# Computer Graphics Questions & Answers – Curve, Text and Exterior Clipping – 1

This set of Computer Graphics Multiple Choice Questions & Answers (MCQs) focuses on “Curve, Text and Exterior Clipping – 1”.

1. Which of the following can be first used to test for overlap of a curve with the clipping window?
a) Edges of the curve
b) The centre of the curve
c) The bounding rectangle for the curve
d) Tangents to the curve

Explanation: The bounding rectangle for the curve can be used to test for overlap of the curve with the clipping window. We can use the regular polygon clipping on the basis of the condition that is fulfilled if the bounding rectangle for the curve comes inside the viewing window or not.

2. Which of the following step is taken if the bounding rectangle for the curve is completely inside the viewing window?
b) Full curve is saved
c) The bounding rectangle cannot be fully inside the viewing window
d) A clipping operation is performed on the curve

Explanation: If the bounding rectangle for the curve is completely inside the viewing window then we save the full curve as the full curve would also be inside the viewing window and there is no need to perform a clipping operation.

3. Which of the following step is taken if the bounding rectangle for the curve is completely outside the viewing window?
b) Full curve is saved
c) The bounding rectangle cannot be fully inside the viewing window
d) A clipping operation is performed on the curve

Explanation: If the bounding rectangle for the curve is completely outside the viewing window then we discard the full curve as the full curve would also be outside the viewing window and there is no need to perform a clipping operation.

4. Which of the following condition is fulfilled if a circle is completely outside the viewing window?
a) Xc + R = XLEFT
b) Xc + R > XLEFT
c) Xc + XLEFT < R
d) Xc + R < XLEFT

Explanation: The condition that is fulfilled if a circle is completely outside the viewing window is Xc + R < XLEFT. Where, Xc denotes the position of circles centre on the x axis, R is the radius of circle and Xleft is the position of the left most edge of the viewing window on x axis.

5. Which of the following set of conditions is fulfilled if a circle is completely outside the viewing window?
a) Yc – R < Ytop
Yc + R > Ybottom
b) Yc – R > Ytop
Yc + R < Ybottom
c) Yc – R < Ytop
Yc + R < Ybottom
d) Yc – R > Ytop
Yc + R > Ybottom

Explanation: The set of conditions that is fulfilled if a circle is completely outside the viewing window is –
Yc – R > Ytop : This condition is fulfilled if a circle is completely outside and above the viewing window.
Yc + R < Ybottom : This condition is fulfilled if a circle is completely outside and below the viewing window.
Here, Yc is the position of centre of circle on y axis. R is the radius of the circle. Ytop and Ybottom is the position of the top and bottom edge of the viewing window on the y axis respectively,

6. Which of the following is used to adjust the shape of Bezier curve?
a) Control points
b) End points
c) Knots
d) Convex Hull

Explanation: The control points are used to adjust the shape of a Bezier curve. A Bezier curve is always determined by its control points which are denoted by P0 to Pn, where n is the degree of curve which tells the shape of the curve. The first and last control points of a Bezier curve are its endpoints.

7. Which of the following curve is formed with polynomial sections satisfying specified continuity conditions?
a) Bezier Curve
b) Spline Curve
c) Both Bezier and Spline Curves
d) Neither Bezier nor Spline Curve

Explanation: A Spline Curve is formed with polynomial sections satisfying continuity conditions at the boundary of the pieces. We specify a spline curve by giving a set of control points which indicates the general shape of the curve.

8. A hull is a line that connects the control points of a curve.
a) True
b) False

Explanation: A hull is a line that connects all the control points of a curve. The shape of the curve is always inside the shape of the hull. In geometry, the convex hull or convex envelope of a shape is the smallest convex set that contains it.

9. Which of the following clipping process handles the clipping of strings?
a) Curve Clipping
b) Shape Clipping
c) Exterior Clipping
d) Text Clipping

Explanation: The process that handles the clipping of strings is Text Clipping. It is the process that decides which part of the string is to be kept based on their position in the view window. There are different types of Text Clippings like all or none character clipping, all or none string clipping etc.

10. In which of the following text clipping method do we only include the strings that are entirely inside the view window?
a) All or none string clipping
b) All or none character clipping
c) Text clipping
d) We don’t consider the strings that are inside the view window

Explanation: The text clipping method that only include the strings that are entirely inside the view window is all or none string clipping. In this method if the whole string is inside the view window then only the string is saved otherwise it is discarded.

Sanfoundry Global Education & Learning Series – Computer Graphics.

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