Rectangle specifies an area in a coordinate space that is
* enclosed by the Rectangle object's upper-left point
* {@code (x,y)}
* in the coordinate space, its width, and its height.
*
* A Rectangle object's width and
* height are public fields. The constructors
* that create a Rectangle, and the methods that can modify
* one, do not prevent setting a negative value for width or height.
*
* Methods which affect only the location of a {@code Rectangle} will * operate on its location regardless of whether or not it has a negative * or zero dimension along either axis. *
* Note that a {@code Rectangle} constructed with the default no-argument * constructor will have dimensions of {@code 0x0} and therefore be empty. * That {@code Rectangle} will still have a location of {@code (0,0)} and * will contribute that location to the union and add operations. * Code attempting to accumulate the bounds of a set of points should * therefore initially construct the {@code Rectangle} with a specifically * negative width and height or it should use the first point in the set * to construct the {@code Rectangle}. * For example: *
* Rectangle bounds = new Rectangle(0, 0, -1, -1);
* for (int i = 0; i < points.length; i++) {
* bounds.add(points[i]);
* }
*
* or if we know that the points array contains at least one point:
*
* Rectangle bounds = new Rectangle(points[0]);
* for (int i = 1; i < points.length; i++) {
* bounds.add(points[i]);
* }
*
*
* This class uses 32-bit integers to store its location and dimensions.
* Frequently operations may produce a result that exceeds the range of
* a 32-bit integer.
* The methods will calculate their results in a way that avoids any
* 32-bit overflow for intermediate results and then choose the best
* representation to store the final results back into the 32-bit fields
* which hold the location and dimensions.
* The location of the result will be stored into the {@link #x} and
* {@link #y} fields by clipping the true result to the nearest 32-bit value.
* The values stored into the {@link #width} and {@link #height} dimension
* fields will be chosen as the 32-bit values that encompass the largest
* part of the true result as possible.
* Generally this means that the dimension will be clipped independently
* to the range of 32-bit integers except that if the location had to be
* moved to store it into its pair of 32-bit fields then the dimensions
* will be adjusted relative to the "best representation" of the location.
* If the true result had a negative dimension and was therefore
* non-existant along one or both axes, the stored dimensions will be
* negative numbers in those axes.
* If the true result had a location that could be represented within
* the range of 32-bit integers, but zero dimension along one or both
* axes, then the stored dimensions will be zero in those axes.
*/
public class Rectangle {
/**
* The X coordinate of the upper-left corner of the Rectangle.
*/
public int x;
/**
* The Y coordinate of the upper-left corner of the Rectangle.
*/
public int y;
/**
* The width of the Rectangle.
*/
public int width;
/**
* The height of the Rectangle.
*/
public int height;
/**
* Constructs a new Rectangle whose upper-left corner
* is at (0, 0) in the coordinate space, and whose width and
* height are both zero.
*/
public Rectangle() {
this(0, 0, 0, 0);
}
/**
* Constructs a new Rectangle, initialized to match
* the values of the specified Rectangle.
* @param r the Rectangle from which to copy initial values
* to a newly constructed Rectangle
*/
public Rectangle(BaseBounds b) {
setBounds(b);
}
/**
* Constructs a new Rectangle, initialized to match
* the values of the specified BaseBounds. Since BaseBounds has
* float values, the Rectangle will be created such that the bounding rectangle
* of the specified BaseBounds would always lie within the bounding box
* specified by this Rectangle.
* @param r the BaseBounds from which to copy initial values
* to a newly constructed Rectangle
*/
public Rectangle(Rectangle r) {
this(r.x, r.y, r.width, r.height);
}
/**
* Constructs a new Rectangle whose upper-left corner is
* specified as
* {@code (x,y)} and whose width and height
* are specified by the arguments of the same name.
