Area Clipping or Polygon Clipping Modify line clipping
- Slides: 13
Area Clipping or Polygon Clipping
• Modify line clipping procedures. • After applying line clipper the polygon is displayed as a series of unconnected line segments.
• For polygon clipping generate algorithm for appropriate area fill
Sutherland Hodgeman Method • Clip the polygon by processing the polygon boundary as a whole against each window. • Process all polygon vertices against each clip rectangle boundary in turn. • First clip the polygon against the left boundary to produce a new sequence of vertices. • The new sequence of vertices is then successive passed to right, bottom and top boundary clipper. • At each step a new sequence of output vertices is generated and passed to the next boundary clipper
Sutherland-Hodgman Polygon Clipping • • Input each edge (vertex pair) successively. Output is a new list of vertices. Each edge goes through 4 clippers. The rule for each edge for each clipper is: – If first input vertex is outside, and second is inside, output the intersection and the second vertex – If both input vertices are inside, then just output second vertex – If first input vertex is inside, and second is outside, output is the intersection – If both vertices are outside, output is nothing. – The last vertex in the list is always added to the first vertex
Sutherland-Hodgeman Polygon Clipping: Four possible scenarios at each clipper outside inside v 2 v 1’ Outside to inside: Output: v 1’ and v 2 outside inside v 2 v 1’ v 1 Inside to inside: Output: v 2 Inside to outside: Output: v 1’ v 1 Outside to outside: Output: nothing
–The last vertex in the list is always added to the first vertex
Sutherland-Hodgeman Polygon Clipping v 2’ v 3 Figure 6 -27, page 332 v 1’ v 3’ Left Clipper v 1 Right Clipper Bottom Clipper v 1 v 2 v 2 v 2’v 3’ v 2 v 3 v 2’v 3’ v 3 v 1 v 3’v 1 v 1 v 2 Edges Output v 2” Top Clipper v 2”v 1’ v 3’v 1 v 1’v 2 v 1’v 2 v 2 v 2’v 2” Output Edges v 2’ v 2” Output Final
Window
• Not applicable polygons where the clipped regions have separate sections. –The last vertex in the list is always added to the first vertex
Text Clipping All or none text clipping All or none character clipping Clipping individual character 2 NG I R ST STRING 1 S 2 G IN TR
- Ppt
- Edge table in computer graphics
- Ayolah
- Polygon and not polygon
- Nicholl-lee-nicholl line clipping
- Cohen sutherland subdivision line clipping algorithm
- Vertical edge
- Line clipping
- Line clipping
- Cohen sutherland line clipping algorithm solved example
- A plain scale of 1 cm=5m and show on it 37m
- How to find the area of a regular polygon
- 10 3 areas of regular polygons
- All polygons are quadrilaterals