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feat: add bresenham's line drawing algorithm (#5779)
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69
src/main/java/com/thealgorithms/geometry/BresenhamLine.java
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69
src/main/java/com/thealgorithms/geometry/BresenhamLine.java
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package com.thealgorithms.geometry;
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import java.awt.Point;
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import java.util.ArrayList;
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import java.util.List;
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/**
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* The {@code BresenhamLine} class implements the Bresenham's line algorithm,
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* which is an efficient way to determine the points of a straight line
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* between two given points in a 2D space.
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*
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* <p>This algorithm uses integer arithmetic to calculate the points,
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* making it suitable for rasterization in computer graphics.</p>
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*
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* For more information, please visit {@link https://en.wikipedia.org/wiki/Bresenham%27s_line_algorithm}
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*/
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public final class BresenhamLine {
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private BresenhamLine() {
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// Private constructor to prevent instantiation.
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}
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/**
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* Finds the list of points that form a straight line between two endpoints.
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*
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* @param x0 the x-coordinate of the starting point
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* @param y0 the y-coordinate of the starting point
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* @param x1 the x-coordinate of the ending point
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* @param y1 the y-coordinate of the ending point
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* @return a {@code List<Point>} containing all points on the line
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*/
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public static List<Point> findLine(int x0, int y0, int x1, int y1) {
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List<Point> line = new ArrayList<>();
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// Calculate differences and steps for each axis
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int dx = Math.abs(x1 - x0); // Change in x
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int dy = Math.abs(y1 - y0); // Change in y
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int sx = (x0 < x1) ? 1 : -1; // Step in x direction
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int sy = (y0 < y1) ? 1 : -1; // Step in y direction
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int err = dx - dy; // Initial error term
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// Loop until we reach the endpoint
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while (true) {
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line.add(new Point(x0, y0)); // Add current point to the line
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// Check if we've reached the endpoint
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if (x0 == x1 && y0 == y1) {
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break; // Exit loop if endpoint is reached
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}
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// Calculate error term doubled for decision making
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final int e2 = err * 2;
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// Adjust x coordinate if necessary
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if (e2 > -dy) {
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err -= dy; // Update error term
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x0 += sx; // Move to next point in x direction
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}
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// Adjust y coordinate if necessary
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if (e2 < dx) {
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err += dx; // Update error term
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y0 += sy; // Move to next point in y direction
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}
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}
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return line; // Return the list of points forming the line
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}
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}
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