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Transcript of 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in...
![Page 1: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/1.jpg)
2-DimensionViewing and Clipping
Chapter 6
Except Text and Curve clipping
Some of the material in these slides may have been adapted from University of Virginia, MIT, and Åbo Akademi University
![Page 2: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/2.jpg)
2
Viewing Pipeline
● World Co-ordinates■ (x,y) values of all points in a single reference frame
● Window: ■ It is the area of the world that was selected to be viewed
● Viewport■ It is the area on the display device on which the window is mapped
● View Transformation■ It is the process of mapping part of a scene in the world co-ordinate
to an area on the display device
● Windows and viewports are usually rectangular● In general, they can be anything (circular, oval, hexagona)
![Page 3: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/3.jpg)
3
Viewing Pipeline
Construct scene in world coordinate using primitives and modeling
Convert world coordinate To viewing coordinates
Map viewing coordinates toNormalized Viewing coordinates
Map Normalized View portTo device coordinates
Viewing coordinatesusually defined within unit squareSeparates transformationsfrom device specifics
![Page 4: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/4.jpg)
4
Clipping Window and Viewport
![Page 5: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/5.jpg)
5
Normalized Viewport
![Page 6: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/6.jpg)
6
Screen Viewport
![Page 7: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/7.jpg)
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![Page 8: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/8.jpg)
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Why Viewing Pipeline
● Need to use any primitives, techniques, and models to construct scenes
● Need to construct scenes in standard coordinates
● Need to view from any angle and zoom
● Need to be able to display on any display device
![Page 9: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/9.jpg)
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Clipping
● We’ve been assuming that all primitives lie entirely within the viewport
● In general, this assumption does not hold
![Page 10: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/10.jpg)
10
Clipping
● What is clipping?■ Analytically calculating the portions of primitives within the viewport
● Primitives can be anything: point, line, polygon, circle, curves,…., etc.
![Page 11: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/11.jpg)
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Why Clip?
● Computer graphics benefits from being able to reduce the amount of work needed to draw objects.
● Objects will be inside the specified region but not visible and therefore skipped
● Bad idea to rasterize outside of framebuffer bounds
● Also, don’t waste time scan converting pixels outside window
![Page 12: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/12.jpg)
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Point Clipping
● Trivial
xmin x xmax
yminy ymax
● Required when scene is constructed from points (e.g. Explosion, sea foam,…, etc.)
● Not common (we usually do lines, polygons, curves,..,etc)
![Page 13: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/13.jpg)
13
Line Clipping
● Typical cases
● First, lets attempt to do a simple pre-processing■ Quickly determine complete acceptance or complete rejection
![Page 14: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/14.jpg)
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Trivial Accepts
● Big optimization: trivial accept/rejects● How can we quickly determine whether a line
segment is entirely inside the viewport?● A: test both endpoints.
xmin xmax
ymax
ymin
A
B
C
D
E
FF
G
H
![Page 15: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/15.jpg)
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Trivial Accepts
● If both endpoints are within the view port■ Completely accept
xmin xmax
ymax
ymin
A
B
C
D
E
FF
G
H
![Page 16: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/16.jpg)
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Trivial Rejects
● How can we know a line is entirely outside viewport?● R: if both endpoints on wrong side of same edge, can
trivially reject line
xmin xmax
ymax
ymin
A
B
C
D
E
FF
G
H
![Page 17: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/17.jpg)
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Simple Line Clipping
● All other lines have end points (x1,y1) (x2,y2) such that one or both endpoints are outside the clipping boundaries
● Need to determine intersection points with boundaries● Represent the line in parametric form
x = x1 + t*(x2 - x1)
y = y1 + t*(y2 - y1) t
● Compute intersection points with the four boundaries xmin, xmax, ymin ,ymax (how can we do that quickly?)
● How can we quickly determine whether a line segment intersects a clipping boundary?
![Page 18: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/18.jpg)
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Simple Line Clipping
● If only one endpoint is inside ■ Display the segment from the boundary Intersection to the
inside endpoint
● If both endpoints are outside ■ Display the segment between the two intersections
● Disadvantages■ Computationally intensive■ More efficient approaches exist
![Page 19: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/19.jpg)
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Cohen-Sutherland Line Clipping
● Divide viewplane into regions defined by viewport edges
● Assign each region a 4-bit outcode:
0000 00100001
1001
0101 0100
1000 1010
0110
xmin xmax
ymax
ymin
![Page 20: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/20.jpg)
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Cohen-Sutherland Line Clipping
● We generate this 4-bit classification using#define LEFT_EDGE 0x1 // 0001#define RIGHT_EDGE 0x2 // 0010#define BOTTOM_EDGE 0x4 // 0100#define TOP_EDGE 0x8 // 1000
● For each point (x,y) we calculateunsigned char code = 0x0if ( x < xmin ) code = code | LEFT_EDGEif ( x > xmax ) code = code | RIGHT_EDGEif ( y < ymin ) code = code | BOTTOM_EDGEif ( y > ymax ) code = code | TOP_EDGE
● At the end, we have assigned a code for every endpoint
![Page 21: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/21.jpg)
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Cohen-Sutherland Line Clipping
● Trivial accept ■ Accept if both endpoints are inside■ How can we do that efficiently?
