C++ 中的两种颜色线性渐变 .ppm 文件

Question

我正在 C++ 中创建一个函数，该函数根据用户输入的颜色和尺寸创建一个双色渐变 .ppm 文件。我遇到的主要问题是颜色的循环，它似乎重新开始进入图像的方式，如此处所示。

当它看起来像图像的左侧但尺寸相同时。这是我用来获取图像的代码。

#include <iomanip>
#include <iostream>
#include <fstream>
#include <string>

using namespace std;

struct Color
{
    int red;
    int green;
    int blue;
};

void smoosh(int rows, int cols, Color leftColor, Color rightColor, string  filename);
int main()
{
    int y;
    int x;
    Color l;
    Color r;
    string f;
    cout << "Left Color: ";
    cin >> l.red >> l.green >> l.blue;
    cout << "\nRight Color: ";
    cin >> r.red >> r.green >> r.blue;
    cout << "\nHeight: ";
    cin >> y;
    cout << "\nWidth: ";
    cin >> x;
    cout << "\nFile Name: ";
    cin >> f;
    smoosh(y, x, l, r, f);


    return 0;
}
void smoosh(int rows, int cols, Color leftColor, Color rightColor, string   filename)
{
    int maxI = 256;
    ofstream fout;
    fout.open(filename);
    fout << "P3\n";
    fout << cols << " " << rows << "\n" << maxI - 1 << "\n";
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            fout << (leftColor.red + ((j / 255.0) * (rightColor.red - leftColor.red))) << " ";
            fout << (leftColor.green + ((j / 255.0) * (rightColor.green - leftColor.green))) << " ";
            fout << (leftColor.blue + ((j / 255.0) * (rightColor.blue - leftColor.blue)))<< " ";
        }
        fout << endl;
    }
    fout.close();
}

上图的用户输入值为 左侧颜色：255 0 0 正确颜色：255 255 0 身高：200 宽度：400，提前感谢您的帮助。

Answer 1

我认为应该是这样的

current.red = leftcolor.red;

in the loop:

    current.red += (rightcolor.red - leftcolor.red)/cols

    fout << current.red

    ...