* @param x the specified X coordinate
* @param y the specified Y coordinate
* @param width the width of the Rectangle
* @param height the height of the Rectangle
*/
public Rectangle(int x, int y, int width, int height) {
this.x = x;
this.y = y;
this.width = width;
this.height = height;
}
/**
* Constructs a new Rectangle whose upper-left corner
* is at (0, 0) in the coordinate space, and whose width and
* height are specified by the arguments of the same name.
* @param width the width of the Rectangle
* @param height the height of the Rectangle
*/
public Rectangle(int width, int height) {
this(0, 0, width, height);
}
/**
* Sets the bounding Rectangle of this Rectangle
* to match the specified Rectangle.
*
* This method is included for completeness, to parallel the
* setBounds method of Component.
* @param r the specified Rectangle
* @see #getBounds
* @see java.awt.Component#setBounds(java.awt.Rectangle)
*/
public void setBounds(Rectangle r) {
setBounds(r.x, r.y, r.width, r.height);
}
/**
* Sets the bounding Rectangle of this
* Rectangle to the specified
* x, y, width,
* and height.
*
* This method is included for completeness, to parallel the
* setBounds method of Component.
* @param x the new X coordinate for the upper-left
* corner of this Rectangle
* @param y the new Y coordinate for the upper-left
* corner of this Rectangle
* @param width the new width for this Rectangle
* @param height the new height for this Rectangle
* @see #getBounds
* @see java.awt.Component#setBounds(int, int, int, int)
*/
public void setBounds(int x, int y, int width, int height) {
reshape(x, y, width, height);
}
public void setBounds(BaseBounds b) {
x = (int) Math.floor(b.getMinX());
y = (int) Math.floor(b.getMinY());
int x2 = (int) Math.ceil(b.getMaxX());
int y2 = (int) Math.ceil(b.getMaxY());
width = x2 - x;
height = y2 - y;
}
/**
* Checks whether or not this Rectangle contains the
* point at the specified location {@code (cx,cy)}.
*
* @param cx the specified X coordinate
* @param cy the specified Y coordinate
* @return true if the point
* {@code (cx,cy)} is inside this
* Rectangle;
* false otherwise.
*/
public boolean contains(int cx, int cy) {
int tw = this.width;
int th = this.height;
if ((tw | th) < 0) {
// At least one of the dimensions is negative...
return false;
}
// Note: if either dimension is zero, tests below must return false...
int tx = this.x;
int ty = this.y;
if (cx < tx || cy < ty) {
return false;
}
tw += tx;
th += ty;
// overflow || intersect
return ((tw < tx || tw > cx) &&
(th < ty || th > cy));
}
/**
* Checks whether or not this Rectangle entirely contains
* the specified Rectangle.
*
* @param r the specified Rectangle
* @return true if the Rectangle
* is contained entirely inside this Rectangle;
* false otherwise
*/
public boolean contains(Rectangle r) {
return contains(r.x, r.y, r.width, r.height);
}
/**
* Checks whether this Rectangle entirely contains
* the Rectangle
* at the specified location {@code (cx,cy)} with the
* specified dimensions {@code (cw,ch)}.
* @param cx the specified X coordinate
* @param cy the specified Y coordinate
* @param cw the width of the Rectangle
* @param ch the height of the Rectangle
* @return true if the Rectangle specified by
* {@code (cx, cy, cw, ch)}
* is entirely enclosed inside this Rectangle;
* false otherwise.
*/
public boolean contains(int cx, int cy, int cw, int ch) {
int tw = this.width;
int th = this.height;
if ((tw | th | cw | ch) < 0) {
// At least one of the dimensions is negative...
return false;
}
// Note: if any dimension is zero, tests below must return false...
int tx = this.x;
int ty = this.y;
if (cx < tx || cy < ty) {
return false;
}
tw += tx;
cw += cx;
if (cw <= cx) {
// cx+cw overflowed or cw was zero, return false if...
// either original tw or cw was zero or
// tx+tw did not overflow or
// the overflowed cx+cw is smaller than the overflowed tx+tw
if (tw >= tx || cw > tw) return false;
} else {
// cx+cw did not overflow and cw was not zero, return false if...
