API的!!!!一个我想了一个星期都不知道怎么解决的问题!!!!!!!!!!!!!!!!!!!!!!!!!!!请高手们帮忙看下,或者帮我顶一下...谢谢。

Question

/* Demonstrate the basic graphics functions. */
#include <windows.h>
#include <math.h>static int line_wide=1;
static float r=0.0;
int round(float x)
{
int y;
if(x-int(x)>=0.5)
{ y=int(x)+1;
return y;
}
else{
y=int(x);
return y;
}
}void SetPixel(HDC hdc,int x0,int y0,int color,int flag)
{
switch(flag)
{
int i,j;
case 1:SetPixel(hdc,x0,y0,color);break;
case 3:for (i=-1;i<=1;i++)
{
for (j=-1;j<=1;j++)
{
SetPixel(hdc,x0+i,y0+j,color);
}
}
break;
case 5:for (i=-2;i<=2;i++)
   {
   for (j=-2;j<=2;j++)
   {
   SetPixel(hdc,x0+i,y0+j,color);
   }
   }
   break;
}
}
void circlePlotPoints(HDC hdc,int xc,int yc,int x,int y)
{
SetPixel(hdc,xc+x,yc+y,RGB(0,0,255));
SetPixel(hdc,xc-x,yc+y,RGB(0,0,255));
SetPixel(hdc,xc+x,yc-y,RGB(0,0,255));
SetPixel(hdc,xc-x,yc-y,RGB(0,0,255));
SetPixel(hdc,xc+y,yc+x,RGB(0,0,255));
SetPixel(hdc,xc-y,yc+x,RGB(0,0,255));
SetPixel(hdc,xc+y,yc-x,RGB(0,0,255));
SetPixel(hdc,xc-y,yc-x,RGB(0,0,255));
}
//void circleMidpoint(HDC hdc,int xc,int yc,int r)
void circleMidpoint(HDC hdc,int xc,int yc,int xp,int yp)
{
 
 r=sqrt((float)((xc-xp)*(xc-xp)+(yc-yp)*(yc-yp)));
float x=0.0;
float y=r;
float d=1-r;
circlePlotPoints(hdc,xc,yc,x,y);
while(x<y)
{
x++;
if(d<0)
d+=2*x+1;
else
{
y--;
d+=2*(x-y)+1;
}
circlePlotPoints(hdc,xc,yc,x,y);
}
}
void linedda(HDC hdc,int x1,int y1,int x2,int y2)
{
float increx,increy,x,y,length;
int i;
if(abs(x2-x1)>abs(y2-y1))
length=abs(x2-x1);
else
length=abs(y2-y1);
increx=(x2-x1)/length;
increy=(y2-y1)/length;
x=x1;
y=y1;
for(i=1;i<=length;i++)
{
SetPixel(hdc,round(x),round(y),RGB(255,0,0),line_wide);
x=x+increx;
y=y+increy;
}
}
int nwidth=1;void MidPointLine(HDC hdc,int x0, int y0,int x1, int y1)
{
int a,b,delta1,delta2,d,x,y,dx,dy,i,s1,s2,width,count;//
width=nwidth/2;
a=y0-y1;
b=x1-x0; x=x0;
y=y0;
SetPixel(hdc,x,y,RGB(0,255,0),line_wide);
dx=abs(b);
dy=abs(a);
if(b>0)
s1=1;
else
s1=-1;
if(a<0)
s2=1;
else
s2=-1;
if(s1<0)
a=-a;
if(s2<0)
b=-b; if(dy<=dx)
{
d=a+a+b;
delta1=a+a;
delta2=delta1+b+b;
if(s1==s2)
{
for(i=0;i<dx;i++)
{
if(d<0)
{
x+=s1;
y+=s2;
d+=delta2;
}
else
{
x+=s1;
d+=delta1;
}
for(count=0;count<=width;count++)
{
SetPixel(hdc,x,y+count,RGB(0,255,0),line_wide);
SetPixel(hdc,x,y-count,RGB(0,255,0),line_wide);
}
}
}
else
{
for(i=0;i<dx;i++)
{
if(d>=0)
{
x+=s1;
y+=s2;
d+=delta2;
}
else
{
x+=s1;
d+=delta1;
}
for(count=0;count<=width;count++)
{
SetPixel(hdc,x,y+count,RGB(0,255,0),line_wide);
SetPixel(hdc,x,y-count,RGB(0,255,0),line_wide);
}
}
}
}
else
{
d=a+b+b;
delta1=b+b;
delta2=delta1+a+a;
if(s1==s2)
{
for(i=0;i<dy;i++)
{
if(d>0)
{
x+=s1;
y+=s2;
d+=delta2;
}
else
{
y+=s2;
d+=delta1;
}
for(count=0;count<=width;count++)
{
SetPixel(hdc,x+count,y,RGB(0,255,0),line_wide);
SetPixel(hdc,x-count,y,RGB(0,255,0),line_wide);
}
}

Answer 1

}
else
{
for(i=0;i<dy;i++)
{
if(d<0)
{
x+=s1;
y+=s2;
d+=delta2;
}
else
{
y+=s2;
d+=delta1;
}
for(count=0;count<=width;count++)
{
SetPixel(hdc,x+count,y,RGB(0,255,0),line_wide);
SetPixel(hdc,x-count,y,RGB(0,255,0),line_wide);
}
}
}
}
}
/*void MidPointLine(HDC hdc,int x1,int y1,int x2,int y2)
{
int dx,dy,n,k,i,f;
int x,y;
dx=abs(x2-x1);
dy=abs(y2-y1);
n=dx+dy;
if(x2>x1){k=y2>=y1?1:4;x=x1;y=y1;}
else {k=y2>=y1?2:3;x=x1;y=y1;}
SetPixel(hdc,x,y,RGB(0,255,0),line_wide);
for(i=0,f=0;i<n;i++)
if(f>=0)
switch(k){
case 1:SetPixel(hdc,x++,y,RGB(0,255,0),line_wide);f-=dy;break;
case 2:SetPixel(hdc,x,y++,RGB(0,255,0),line_wide);f-=dx;break;
case 3:SetPixel(hdc,x--,y,RGB(0,255,0),line_wide);f-=dy;break;
case 4:SetPixel(hdc,x,y--,RGB(0,255,0),line_wide);f-=dx;break;
}
else
switch(k){
case 1:SetPixel(hdc,x,y++,RGB(0,255,0),line_wide);f+=dx;break;
case 2:SetPixel(hdc,x--,y,RGB(0,255,0),line_wide);f+=dy;break;
case 3:SetPixel(hdc,x,y--,RGB(0,255,0),line_wide);f+=dx;break;
case 4:SetPixel(hdc,x++,y,RGB(0,255,0),line_wide);f+=dy;break;
}
}*/
#include "graph.h"
#include "MappingMode.h"
static int flag=1;LRESULT CALLBACK WindowFunc(HWND, UINT, WPARAM, LPARAM);char szWinName[] = "MyWin"; /* name of window class */char str[255]; /* holds output strings */int maxX,maxY; /* screen dimensions */
int orgX=0,orgY=0; /* viewport orgin */HDC hmemdc; /* store the virtual device handle */
HBITMAP hbit; /* store the virtual bitmap */
HBRUSH hbrush; /* store the brush handle */
HGDIOBJ hOldBit,hOldbrush;HDC hdc;
/* create pens */
HPEN hOldpen; /* handle of old pen */
//HPEN hWhitePen;
HWND hwnd;HDC hmemdc2;
HBITMAP hbit2,hOldBit2;
int xP,yP,xS,yS;
int WINAPI WinMain(HINSTANCE hThisInst, HINSTANCE hPrevInst, LPSTR lpszArgs,int nWinMode)
{
MSG msg;
WNDCLASSEX wcl;
HACCEL hAccel; /* Define a window class. */
wcl.cbSize = sizeof(WNDCLASSEX);
wcl.hInstance = hThisInst; /* handle to this instance */
wcl.lpszClassName = szWinName; /* window class name */
wcl.lpfnWndProc = WindowFunc; /* window function */
wcl.style = 0; /* default style */ wcl.hIcon = LoadIcon(NULL,IDI_APPLICATION); /* standard icon */
wcl.hIconSm = LoadIcon(NULL,IDI_WINLOGO); /* SMALL ICON */
wcl.hCursor = LoadCursor(NULL,IDC_ARROW); /* cursor style */ /* Specify name of menu resource. This will be overridden. */
wcl.lpszMenuName = "MYMENU"; /* main menu */
wcl.cbClsExtra = 0; /* no extra information needed */
wcl.cbWndExtra = 0; /* no extra information needed */

