Computer graphics windowing: In raster graphics, “scissoring” (clipping to a rectangular window) enables which type of display behavior?
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Aa part of data to be displayed
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Bentire data to be displayed
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Cfull data display on full area of screen
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Dno data to be displayed
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ENone of the above
Answer
Correct Answer: a part of data to be displayed
Explanation
Introduction / Context:Scissoring, often called rectangular clipping, is a fundamental graphics operation. It restricts rendering to a specified window (region) so that primitives outside the window are not drawn. This is used in GUI toolkits, game engines, and visualization pipelines to optimize and control drawing.
Given Data / Assumptions:
- The display area supports a defined clipping rectangle.
- Graphics primitives can extend beyond the visible region.
- We want to know what scissoring enables with respect to what is shown.
Concept / Approach:With scissoring, the pipeline discards fragments (or clamps primitives) lying outside a defined window, ensuring that only content intersecting the window is rendered. This results in partial display of the overall dataset when only a subset falls within the scissor rectangle.
Step-by-Step Solution:
Define a scissor rectangle in screen coordinates.Enable scissoring so that rendering is constrained to that rectangle.Submit geometry; only the intersection with the rectangle is rasterized/displayed.Observe that only part of the overall data appears—namely, what lies inside the window.Verification / Alternative check:In APIs (OpenGL, Direct3D, Vulkan), enabling the scissor test limits fragment processing to the specified rectangle, confirming partial display behavior.
Why Other Options Are Wrong:“Entire data” or “full data on full screen” contradicts the clipping function. “No data” would require an empty window, not normal scissoring.
Common Pitfalls:Confusing scissoring with viewport scaling; the viewport maps coordinates, while scissoring filters pixels to a region.
Final Answer:a part of data to be displayed