// original tw was zero or
// tx+tw did not overflow and tx+tw is smaller than cx+cw
if (tw >= tx && cw > tw) return false;
}
th += ty;
ch += cy;
if (ch <= cy) {
if (th >= ty || ch > th) return false;
} else {
if (th >= ty && ch > th) return false;
}
return true;
}
public Rectangle intersection(Rectangle r) {
Rectangle ret = new Rectangle(this);
ret.intersectWith(r);
return ret;
}
public void intersectWith(Rectangle r) {
if (r == null) {
return;
}
int tx1 = this.x;
int ty1 = this.y;
int rx1 = r.x;
int ry1 = r.y;
long tx2 = tx1; tx2 += this.width;
long ty2 = ty1; ty2 += this.height;
long rx2 = rx1; rx2 += r.width;
long ry2 = ry1; ry2 += r.height;
if (tx1 < rx1) tx1 = rx1;
if (ty1 < ry1) ty1 = ry1;
if (tx2 > rx2) tx2 = rx2;
if (ty2 > ry2) ty2 = ry2;
tx2 -= tx1;
ty2 -= ty1;
// tx2,ty2 will never overflow (they will never be
// larger than the smallest of the two source w,h)
// they might underflow, though...
if (tx2 < Integer.MIN_VALUE) tx2 = Integer.MIN_VALUE;
if (ty2 < Integer.MIN_VALUE) ty2 = Integer.MIN_VALUE;
setBounds(tx1, ty1, (int) tx2, (int) ty2);
}
/**
* Translates this Rectangle the indicated distance,
* to the right along the X coordinate axis, and
* downward along the Y coordinate axis.
* @param dx the distance to move this Rectangle
* along the X axis
* @param dy the distance to move this Rectangle
* along the Y axis
* @see java.awt.Rectangle#setLocation(int, int)
* @see java.awt.Rectangle#setLocation(java.awt.Point)
*/
public void translate(int dx, int dy) {
int oldv = this.x;
int newv = oldv + dx;
if (dx < 0) {
// moving leftward
if (newv > oldv) {
// negative overflow
// Only adjust width if it was valid (>= 0).
if (width >= 0) {
// The right edge is now conceptually at
// newv+width, but we may move newv to prevent
// overflow. But we want the right edge to
// remain at its new location in spite of the
// clipping. Think of the following adjustment
// conceptually the same as:
// width += newv; newv = MIN_VALUE; width -= newv;
width += newv - Integer.MIN_VALUE;
// width may go negative if the right edge went past
// MIN_VALUE, but it cannot overflow since it cannot
// have moved more than MIN_VALUE and any non-negative
// number + MIN_VALUE does not overflow.
}
newv = Integer.MIN_VALUE;
}
} else {
// moving rightward (or staying still)
if (newv < oldv) {
// positive overflow
if (width >= 0) {
// Conceptually the same as:
// width += newv; newv = MAX_VALUE; width -= newv;
width += newv - Integer.MAX_VALUE;
// With large widths and large displacements
// we may overflow so we need to check it.
if (width < 0) width = Integer.MAX_VALUE;
}
newv = Integer.MAX_VALUE;
}
}
this.x = newv;
oldv = this.y;
newv = oldv + dy;
if (dy < 0) {
// moving upward
if (newv > oldv) {
// negative overflow
if (height >= 0) {
height += newv - Integer.MIN_VALUE;
// See above comment about no overflow in this case
}
newv = Integer.MIN_VALUE;
}
} else {
// moving downward (or staying still)
if (newv < oldv) {
// positive overflow
if (height >= 0) {
height += newv - Integer.MAX_VALUE;
if (height < 0) height = Integer.MAX_VALUE;
}
newv = Integer.MAX_VALUE;
}
}
this.y = newv;
}
public RectBounds toRectBounds() {
return new RectBounds(x, y, x+width, y+height);
}
/**
* Adds a point, specified by the integer arguments {@code newx,newy}
* to the bounds of this {@code Rectangle}.
