Line Clipping Against Non-Rectangular Clip Windows
Clipping lines against non-rectangular clip windows involves ensuring that only the visible portions of the line are displayed within the specified region. Here's a step-by-step guide:
Step 1: Define the Non-Rectangular Clip Window
Identify the vertices of the clip window and define it in terms of its boundary.
Step 2: Determine Line Segments
Split the line into segments, each between consecutive vertices of the line.
Step 3: Clip Each Segment
For each line segment, determine if it lies completely inside, completely outside, or partially inside the clip window.
Step 4: Apply Clipping Algorithms
Use algorithms like Cohen-Sutherland or Cyrus-Beck to clip the line segments against the clip window.
Step 5: Draw Clipped Segments
Draw the resulting clipped line segments within the clip window.
Example:
Consider a clip window defined by vertices A(100, 100), B(200, 100), C(200, 200), and D(100, 200). We want to clip a line segment with endpoints P(150, 50) and Q(150, 250) against this clip window.
After applying the Cohen-Sutherland algorithm, we find that the clipped line segment lies between points P'(150, 100) and Q'(150, 200). These points are then drawn on the screen.