WIDTH (function)

The _WIDTH (function) function returns the width of an image handle or of the current write page.

Syntax

columns& = _WIDTH (function)[(imageHandle&)]

Description

• If imageHandle& is omitted, it's assumed to be the handle of the current SCREEN or write page.
• To get the width of the current program SCREEN window use zero for the handle value or nothing: columns& = _WIDTH (function)(0) or columns& = _WIDTH (function)
• If the image specified by imageHandle& is in text only(SCREEN 0) mode, the number of characters per row is returned.
• If the image specified by imageHandle& is in graphics mode, the number of pixels per row is returned.
• If imageHandle& is an invalid handle, then an ERROR Codes is returned.
• The last visible pixel coordinate of a program SCREEN is _WIDTH (function) - 1.

Example(s)

Example(s)

A SUB program that centers text in any graphic screen mode except text mode SCREEN (statement) 0.

s& = _NEWIMAGE(800, 600, 256)
SCREEN s&
Align 15, 5, s&, "This text is centered on the screen!"

SUB Align (Tcolor, Trow, mode&, txt$)    
  center& = _WIDTH (mode&) \ 2     'returns pixels in graphic modes 
  MaxCol = (center& \ 8) + 1              'screen text width = 8 pixels
  Tcol = MaxCol - (LEN(txt$) \ 2)
  COLOR Tcolor: LOCATE Trow, Tcol: PRINT txt$;  
END SUB

Explanation: _NEWIMAGE enlarges a screen to 800 pixels wide which is what _WIDTH (function) function will return. The center is 800 \ 2 or 400. Since the text width is 8 pixels, that is divided by 8 to get 50 as the center text column. Then half of the text length is subtracted to find the starting text print LOCATE column.

Note: The screen handle parameter is required because using no handle could assume other page handles created by functions like _NEWIMAGE or _PUTIMAGE. Use the correct handle in the SUB call! When using SCREEN 0, the MaxCol variable is not needed because _WIDTH returns the number of text columns, not pixels. Use the center value and add 1. Tcol = (center& + 1) - LEN(txt$) \ 2

See Also

• _HEIGHT, _LOADIMAGE, _NEWIMAGE
• WIDTH
• Bitmaps