/* Make the windows backgraoud white */
wcl.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH); /* Register the window class. */
if(!RegisterClassEx(&wcl))
return 0; /* Now that a window class has been registered, a window can be created. */
hwnd = CreateWindow(
szWinName, /* name of window class */
"Changing Mapping Modes", /* title */
WS_VISIBLE|WS_CAPTION|WS_BORDER|WS_MINIMIZEBOX|WS_SYSMENU, /* window style - normal */
CW_USEDEFAULT, /* X coordinate - let Winodws decide */
CW_USEDEFAULT, /* Y coordinate - let Windows decide */
CW_USEDEFAULT, /* width - let Windows decide */
CW_USEDEFAULT, /* height - let Windows decide */
HWND_DESKTOP, /* no parent window */
NULL,  /*  no menu */
hThisInst, /* handle of this instance of the program */
NULL /* no additional arguments */
); /* Load accelerators. */
hAccel = LoadAccelerators(hThisInst,"MyMenu"); /* Display the windows. */
ShowWindow(hwnd, nWinMode);
UpdateWindow(hwnd); /* Createthe message loop. */
while(GetMessage(&msg, NULL, 0,0 )) {
if(!TranslateAccelerator(hwnd,hAccel,&msg)) {
TranslateMessage(&msg); /* translate keyboard messages */
DispatchMessage(&msg); /* return control to Windows 98 */
}
}
return msg.wParam;
}

Answer 2

/* This function is called by Windows 98 and is passed 
messages from the message gueue.
*/
LRESULT CALLBACK WindowFunc(HWND hwnd, UINT message,WPARAM wParam, LPARAM lParam)
{
PAINTSTRUCT ps;
RECT *pr;
int response;
static StartDraw = 0;
int nTop,nLeft,nRight,nBottom,nPositionF,nPositionS;
switch(message) {
case WM_CREATE: { /*load the bitmap */

/* get screen coordinates */
maxX = GetSystemMetrics(SM_CXSCREEN);
maxY = GetSystemMetrics(SM_CYSCREEN); /* make a compatible memory image */
hdc = GetDC(hwnd);
hmemdc = CreateCompatibleDC(hdc);

hbit = CreateCompatibleBitmap(hdc,maxX,maxY);
hOldBit = SelectObject(hmemdc,hbit);
hbrush = (HBRUSH)GetStockObject(WHITE_BRUSH);
hOldbrush = SelectObject(hmemdc,hbrush);
PatBlt(hmemdc,0,0,maxX,maxY,PATCOPY);//非常重要，要么屏幕会黑
// hWhitePen = (HPEN) GetStockObject(WHITE_PEN);//利用双缓冲区
hmemdc2 = CreateCompatibleDC(hdc);
hbit2 = CreateCompatibleBitmap(hdc,maxX,maxY);
hOldBit2 = (HBITMAP)SelectObject(hmemdc2,hbit2);


PatBlt(hmemdc2,0,0,maxX,maxY,PATCOPY);//非常重要，要么屏幕会黑
/* save default pen */
// hOldpen = (HPEN)SelectObject(memdc,hRedpen);
// SelelctObject(memdc,hOldpen);
ReleaseDC(hwnd,hdc);
break;
}
case WM_COMMAND:
switch(LOWORD(wParam)) {
case IDM_LINES1:
flag=1;
break;
case IDM_LINES2:
flag=2;
break;
case IDM_CIRCLE:
flag=3;
break; 
/* increment size by 10 each time */
// case IDM_SIZE:
case IDM_RESET:
MoveToEx(hmemdc,0,0,NULL);
MoveToEx(hmemdc2,0,0,NULL);
PatBlt(hmemdc,0,0,maxX,maxY,PATCOPY);
PatBlt(hmemdc2,0,0,maxX,maxY,PATCOPY);
InvalidateRect(hwnd,NULL,1);
break;
// case IDM_ELLIPSES: { // break;
// }
}
break;
case WM_MOUSEMOVE:

if(flag==3){
if (!StartDraw) 
break;
nLeft=xS-r;
nTop=yS-r;
nRight=xS+r;
nBottom=yS+r;

BitBlt(hmemdc,nLeft,nTop,nRight-nLeft+1,nBottom-nTop+1,hmemdc2,nLeft,nTop,SRCCOPY);
}
else
{

if (!StartDraw) 
break;
if ( xS<=xP ) {
nLeft = xS;
nRight = xP;
} else {
nLeft = xP;
nRight = xS;
}
if ( yS<=yP ) {
nTop = yS;
nBottom = yP;
} else {
nTop = yP;
nBottom = yS;
}
BitBlt(hmemdc,nLeft,nTop,nRight -nLeft+1,nBottom-nTop+1,hmemdc2,nLeft,nTop,SRCCOPY);
}


xP = LOWORD(lParam);  // horizontal position of cursor 
yP = HIWORD(lParam);  // vertical position of cursor 
if(flag==3){
nLeft=xS-r;
nTop=yS-r;
nRight=xS+r;
nBottom=yS+r;
BitBlt(hmemdc2,nLeft,nTop,nRight-nLeft+1,nBottom-nTop+1,hmemdc,nLeft,nTop,SRCCOPY);
}
else
{

if ( xS<=xP ) {
nLeft = xS;
nRight = xP;
} else {
nLeft = xP;
nRight = xS;
}
if ( yS<=yP ) {
nTop = yS;
nBottom = yP;
} else {
nTop = yP;
nBottom = yS;
}
BitBlt(hmemdc2,nLeft,nTop,nRight-nLeft+1,nBottom-nTop+1,hmemdc,nLeft,nTop,SRCCOPY);
}
switch(flag){ case 1:
linedda(hmemdc,xS,yS,xP,yP);
break;
case 2:
MidPointLine(hmemdc,xS,yS,xP,yP);
break;
case 3:
//MidPointLine(hmemdc,xS,yS,xP,yP);
circleMidpoint(hmemdc,xS,yS,xP,yP);
break; }


InvalidateRect(hwnd,NULL,0); break;

case WM_LBUTTONDOWN:
xP = xS = LOWORD(lParam);  // horizontal position of cursor 
yP = yS = HIWORD(lParam);  // vertical position of cursor 
StartDraw = 1;
break;
case WM_LBUTTONUP:
StartDraw = 0;
if(flag==3)
{
r=0;
}
break;
case IDM_EXIT:
response = MessageBox(hwnd,"Quit the Program?","Ext",MB_YESNO);
if(response == IDYES)
PostQuitMessage(0);
break;
case WM_PAINT:
hdc = BeginPaint(hwnd,&ps); /* get DC */
// pr = &ps.rcPaint; /* set mapping mode, window and viewport extents */
SetMapMode(hdc,MM_ANISOTROPIC);
SetWindowExtEx(hdc,100,100,NULL);
SetViewportExtEx(hdc,100,100,NULL);
SetViewportOrgEx(hdc,orgX,orgY,NULL); /* now,copy memory image onto screen */
//BitBlt(hdc,pr->left,pr->top,pr->right-pr->left,pr->bottom-pr->top,hmemdc,pr->left,pr->top,SRCCOPY);
BitBlt(hdc,0,0,maxX,maxY,hmemdc,0,0,SRCCOPY);
EndPaint(hwnd,&ps); /* release DC */
break;
case WM_DESTROY: /* terminate the program */ SelectObject(hmemdc,hOldbrush);
DeleteObject(hbrush);
// DeleteObject(hWhitePen);
SelectObject(hmemdc,hOldBit);
DeleteObject(hbit);
DeleteDC(hmemdc); SelectObject(hmemdc2,hOldBit2);
DeleteDC(hmemdc2);
DeleteObject(hbit2); PostQuitMessage(0);
break;
default:
/* Let Windows 98 process any messages not specified in the preceding switch statement. */
return DefWindowProc(hwnd,message,wParam,lParam);
}
return 0;
}用双缓冲画圆有问题,有什么办法解决吗,用我的思路来解决.............
谢谢各位..................

