Dimension classes

Last modified: February 03, 2010

Contents

This is a reference chapter for the various classes that manage coordinates, dimensions and bounding boxes.

Point

__init__(Int x, Int y)

Point stores an (x, y) coordinate point.

Most functions that take a Point as an argument can also take a 2-element sequence. For example, the following are all equivalent:

px = image.get(Point(5, 2))
px = image.get((5, 2))
px = image.get([5, 2])

init

Point (Int x, Int y)

`x`

(int property)

The current x value

`y`

(int property)

The current y value

Size

Size stores a size (width, height). This is almost the same as Dim, but stores the number of columns/rows minus one:

width == ncols - 1

height == nrows - 1

init

Size (Int width, Int height)

`width`

(int property)

The width of an object is the right boundary minus the left. This is the same as the number of columns minus one.

`height`

(int property)

The height of an object is the lower boundary minus the upper boundary (remember that y is counted in the negative direction). This is the same as the number of rows minus one.

Dim

__init__(Int ncols, Int nrows)

Dim stores a dimension (ncols, nrows)

init

Dim (Int ncols, Int nrows)

`ncols`

(int property get/set)

the current number of columns

`nrows`

(int property get/set)

The current number of rows

Rect

There are a number of ways to initialize a Rect object:

Rect (Point upper_left, Point lower_right)

Rect (Point upper_left, Size size)

Rect (Point upper_left, Dim dim)

Rect (Rect rectangle)

The Rect class manages bounding boxes, and has a number of methods to modify and analyse those bounding boxes.

Position and dimensions

`ul`

(Point property)

The upper-left coordinate of the rectangle in logical coordinate space.

`ul_x`

(int property)

The left edge of the rectangle in logical coordinate space.

`ul_y`

(int property)

The upper edge of the rectangle in logical coordinate space.

`ur`

(Point property)

The upper-right coordinate of the rectangle in logical coordinate space.

`ur_x`

(int property)

The right edge of the rectangle in logical coordinate space.

`ur_y`

(int property)

The upper edge of the rectangle in logical coordinate space.

`lr`

(Point property)

The lower-right coordinate of the rectangle in logical coordinate space.

`lr_x`

(int property)

The right edge of the rectangle in logical coordinate space.

`lr_y`

(int property)

The lower edge of the rectangle in logical coordinate space.

`ll`

(Point property)

The lower-left coordinate of the rectangle in logical coordinate space.

`ll_x`

(int property)

The left edge of the rectangle in logical coordinate space.

`ll_y`

(int property)

The lower edge of the rectangle in logical coordinate space.

`size`

(Size property)

The size of the rectangle. Equivalent to Size(image.width, image.height).

`nrows`

(int property)

The number of rows in the rectangle.

`ncols`

(int property)

The number of columns in the rectangle.

`width`

(int property)

The width of the rectangle.

`height`

(int property)

The height of the rectangle.

`offset_x`

(int property)

The left edge of the rectangle in the logical coordinate space.

`offset_y`

(int property)

The upper edge of the rectable in the logical coordinate space.

Center

`center`

(Point property)

The coordinate at the exact center of the rectangle in the logical coordinate space.

`center_x`

(int property)

The x-location at the exact center of the rectangle in the logical coordinate space.

`center_y`

(int property)

The y-location at the exact center of the rectangle in the logical coordinate space.

Containment

`contains_x`

bool contains_x (Int x)

True if the rectangle contains the given x-value in logical coordinate space.

`contains_y`

bool contains_y (Int y)

True if the rectangle contains the given y-value in logical coordinate space.

`contains_point`

bool contains_point (Point point)

True if the rectangle contains the given Point in logical coordinate space

`contains_rect`

bool contains_rect (Rect other)

True if rectangle completely contains the given rectangle in logical coordinate space.

Intersection

`intersects`

bool intersects (Rect other)

True if rectangle intersects with the given rectangle.

`intersects_x`

bool intersects_x (Rect other)

True if rectangle intersects the given rectangle in the x direction (completely ignoring the y direction). (True if the two rectangles are merely "vertically aligned".)

`intersects_y`

bool intersects_y (Rect other)

True if rectangle intersects the given rectangle in the y direction (completely ignoring the x direction). (True if the two rectangles are merely "horizontally aligned".)

`intersection`

bool intersection (Rect other)

Returns a new Rect that is the intersection of self and the given Rect object.

Union

`union`

union (Rect other)

Expands the rectangle to include the given rectangle and itself.

`union_rects`

Rect union_rects (RectList rects)

Returns a new rectangle that encloses all of the given rectangles in a list.

Distance

`distance_euclid`

float distance_euclid (Rect other)

Returns the Euclidean distance between the center points of this rectangle and the given rectangle.

`distance_bb`

float distance_bb (Rect other)

Returns the closest (Euclidean) distance between the edges of this rectangle and the edges of the given rectangle.

`distance_cx`

int distance_cx (Rect other)

Returns the distance of the center points of this rectangle and the given rectangle in the horizontal direction.

`distance_cy`

int distance_cy (Rect other)

Returns the distance of the center points of this rectangle and the given rectangle in the vertical direction.