Rubband(3I)

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)