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# docs.GL

OpenGL 4
OpenGL 3
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# glLineWidth

## Name

glLineWidth — specify the width of rasterized lines

## C Specification

`void glLineWidth(` | GLfloat width`)`;

## Parameters

`width`

  Specifies the width of rasterized lines. The initial value is 1.

## Description

`glLineWidth` specifies the rasterized width of lines.

The actual width is determined by rounding the supplied width to the nearest integer. (If the rounding results in the value 0, it is as if the line width were 1.) If Δ x >= Δ y , i pixels are filled in each column that is rasterized, where i is the rounded value of `width`. Otherwise, i pixels are filled in each row that is rasterized.

There is a range of supported line widths. Only width 1 is guaranteed to be supported; others depend on the implementation. To query the range of supported widths, call glGet with argument `GL_ALIASED_LINE_WIDTH_RANGE`.

## Notes

The line width specified by `glLineWidth` is always returned when `GL_LINE_WIDTH` is queried. Clamping and rounding have no effect on the specified value.

Line width may be clamped to an implementation-dependent maximum. Call glGet with `GL_ALIASED_LINE_WIDTH_RANGE` to determine the maximum width.

## Errors

`GL_INVALID_VALUE` is generated if `width` is less than or equal to 0.

## Associated Gets

glGet with argument `GL_LINE_WIDTH`

glGet with argument `GL_ALIASED_LINE_WIDTH_RANGE`

## See Also

glEnable

## Copyright

Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see https://web.archive.org/web/20171022161616/http://oss.sgi.com/projects/FreeB/.

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