Answer 3

程序在下面链接:
http://fyr000000.ys168.com/
密码：000000 
名字:复件 DrawLine2.rar

Answer 4

各位大虾,不好意思,我又改过一点,
程序在下面链接:
http://fyr000000.ys168.com/
密码：000000 
名字:02122898(原始版).rar老问题还是有,现在又出现了新问题,为什么线加粗,就会出现奇异情况,错在哪里????实在看不懂啊。

Answer 5

我改后的MappingMode.cpp文件，覆盖到文件夹下，思路等一下再写#include <windows.h>
#include <math.h>static int line_wide=1;
static int line_shape=1;
static float r=0.0;
int round(float x)
{
int y;
if(x-int(x)>=0.5)
{ y=int(x)+1;
return y;
}
else{
y=int(x);
return y;
}
}
void SetPixel(HDC hdc,int x0,int y0,int color,int flag)
{
switch(flag)
{
int i,j;
case 1:SetPixel(hdc,x0,y0,color);break;
case 3:for (i=-1;i<=1;i++)
{
for (j=-1;j<=1;j++)
{
SetPixel(hdc,x0+i,y0+j,color);
}
}
break;
case 5:for (i=-2;i<=2;i++)
   {
   for (j=-2;j<=2;j++)
   {
   SetPixel(hdc,x0+i,y0+j,color);
   }
   }
   break;
}
}void SetPixel(HDC hdc,int x0,int y0,int color,int flag,int n)
{
static int i=1;
if(i%n==0)
{
SetPixel(hdc,x0,y0,color,flag);
}
i++;
}
void circlePlotPoints(HDC hdc,int xc,int yc,int x,int y)
{
SetPixel(hdc,xc+x,yc+y,RGB(0,0,255),line_wide,line_shape);
SetPixel(hdc,xc-x,yc+y,RGB(0,0,255),line_wide,line_shape);
SetPixel(hdc,xc+x,yc-y,RGB(0,0,255),line_wide,line_shape);
SetPixel(hdc,xc-x,yc-y,RGB(0,0,255),line_wide,line_shape);
SetPixel(hdc,xc+y,yc+x,RGB(0,0,255),line_wide,line_shape);
SetPixel(hdc,xc-y,yc+x,RGB(0,0,255),line_wide,line_shape);
SetPixel(hdc,xc+y,yc-x,RGB(0,0,255),line_wide,line_shape);
SetPixel(hdc,xc-y,yc-x,RGB(0,0,255),line_wide,line_shape);
}
//void circleMidpoint(HDC hdc,int xc,int yc,int r)
void circleMidpoint(HDC hdc,int xc,int yc,int xp,int yp)
{
 
 r=sqrt((float)((xc-xp)*(xc-xp)+(yc-yp)*(yc-yp)));
float x=0.0;
float y=r;
float d=1-r;
circlePlotPoints(hdc,xc,yc,x,y);
while(x<y)
{
x++;
if(d<0)
d+=2*x+1;
else
{
y--;
d+=2*(x-y)+1;
}
circlePlotPoints(hdc,xc,yc,x,y);
}
}
void linedda(HDC hdc,int x1,int y1,int x2,int y2)
{
float increx,increy,x,y,length;
int i;
if(abs(x2-x1)>abs(y2-y1))
length=abs(x2-x1);
else
length=abs(y2-y1);
increx=(x2-x1)/length;
increy=(y2-y1)/length;
x=x1;
y=y1;
for(i=1;i<=length;i++)
{
SetPixel(hdc,round(x),round(y),RGB(255,0,0),line_wide,line_shape);
x=x+increx;
y=y+increy;
}
}
int nwidth=1;void MidPointLine(HDC hdc,int x0, int y0,int x1, int y1)
{
int a,b,delta1,delta2,d,x,y,dx,dy,i,s1,s2,width,count;//
width=nwidth/2;
a=y0-y1;
b=x1-x0; x=x0;
y=y0;
SetPixel(hdc,x,y,RGB(0,255,0),line_wide,line_shape);
dx=abs(b);
dy=abs(a);
if(b>0)
s1=1;
else
s1=-1;
if(a<0)
s2=1;
else
s2=-1;
if(s1<0)
a=-a;
if(s2<0)
b=-b; if(dy<=dx)
{
d=a+a+b;
delta1=a+a;
delta2=delta1+b+b;
if(s1==s2)
{
for(i=0;i<dx;i++)
{
if(d<0)
{
x+=s1;
y+=s2;
d+=delta2;
}
else
{
x+=s1;
d+=delta1;
}
for(count=0;count<=width;count++)
{
SetPixel(hdc,x,y+count,RGB(0,255,0),line_wide,line_shape);
SetPixel(hdc,x,y-count,RGB(0,255,0),line_wide,line_shape);
}
}
}
else
{
for(i=0;i<dx;i++)
{
if(d>=0)
{
x+=s1;
y+=s2;
d+=delta2;
}
else
{
x+=s1;
d+=delta1;
}
for(count=0;count<=width;count++)
{
SetPixel(hdc,x,y+count,RGB(0,255,0),line_wide,line_shape);
SetPixel(hdc,x,y-count,RGB(0,255,0),line_wide,line_shape);
}
}
}
}
else
{
d=a+b+b;
delta1=b+b;
delta2=delta1+a+a;
if(s1==s2)
{
for(i=0;i<dy;i++)
{
if(d>0)
{
x+=s1;
y+=s2;
d+=delta2;
}
else
{
y+=s2;
d+=delta1;
}
for(count=0;count<=width;count++)
{
SetPixel(hdc,x+count,y,RGB(0,255,0),line_wide,line_shape);
SetPixel(hdc,x-count,y,RGB(0,255,0),line_wide,line_shape);
}
}
}
else
{
for(i=0;i<dy;i++)
{
if(d<0)
{
x+=s1;
y+=s2;
d+=delta2;
}
else
{
y+=s2;
d+=delta1;
}
for(count=0;count<=width;count++)
{
SetPixel(hdc,x+count,y,RGB(0,255,0),line_wide,line_shape);
SetPixel(hdc,x-count,y,RGB(0,255,0),line_wide,line_shape);
}
}
}
}
}
/*void MidPointLine(HDC hdc,int x1,int y1,int x2,int y2)
{
int dx,dy,n,k,i,f;
int x,y;
dx=abs(x2-x1);
dy=abs(y2-y1);
n=dx+dy;
if(x2>x1){k=y2>=y1?1:4;x=x1;y=y1;}
else {k=y2>=y1?2:3;x=x1;y=y1;}
SetPixel(hdc,x,y,RGB(0,255,0),line_wide);
for(i=0,f=0;i<n;i++)
if(f>=0)
switch(k){
case 1:SetPixel(hdc,x++,y,RGB(0,255,0),line_wide);f-=dy;break;
case 2:SetPixel(hdc,x,y++,RGB(0,255,0),line_wide);f-=dx;break;
case 3:SetPixel(hdc,x--,y,RGB(0,255,0),line_wide);f-=dy;break;
case 4:SetPixel(hdc,x,y--,RGB(0,255,0),line_wide);f-=dx;break;
}
else
switch(k){
case 1:SetPixel(hdc,x,y++,RGB(0,255,0),line_wide);f+=dx;break;
case 2:SetPixel(hdc,x--,y,RGB(0,255,0),line_wide);f+=dy;break;
case 3:SetPixel(hdc,x,y--,RGB(0,255,0),line_wide);f+=dx;break;
case 4:SetPixel(hdc,x++,y,RGB(0,255,0),line_wide);f+=dy;break;
}
}*/
#include "graph.h"
#include "MappingMode.h"
static int flag=1;LRESULT CALLBACK WindowFunc(HWND, UINT, WPARAM, LPARAM);char szWinName[] = "MyWin"; /* name of window class */char str[255]; /* holds output strings */int maxX,maxY; /* screen dimensions */
int orgX=0,orgY=0; /* viewport orgin */HDC hmemdc; /* store the virtual device handle */
HBITMAP hbit; /* store the virtual bitmap */
HBRUSH hbrush; /* store the brush handle */
HGDIOBJ hOldBit,hOldbrush;HDC hdc;
/* create pens */
HPEN hOldpen; /* handle of old pen */
//HPEN hWhitePen;
HWND hwnd;HDC hmemdc2;
HDC hmemdc3;HBITMAP hbit2,hOldBit2;
int xP,yP,xS,yS;
int WINAPI WinMain(HINSTANCE hThisInst, HINSTANCE hPrevInst, LPSTR lpszArgs,int nWinMode)
{
MSG msg;
WNDCLASSEX wcl;
HACCEL hAccel; /* Define a window class. */
wcl.cbSize = sizeof(WNDCLASSEX);
wcl.hInstance = hThisInst; /* handle to this instance */
wcl.lpszClassName = szWinName; /* window class name */
wcl.lpfnWndProc = WindowFunc; /* window function */
wcl.style = 0; /* default style */ wcl.hIcon = LoadIcon(NULL,IDI_APPLICATION); /* standard icon */
wcl.hIconSm = LoadIcon(NULL,IDI_WINLOGO); /* SMALL ICON */
wcl.hCursor = LoadCursor(NULL,IDC_ARROW); /* cursor style */ /* Specify name of menu resource. This will be overridden. */
wcl.lpszMenuName = "MYMENU"; /* main menu */
wcl.cbClsExtra = 0; /* no extra information needed */
wcl.cbWndExtra = 0; /* no extra information needed */