● Trivial reject■ Reject if both endpoints are on the wrong side of an edge■ How can we do that efficiently?■ How can we determine which wrong side?
![Page 22: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/22.jpg)
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Cohen-Sutherland Line Clipping
● Trivial accept ■ Accept if both endpoints are inside■ How can we do that efficiently?
● Trivial reject■ Reject of both endpoints are on the wrong side of an edge■ How can we do that efficiently■ How can we determine which wrong side?
Use bitwise AND between the codes of the endpoints
![Page 23: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/23.jpg)
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Cohen-Sutherland Line Clipping Example
xmin
xmax
ymax
ymin
A
B
C
D
E
FF
G
H
0000 00100001
1001
0101 0100
1000 1010
0110
![Page 24: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/24.jpg)
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Cohen-Sutherland Line Clipping Algorithm
● Given a line segment with endpoint p1(x1,y1) and p2(x2,y2)
● Compute the 4-bit codes for each endpoint. ● If both codes are 0000,(bitwise OR of the codes
yields 0000 ) line lies completely inside the window: pass the endpoints to the draw routine.
● If both codes have a 1 in the same bit position (bitwise AND of the codes is not 0000), the line lies outside the window. It can be trivially rejected.
![Page 25: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/25.jpg)
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Cohen-Sutherland Line Clipping Algorithm
● Lines that cannot be trivially accepted or rejected have one or both endpoints outside
● Examine one of the endpoints, say P1=(x1,y1). Read P1's 4-bit code in order: Left-to-Right, Bottom-to-Top.
● When a set bit (1) is found, compute the intersection I of the corresponding window edge with the line from P1 to P2. Replace P1 with I and repeat the algorithm.
● Discard portion on wrong side of edge and assign outcode to new vertex
● Apply trivial accept/reject tests; ● Repeat if necessary until the entire line is finished● Proceed to the next line
![Page 26: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/26.jpg)
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Cohen-Sutherland Line Clipping Example
xmin
xmax
ymax
ymin
G
H
0000 00100001
1001
0101 0100
1000 1010
0110
I
J
A
B
C
D
E
● Pick J Clip JI Pick G Clip GH● Pick E Clip ED Pick A Clip AB Pick B Clip BC
![Page 27: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/27.jpg)
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Cohen-Sutherland Line Clipping
● We have accepted/discarded lines inside/outside the window
● We have chosen the subsection of the line which is inside the window
● Algorithm can be modified for 3D● Still not efficient enough
■ Need to compute up to 4 intersections per line
● Fundamentally more efficient algorithms:■ Liang-Barsky uses parametric lines■ Nicholl-Lee-Nicholl
![Page 28: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/28.jpg)
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Polygon Clipping
● Convex and Concave● Splitting Concave Polygon● Sutherland-Hodgman Clipping
![Page 29: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/29.jpg)
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Convex and Concave
● Definition: A closed shape (not necessarily a polygon) is said to be convex if the straight line between two internal points lies completely inside the shape`
![Page 30: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/30.jpg)
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Splitting Concave Polygon
● Detecting concavity: ■ Calculate cross products of consecutive polygon edges ■ If there is at least one change of sign in z-component,
then the polygon is concave■ How to detect concavity on a continuous curve?
![Page 31: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/31.jpg)
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Splitting Concave Polygon
● Some polygon clipping algorithm assume convex polygon
● Concave polygons can be decomposed into convex polygons.
