| Extracted from Pike v7.8 release 866 at 2016-04-05.

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GL

# Method GL.glViewport()

Method glViewport

  `void glViewport(int x, int y, int width, int height)`

Description

  glViewport specifies the affine transformation of x and y from normalized device coordinates to window coordinates. Let (x sub nd, y sub nd) be normalized device coordinates. Then the window coordinates (x sub w, y sub w) are computed as follows: .sp .ce .EQ x sub w ~=~ ( x sub nd + 1 ) left ( "width" over 2 right ) ~+~ "x" .EN .sp .ce .EQ y sub w ~=~ ( y sub nd + 1 ) left ( "height" over 2 right ) ~+~ "y" .EN .RE

  Viewport width and height are silently clamped to a range that depends on the implementation. To query this range, call glGet with argument GL_MAX_VIEWPORT_DIMS .

Parameter `x`

  Specify the lower left corner of the viewport rectangle, in pixels. The initial value is (0,0).

Parameter `width`

  Specify the width and height of the viewport. When a GL context is first attached to a window, width and height are set to the dimensions of that window.

Throws

  GL_INVALID_VALUE is generated if either width or height is negative.

  GL_INVALID_OPERATION is generated if glViewport is executed between the execution of glBegin and the corresponding execution of glEnd .