Legacy Document

Inside Macintosh: Imaging With QuickDraw /

Chapter 2 - Basic QuickDraw / Basic QuickDraw Reference

Data Structures /

Rect

You can use a rectangle, which is a data structure of type Rect, to define areas on the screen and to specify the locations and sizes for various graphics operations. For example, a port rectangle represents the area of a graphics port (described on page 2-27) available for drawing.

The Rect data type can be defined by two points or four integers. The two points define the upper-left and lower-right corners of a rectangle; the four integers define the vertical and horizontal coordinates of the two points.

TYPE Rect = 
RECORD 
   CASE Integer OF            {cases: 4 boundaries or 2 corners}
      0: (top:       Integer;    {upper boundary of rectangle}
          left:      Integer;    {left boundary of rectangle}
          bottom:    Integer;    {lower boundary of rectangle}
          right:     Integer);   {right boundary of rectangle}
      1: (topLeft:   Point;      {upper-left corner of rectangle}
          botRight:  Point);     {lower-right corner of rectangle}
END;

Field Description

top

The vertical coordinate of the upper-left point of the rectangle.

left

The horizontal coordinate of the upper-left point of the rectangle.

bottom

The vertical coordinate of the lower-right point of the rectangle.

right

The horizontal coordinate of the lower-right point of the rectangle.

topLeft

The upper-left corner of the rectangle.

botRight

The lower-right corner of the rectangle.

Note that while the vertical coordinate appears first in this data structure, followed by the horizontal coordinate, the parameters to all QuickDraw routines expect the horizontal coordinate first and the vertical coordinate second.

See the chapter "QuickDraw Drawing" for descriptions of the QuickDraw routines you can use for calculating and manipulating rectangles for drawing purposes.