openGL and JOGL

Magnifying or Reducing an Image

Normally, each pixel in an image is written to a single pixel on the screen. However, you can arbitrarily magnify or reduce an image by using

  glPixelZoom(). void glPixelZoom(GLfloat zoomx, GLfloat zoomy);

Sets the magnification or reduction factors for pixel-write operations, in the x- and y-dimensions. By default, zoomx and zoomy are 1.0.
If they're both 2.0, each image pixel is drawn to 4 screen pixels. Note that fractional magnification or reduction factors are allowed, as are negative factors.

You can use negative values to flip the image.