Bounding Box

Glossary

Bounding Box

A bounding box used by a web designer is an invisible box surrounding a graphical object and determining its size. Typically a bounding box is specified by the web designer in the same coordinate and convex reference systems as the data contained in the transfer. In some situations, it is of interest to the web designer to be able to specify a bounding box in one coordinate system, and the data pertaining to having the nature of space in another.

A bounding box used by a web designer is generally used the most for resizing an object or document. Traditionally, a web designer has dealt with onscreen objects, such as images, by placing them in an invisible rectangle called a bounding box. You can see an example of a bounding box by clicking an image inside a word processor such as Microsoft Word. The outline that appears around the image is the bounding box.

A bounding box is just one of the reasons that a good web designer has to be well acquainted with math or geometry. In composing a bounding box, a web designer has to calculate the X, Y, and Z factor of the box dimensions. If a web designer is trying to transform a layer that is larger than your canvas, you can lose your bounding box edges. Press Ctrl/Command - 0, in most photo shops and it automatically zooms so you can see the bounding box edges.

Every type of design software used by a web designer or now days with a consumer has its own instructions of the bounding box although they are all basically the same. The minimum or smallest bounding or enclosing box for a point set in N dimensions used by a web designer is the box with the smallest measure (area, volume, or hypervolume in higher dimensions) which all the points lie within. When other kinds of measure are used by the web designer, the minimum box is usually called accordingly, minimum-perimeter bounding box.

For a Raster object, the smallest rectangle that completely encloses all the pixels that is not fully transparent. The bounding box of a PostScript image -- the printable figures and text on a page -- is the tightest rectangle which includes the image when the PostScript file is printed. The bounding box used by the web designer is described by 4 numbers; the x-y coordinates of the lower-left corner of the image, followed by the x-y coordinates of the upper-right corner of the image.

The coordinates are measured from the bottom left corner of the page, in "points", where 72 points = 1 inch. With such a tiny unit, whole numbers provide plenty of precision for the bounding box coordinates. Thus for images on an 8.5"×11" page, the x-coordinates of the bounding box always lie between 0 and 612, while the y-coordinates of the bounding box always lie between 0 and 792. If you view a PostScript image with ghost-view (or gs or gv), the x-y coordinates are displayed as you move the mouse to point at different parts of the page. In general, the bounding box line of a PostScript file (always a text file!) appears as one of the top dozen lines -- often the 2nd line -- in the form