section of a B-spline defined by n control
points that changes shape as the control point indexed by pt is set
to the tracking point.
- RubberHandles(
- Painter*, Canvas*, Coord x[], y[], int n, pt,
size,
- Coord offx = 0, offy = 0
- )
-
A rubber handles object is a set of filled squares centered about each point
in the list. The point index by pt follows the tracking point.
- SlidingPointList(
- Painter*, Canvas*, Coord x[], y[], int n, pt, Coord
rfx, rfy,
- Coord offx = 0, offy = 0
- )
-
A sliding point list slides around the screen without changing its
appearance as the tracking point moves around a reference point.
- SlidingLineList(
- Painter*, Canvas*, Coord x[], y[], int n, pt, Coord
rfx, rfy,
- Coord offx = 0, offy = 0
- )
-
A sliding line list slides around the screen without changing the appearance
of its connected lines as the tracking point moves around (
rfx, rfy).
- ScalingLineList(
- Painer*, Canvas*, Coord x[], Coord y[], int n,
- Coord cx, cy, rfx, rfy, offx = 0, offy = 0
- )
-
A scaling line list scales a list of lines about ( cx, cy) to keep
the line list's bounding box intersecting the tracking point.
- RotatingLineList(
- Painer*, Canvas*, Coord x[], Coord y[], int n,
- Coord cx, cy, rfx, rfy, offx = 0, offy = 0
- )
-
A rotating line list rotates a list of lines about ( cx, cy) based on
the angle between the radius from ( cx, cy) to (
rfx, rfy) and the radius from
(cx, cy) to the tracking point.
- GrowingVertices(
- Painter*, Canvas*, Coord x[], y[], int n,
- int pt = -1, int handleSize = -1
- )
-
- GrowingMultiLine(
- Painter*, Canvas*, Coord x[], y[], int n,
- int pt = -1, int handleSize = -1
- )
-
- GrowingPolygon(
- Painter*, Canvas*, Coord x[], y[], int n,
- int pt = -1, int handleSize = -1
- )
-
- GrowingBSpline(
- Painter*, Canvas*, Coord x[], y[], int n,
- int pt = -1, int handleSize = -1
- )
-
- GrowingClosedBSpline(
- Painter*, Canvas*, Coord x[], y[], int n,
- int pt = -1, int handleSize = -1
- )
-
- virtual void AddVertex(Coord, Coord)
- virtual void RemoveVertex()
- GrowingVertices is an abstract rubberband containing a list
of vertices that grows or shrinks dynamically. The pt parameter
specifies the index of the vertex that will follow the tracking point; a
value of -1 specifies a vertex after the last one in the list. The
handleSize parameter specifies the size of the handle drawn at each
vertex (as in RubberHandles above); a value of -1 specifies that no
handles be drawn.
The AddVertex operation adds a new vertex at the tracking point to the list
and makes the next (or last) vertex in the list follow the tracking point.
RemoveVertex removes the vertex at the tracking point and makes the
previous (or first) vertex the new tracking point. GrowingMultiLine,
GrowingPolygon, GrowingBSpline, and GrowingClosedBSpline are
GrowingVertices subclasses that draw a multiline, polygon, B-spline, and
closed B-spline, respectively.
- RubberGroup(Painter*, Canvas*)
- void Append(
- Rubberband*, Rubberband* = nil, Rubberband* =
nil,
- Rubberband* = nil
- )
-
- void Remove(Rubberband*)
- void RemoveCur()
- void SetCurrent(Rubberband*)
- Rubberband* GetCurrent()
- Rubberband* First()
- Rubberband* Last()
- Rubberband* Next()
- Rubberband* Prev()
- boolean IsEmpty()
- boolean AtEnd()
- A RubberGroup composes other rubberbands, providing
operations for including, excluding, and traversing its children.
RubberGroups are useful for combining the behavior of several rubberbands
into one, eliminating the need to call Track on multiple rubberbands. The
RubberGroup's SetCanvas and SetPainter operations set the children's
canvas and painter as well as the RubberGroup's, but the children do not
otherwise inherit the group's canvas and painter. The Track operation
calls Track on each child with the same parameters.
- virtual void Draw()
- void Redraw()
- virtual void Erase()
- Explicitly draw, redraw, and erase the rubberband. Multiple
calls to Draw without an intervening Erase will only draw the rubberband
once. Redraw forces the rubberband to be drawn. Since rubberbands are
drawn in XOR mode, Redraw will erase the rubberband every other time it is
called. These functions are used only on occasion, for example, when part
of the screen is erased while a rubberband is visible. The Track function
is normally used to draw the rubberband in response to mouse input.
- virtual void Track(Coord x, Coord y)
- Erase the rubberband and redraw it using the new tracking
point.
- void GetOriginal(Coord& x1, Coord& y2,
Coord& x2, Coord& y2)
- void GetCurrent(Coord& x1, Coord& y2, Coord&
x2, Coord& y2)
- GetOriginal obtains the original points specified for the
rubberband. GetCurrent obtains the current points based on the most recent
call to Track. The meaning of the points depends on the kind of
rubberband. For lines, the points are the endpoints; for rectangles, the
points are opposite corners; for curves, ( x1, y1) is
the center and x2 and y2 are the radii.
- virtual void SetPainter(Painter*)
- Painter* GetPainter()
- Explicitly set and get the painter used by the rubberband.
By default, rubberbands use a copy of the painter passed to their
constructor. The user can specify a particular painter to use by passing a
nil painter to the constructor and later calling SetPainter. N.B.:
the rubberband may alter the painter specified via SetPainter.
- virtual void SetCanvas(Canvas*)
- Canvas* GetCanvas()
- Explicitly set and get the canvas used by the
rubberband.
SEE ALSO¶
Canvas(3I), Painter(3I)