What is polygon clipping algorithm?
Sutherland Hodgeman polygon clipping algorithm is used for polygon clipping. In this algorithm, all the vertices of the polygon are clipped against each edge of the clipping window. First the polygon is clipped against the left edge of the polygon window to get new vertices of the polygon.
What is polygon clipping and its types?
Polygon clipping is defined by Liang and. Barsky (1983) as the process of removing those parts of a polygon that lie outside a. clipping window. A polygon clipping algorithm receives a polygon and a clipping window. as input.
What are the various types of polygon clipping in computer graphics?
Four Cases of polygon clipping against one edge
- Case 1 : Wholly inside visible region – save endpoint.
- Case 2 : Exit visible region – save the intersection.
- Case 3 : Wholly outside visible region – save nothing.
- Case 4 : Enter visible region – save intersection and endpoint.
What are the four rules for polygon clipping?
The first of all polygons are stored in original form. Then clipping against left edge done and output is stored. Then clipping against right edge done, then top edge. Finally, the bottom edge is clipped.
What are different types of clipping?
Types of Clipping:
- Point Clipping.
- Line Clipping.
- Area Clipping (Polygon)
- Curve Clipping.
- Text Clipping.
- Exterior Clipping.
How many cases are there in polygon clipping?
The polygon clipping algorithm deals with four different clipping cases. The output of each case is input for the next case.
Which clipping algorithm is used for polygon clipping?
Sutherland–Hodgman algorithm
The Sutherland–Hodgman algorithm is an algorithm used for clipping polygons. It works by extending each line of the convex clip polygon in turn and selecting only vertices from the subject polygon that are on the visible side.
What is properties of polygon?
When working with polygons the main properties which are important are:
- The number of sides of the shape.
- The angles between the sides of the shape.
- The length of the sides of the shape.
What are the rules for polygons?
A polygon is a flat, two-dimensional (2D) shape with straight sides that is fully closed (all the sides are joined up). The sides must be straight. Polygons may have any number of sides. A shape with curved sides is not a polygon.
What is Cohen Sutherland line clipping algorithm?
The Cohen–Sutherland algorithm is a computer-graphics algorithm used for line clipping. The algorithm divides a two-dimensional space into 9 regions and then efficiently determines the lines and portions of lines that are visible in the central region of interest (the viewport).
What are polygon clipping algorithms in computer graphics?
So there are Polygon Clipping Algorithms in Computer Graphics along with the Line Clipping Algorithms. We process vertices of polygon against each Window boundary one by one. So it goes like that. We will process these vertices in a sequence either clockwise or anticlockwise.
How to display concave polygon in a clipping window?
When the clipped polygons have two or more separate sections, then it is the concave polygon handled by this algorithm. The vertex-processing procedures for window boundaries are modified so that concave polygon is displayed. Let the clipping window be initially called clip polygon and the polygon to be clipped the subject polygon.
How to clip a polygon in AutoCAD?
Let the clipping window be initially called clip polygon and the polygon to be clipped the subject polygon. We start with an arbitrary vertex of the subject polygon and trace around its border in the clockwise direction until an intersection with the clip polygon is encountered:
How to convert clip polygon to subject polygon?
If the edge leaves the clip polygon, record the intersection point and make a right turn to follow the clip polygon in the same manner (i.e., treat the clip polygon as subject polygon and the subject polygon as clip polygon and proceed as before).