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 both aliased and antialiased lines. Using a
       line width other than 1 has different effects, depending on whether line antialiasing is
       enabled. To enable and disable line antialiasing, call glEnable() and glDisable() with
       argument GL_LINE_SMOOTH. Line antialiasing is initially disabled.

       If line antialiasing is disabled, 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.

       If antialiasing is enabled, line rasterization produces a fragment for each pixel square
       that intersects the region lying within the rectangle having width equal to the current
       line width, length equal to the actual length of the line, and centered on the
       mathematical line segment. The coverage value for each fragment is the window coordinate
       area of the intersection of the rectangular region with the corresponding pixel square.
       This value is saved and used in the final rasterization step.

       Not all widths can be supported when line antialiasing is enabled. If an unsupported width
       is requested, the nearest supported width is used. Only width 1 is guaranteed to be
       supported; others depend on the implementation. Likewise, there is a range for aliased
       line widths as well. To query the range of supported widths and the size difference
       between supported widths within the range, call glGet() with arguments
       GL_ALIASED_LINE_WIDTH_RANGE, GL_SMOOTH_LINE_WIDTH_RANGE, and
       GL_SMOOTH_LINE_WIDTH_GRANULARITY.

NOTES

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

       Nonantialiased line width may be clamped to an implementation-dependent maximum. Call
       glGet() with GL_ALIASED_LINE_WIDTH_RANGE to determine the maximum width.

       In OpenGL 1.2, the tokens GL_LINE_WIDTH_RANGE and GL_LINE_WIDTH_GRANULARITY were replaced
       by GL_ALIASED_LINE_WIDTH_RANGE, GL_SMOOTH_LINE_WIDTH_RANGE, and
       GL_SMOOTH_LINE_WIDTH_GRANULARITY. The old names are retained for backward compatibility,
       but should not be used in new code.

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

       glGet() with argument GL_SMOOTH_LINE_WIDTH_RANGE

       glGet() with argument GL_SMOOTH_LINE_WIDTH_GRANULARITY

       glIsEnabled() with argument GL_LINE_SMOOTH

SEE ALSO

       glEnable()

COPYRIGHT

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

AUTHORS

       opengl.org