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Clip (ArcGIS, QGIS, GRASS, Manifold; Extract Inside in TNTmips): The result includes the portions of polygons of one layer where they intersect the other layer. The outline is the same as the intersection, but the interior only includes the polygons of one layer rather than computing the LCGUs. Non-commutative, non-associative
Clip regions are commonly specified to improve render performance. A well-chosen clip [clarification needed] allows the renderer to save time and energy by skipping calculations related to pixels that the user cannot see. Pixels that will be drawn are said to be within the clip region. Pixels that will not be drawn are outside the clip region.
The difference is that Liang–Barsky is a simplified Cyrus–Beck variation that was optimized for a rectangular clip window. The Cyrus–Beck algorithm is primarily intended for clipping a line in the parametric form against a convex polygon in 2 dimensions or against a convex polyhedron in 3 dimensions. [2]
Given polygon A as the clipping region and polygon B as the subject polygon to be clipped, the algorithm consists of the following steps: List the vertices of the clipping-region polygon A and those of the subject polygon B. Label the listed vertices of subject polygon B as either inside or outside of clipping region A.
Clipping is defined as the interaction of subject and clip polygons. While clipping usually involves finding the intersections (regions of overlap) of subject and clip polygons, clipping algorithms can also be applied with other boolean clipping operations: difference, where the clipping polygons remove overlapping regions from the subject; union, where clipping returns the regions covered by ...
Cyrus–Beck is a general algorithm and can be used with a convex polygon clipping window, unlike Cohen-Sutherland, which can be used only on a rectangular clipping area. Here the parametric equation of a line in the view plane is p ( t ) = t p 1 + ( 1 − t ) p 0 {\displaystyle \mathbf {p} (t)=t\mathbf {p} _{1}+(1-t)\mathbf {p} _{0}} where 0 ...
Note that if the subject polygon was concave at vertices outside the clipping polygon, the new polygon may have coincident (i.e., overlapping) edges – this is acceptable for rendering, but not for other applications such as computing shadows. All steps for clipping concave polygon 'W' with a 5-sided convex polygon
The Greiner-Hormann algorithm is used in computer graphics for polygon clipping. [1] It performs better than the Vatti clipping algorithm, but cannot handle degeneracies. [2] It can process both self-intersecting and non-convex polygons. It can be trivially generalized to compute other Boolean operations on polygons, such as union and difference.