Da li mozete da mi objasnite ove kordinate kod procedura...-Delphi

Use Arc to draw an elliptically curved line with the current Pen. The arc traverses the perimeter of an ellipse that is bounded by the points (X1,Y1) and (X2,Y2). The arc is drawn following the perimeter of the ellipse, counterclockwise, from the starting point to the ending point. The starting point is defined by the intersection of the ellipse and a line defined by the center of the ellipse and (X3,Y3). The ending point is defined by the intersection of the ellipse and a line defined by the center of the ellipse and (X4, Y4).

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Use Chord to create a shape that is defined by an arc and a line that joins the endpoints of the arc. The chord consists of a portion of an ellipse that is bounded by the points (X1,Y1) and (X2,Y2). The ellipse is bisected by a line that runs between the points (X3,Y3) and (X4,Y4).

The perimeter of the chord runs counter clockwise from (X3, Y3), counterclockwise along the ellipse to (X4,Y4), and straight back to (X3,Y3). If (X3,Y3) and (X4,Y4) are not on the surface of the ellipse, the corresponding corners on the chord are the closest points on the perimeter that intersect the line. The outline of the chord is drawn using the value of Pen, and the shape is filled using the value of Brush.

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Use Pie to draw a pie-shaped wedge on the image. The wedge is defined by the ellipse bounded by the rectangle determined by the points (X1, Y1) and X2, Y2). The section drawn is determined by two lines radiating from the center of the ellipse through the points (X3, Y3) and (X4, Y4).

The wedge is outlined using Pen, and filled using Brush.