The SHOW statement specifies the bounds of the data values to be displayed within the VIEWPORT in isotropic units so that the X and Y units are of equal length. You specify the left, right, bottom, and top coordinate bounds as follows:
SHOW Left,Right,Bottom,Top
The SHOW values are manipulated internally to give you isotropic units in both the X and Y directions. The SHOW statement finds the difference between the X and Y ranges and the smaller range is scaled into the larger, causing the specified area to be centered within the plotting area. For example:
SHOW -100,100,2,10
For a screen with square pixels the calculations would be: an X difference of 200 and Y difference of 8 is found by subtracting the lower bound from the upper. The smaller Y range is scaled into the larger X range. The difference between the X and Y ranges is 192 (200-8), and half of this, 96, is applied to each Y value. The new minimum Y value is -94 (2-96) and the maximum value is 106 (10+96).
For screens that don’t have square pixels, the values are automatically adjusted to prevent distortion.
