Bresenham直線アルゴリズムの実現
6868 ワード
計算方法は簡単ですが、ドナルドHearnとM.Pauline Bakerの神作『コンピュータグラフィックス』では、|m124;だけに与えられました.直接プログラムしました.
#include
#include
/* Declare Windows procedure */
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);
void LineBresenham(HDC hdc, int x0, int y0, int xEnd, int yEnd);
/* Make the class name into a global variable */
char szClassName[ ] = "BresenhamDemo";
int WINAPI WinMain (HINSTANCE hThisInstance,
HINSTANCE hPrevInstance,
LPSTR lpszArgument,
int nCmdShow)
{
HWND hwnd; /* This is the handle for our window */
MSG messages; /* Here messages to the application are saved */
WNDCLASSEX wincl; /* Data structure for the windowclass */
/* The Window structure */
wincl.hInstance = hThisInstance;
wincl.lpszClassName = szClassName;
wincl.lpfnWndProc = WindowProcedure; /* This function is called by windows */
wincl.style = CS_DBLCLKS; /* Catch double-clicks */
wincl.cbSize = sizeof (WNDCLASSEX);
/* Use default icon and mouse-pointer */
wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
wincl.lpszMenuName = NULL; /* No menu */
wincl.cbClsExtra = 0; /* No extra bytes after the window class */
wincl.cbWndExtra = 0; /* structure or the window instance */
/* Use Windows's default colour as the background of the window */
wincl.hbrBackground = (HBRUSH) GetStockObject(WHITE_BRUSH);
/* Register the window class, and if it fails quit the program */
if (!RegisterClassEx (&wincl))
return 0;
/* The class is registered, let's create the program*/
hwnd = CreateWindowEx (
0, /* Extended possibilites for variation */
szClassName, /* Classname */
"BresenhamDemo", /* Title Text */
WS_OVERLAPPEDWINDOW, /* default window */
CW_USEDEFAULT, /* Windows decides the position */
CW_USEDEFAULT, /* where the window ends up on the screen */
544, /* The programs width */
375, /* and height in pixels */
HWND_DESKTOP, /* The window is a child-window to desktop */
NULL, /* No menu */
hThisInstance, /* Program Instance handler */
NULL /* No Window Creation data */
);
/* Make the window visible on the screen */
ShowWindow (hwnd, nCmdShow);
/* Run the message loop. It will run until GetMessage() returns 0 */
while (GetMessage (&messages, NULL, 0, 0))
{
/* Translate virtual-key messages into character messages */
TranslateMessage(&messages);
/* Send message to WindowProcedure */
DispatchMessage(&messages);
}
/* The program return-value is 0 - The value that PostQuitMessage() gave */
return messages.wParam;
}
/* This function is called by the Windows function DispatchMessage() */
LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
static POINT ptBeg, ptEnd;
HDC hdc;
PAINTSTRUCT ps;
switch (message) /* handle the messages */
{
case WM_LBUTTONDOWN:
ptBeg.x = LOWORD (lParam);
ptBeg.y = HIWORD (lParam);
ptEnd = ptBeg;
InvalidateRect (hwnd, NULL, TRUE);
break;
case WM_MOUSEMOVE:
if (wParam & MK_LBUTTON)
{
hdc = GetDC (hwnd);
SelectObject (hdc, GetStockObject(BLACK_PEN));
SetROP2 (hdc, R2_NOTXORPEN);
LineBresenham (hdc, ptBeg.x, ptBeg.y, ptEnd.x, ptEnd.y);
ptEnd.x = LOWORD (lParam);
ptEnd.y = HIWORD (lParam);
LineBresenham (hdc, ptBeg.x, ptBeg.y, ptEnd.x, ptEnd.y);
ReleaseDC (hwnd, hdc);
}
break;
case WM_LBUTTONUP:
InvalidateRect (hwnd, NULL, TRUE);
break;
case WM_PAINT:
hdc=BeginPaint (hwnd, &ps);
LineBresenham (hdc, ptBeg.x, ptBeg.y, ptEnd.x, ptEnd.y);
EndPaint (hwnd, &ps);
break;
case WM_DESTROY:
PostQuitMessage (0); /* send a WM_QUIT to the message queue */
break;
default: /* for messages that we don't deal with */
return DefWindowProc (hwnd, message, wParam, lParam);
}
return 0;
}
/*Bresenham , 0xEnd)
{
x=xEnd;
y=yEnd;
xEnd=x0;
}
else
{
x=x0;
y=y0;
}
SetPixel(hdc, x, y, 0);
while(x0?(y++):(y--);
p+=twoDyMinusDx;
}
SetPixel(hdc, x, y, 0);
}
}
/* Bresenham ，|m|>1*/
void Bresenham2(HDC hdc , int x0, int y0, int xEnd, int yEnd)
{
int delta=(xEnd-x0)*(yEnd-y0);
int dx=fabs(x0-xEnd), dy=fabs(y0-yEnd);
int p=2*dx-dy;
int twoDx=2*dx, twoDxMinusDy=2*dx-2*dy;
int x, y;
if(y0>yEnd)
{
y=yEnd;
x=xEnd;
yEnd=y0;
}
else
{
y=y0;
x=x0;
}
SetPixel(hdc, x, y, 0);
while(y0?(x++):(x--);
p+=twoDxMinusDy;
}
SetPixel(hdc, x, y, 0);
}
}
/*Bresenham */
void LineBresenham(HDC hdc, int x0, int y0, int xEnd, int yEnd)
{
int dx=fabs(xEnd-x0), dy=fabs(yEnd-y0);
int x, y;
if(x0==xEnd)
{
y=(y0>yEnd?yEnd:y0);
SetPixel(hdc, x0, y, 0);
while(yxEnd?xEnd:x0);
SetPixel(hdc, x, y0, 0);
while(xdy)
{
Bresenham1(hdc, x0, y0, xEnd, yEnd);
}
else if(dxxEnd)
{
x=xEnd;
y=yEnd;
xEnd=x0;
}
else
{
x=x0;
y=y0;
}
SetPixel(hdc, x, y, 0);
while(x