使用Java计算屏幕的PPI的方法详解

public class PPICalculator {

    /**
     * 计算屏幕的PPI（每英寸像素数）
     *
     * @param screenWidth  屏幕宽度（像素）
     * @param screenHeight 屏幕高度（像素）
     * @param screenInch   屏幕对角线长度（英寸）
     * @return PPI值（整数）
     */
    public static int calculatePPI(int screenWidth, int screenHeight, double screenInch) {
        // 计算对角线像素数
        double diagonalPixels = Math.sqrt(Math.pow(screenWidth, 2) + Math.pow(screenHeight, 2));

        // 计算PPI
        double ppi = diagonalPixels / screenInch;

        // 取整并返回
        return (int) ppi;
    }

    public static void main(String[] args) {
        // 示例数据：屏幕宽度720像素，高度1280像素，对角线长度5.0英寸
        int screenWidth = 720;
        int screenHeight = 1280;
        double screenInch = 5.0;

        // 计算PPI
        int ppi = calculatePPI(screenWidth, screenHeight, screenInch);

        // 输出结果
        System.out.println("屏幕宽度（像素）: " + screenWidth);
        System.out.println("屏幕高度（像素）: " + screenHeight);
        System.out.println("屏幕对角线长度（英寸）: " + screenInch);
        System.out.println("PPI: " + ppi);
    }
}

屏幕宽度（像素）: 720
屏幕高度（像素）: 1280
屏幕对角线长度（英寸）: 5.0
PPI: 293

public static double calculatePPI(int screenWidth, int screenHeight, double screenInch) {
    double diagonalPixels = Math.sqrt(Math.pow(screenWidth, 2) + Math.pow(screenHeight, 2));
    return diagonalPixels / screenInch;
}

import java.util.Scanner;

public class PPICalculator {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        // 获取用户输入
        System.out.print("请输入屏幕宽度（像素）: ");
        int screenWidth = scanner.nextInt();

        System.out.print("请输入屏幕高度（像素）: ");
        int screenHeight = scanner.nextInt();

        System.out.print("请输入屏幕对角线长度（英寸）: ");
        double screenInch = scanner.nextDouble();

        // 计算PPI
        int ppi = calculatePPI(screenWidth, screenHeight, screenInch);

        // 输出结果
        System.out.println("PPI: " + ppi);
    }
}

public static void comparePPI(int[] widths, int[] heights, double[] inches) {
    for (int i = 0; i < widths.length; i++) {
        int ppi = calculatePPI(widths[i], heights[i], inches[i]);
        System.out.println("设备 " + (i + 1) + " 的PPI: " + ppi);
    }
}