Class Coordinates

java.lang.Object
   |
   +----Coordinates

public class Coordinates
extends Object

Coordinates is an object that manages conversions between coordinate systems. There are three kinds of coordinates:

VIRTUAL: Each vertex has an x and y coordinate that are potentially infinite. These coordinates only change when the vertex's physical location in space is actually changed. As vertices are placed farther and farther out in the positive and negative directions, these coordinates get larger and larger. There may be limitations on how far someone could actually go based on the maximum size of a double.
SCREEN: Position of a vertex in pixels from the top-left of the current location of the window. These coordinates are different after a scroll or zoom occurs.
UNIT: The actual positions of vertices are mapped onto a unit square. We don't actually use these coordinates, but maintain a way for referencing them in this way in case filters prefer this type of view. These coordinates change whenever vertices are added of removed in such a way that the minimum rectangle containing all vertices is changed.

There should be a single Coordinates object for each canvas that is viewing a graph. Coordinates maintains a pair of scrollbars and information about the current position, size, and zoom-level of the canvas. Coordinates must be informed upon any of the following occurences:

adding a new vertex to the graph
deleting a vertex from the graph
changing the size of the canvas
changing the zoom level

Coordinates(int, int): create a window of initial size `width' by `height' pixels.
Coordinates(): default constructor is 100 by 100 window.

addV(Vertex): inform Coordinates that the vertex `V' has been added to the graph.
canvasResize(int, int): inform Coordinates that the size of the canvas has changed.
delAll(Vertex): inform Coordinates that all vertices have been deleted from the graph.
delV(Vertex, Vertex): inform Coordinates that the vertex `V' has been deleted from the graph.
disable(): greys out the scrollbars and makes them unusable.
enable(): reverses the effect of disable.
getMag(): returns the current zoom level.
getsbX(): gets the AWT scrollbar object that is the horizontal scrollbar used by this Coordinates.
getsbY(): gets the AWT scrollbar object that is the vertical scrollbar used by this Coordinates.
magRange(double, double, double, double): !WARNING! This method has never been tested! !WARNING!
magnify the rectangle between P1 and P2.
setMag(double): change zoom level to `newmag'.
toString(): prints internal information about the coordinates.
xStoV(int): screen: x coordinate in the screen coordinate system
returns: `screen' in virtual coordinates.
xUtoV(double): unit: x coordinate in the unit coordinate system
returns: `unit' in virtual coordinates.
xVtoS(double): virtual: x coordinate in the virtual coordinate system
returns: virtual in screen coordinates.
xVtoU(double): virtual: x coordinate in the virtual coordinate system
returns: virtual in unit coordinates.
yStoV(int): screen: y coordinate in the screen coordinate system
returns: `screen' in virtual coordinates.
yUtoV(double): unit: y coordinate in the unit coordinate system
returns: `unit' in virtual coordinates.
yVtoS(double): virtual: y coordinate in the virtual coordinate system
returns: `virtual' in screen coordinates.
yVtoU(double): virtual: y coordinate in the virtual coordinate system
returns: virtual in unit coordinates.

Coordinates

  public Coordinates(int width,
                     int height)

create a window of initial size `width' by `height' pixels.

Coordinates

  public Coordinates()

default constructor is 100 by 100 window.

toString

  public String toString()

prints internal information about the coordinates.

Overrides:: toString in class Object

disable

  public void disable()

greys out the scrollbars and makes them unusable.

enable

  public void enable()

reverses the effect of disable.

xVtoS

  public int xVtoS(double virtual)

virtual: x coordinate in the virtual coordinate system
returns: virtual in screen coordinates.

yVtoS

  public int yVtoS(double virtual)

virtual: y coordinate in the virtual coordinate system
returns: `virtual' in screen coordinates.

xStoV

  public double xStoV(int screen)

screen: x coordinate in the screen coordinate system
returns: `screen' in virtual coordinates.

yStoV

  public double yStoV(int screen)

screen: y coordinate in the screen coordinate system
returns: `screen' in virtual coordinates.

xVtoU

  public double xVtoU(double virtual)

virtual: x coordinate in the virtual coordinate system
returns: virtual in unit coordinates.

yVtoU

  public double yVtoU(double virtual)

virtual: y coordinate in the virtual coordinate system
returns: virtual in unit coordinates.

xUtoV

  public double xUtoV(double unit)

unit: x coordinate in the unit coordinate system
returns: `unit' in virtual coordinates.

yUtoV

  public double yUtoV(double unit)

unit: y coordinate in the unit coordinate system
returns: `unit' in virtual coordinates.

getsbX

  public Scrollbar getsbX()

gets the AWT scrollbar object that is the horizontal scrollbar used by this Coordinates.

getsbY

  public Scrollbar getsbY()

gets the AWT scrollbar object that is the vertical scrollbar used by this Coordinates.

addV

  public void addV(Vertex V)

inform Coordinates that the vertex `V' has been added to the graph.

delV

  public void delV(Vertex V,
                   Vertex Vlist)

inform Coordinates that the vertex `V' has been deleted from the graph.
`Vlist' is the "first" vertex in the graph. It represents a list of vertices that are used to calculate the new minimum rectangle containing all vertices. Typically, a call of delV is something like "delV(vertexToDelete, graph.getV())".

delAll

  public void delAll(Vertex emptyObjList)

inform Coordinates that all vertices have been deleted from the graph.
`Vlist' is the "first" vertex in the graph. It represents a list of vertices that are used to calculate the new minimum rectangle containing all vertices. Typically, a call of delAll is something like "delAll(graph.getV())".

canvasResize

  public void canvasResize(int width,
                           int height)

inform Coordinates that the size of the canvas has changed.
Typically, a call of canvasResize is something like "canvasResize(canvas.size().width, canvas.size().height)".

setMag

  public void setMag(double newmag)

change zoom level to `newmag'.
Magnification is the number of virtual coordinates per pixel coordinate. Doubling the magnification halves the size of objects on the screen.

getMag

  public double getMag()

returns the current zoom level.
Magnification is the number of virtual coordinates per pixel coordinate. Doubling the magnification halves the size of objects on the screen.

magRange

  public void magRange(double p1x,
                       double p1y,
                       double p2x,
                       double p2y)

!WARNING! This method has never been tested! !WARNING!
magnify the rectangle between P1 and P2.
note that this will actually magnify less than that amount in one dimension in order to preserve the aspect ratio.