/* Make the windows backgraoud white */
wcl.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH); /* Register the window class. */
if(!RegisterClassEx(&wcl))
return 0; /* Now that a window class has been registered, a window can be created. */
hwnd = CreateWindow(
szWinName, /* name of window class */
"Changing Mapping Modes", /* title */
WS_VISIBLE|WS_CAPTION|WS_BORDER|WS_MINIMIZEBOX|WS_SYSMENU, /* window style - normal */
CW_USEDEFAULT, /* X coordinate - let Winodws decide */
CW_USEDEFAULT, /* Y coordinate - let Windows decide */
CW_USEDEFAULT, /* width - let Windows decide */
CW_USEDEFAULT, /* height - let Windows decide */
HWND_DESKTOP, /* no parent window */
NULL,  /*  no menu */
hThisInst, /* handle of this instance of the program */
NULL /* no additional arguments */
); /* Load accelerators. */
hAccel = LoadAccelerators(hThisInst,"MyMenu"); /* Display the windows. */
ShowWindow(hwnd, nWinMode);
UpdateWindow(hwnd);

Answer 6

/* Createthe message loop. */
while(GetMessage(&msg, NULL, 0,0 )) {
if(!TranslateAccelerator(hwnd,hAccel,&msg)) {
TranslateMessage(&msg); /* translate keyboard messages */
DispatchMessage(&msg); /* return control to Windows 98 */
}
}
return msg.wParam;
}
/* This function is called by Windows 98 and is passed 
messages from the message gueue.
*/
LRESULT CALLBACK WindowFunc(HWND hwnd, UINT message,WPARAM wParam, LPARAM lParam)
{
PAINTSTRUCT ps;
RECT *pr;
int response;
static StartDraw = 0;
int nTop,nLeft,nRight,nBottom,nPositionF,nPositionS;
switch(message) {
// case WM_HELP: /* user pressed F1 or used ? button */
//
// WinHelp((HWND)((LPHELPINFO) lParam) -> hItemHandle,
// "ABC.hlp",HELP_WM_HELP,
// (DWORD)IDM_HELP);
// return 1;
// case IDM_HELPTHIS:
// WinHelp(hwnd,"helptest.hlp",HELP_CONTEXTPOPUP,
// (DWORD)IDH_MENUABOUT);
// break;
// case IDM_EXIT:
// WinHelp(hwnd,"helptest.hlp",HELP_CONTEXTPOPUP,
// (DWORD)IDH_MENUEXIT);
// break;
// default:
/* menu bar selected,but no option heghighted */
// WinHelp(hwnd,"helptest.hlp",HELP_CONTEXTPOPUP,(DWORD)IDH_MENUMAIN);
// }
// }
// else
/* standard help for main window */
// WinHelp(hwnd,"helptest.hlp",HELP_KEY,(DWORD)"Main Window");
/// break;
// case WM_CONTEXTMENU: /* user right - clicked mouse */
/* context help about main window */
// WinHelp(hwnd,"helptest.hlp",HELP_CONTEXTPOPUP,IDH_MAIN);
// break; case WM_CREATE: { /*load the bitmap */

/* get screen coordinates */
maxX = GetSystemMetrics(SM_CXSCREEN);
maxY = GetSystemMetrics(SM_CYSCREEN); /* make a compatible memory image */
hdc = GetDC(hwnd);
hmemdc = CreateCompatibleDC(hdc);

hbit = CreateCompatibleBitmap(hdc,maxX,maxY);
hOldBit = SelectObject(hmemdc,hbit);
hbrush = (HBRUSH)GetStockObject(WHITE_BRUSH);
hOldbrush = SelectObject(hmemdc,hbrush);
PatBlt(hmemdc,0,0,maxX,maxY,PATCOPY);//非常重要，要么屏幕会黑
// hWhitePen = (HPEN) GetStockObject(WHITE_PEN);//利用双缓冲区
hmemdc2 = CreateCompatibleDC(hdc);
// hmemdc3 = CreateCompatibleDC(hdc);
hbit2 = CreateCompatibleBitmap(hdc,maxX,maxY);
hOldBit2 = (HBITMAP)SelectObject(hmemdc2,hbit2);


PatBlt(hmemdc2,0,0,maxX,maxY,PATCOPY);//非常重要，要么屏幕会黑
/* save default pen */
// hOldpen = (HPEN)SelectObject(memdc,hRedpen);
// SelelctObject(memdc,hOldpen);
ReleaseDC(hwnd,hdc);
break;
}
case WM_COMMAND: switch(LOWORD(wParam)) {
case IDM_HELP:
WinHelp(hwnd,"abc.hlp",HELP_FINDER,0);
break;
case ID_1:
line_wide=1;
break;
case ID_2:
line_wide=3;
break;
case ID_3:
line_wide=5;
break;
case ID_4:
line_shape=1;
break;
case ID_5:
line_shape=18;
break;
case ID_6:
line_shape=35;
break;
case IDM_LINES1:
flag=1;
break;
case IDM_LINES2:
flag=2;
break;
case IDM_CIRCLE:
flag=3;
break; 

/* increment size by 10 each time */
// case IDM_SIZE:
case IDM_RESET:
MoveToEx(hmemdc,0,0,NULL);
MoveToEx(hmemdc2,0,0,NULL);
PatBlt(hmemdc,0,0,maxX,maxY,PATCOPY);
PatBlt(hmemdc2,0,0,maxX,maxY,PATCOPY);
InvalidateRect(hwnd,NULL,1);
break;
case IDM_EXIT:
response = MessageBox(hwnd,"Quit the Program?","Exit",MB_YESNO);
if(response == IDYES)
PostQuitMessage(0);
break;
// case IDM_ELLIPSES: { // break;
// }
}
break;
case WM_MOUSEMOVE:

if(flag==3)
{
if (!StartDraw) 
break;
nLeft=xS-r;
nTop=yS-r;
nRight=xS+r;
nBottom=yS+r;

//BitBlt(hmemdc,nLeft,nTop,nRight-nLeft+1,nBottom-nTop+1,hmemdc2,nLeft,nTop,SRCCOPY);
// BitBlt(hmemdc2,0,0,maxX,maxY,hmemdc,0,0,SRCCOPY);

