ellipseMode(mode)

The origin of new ellipses is modified by the ellipseMode() function. The default configuration is ellipseMode(CENTER), which specifies the location of the ellipse as the center of the shape. The RADIUS mode is the same, but the w and h parameters to ellipse() specify the radius of the ellipse, rather than the diameter. The CORNER mode draws the shape from the upper-left corner of its bounding box. The CORNERS mode uses the four parameters to ellipse() to set two opposing corners of the ellipse’s bounding box.