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GET (Graphics) Statement Details
 
Syntax
  GET [STEP](x1,y1)-[STEP](x2,y2),arrayname[(indices)]
 
  Argument      Description
 
  x1,y1,x2,y2   Coordinates marking a rectangular area on the screen.
                The placeholders x1, y1, x2, and y2 are numeric
                expressions that are the coordinates of diagonally
                opposite corners of the rectangle.
 
  STEP          Keyword indicating that coordinates are relative to
                the most recently plotted point. For example, if the
                last point plotted were (10,10), then the actual
                coordinates referred to by STEP (5,10) would be
                (5+10,10+10) or (15,20). If the second coordinate pair
                in a GET statement has a STEP argument, it is relative
                to the first coordinate pair in the statement.
 
  arrayname     Name assigned to the array that holds the image. This
                array can be of any numeric type; its dimensions must
                be large enough to hold the entire image.
 
  indices       Numeric constants or variables indicating the element
                of the array where the saved image starts.
 
 
The GET statement transfers a screen image into the array specified
by arrayname. The PUT statement, associated with GET, transfers the
image stored in the array onto the screen.
 
The following formula gives the required size of the array in bytes:
 
  4 + INT(((x2 - x1 + 1) * (bits-per-pixel-per-plane) + 7)/8)
                         * planes * ((y2 - y1) + 1)
 
The bits-per-pixel-per-plane and planes values depend on the
specification set in the SCREEN statement. The table below shows the
number of bits per pixel per plane and the number of planes for each
screen mode.
 
  Values for Bits per Pixel per Plane and for Planes
 
                 Bits per Pixel
  Screen Mode    per Plane        Planes
 
   1               2                1
   2               1                1
   7               1                4
   8               1                4
   9               1                2   (if   64K of EGA  memory)
                                    4   (if > 64K of EGA  memory)
  10               1                2
  11               1                1
  12               1                4
  13               8                1
 
 
The bytes per element of an array are as follows:
 
  ■ Two bytes for an integer array element
  ■ Four bytes for a long-integer array element
  ■ Four bytes for a single-precision array element
  ■ Eight bytes for a double-precision array element
 
For example, suppose you wanted to use the GET statement to store an
image in high resolution (SCREEN 2). If the coordinates of the upper-
left corner of the image are (0,0), and the coordinates of the lower-
right corner are (32,32), then the required size of the array in bytes
is 4 + INT((33 * 1 + 7)/8) * 1 * (33), or 169. This means an integer
array with 85 elements would be large enough to hold the image.
 
Unless the array type is integer or long, the contents of an array
after a GET appear meaningless when inspected directly. Examining
or manipulating noninteger arrays containing graphics images may cause
run-time errors.
 
One of the most useful things that can be done with GET and
PUT is animation.