}
else
{

if (!StartDraw) 
break;
if ( xS<=xP ) 
{
nLeft = xS;
nRight = xP;
} else
{
nLeft = xP;
nRight = xS;
}
if ( yS<=yP ) 
{
nTop = yS;
nBottom = yP;
} 
else 
{
nTop = yP;
nBottom = yS;
}
// BitBlt(hmemdc,0,0,maxX,maxY,hmemdc2,0,0,SRCCOPY);
}


xP = LOWORD(lParam);  // horizontal position of cursor 
yP = HIWORD(lParam);  // vertical position of cursor 
if(flag==3)
{
nLeft=xS-r;
nTop=yS-r;
nRight=xS+r;
nBottom=yS+r;
// BitBlt(hmemdc2,0,0,maxX,maxY,hmemdc,0,0,SRCCOPY);
}
else
{

if ( xS<=xP ) 
{
nLeft = xS;
nRight = xP;
} 
else
{
nLeft = xP;
nRight = xS;
}
if ( yS<=yP )
{
nTop = yS;
nBottom = yP;
} 
else 
{
nTop = yP;
nBottom = yS;
}
// BitBlt(hmemdc2,0,0,maxX,maxY,hmemdc,0,0,SRCCOPY);
}

if (!StartDraw) 
break;
BitBlt(hmemdc,0,0,maxX,maxY,hmemdc2,0,0,SRCCOPY);
switch(flag){ case 1:
linedda(hmemdc,xS,yS,xP,yP);
break;
case 2:
MidPointLine(hmemdc,xS,yS,xP,yP);
break;
case 3:
//MidPointLine(hmemdc,xS,yS,xP,yP);
circleMidpoint(hmemdc,xS,yS,xP,yP);
break; }


InvalidateRect(hwnd,NULL,0); break;

case WM_LBUTTONDOWN:
xP = xS = LOWORD(lParam);  // horizontal position of cursor 
yP = yS = HIWORD(lParam);  // vertical position of cursor 
StartDraw = 1;
BitBlt(hmemdc2,0,0,maxX,maxY,hmemdc,0,0,SRCCOPY);//xjj break;
case WM_LBUTTONUP:
BitBlt(hmemdc2,0,0,maxX,maxY,hmemdc,0,0,SRCCOPY);//xjj StartDraw = 0;
if(flag==3)
{
r=0;
}
break;

case WM_PAINT:
hdc = BeginPaint(hwnd,&ps); /* get DC */
// pr = &ps.rcPaint; /* set mapping mode, window and viewport extents */
SetMapMode(hdc,MM_ANISOTROPIC);
SetWindowExtEx(hdc,100,100,NULL);
SetViewportExtEx(hdc,100,100,NULL);
SetViewportOrgEx(hdc,orgX,orgY,NULL); /* now,copy memory image onto screen */
//BitBlt(hdc,pr->left,pr->top,pr->right-pr->left,pr->bottom-pr->top,hmemdc,pr->left,pr->top,NOTSRCERASE);
// BitBlt(hdc,0,0,maxX,maxY,hmemdc2,0,0,SRCCOPY);
BitBlt(hdc,0,0,maxX,maxY,hmemdc,0,0,SRCCOPY);
EndPaint(hwnd,&ps); /* release DC */
break;
case WM_DESTROY: /* terminate the program */ SelectObject(hmemdc,hOldbrush);
DeleteObject(hbrush);
// DeleteObject(hWhitePen);
SelectObject(hmemdc,hOldBit);
DeleteObject(hbit);
DeleteDC(hmemdc); SelectObject(hmemdc2,hOldBit2);
DeleteDC(hmemdc2);
DeleteObject(hbit2); PostQuitMessage(0);
break;
default:
/* Let Windows 98 process any messages not specified in the preceding switch statement. */
return DefWindowProc(hwnd,message,wParam,lParam);
}
return 0;
}

Answer 7

/* Createthe message loop. */
while(GetMessage(&msg, NULL, 0,0 )) {
if(!TranslateAccelerator(hwnd,hAccel,&msg)) {
TranslateMessage(&msg); /* translate keyboard messages */
DispatchMessage(&msg); /* return control to Windows 98 */
}
}
return msg.wParam;
}
/* This function is called by Windows 98 and is passed 
messages from the message gueue.
*/
LRESULT CALLBACK WindowFunc(HWND hwnd, UINT message,WPARAM wParam, LPARAM lParam)
{
PAINTSTRUCT ps;
RECT *pr;
int response;
static StartDraw = 0;
int nTop,nLeft,nRight,nBottom,nPositionF,nPositionS;
switch(message) {
// case WM_HELP: /* user pressed F1 or used ? button */
//
// WinHelp((HWND)((LPHELPINFO) lParam) -> hItemHandle,
// "ABC.hlp",HELP_WM_HELP,
// (DWORD)IDM_HELP);
// return 1;
// case IDM_HELPTHIS:
// WinHelp(hwnd,"helptest.hlp",HELP_CONTEXTPOPUP,
// (DWORD)IDH_MENUABOUT);
// break;
// case IDM_EXIT:
// WinHelp(hwnd,"helptest.hlp",HELP_CONTEXTPOPUP,
// (DWORD)IDH_MENUEXIT);
// break;
// default:
/* menu bar selected,but no option heghighted */
// WinHelp(hwnd,"helptest.hlp",HELP_CONTEXTPOPUP,(DWORD)IDH_MENUMAIN);
// }
// }
// else
/* standard help for main window */
// WinHelp(hwnd,"helptest.hlp",HELP_KEY,(DWORD)"Main Window");
/// break;
// case WM_CONTEXTMENU: /* user right - clicked mouse */
/* context help about main window */
// WinHelp(hwnd,"helptest.hlp",HELP_CONTEXTPOPUP,IDH_MAIN);
// break; case WM_CREATE: { /*load the bitmap */

/* get screen coordinates */
maxX = GetSystemMetrics(SM_CXSCREEN);
maxY = GetSystemMetrics(SM_CYSCREEN); /* make a compatible memory image */
hdc = GetDC(hwnd);
hmemdc = CreateCompatibleDC(hdc);

hbit = CreateCompatibleBitmap(hdc,maxX,maxY);
hOldBit = SelectObject(hmemdc,hbit);
hbrush = (HBRUSH)GetStockObject(WHITE_BRUSH);
hOldbrush = SelectObject(hmemdc,hbrush);
PatBlt(hmemdc,0,0,maxX,maxY,PATCOPY);//非常重要，要么屏幕会黑
// hWhitePen = (HPEN) GetStockObject(WHITE_PEN);//利用双缓冲区
hmemdc2 = CreateCompatibleDC(hdc);
// hmemdc3 = CreateCompatibleDC(hdc);
hbit2 = CreateCompatibleBitmap(hdc,maxX,maxY);
hOldBit2 = (HBITMAP)SelectObject(hmemdc2,hbit2);


PatBlt(hmemdc2,0,0,maxX,maxY,PATCOPY);//非常重要，要么屏幕会黑
/* save default pen */
// hOldpen = (HPEN)SelectObject(memdc,hRedpen);
// SelelctObject(memdc,hOldpen);
ReleaseDC(hwnd,hdc);
break;
}
case WM_COMMAND: switch(LOWORD(wParam)) {
case IDM_HELP:
WinHelp(hwnd,"abc.hlp",HELP_FINDER,0);
break;
case ID_1:
line_wide=1;
break;
case ID_2:
line_wide=3;
break;
case ID_3:
line_wide=5;
break;
case ID_4:
line_shape=1;
break;
case ID_5:
line_shape=18;
break;
case ID_6:
line_shape=35;
break;
case IDM_LINES1:
flag=1;
break;
case IDM_LINES2:
flag=2;
break;
case IDM_CIRCLE:
flag=3;
break; 

/* increment size by 10 each time */
// case IDM_SIZE:
case IDM_RESET:
MoveToEx(hmemdc,0,0,NULL);
MoveToEx(hmemdc2,0,0,NULL);
PatBlt(hmemdc,0,0,maxX,maxY,PATCOPY);
PatBlt(hmemdc2,0,0,maxX,maxY,PATCOPY);
InvalidateRect(hwnd,NULL,1);
break;
case IDM_EXIT:
response = MessageBox(hwnd,"Quit the Program?","Exit",MB_YESNO);
if(response == IDYES)
PostQuitMessage(0);
break;
// case IDM_ELLIPSES: { // break;
// }
}
break;
case WM_MOUSEMOVE:

if(flag==3)
{
if (!StartDraw) 
break;
nLeft=xS-r;
nTop=yS-r;
nRight=xS+r;
nBottom=yS+r;