*
* If this {@code Rectangle} has any dimension less than zero, * the rules for non-existant * rectangles apply. * In that case, the new bounds of this {@code Rectangle} will * have a location equal to the specified coordinates and * width and height equal to zero. *
* After adding a point, a call to contains with the
* added point as an argument does not necessarily return
* true. The contains method does not
* return true for points on the right or bottom
* edges of a Rectangle. Therefore, if the added point
* falls on the right or bottom edge of the enlarged
* Rectangle, contains returns
* false for that point.
* If the specified point must be contained within the new
* {@code Rectangle}, a 1x1 rectangle should be added instead:
*
* r.add(newx, newy, 1, 1);
*
* @param newx the X coordinate of the new point
* @param newy the Y coordinate of the new point
*/
public void add(int newx, int newy) {
if ((width | height) < 0) {
this.x = newx;
this.y = newy;
this.width = this.height = 0;
return;
}
int x1 = this.x;
int y1 = this.y;
long x2 = this.width;
long y2 = this.height;
x2 += x1;
y2 += y1;
if (x1 > newx) x1 = newx;
if (y1 > newy) y1 = newy;
if (x2 < newx) x2 = newx;
if (y2 < newy) y2 = newy;
x2 -= x1;
y2 -= y1;
if (x2 > Integer.MAX_VALUE) x2 = Integer.MAX_VALUE;
if (y2 > Integer.MAX_VALUE) y2 = Integer.MAX_VALUE;
reshape(x1, y1, (int) x2, (int) y2);
}
/**
* Adds a Rectangle to this Rectangle.
* The resulting Rectangle is the union of the two
* rectangles.
* * If either {@code Rectangle} has any dimension less than 0, the * result will have the dimensions of the other {@code Rectangle}. * If both {@code Rectangle}s have at least one dimension less * than 0, the result will have at least one dimension less than 0. *
* If either {@code Rectangle} has one or both dimensions equal * to 0, the result along those axes with 0 dimensions will be * equivalent to the results obtained by adding the corresponding * origin coordinate to the result rectangle along that axis, * similar to the operation of the {@link #add(Point)} method, * but contribute no further dimension beyond that. *
* If the resulting {@code Rectangle} would have a dimension
* too large to be expressed as an {@code int}, the result
* will have a dimension of {@code Integer.MAX_VALUE} along
* that dimension.
* @param r the specified Rectangle
*/
public void add(Rectangle r) {
long tx2 = this.width;
long ty2 = this.height;
if ((tx2 | ty2) < 0) {
reshape(r.x, r.y, r.width, r.height);
}
long rx2 = r.width;
long ry2 = r.height;
if ((rx2 | ry2) < 0) {
return;
}
int tx1 = this.x;
int ty1 = this.y;
tx2 += tx1;
ty2 += ty1;
int rx1 = r.x;
int ry1 = r.y;
rx2 += rx1;
ry2 += ry1;
if (tx1 > rx1) tx1 = rx1;
if (ty1 > ry1) ty1 = ry1;
if (tx2 < rx2) tx2 = rx2;
if (ty2 < ry2) ty2 = ry2;
tx2 -= tx1;
ty2 -= ty1;
// tx2,ty2 will never underflow since both original
// rectangles were non-empty
// they might overflow, though...
if (tx2 > Integer.MAX_VALUE) tx2 = Integer.MAX_VALUE;
if (ty2 > Integer.MAX_VALUE) ty2 = Integer.MAX_VALUE;
reshape(tx1, ty1, (int) tx2, (int) ty2);
}
/**
* Resizes the Rectangle both horizontally and vertically.
*
* This method modifies the Rectangle so that it is
* h units larger on both the left and right side,
* and v units larger at both the top and bottom.
*
* The new Rectangle has {@code (x - h, y - v)}
* as its upper-left corner,
* width of {@code (width + 2h)},
* and a height of {@code (height + 2v)}.
*
* If negative values are supplied for h and
* v, the size of the Rectangle
* decreases accordingly.
