坐标计算程序

Question

我想为窗口制作一个简单的坐标计算程序： 应用

可以通过鼠标左键移动X_Line(红色(和Y_Line(蓝色(并显示坐标。

但是我需要帮助使坐标成为这种情况的一部分和功能。

请帮助我完成您可以?!的程序的任何部分

感谢您的帮助，

Answer 1

处理WM_LBUTTONDOWN并记录鼠标位置，然后发送绘制消息以在该坐标处绘制。

#include <Windows.h>
LRESULT CALLBACK WndProc(HWND hWnd, UINT msg, WPARAM wparam, LPARAM lparam)
{
static int xcoord = -1;
static int ycoord = -1;
switch(msg)
{
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hWnd, &ps);
if(xcoord >= 0 && ycoord >= 0)
{
RECT rc;
GetClientRect(hWnd, &rc);
//draw horizontal line
MoveToEx(hdc, 0, ycoord, NULL);
LineTo(hdc, rc.right, ycoord);
//draw vertical line
MoveToEx(hdc, xcoord, 0, NULL);
LineTo(hdc, xcoord, rc.bottom);
}
EndPaint(hWnd, &ps);
return 0;
}
case WM_LBUTTONDOWN:
{
xcoord = ((int)(short)LOWORD(lparam));
ycoord = ((int)(short)HIWORD(lparam));
InvalidateRect(hWnd, NULL, TRUE);
return 0;
}
case WM_DESTROY:
PostQuitMessage(0);
return 0;
}
return DefWindowProc(hWnd, msg, wparam, lparam);
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE, LPTSTR, int)
{
WNDCLASSEX wcex = { sizeof(WNDCLASSEX) };
wcex.lpfnWndProc = WndProc;
wcex.hInstance = hInstance;
wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
wcex.lpszClassName = TEXT("classname");
RegisterClassEx(&wcex);
CreateWindow(wcex.lpszClassName, NULL, WS_VISIBLE | WS_OVERLAPPEDWINDOW,
0, 0, 600, 400, 0, 0, hInstance, 0);
MSG msg;
while(GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return (int)msg.wParam;
}