//BitBlt(hmemdc,nLeft,nTop,nRight-nLeft+1,nBottom-nTop+1,hmemdc2,nLeft,nTop,SRCCOPY);
// BitBlt(hmemdc2,0,0,maxX,maxY,hmemdc,0,0,SRCCOPY);

}
else
{

if (!StartDraw) 
break;
if ( xS<=xP ) 
{
nLeft = xS;
nRight = xP;
} else
{
nLeft = xP;
nRight = xS;
}
if ( yS<=yP ) 
{
nTop = yS;
nBottom = yP;
} 
else 
{
nTop = yP;
nBottom = yS;
}
// BitBlt(hmemdc,0,0,maxX,maxY,hmemdc2,0,0,SRCCOPY);
}


xP = LOWORD(lParam);  // horizontal position of cursor 
yP = HIWORD(lParam);  // vertical position of cursor 
if(flag==3)
{
nLeft=xS-r;
nTop=yS-r;
nRight=xS+r;
nBottom=yS+r;
// BitBlt(hmemdc2,0,0,maxX,maxY,hmemdc,0,0,SRCCOPY);
}
else
{

if ( xS<=xP ) 
{
nLeft = xS;
nRight = xP;
} 
else
{
nLeft = xP;
nRight = xS;
}
if ( yS<=yP )
{
nTop = yS;
nBottom = yP;
} 
else 
{
nTop = yP;
nBottom = yS;
}
// BitBlt(hmemdc2,0,0,maxX,maxY,hmemdc,0,0,SRCCOPY);
}

if (!StartDraw) 
break;
BitBlt(hmemdc,0,0,maxX,maxY,hmemdc2,0,0,SRCCOPY);
switch(flag){ case 1:
linedda(hmemdc,xS,yS,xP,yP);
break;
case 2:
MidPointLine(hmemdc,xS,yS,xP,yP);
break;
case 3:
//MidPointLine(hmemdc,xS,yS,xP,yP);
circleMidpoint(hmemdc,xS,yS,xP,yP);
break; }


InvalidateRect(hwnd,NULL,0); break;

case WM_LBUTTONDOWN:
xP = xS = LOWORD(lParam);  // horizontal position of cursor 
yP = yS = HIWORD(lParam);  // vertical position of cursor 
StartDraw = 1;
BitBlt(hmemdc2,0,0,maxX,maxY,hmemdc,0,0,SRCCOPY);//xjj break;
case WM_LBUTTONUP:
BitBlt(hmemdc2,0,0,maxX,maxY,hmemdc,0,0,SRCCOPY);//xjj StartDraw = 0;
if(flag==3)
{
r=0;
}
break;

case WM_PAINT:
hdc = BeginPaint(hwnd,&ps); /* get DC */
// pr = &ps.rcPaint; /* set mapping mode, window and viewport extents */
SetMapMode(hdc,MM_ANISOTROPIC);
SetWindowExtEx(hdc,100,100,NULL);
SetViewportExtEx(hdc,100,100,NULL);
SetViewportOrgEx(hdc,orgX,orgY,NULL); /* now,copy memory image onto screen */
//BitBlt(hdc,pr->left,pr->top,pr->right-pr->left,pr->bottom-pr->top,hmemdc,pr->left,pr->top,NOTSRCERASE);
// BitBlt(hdc,0,0,maxX,maxY,hmemdc2,0,0,SRCCOPY);
BitBlt(hdc,0,0,maxX,maxY,hmemdc,0,0,SRCCOPY);
EndPaint(hwnd,&ps); /* release DC */
break;
case WM_DESTROY: /* terminate the program */ SelectObject(hmemdc,hOldbrush);
DeleteObject(hbrush);
// DeleteObject(hWhitePen);
SelectObject(hmemdc,hOldBit);
DeleteObject(hbit);
DeleteDC(hmemdc); SelectObject(hmemdc2,hOldBit2);
DeleteDC(hmemdc2);
DeleteObject(hbit2); PostQuitMessage(0);
break;
default:
/* Let Windows 98 process any messages not specified in the preceding switch statement. */
return DefWindowProc(hwnd,message,wParam,lParam);
}
return 0;
}

Answer 8

这个程序已经改的很不错，但是还有一个BUG，就是Line_shape=18时候用粗线茂密画圆会出现只有右半圆情况。经过几次测试，Line_shape为奇数时不会出现此情况，为偶数就有这种情况。
感谢！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！
希望能帮我再看一下，分数我会再多给你。

Answer 9

#include <windows.h>
#include <math.h>static int line_wide=1;
static int line_shape=1;
static float r=0.0;
extern  int flag;int round(float x)
{
int y;
if(x-int(x)>=0.5)
{ y=int(x)+1;
return y;
}
else{
y=int(x);
return y;
}
}
void SetPixel(HDC hdc,int x0,int y0,int color,int flag)
{
switch(flag)
{
int i,j;
case 1:SetPixel(hdc,x0,y0,color);break;
case 3:for (i=-1;i<=1;i++)
{
for (j=-1;j<=1;j++)
{
SetPixel(hdc,x0+i,y0+j,color);
}
}
break;
case 5:for (i=-2;i<=2;i++)
   {
   for (j=-2;j<=2;j++)
   {
   SetPixel(hdc,x0+i,y0+j,color);
   }
   }
   break;
}
}
static int i=1;void SetPixel(HDC hdc,int x0,int y0,int color,int flag,int n)
{
if(i%n==0)
{
SetPixel(hdc,x0,y0,color,flag);
}
if(::flag!=3)
{
i++;
}
}
void circlePlotPoints(HDC hdc,int xc,int yc,int x,int y)
{
SetPixel(hdc,xc+x,yc+y,RGB(0,0,255),line_wide,line_shape);
SetPixel(hdc,xc-x,yc+y,RGB(0,0,255),line_wide,line_shape);
SetPixel(hdc,xc+x,yc-y,RGB(0,0,255),line_wide,line_shape);
SetPixel(hdc,xc-x,yc-y,RGB(0,0,255),line_wide,line_shape);
SetPixel(hdc,xc+y,yc+x,RGB(0,0,255),line_wide,line_shape);
SetPixel(hdc,xc-y,yc+x,RGB(0,0,255),line_wide,line_shape);
SetPixel(hdc,xc+y,yc-x,RGB(0,0,255),line_wide,line_shape);
SetPixel(hdc,xc-y,yc-x,RGB(0,0,255),line_wide,line_shape);
if(::flag==3)
{
i++;
}}
//void circleMidpoint(HDC hdc,int xc,int yc,int r)
void circleMidpoint(HDC hdc,int xc,int yc,int xp,int yp)
{
 
