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Version: 1.6.0

Coordinate System

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Understanding the coordinate system is an important part of graphical programming. The coordinate system represents the positions of the graphic objects on the screen.

Cartesian Coordinate System​

The Cartesian coordinate system divides a two-dimensional plane into four regions, also called quartets, and two axes: x and y. The X axis is indicated by a horizontal line and the y axis by a vertical line. A given x and y position pair defines a point in a plane. The origin of the plane is a point with x = 0 and y = 0, and the dials divide the plane by origin.

To find out which point is falling, we compare the x and y positions of the point by origin.

  • Quadrant I: x > 0 and y > 0
  • Quadrant II: x < 0 and y > 0
  • Quadrant III: x < 0 and y < 0
  • Quadrant IV: x > 0 and y < 0

A point with positive x and y values will fall to the first quadrant. A point with positive -x and y values will fall to the second quadrant. A point with positive -x and -y values will fall to the third quadrant. A point with positive x and -y values will fall to the fourth quadrant.

TGI Coordinate System​

Unlike the Cartesian coordinate system, the default TGI coordinate system starts with the origin in the upper left corner. By default, the x-axis points to the right and the y-axis points down.As shown in the figure below, the upper left corner starts with x = 0 and y = 0 points.

Because the TGI coordinate system starts with the upper-left corner (x = 0, y = 0) of the screen, you can see only the points with x and y values by default. Objects with -x or -y values do not appear on the screen. However, you can apply translate transform to move objects with negative values to the visible area.