03-DDA画线算法

参考1：https://www.bilibili.com/video/BV1cd4y1U7TC/?spm_id_from=333.999.0.0&vd_source=5b4cd3f84aab3b0261aa6b6791252d89参考2：https://blog.csdn.net/u013378269/article/details/103555482

CMakelist + Win32 API  图形学算法：03-DDA画线算法

#ifndef UNICODE
#define UNICODE
#endif 
#include <math.h>
#include <Windows.h>
#include <stdio.h>
#include <wchar.h>
#include <WinBase.h>
#define PI 3.1415926         // PI 
#define ROUND(d) int(d+0.5)  // 四舍五入// 点
class CP2
{
public:CP2():_x(0),_y(0) {}CP2(double x, double y):_x(x),_y(y) {}   virtual ~CP2() {};
public:double _x;double _y;
};// DDA 算法
void DDALine(HDC hdc, CP2 p1, CP2 p2)
{int dx = p2._x - p1._x;int dy = p2._y - p1._y;int steps;     // 步数int direction; // 方向 0--x方向  1--y方向double xIncrement, yIncrement; // 每一步增加的数值 斜率double x = p1._x, y = p1._y;if (abs(dx)>abs(dy)) {steps = abs(dx);direction = 0; // 确认X步进主方向}else{steps = abs(dy);direction = 1; // 确认y步进主方向, }xIncrement = double(dx) / double(steps);  // x 每步骤增量yIncrement = double(dy) / double(steps);  // y 的每步增量for (size_t k = 0; k <= steps; k++){if (direction==0){SetPixel(hdc, int(x), ROUND(y), 0x00FF0000);}else{SetPixel(hdc, ROUND(x), int(y),  0x00FF0000);}x += xIncrement; // x点+增量y += yIncrement; // y点+增量}  }LRESULT CALLBACK WindowProc( HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{PAINTSTRUCT ps;HDC hdc;RECT rc;switch (uMsg){case WM_DESTROY:PostQuitMessage(0);return 0;case WM_PAINT:{hdc = BeginPaint(hwnd, &ps);GetClientRect(hwnd, &rc);SetMapMode(hdc, MM_ANISOTROPIC);SetWindowExtEx(hdc, rc.right, rc.bottom, NULL);SetViewportExtEx(hdc, rc.right, -rc.bottom, NULL);SetViewportOrgEx(hdc, rc.right / 2, rc.bottom / 2, NULL);int r = 200;// 1. 绘制一条直线DDALine(hdc, CP2(-300, 150), CP2(-300, -150));// 2. 直线角间隔 5°for (size_t i = 0; i < 360; i+=5){double angle = i * PI / 180.0;DDALine(hdc, CP2(0, 0), CP2(ROUND(cos(angle) * r), ROUND(sin(angle) * r)));}EndPaint(hwnd, &ps);}return 0;}return DefWindowProc(hwnd, uMsg, wParam, lParam);
}int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PWSTR pCmdLine, int nCmdShow)
{// Register the window class.const wchar_t CLASS_NAME[] = L"03-DDA画线算法";WNDCLASS wc = { };wc.style = CS_HREDRAW | CS_VREDRAW; // 重新绘制整个工作区wc.lpfnWndProc = WindowProc;wc.hInstance = hInstance;wc.lpszClassName = CLASS_NAME;wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);wc.hCursor = LoadCursor(NULL, IDC_ARROW);RegisterClass(&wc);HWND hwnd = CreateWindowEx(0,                              // Optional window styles.CLASS_NAME,                     // Window classL"03-DDA画线算法",               // Window textWS_OVERLAPPEDWINDOW,            // Window style// Size and positionCW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,NULL,       // Parent window    NULL,       // MenuhInstance,  // Instance handleNULL        // Additional application data);if (hwnd == NULL){return 0;}ShowWindow(hwnd, nCmdShow);MSG msg = { };while (GetMessage(&msg, NULL, 0, 0) > 0){TranslateMessage(&msg);DispatchMessage(&msg);}return 0;
}