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45 lines
2.4 KiB
Markdown
45 lines
2.4 KiB
Markdown
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The [_WIDTH (function)](_WIDTH-(function)) function returns the width of an image handle or of the current write page.
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## Syntax
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> columns& = [_WIDTH (function)](_WIDTH-(function))[(imageHandle&)]
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## Description
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* If imageHandle& is omitted, it's assumed to be the handle of the current [SCREEN](SCREEN) or write page.
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* To get the width of the current program [SCREEN](SCREEN) window use zero for the handle value or nothing: columns& = [_WIDTH (function)](_WIDTH-(function))(0) *or* columns& = [_WIDTH (function)](_WIDTH-(function))
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* If the image specified by imageHandle& is in text only([SCREEN](SCREEN) 0) mode, the number of characters per row is returned.
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* If the image specified by imageHandle& is in graphics mode, the number of pixels per row is returned.
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* If imageHandle& is an invalid handle, then an [ERROR Codes](ERROR-Codes) is returned.
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* The last visible pixel coordinate of a program [SCREEN](SCREEN) is **[_WIDTH (function)](_WIDTH-(function)) - 1**.
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## Example(s)
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## Example(s)
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A SUB program that centers text in any graphic screen mode except text mode [SCREEN (statement)](SCREEN-(statement)) 0.
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```vb
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s& = _NEWIMAGE(800, 600, 256)
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SCREEN s&
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Align 15, 5, s&, "This text is centered on the screen!"
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SUB Align (Tcolor, Trow, mode&, txt$)
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center& = _WIDTH (mode&) \ 2 'returns pixels in graphic modes
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MaxCol = (center& \ 8) + 1 'screen text width = 8 pixels
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Tcol = MaxCol - (LEN(txt$) \ 2)
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COLOR Tcolor: LOCATE Trow, Tcol: PRINT txt$;
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END SUB
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```
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> *Explanation:* [_NEWIMAGE](_NEWIMAGE) enlarges a screen to 800 pixels wide which is what [_WIDTH (function)](_WIDTH-(function)) function will return. The center is 800 \ 2 or 400. Since the text width is 8 pixels, that is divided by 8 to get 50 as the center text column. Then half of the text length is subtracted to find the starting text print [LOCATE](LOCATE) column.
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> *Note:* The screen handle parameter is required because using no handle could assume other page handles created by functions like [_NEWIMAGE](_NEWIMAGE) or [_PUTIMAGE](_PUTIMAGE). Use the correct handle in the SUB call! When using SCREEN 0, the MaxCol variable is not needed because _WIDTH returns the number of text columns, not pixels. Use the center value and add 1. **Tcol = (center& + 1) - LEN(txt$) \ 2**
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## See Also
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* [_HEIGHT](_HEIGHT), [_LOADIMAGE](_LOADIMAGE), [_NEWIMAGE](_NEWIMAGE)
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* [WIDTH](WIDTH)
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* [Bitmaps](Bitmaps)
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