使用 GDI C++ 制作正方形动画

Question

我想制作一些正方形的动画。在这个例子中，我创建了两个正方形。当我构建并运行时，我可以看到那 2 个方块，但它们并没有移动。

我创建了一个代表正方形的类

#pragma once
#include <windows.h>

class Square {


private:
     int x,y;

     int moveWith_x, moveWith_y;

public:
    void DrawSquare(HDC,int,int,int,int);
    void MoveSquare(int,int);

    Square(void);
    ~Square(void);
};

和实现文件（这里我使用 DrawSquare 中的 Rectangle 函数创建正方形）并尝试在 MoveSquares 中为运动设置动画：

    #include "Square.h"

    void Square::DrawSquare(HDC hdc,int rx,int ry, int lx, int ly) {

        Rectangle(hdc,rx,ry,lx,ly); 
    }

void Square::MoveSquare(int mod_x_Size,int mod_y_Size) {

        x=x+ moveWith_x;
        y=y+ moveWith_y;

            if ( x >= mod_x_Size - 30)  {

                 x= mod_x_Size - 30 ;
                 moveWith_x =  -moveWith_x++;
            }


            if ( y >= mod_y_Size -30) {
                  y=mod_y_Size - 30 ;
                 moveWith_y= -moveWith_y++;
            }

            if ( x < 30) {

             x=30;
             moveWith_x= -moveWith_x++;
            }

            if ( y <30) {

                 y=50;
                 moveWith_y= -moveWith_x++; 
            }
    }

 Square::Square(void) {
        x=0;
        y=0;

        moveWith_x = 0;
        moveWith_y = 0; 
    }

    Square::~Square(void) {

    }

在我的 main.cpp 中，我设置了一个计时器，创建并绘制给定数量的 od 正方形（用白色画笔）

#include <windows.h>
#include <windowsx.h>

#include "Square.h"

#define NUMARUL_DE_FIGURI  2


LRESULT CALLBACK WndProc (HWND,UINT,WPARAM,LPARAM);
void moveObject(int,int);

    //Coordonatele in caz de redimensionare a ferestrei
    static int mod_x_Size, mod_y_Size;

    // Crearea ferestrei de lucru
HWND hwnd;

int WINAPI WinMain (HINSTANCE hInt, HINSTANCE,LPSTR,int) {

char atitle[] = "Drawing with GDI";
char className[] = "Main Window";

MSG msg;

// Crearea si initializarea ferestrei principale
WNDCLASS wnd;
ZeroMemory(&wnd,sizeof(wnd));

wnd.lpfnWndProc = WndProc;
wnd.hInstance = hInt;
wnd.hIcon = LoadIcon (NULL,IDI_APPLICATION);
wnd.hCursor = LoadCursor (NULL,IDC_ARROW);
wnd.hbrBackground = GetStockBrush (BLACK_BRUSH);
wnd.lpszClassName = className;

// Inregistrarea clasei in SO
RegisterClass (&wnd);


    // Crearea unui timer
 SetTimer (hwnd, 1, 40, NULL) ;

hwnd = CreateWindow (className,atitle,WS_OVERLAPPEDWINDOW,200,200,600,600,HWND_DESKTOP,NULL,hInt,NULL);

//Afisarea ferestrei in mod obisnuit
ShowWindow (hwnd,SW_SHOWNORMAL);

// Daca aplicatia primeste mesaj de la SO are loc transmiterea p-u prelucrare
while (GetMessage(&msg,NULL,0,0)) DispatchMessage(&msg);

     return 0;
}

// Prelucrarea mesajelor
LRESULT CALLBACK WndProc (HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam) {

    // Structura ce detine informatii despre dispozitivul de desenare
    PAINTSTRUCT ps;

    // Descriptorul dispozitivului de desen
    HDC hdc;

    Square square[NUMARUL_DE_FIGURI];

    // Culoarea figurii
    HBRUSH shapeColor;

    switch (msg) {

// Prelucrarea mesajelor primite la modificarea dimensiunilor ferestrei
case WM_SIZE :      

        //La fiecare redimensionare a ferestrei se reinnoiesc coordonatele speciale 
        mod_x_Size = LOWORD (lparam) ;
        mod_y_Size = HIWORD (lparam) ;
        break ;

// Prelucrarea mesajelor primite la fiecare interval al timerului
case WM_TIMER:

    InvalidateRect (hwnd, NULL, TRUE) ;

for (int i=0;i<NUMARUL_DE_FIGURI;i++) {

    square[i].MoveSquare( mod_x_Size, mod_y_Size);

}



// Prelucrarea mesajului de desenare 
case WM_PAINT: 

    // Permite desenarea pe dispozitivul de desenare
    hdc = BeginPaint(hwnd, &ps);

    // Crearea patratelor
   for (int i=0;i<NUMARUL_DE_FIGURI;i++) {

        shapeColor = (HBRUSH)SelectObject(hdc, CreateSolidBrush(RGB(255,255,255)));

        square[i].DrawSquare(hdc,mod_x_Size-((i*200)+50),mod_y_Size-((i*200)+50),mod_x_Size-((i*20)+100),mod_y_Size-((i*20)+100)); 
    }

  // 
    //ReleaseDC(hwnd,hdc);

   // Finiseaza procesul de desenare pe dispozitiv
    EndPaint(hwnd, &ps);

    break;

// Distrugerea ferestrei aplicatiei
case WM_DESTROY:
        PostQuitMessage(0);
        break;

    default:
        return DefWindowProc(hwnd, msg, wparam, lparam);
    }

    return 0;
}

我哪里错了？ 如果您希望我更具体地解决问题，请原谅我的代码 cmets（这是我的语言）。

Answer 1

// Crearea unui timer
SetTimer (hwnd, 1, 40, NULL) ;

hwnd = CreateWindow (className,atitle,WS_OVERLAPPEDWINDOW,200,200,600,600,HWND_DESKTOP,NULL,hInt,NULL);

在将窗口句柄分配给hwnd之前调用SetTimer，它应该在CreateWindow之后调用。

此外，只要调整主窗口的大小，您的代码就会将它们调整为客户区的大小。 不确定您是否打算这样做。

Answer 2

// Prelucrarea mesajelor primite la fiecare interval al timerului
case WM_TIMER:
    InvalidateRect (hwnd, NULL, TRUE);
    for (int i=0;i<NUMARUL_DE_FIGURI;i++) {
        square[i].MoveSquare(mod_x_Size, mod_y_Size);
    }

这似乎是错误的，这将在每次收到计时器消息时执行 for -loop，并且 结果的位置每次都是i==NUMARUL_DE_FIGURI。

您需要将int i 设为（类成员？）状态变量，然后

case WM_TIMER:
    if (i<0) i =0;
    if (i<NUMARUL_DE_FIGURI)
    {
        square[i].MoveSquare(mod_x_Size, mod_y_Size);
        InvalidateRect (hwnd, NULL, TRUE);        
    }
    i++;