* The {@code grow} method will check for integer overflow
* and underflow, but does not check whether the resulting
* values of {@code width} and {@code height} grow
* from negative to non-negative or shrink from non-negative
* to negative.
* @param h the horizontal expansion
* @param v the vertical expansion
*/
public void grow(int h, int v) {
long x0 = this.x;
long y0 = this.y;
long x1 = this.width;
long y1 = this.height;
x1 += x0;
y1 += y0;
x0 -= h;
y0 -= v;
x1 += h;
y1 += v;
if (x1 < x0) {
// Non-existant in X direction
// Final width must remain negative so subtract x0 before
// it is clipped so that we avoid the risk that the clipping
// of x0 will reverse the ordering of x0 and x1.
x1 -= x0;
if (x1 < Integer.MIN_VALUE) x1 = Integer.MIN_VALUE;
if (x0 < Integer.MIN_VALUE) x0 = Integer.MIN_VALUE;
else if (x0 > Integer.MAX_VALUE) x0 = Integer.MAX_VALUE;
} else { // (x1 >= x0)
// Clip x0 before we subtract it from x1 in case the clipping
// affects the representable area of the rectangle.
if (x0 < Integer.MIN_VALUE) x0 = Integer.MIN_VALUE;
else if (x0 > Integer.MAX_VALUE) x0 = Integer.MAX_VALUE;
x1 -= x0;
// The only way x1 can be negative now is if we clipped
// x0 against MIN and x1 is less than MIN - in which case
// we want to leave the width negative since the result
// did not intersect the representable area.
if (x1 < Integer.MIN_VALUE) x1 = Integer.MIN_VALUE;
else if (x1 > Integer.MAX_VALUE) x1 = Integer.MAX_VALUE;
}
if (y1 < y0) {
// Non-existant in Y direction
y1 -= y0;
if (y1 < Integer.MIN_VALUE) y1 = Integer.MIN_VALUE;
if (y0 < Integer.MIN_VALUE) y0 = Integer.MIN_VALUE;
else if (y0 > Integer.MAX_VALUE) y0 = Integer.MAX_VALUE;
} else { // (y1 >= y0)
if (y0 < Integer.MIN_VALUE) y0 = Integer.MIN_VALUE;
else if (y0 > Integer.MAX_VALUE) y0 = Integer.MAX_VALUE;
y1 -= y0;
if (y1 < Integer.MIN_VALUE) y1 = Integer.MIN_VALUE;
else if (y1 > Integer.MAX_VALUE) y1 = Integer.MAX_VALUE;
}
reshape((int) x0, (int) y0, (int) x1, (int) y1);
}
private void reshape(int x, int y, int width, int height) {
this.x = x;
this.y = y;
this.width = width;
this.height = height;
}
/**
* {@inheritDoc}
*/
public boolean isEmpty() {
return (width <= 0) || (height <= 0);
}
/**
* Checks whether two rectangles are equal.
*
* The result is true if and only if the argument is not
* null and is a Rectangle object that has the
* same upper-left corner, width, and height as
* this Rectangle.
* @param obj the Object to compare with
* this Rectangle
* @return true if the objects are equal;
* false otherwise.
*/
@Override
public boolean equals(Object obj) {
if (obj instanceof Rectangle) {
Rectangle r = (Rectangle)obj;
return ((x == r.x) &&
(y == r.y) &&
(width == r.width) &&
(height == r.height));
}
return super.equals(obj);
}
@Override
public int hashCode() {
int bits = Float.floatToIntBits(x);
bits += Float.floatToIntBits(y) * 37;
bits += Float.floatToIntBits(width) * 43;
bits += Float.floatToIntBits(height) * 47;
return bits;
}
/**
* Returns a String representing this
* Rectangle and its values.
* @return a String representing this
* Rectangle object's coordinate and size values.
*/
@Override
public String toString() {
return getClass().getName() + "[x=" + x + ",y=" + y + ",width=" + width + ",height=" + height + "]";
}
}