 r=sqrt((float)((xc-xp)*(xc-xp)+(yc-yp)*(yc-yp)));
float x=0.0;
float y=r;
float d=1-r;
circlePlotPoints(hdc,xc,yc,x,y);
while(x<y)
{
x++;
if(d<0)
d+=2*x+1;
else
{
y--;
d+=2*(x-y)+1;
}
circlePlotPoints(hdc,xc,yc,x,y);
}
}
void linedda(HDC hdc,int x1,int y1,int x2,int y2)
{
float increx,increy,x,y,length;
int i;
if(abs(x2-x1)>abs(y2-y1))
length=abs(x2-x1);
else
length=abs(y2-y1);
increx=(x2-x1)/length;
increy=(y2-y1)/length;
x=x1;
y=y1;
for(i=1;i<=length;i++)
{
SetPixel(hdc,round(x),round(y),RGB(255,0,0),line_wide,line_shape);
x=x+increx;
y=y+increy;
}
}
int nwidth=1;void MidPointLine(HDC hdc,int x0, int y0,int x1, int y1)
{
int a,b,delta1,delta2,d,x,y,dx,dy,i,s1,s2,width,count;//
width=nwidth/2;
a=y0-y1;
b=x1-x0; x=x0;
y=y0;
SetPixel(hdc,x,y,RGB(0,255,0),line_wide,line_shape);
dx=abs(b);
dy=abs(a);
if(b>0)
s1=1;
else
s1=-1;
if(a<0)
s2=1;
else
s2=-1;
if(s1<0)
a=-a;
if(s2<0)
b=-b; if(dy<=dx)
{
d=a+a+b;
delta1=a+a;
delta2=delta1+b+b;
if(s1==s2)
{
for(i=0;i<dx;i++)
{
if(d<0)
{
x+=s1;
y+=s2;
d+=delta2;
}
else
{
x+=s1;
d+=delta1;
}
for(count=0;count<=width;count++)
{
SetPixel(hdc,x,y+count,RGB(0,255,0),line_wide,line_shape);
SetPixel(hdc,x,y-count,RGB(0,255,0),line_wide,line_shape);
}
}
}
else
{
for(i=0;i<dx;i++)
{
if(d>=0)
{
x+=s1;
y+=s2;
d+=delta2;
}
else
{
x+=s1;
d+=delta1;
}
for(count=0;count<=width;count++)
{
SetPixel(hdc,x,y+count,RGB(0,255,0),line_wide,line_shape);
SetPixel(hdc,x,y-count,RGB(0,255,0),line_wide,line_shape);
}
}
}
}
else
{
d=a+b+b;
delta1=b+b;
delta2=delta1+a+a;
if(s1==s2)
{
for(i=0;i<dy;i++)
{
if(d>0)
{
x+=s1;
y+=s2;
d+=delta2;
}
else
{
y+=s2;
d+=delta1;
}
for(count=0;count<=width;count++)
{
SetPixel(hdc,x+count,y,RGB(0,255,0),line_wide,line_shape);
SetPixel(hdc,x-count,y,RGB(0,255,0),line_wide,line_shape);
}
}
}
else
{
for(i=0;i<dy;i++)
{
if(d<0)
{
x+=s1;
y+=s2;
d+=delta2;
}
else
{
y+=s2;
d+=delta1;
}
for(count=0;count<=width;count++)
{
SetPixel(hdc,x+count,y,RGB(0,255,0),line_wide,line_shape);
SetPixel(hdc,x-count,y,RGB(0,255,0),line_wide,line_shape);
}
}
}
}
}
/*void MidPointLine(HDC hdc,int x1,int y1,int x2,int y2)
{
int dx,dy,n,k,i,f;
int x,y;
dx=abs(x2-x1);
dy=abs(y2-y1);
n=dx+dy;
if(x2>x1){k=y2>=y1?1:4;x=x1;y=y1;}
else {k=y2>=y1?2:3;x=x1;y=y1;}
SetPixel(hdc,x,y,RGB(0,255,0),line_wide);
for(i=0,f=0;i<n;i++)
if(f>=0)
switch(k){
case 1:SetPixel(hdc,x++,y,RGB(0,255,0),line_wide);f-=dy;break;
case 2:SetPixel(hdc,x,y++,RGB(0,255,0),line_wide);f-=dx;break;
case 3:SetPixel(hdc,x--,y,RGB(0,255,0),line_wide);f-=dy;break;
case 4:SetPixel(hdc,x,y--,RGB(0,255,0),line_wide);f-=dx;break;
}
else
switch(k){
case 1:SetPixel(hdc,x,y++,RGB(0,255,0),line_wide);f+=dx;break;
case 2:SetPixel(hdc,x--,y,RGB(0,255,0),line_wide);f+=dy;break;
case 3:SetPixel(hdc,x,y--,RGB(0,255,0),line_wide);f+=dx;break;
case 4:SetPixel(hdc,x++,y,RGB(0,255,0),line_wide);f+=dy;break;
}
}*/

Answer 10

#include "graph.h"
#include "MappingMode.h"
static int flag=1;LRESULT CALLBACK WindowFunc(HWND, UINT, WPARAM, LPARAM);char szWinName[] = "MyWin"; /* name of window class */char str[255]; /* holds output strings */int maxX,maxY; /* screen dimensions */
int orgX=0,orgY=0; /* viewport orgin */HDC hmemdc; /* store the virtual device handle */
HBITMAP hbit; /* store the virtual bitmap */
HBRUSH hbrush; /* store the brush handle */
HGDIOBJ hOldBit,hOldbrush;HDC hdc;
/* create pens */
HPEN hOldpen; /* handle of old pen */
//HPEN hWhitePen;
HWND hwnd;HDC hmemdc2;
HDC hmemdc3;HBITMAP hbit2,hOldBit2;
int xP,yP,xS,yS;
int WINAPI WinMain(HINSTANCE hThisInst, HINSTANCE hPrevInst, LPSTR lpszArgs,int nWinMode)
{
MSG msg;
WNDCLASSEX wcl;
HACCEL hAccel; /* Define a window class. */
wcl.cbSize = sizeof(WNDCLASSEX);
wcl.hInstance = hThisInst; /* handle to this instance */
wcl.lpszClassName = szWinName; /* window class name */
wcl.lpfnWndProc = WindowFunc; /* window function */
wcl.style = 0; /* default style */ wcl.hIcon = LoadIcon(NULL,IDI_APPLICATION); /* standard icon */
wcl.hIconSm = LoadIcon(NULL,IDI_WINLOGO); /* SMALL ICON */
wcl.hCursor = LoadCursor(NULL,IDC_ARROW); /* cursor style */ /* Specify name of menu resource. This will be overridden. */
wcl.lpszMenuName = "MYMENU"; /* main menu */
wcl.cbClsExtra = 0; /* no extra information needed */
wcl.cbWndExtra = 0; /* no extra information needed */

/* Make the windows backgraoud white */
wcl.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH); /* Register the window class. */
if(!RegisterClassEx(&wcl))
return 0; /* Now that a window class has been registered, a window can be created. */
hwnd = CreateWindow(
szWinName, /* name of window class */
"Changing Mapping Modes", /* title */
WS_VISIBLE|WS_CAPTION|WS_BORDER|WS_MINIMIZEBOX|WS_SYSMENU, /* window style - normal */
CW_USEDEFAULT, /* X coordinate - let Winodws decide */
CW_USEDEFAULT, /* Y coordinate - let Windows decide */
CW_USEDEFAULT, /* width - let Windows decide */
CW_USEDEFAULT, /* height - let Windows decide */
HWND_DESKTOP, /* no parent window */
NULL,  /*  no menu */
hThisInst, /* handle of this instance of the program */
NULL /* no additional arguments */
); /* Load accelerators. */
hAccel = LoadAccelerators(hThisInst,"MyMenu"); /* Display the windows. */
ShowWindow(hwnd, nWinMode);
UpdateWindow(hwnd);/* Createthe message loop. */
while(GetMessage(&msg, NULL, 0,0 )) {
if(!TranslateAccelerator(hwnd,hAccel,&msg)) {
TranslateMessage(&msg); /* translate keyboard messages */
DispatchMessage(&msg); /* return control to Windows 98 */
}
}
return msg.wParam;
}
/* This function is called by Windows 98 and is passed 
messages from the message gueue.
*/
LRESULT CALLBACK WindowFunc(HWND hwnd, UINT message,WPARAM wParam, LPARAM lParam)
{
PAINTSTRUCT ps;
RECT *pr;
int response;
static StartDraw = 0;
int nTop,nLeft,nRight,nBottom,nPositionF,nPositionS;
switch(message) {
// case WM_HELP: /* user pressed F1 or used ? button */
//
// WinHelp((HWND)((LPHELPINFO) lParam) -> hItemHandle,
// "ABC.hlp",HELP_WM_HELP,
// (DWORD)IDM_HELP);
// return 1;
// case IDM_HELPTHIS:
// WinHelp(hwnd,"helptest.hlp",HELP_CONTEXTPOPUP,
// (DWORD)IDH_MENUABOUT);
// break;
// case IDM_EXIT:
// WinHelp(hwnd,"helptest.hlp",HELP_CONTEXTPOPUP,
// (DWORD)IDH_MENUEXIT);
// break;
// default:
/* menu bar selected,but no option heghighted */
// WinHelp(hwnd,"helptest.hlp",HELP_CONTEXTPOPUP,(DWORD)IDH_MENUMAIN);
// }
// }
// else
/* standard help for main window */
// WinHelp(hwnd,"helptest.hlp",HELP_KEY,(DWORD)"Main Window");
/// break;
// case WM_CONTEXTMENU: /* user right - clicked mouse */
/* context help about main window */
// WinHelp(hwnd,"helptest.hlp",HELP_CONTEXTPOPUP,IDH_MAIN);
// break; case WM_CREATE: { /*load the bitmap */

