/ comp / gb.opengl / gl / linewidth
Gl.LineWidth (gb.opengl)
Syntax

    STATIC SUB LineWidth ( Width AS Float )

### Specify the width of rasterized lines

#### Parameters

- Width specifies the width of rasterized lines. The default is 1.0.

#### Description

Gl.LineWidth specifies the rasterized width of both aliased and antialiased lines. Using a line width other than 1.0 has different effects, depending on whether line antialiasing is enabled. Line antialiasing is controlled by calling Gl.Enable and Gl.Disable with argument Gl.GL_LINE_SMOOTH.

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 |dx| >= |dy| 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 1.0 is guaranteed to be supported; others depend on the implementation. The range of supported widths and the size difference between supported widths within the range can be queried by calling Gl.GetLineWidthRange and Gl.GetLineWidthGranularity.

| The line width specified by Gl.LineWidth is always returned when Gl.GetLineWidth is called. Clamping and rounding for aliased and antialiased lines have no effect on the specified value. Non-antialiased line width may be clamped to an implementation-dependent maximum. Although this maximum cannot be queried, it must be no less than the maximum value for antialiased lines, rounded to the nearest integer value.

#### Errors

Gl.GL_INVALID_VALUE is generated if width is less than or equal to zero.
Gl.GL_INVALID_OPERATION is generated if Gl.LineWidth is called between a call to Gl.Begin and the corresponding call to Gl.End.

#### Associated Gets

Gl.GetLineWidth
Gl.GetLineWidthRange
Gl.GetLineWidthGranularity
Gl.IsEnabled with argument Gl.GL_LINE_SMOOTH

### See also

Gl.Enable