● There are Several solutions!■ Vector Method■ Rational Method■ Both method work non-intersecting polygons only
![Page 32: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/32.jpg)
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Splitting Concave PolygonVector Method
● Walk around the polygon in counter-clockwise direction● Cross product every consecutive edges
● When the sign of (En x En+1) changes, split along En
● Calculate new edge and the new polygon
![Page 33: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/33.jpg)
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Splitting Concave PolygonRational Method
● Walk the polygon counter-clockwise● For each two consecutive edges E1, E2 consisting of V1, V2, V3● Translate V1 to origin● Rotate clockwise such that V1,V2 is on the x-axis● If line is below X-axis (I.e. y3 < 0)
■ Polygon is concave■ Split along x-axis
![Page 34: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/34.jpg)
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Clipping Polygons
● Clipping polygons is more complex than clipping the individual lines
■ Input: polygon■ Output: polygon, or nothing
● Simply applying line clipping would not work !!● We do not want broken lines. We want a polygon
![Page 35: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/35.jpg)
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● Many possible outcomes:
triangletriangle
Why Is Polygon Clipping Hard?
trianglequad triangle5-gon
triangle6-gon triangle7-gon
![Page 36: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/36.jpg)
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● A really tough case:
Why Is Polygon Clipping Hard?
![Page 37: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/37.jpg)
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● A really tough case:
Why Is Polygon Clipping Hard?
concave polygonmultiple polygons
![Page 38: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/38.jpg)
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Why Is Polygon Clipping Hard?
● Not easy to trivially reject● Even if most of lines can be trivially rejected, we may
still need to display a polygon
![Page 39: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/39.jpg)
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Sutherland-Hodgman ClippingBasic Idea
● Initial Input: Polygon = {ordered list of vertices}● Process only against one clipping boundary at a time!● Clip each line in the polygon against each clip boundary
in turn: left, right, bottom, top.● Basic steps
■ Input: Polygon = {ordered list of vertices}■ After finishing each boundary, the output vertex list is generated■ The output vertex list is the new polygon input to the next
boundary■ Final output list of vertices is the clipped polygon
![Page 40: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/40.jpg)
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Sutherland-Hodgman ClippingRules to generate the Vertex list
● Apply the following rules for every pair of vertices■ If the first vertex is outside and the second is inside, then move the first
vertex to the clipping boundary and accept both vertices.○ Calculate intersection point with the boundary○ Replace the first vertex with the intersection point○ Put the new first vertex and the second vertex in the output list
■ If both vertices are inside, put the second vertex in the output list.■ If the first vertex is inside and the second is outside, then move the
second to the clipping boundary and accept the second.○ Calculate intersection point with the boundary○ Replace the second vertex with the intersection point○ Put the new second vertex in the output list
■ If both vertices are outside, reject both.
● How to determine wither a point is inside or outside a given boundary?
![Page 41: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/41.jpg)
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Sutherland-Hodgman ClippingHow to determine Inside and Outside
● Lets say a line endpoint has the co-rdinates (x,y)
● Inside Xmin means x > Xmin
● Inside Xmax means x < Xmax
● Inside Ymin means y > Ymin
● Inside Ymax means y < Ymax
![Page 42: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/42.jpg)
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Sutherland-Hodgman ClippingIllustration
outinSave V’1, V2
inin
Save V2
inout
Save V’1
outout
Save non
![Page 43: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/43.jpg)
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Sutherland-Hodgman ClippingExample
V1
V2
V3
![Page 44: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/44.jpg)
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Sutherland-Hodgman ClippingExample
V1
V2
V3
V’1
V’2
● V2V3V2’, V3● V3V1V1● V1V2V1’
● Final List:● V2’,V3,V1,V1’
![Page 45: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/45.jpg)
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Sutherland-Hodgman ClippingExample
V1
V3
V’1
V’2
● V2’V3V3● V3V1V3’● V1V1’● V1’V2’V2’’V2’
● Final List:● V3,V3’,V2’’,V2’ V’3
V’’2
![Page 46: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/46.jpg)
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Sutherland-Hodgman ClippingExample
V1
V3
V’1
V’2
● V2’V3V3● V3V1V3’● V1V1’● V1’V2’V2’’V2’
● Final List:● V3,V3’,V2’’,V2’
V’3V’’2
![Page 47: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/47.jpg)
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Sutherland-Hodgman ClippingAnother Example
![Page 48: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/48.jpg)
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Sutherland-Hodgman Clipping Another Example
![Page 49: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/49.jpg)
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Sutherland-Hodgman Clipping Another Example
![Page 50: 2-Dimension Viewing and Clipping Chapter 6 Except Text and Curve clipping Some of the material in these slides may have been adapted from University of.](https://reader035.fdocuments.in/reader035/viewer/2022062407/56649e175503460f94b03142/html5/thumbnails/50.jpg)
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Sutherland-Hodgman Clipping
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Sutherland-Hodgman Clipping
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Sutherland-Hodgman Clipping
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Sutherland-Hodgman Clipping
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Sutherland-Hodgman Clipping
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● Convex polygons correctly processed● Concave polygons may produce extraneous lines
■ We only have one lisone list■ Last point is always joined to first ■ We need two vertex lists because the polygon is divided into two
polygons
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