/* get screen coordinates */
maxX = GetSystemMetrics(SM_CXSCREEN);
maxY = GetSystemMetrics(SM_CYSCREEN); /* make a compatible memory image */
hdc = GetDC(hwnd);
hmemdc = CreateCompatibleDC(hdc);

hbit = CreateCompatibleBitmap(hdc,maxX,maxY);
hOldBit = SelectObject(hmemdc,hbit);
hbrush = (HBRUSH)GetStockObject(WHITE_BRUSH);
hOldbrush = SelectObject(hmemdc,hbrush);
PatBlt(hmemdc,0,0,maxX,maxY,PATCOPY);//非常重要，要么屏幕会黑
// hWhitePen = (HPEN) GetStockObject(WHITE_PEN);//利用双缓冲区
hmemdc2 = CreateCompatibleDC(hdc);
// hmemdc3 = CreateCompatibleDC(hdc);
hbit2 = CreateCompatibleBitmap(hdc,maxX,maxY);
hOldBit2 = (HBITMAP)SelectObject(hmemdc2,hbit2);


PatBlt(hmemdc2,0,0,maxX,maxY,PATCOPY);//非常重要，要么屏幕会黑
/* save default pen */
// hOldpen = (HPEN)SelectObject(memdc,hRedpen);
// SelelctObject(memdc,hOldpen);
ReleaseDC(hwnd,hdc);
break;
}
case WM_COMMAND: switch(LOWORD(wParam)) {
case IDM_HELP:
WinHelp(hwnd,"abc.hlp",HELP_FINDER,0);
break;
case ID_1:
line_wide=1;
break;
case ID_2:
line_wide=3;
break;
case ID_3:
line_wide=5;
break;
case ID_4:
line_shape=1;
break;
case ID_5:
line_shape=18;
break;
case ID_6:
line_shape=35;
break;
case IDM_LINES1:
flag=1;
break;
case IDM_LINES2:
flag=2;
break;
case IDM_CIRCLE:
flag=3;
break; 

/* increment size by 10 each time */
// case IDM_SIZE:
case IDM_RESET:
MoveToEx(hmemdc,0,0,NULL);
MoveToEx(hmemdc2,0,0,NULL);
PatBlt(hmemdc,0,0,maxX,maxY,PATCOPY);
PatBlt(hmemdc2,0,0,maxX,maxY,PATCOPY);
InvalidateRect(hwnd,NULL,1);
break;
case IDM_EXIT:
response = MessageBox(hwnd,"Quit the Program?","Exit",MB_YESNO);
if(response == IDYES)
PostQuitMessage(0);
break;
// case IDM_ELLIPSES: { // break;
// }
}
break;
case WM_MOUSEMOVE:

if(flag==3)
{
if (!StartDraw) 
break;
nLeft=xS-r;
nTop=yS-r;
nRight=xS+r;
nBottom=yS+r;

//BitBlt(hmemdc,nLeft,nTop,nRight-nLeft+1,nBottom-nTop+1,hmemdc2,nLeft,nTop,SRCCOPY);
// BitBlt(hmemdc2,0,0,maxX,maxY,hmemdc,0,0,SRCCOPY);

Answer 11

}
else
{

if (!StartDraw) 
break;
if ( xS<=xP ) 
{
nLeft = xS;
nRight = xP;
} else
{
nLeft = xP;
nRight = xS;
}
if ( yS<=yP ) 
{
nTop = yS;
nBottom = yP;
} 
else 
{
nTop = yP;
nBottom = yS;
}
// BitBlt(hmemdc,0,0,maxX,maxY,hmemdc2,0,0,SRCCOPY);
}


xP = LOWORD(lParam);  // horizontal position of cursor 
yP = HIWORD(lParam);  // vertical position of cursor 
if(flag==3)
{
nLeft=xS-r;
nTop=yS-r;
nRight=xS+r;
nBottom=yS+r;
// BitBlt(hmemdc2,0,0,maxX,maxY,hmemdc,0,0,SRCCOPY);
}
else
{

if ( xS<=xP ) 
{
nLeft = xS;
nRight = xP;
} 
else
{
nLeft = xP;
nRight = xS;
}
if ( yS<=yP )
{
nTop = yS;
nBottom = yP;
} 
else 
{
nTop = yP;
nBottom = yS;
}
// BitBlt(hmemdc2,0,0,maxX,maxY,hmemdc,0,0,SRCCOPY);
}

if (!StartDraw) 
break;
BitBlt(hmemdc,0,0,maxX,maxY,hmemdc2,0,0,SRCCOPY);
switch(flag){ case 1:
linedda(hmemdc,xS,yS,xP,yP);
break;
case 2:
MidPointLine(hmemdc,xS,yS,xP,yP);
break;
case 3:
//MidPointLine(hmemdc,xS,yS,xP,yP);
circleMidpoint(hmemdc,xS,yS,xP,yP);
break; }


InvalidateRect(hwnd,NULL,0); break;

case WM_LBUTTONDOWN:
xP = xS = LOWORD(lParam);  // horizontal position of cursor 
yP = yS = HIWORD(lParam);  // vertical position of cursor 
StartDraw = 1;
BitBlt(hmemdc2,0,0,maxX,maxY,hmemdc,0,0,SRCCOPY);//xjj break;
case WM_LBUTTONUP:
BitBlt(hmemdc2,0,0,maxX,maxY,hmemdc,0,0,SRCCOPY);//xjj StartDraw = 0;
if(flag==3)
{
r=0;
}
break;

case WM_PAINT:
hdc = BeginPaint(hwnd,&ps); /* get DC */
// pr = &ps.rcPaint; /* set mapping mode, window and viewport extents */
SetMapMode(hdc,MM_ANISOTROPIC);
SetWindowExtEx(hdc,100,100,NULL);
SetViewportExtEx(hdc,100,100,NULL);
SetViewportOrgEx(hdc,orgX,orgY,NULL); /* now,copy memory image onto screen */
//BitBlt(hdc,pr->left,pr->top,pr->right-pr->left,pr->bottom-pr->top,hmemdc,pr->left,pr->top,NOTSRCERASE);
// BitBlt(hdc,0,0,maxX,maxY,hmemdc2,0,0,SRCCOPY);
BitBlt(hdc,0,0,maxX,maxY,hmemdc,0,0,SRCCOPY);
EndPaint(hwnd,&ps); /* release DC */
break;
case WM_DESTROY: /* terminate the program */ SelectObject(hmemdc,hOldbrush);
DeleteObject(hbrush);
// DeleteObject(hWhitePen);
SelectObject(hmemdc,hOldBit);
DeleteObject(hbit);
DeleteDC(hmemdc); SelectObject(hmemdc2,hOldBit2);
DeleteDC(hmemdc2);
DeleteObject(hbit2); PostQuitMessage(0);
break;
default:
/* Let Windows 98 process any messages not specified in the preceding switch statement. */
return DefWindowProc(hwnd,message,wParam,lParam);
}
return 0;
}////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////
/*
我的方法是，在MappingMode.cpp中static float r=0.0;行的后面加一条语句extern  int flag;把void SetPixel(HDC hdc,int x0,int y0,int color,int flag,int n)中的static int i=1;定义为//全局静态变量，即把static int i=1;这一句移出void SetPixel(HDC hdc,int x0,int y0,int color,int flag,int n)，把其中的i++;改为
if(::flag!=3)
{
i++;
}
在void circlePlotPoints(HDC hdc,int xc,int yc,int x,int y)最后加上一句
if(::flag==3)
{
i++;
}*/