Windows的图形设备接口与Windows绘图
本次学习目标
理解DC, 映像模式, 坐标系统, 窗口和视口; 学习获取绘图工具(画笔/画刷)的句柄, 设置颜色, 能定义映像模式; 会使用常用的绘图函数.
编写程序: 在屏幕上出现一个圆心沿正弦曲线轨迹移动的实心圆.
1. 理解DC, 映像模式, 坐标系统, 窗口和视口;
编写基本的windows绘图程序,获取DC并绘图,然后改变其映射模式、坐标、窗口和视口原点,观察图像输出的变化,理解DC, 映像模式, 坐标系统, 窗口和视口的工作方式。
程序代码如下:
#include<windows.h>
#include<stdlib.h>
#include<string.h>
long WINAPI WndProc(HWND hWnd,UINT iMessage,UINT wParam,LONG
lParam);
BOOL InitWindowsClass(HINSTANCE hInstance);
BOOL InitWindows(HINSTANCE hInstance,int nCmdShow);
int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE
hPrevInstance,LPSTR lpCmdLine,int nCmdShow)
{
MSG Message;
if(!InitWindowsClass(hInstance))
return
FALSE;
if(!InitWindows(hInstance,nCmdShow))
return
FALSE;
while(GetMessage(&Message,0,0,0)) //消息循环
{
TranslateMessage(&Message);
DispatchMessage(&Message);
}
return Message.wParam;
}
long WINAPI WndProc(HWND hWnd,UINT iMessage,UINT
wParam,LONG lParam)
{
HDC hDC;
//定义指向设备上下文的句柄
HPEN
hPen; //定义指向画笔的句柄
PAINTSTRUCT PtStr;
//定义指向包含绘图信息的结构体变量
switch(iMessage)
//处理消息
{
case WM_PAINT:
//处理绘图消息
hDC=BeginPaint(hWnd,&PtStr);
SetMapMode(hDC,MM_ANISOTROPIC);
//设置映射模式为MM_ANISOTROPIC
hPen=(HPEN)GetStockObject(BLACK_PEN);//设置画笔为系统预定定义的黑色画笔
SelectObject(hDC,hPen);
//选择画笔
RoundRect(hDC,50,120,200,-200,15,15); //圆角矩形
Ellipse(hDC,100,50,200,100);
//椭圆
EndPaint(hWnd,&PtStr);
//结束绘图
return
0;
case WM_DESTROY:
//结束应用程序
PostQuitMessage(0);
return
0;
default: //其他消息处理程序
return(DefWindowProc(hWnd,iMessage,wParam,lParam))
;
}
}
BOOL InitWindows(HINSTANCE hInstance,int
nCmdShow) //初始化窗口
{
HWND hWnd;
hWnd=CreateWindow("WinFill",
//生成窗口
"填充示例程序",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
0,
CW_USEDEFAULT,
0,
NULL,
NULL,
hInstance,
NULL);
if(!hWnd)
return
FALSE;
ShowWindow(hWnd,nCmdShow); //显示窗口
UpdateWindow(hWnd);
return
TRUE;
}
BOOL InitWindowsClass(HINSTANCE hInstance)
//定义窗口类
{
WNDCLASS
WndClass;
WndClass.cbClsExtra=0;
WndClass.cbWndExtra=0;
WndClass.hbrBackground=(HBRUSH)(GetStockObject(WHITE_BRUSH));
WndClass.hCursor=LoadCursor(NULL,IDC_ARROW);
WndClass.hIcon=LoadIcon(NULL,"END");
WndClass.hInstance=hInstance;
WndClass.lpfnWndProc=WndProc;
WndClass.lpszClassName="WinFill";
WndClass.lpszMenuName=NULL;
WndClass.style=CS_HREDRAW|CS_VREDRAW;
return
RegisterClass(&WndClass);
}
编译并调试程序,
分别改变其映射模式、坐标、窗口和视口原点,观察图像输出的变化
2. 获取绘图工具(画笔/画刷)的句柄, 设置颜色
修改绘图代码为:
hPen=(HPEN)GetStockObject(BLACK_PEN);//设置画笔为系统预定定义的黑色画笔
hBrush=(HBRUSH)GetStockObject(DKGRAY_BRUSH);
//采用系统预定义的深灰色画刷
SelectObject(hDC,hBrush);
//选择画刷
SelectObject(hDC,hPen);
//选择画笔
RoundRect(hDC,50,120,200,-200,15,15);
//圆角矩形
hBrush=CreateSolidBrush(RGB(220,32,70));
SelectObject(hDC,hBrush);
//选择画刷
Ellipse(hDC,100,50,200,100);
//椭圆
编译并调试程序
3.在屏幕上绘制一个圆心沿正弦曲线轨迹移动的实心圆
程序源代码如下:
#include <windows.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#define Pi 3.1415926
long WINAPI WndProc(HWND hWnd,UINT
iMessage,UINT wParam,LONG
lParam); //消息处理函数声明.
double
dfTheta=0,dfRange=100.0; //正弦曲线的角度变量.
long i=0,j=0;
long
lCentreX=0,lCentreY=0,lRadious=(long)(0.5*dfRange);
//定义圆心坐标和圆坐标.
POINT
lpSin[100]; //定义正弦曲线的点坐标.
int WINAPI WinMain(HINSTANCE
hInstance,HINSTANCE hPrevInstance,LPSTR lpCmdLine,int
nCmdShow) //主函数
{
MSG
Message; //定义消息变量.
HWND
hWnd; //定义窗口句柄.
WNDCLASS
WndClass; //定义窗口类.
WndClass.cbClsExtra=0; //无窗口类扩展.
WndClass.cbWndExtra=0; //无窗口实例扩展.
WndClass.hbrBackground=(HBRUSH)(GetStockObject(WHITE_BRUSH));//背景为白色.
WndClass.hCursor=LoadCursor(NULL,IDC_ARROW); //窗口采用箭头光标.
WndClass.hIcon=LoadIcon(NULL,IDI_APPLICATION); //采用缺省图标.
WndClass.hInstance=hInstance; //当前应用程序句柄.
WndClass.lpfnWndProc=WndProc; //窗口处理函数.
WndClass.lpszClassName="SIN"; //窗口类名称.
WndClass.lpszMenuName=NULL; //无窗口菜单.
WndClass.style=0; //窗口类型为缺省类型.
if(!RegisterClass(&WndClass)) //注册窗口.
{
MessageBeep(0);
return
FALSE;
}
hWnd=CreateWindow("SIN", //窗口类名.
"yuan", //标题名.
WS_OVERLAPPEDWINDOW, //带标题栏,最大和最小按钮的窗口.
CW_USEDEFAULT, //窗口左上角坐标.
0,
CW_USEDEFAULT, //采用缺省的宽度和高度.
0,
NULL, //无父窗口.
NULL, //无主菜单.
hInstance, //当前实例句柄.
NULL); //不要此参数.
ShowWindow(hWnd,nCmdShow); //显示窗口.
UpdateWindow(hWnd); //更新并绘制用户区.
for(int
j=0;j<100;j++) //生成正弦曲线的点坐标.
{
lpSin[j].x=(long)(j*2*Pi/100*60);
lpSin[j].y=(long)(dfRange*sin(j*2*Pi/100));
}
while(GetMessage(&Message,0,0,0))
{
TranslateMessage(&Message); //消息循环.
DispatchMessage(&Message);
}
return
Message.wParam;
}
long WINAPI WndProc(HWND hWnd,
UINT
iMessage,
UINT
wParam,
LONG
lParam) //消息处理函数.
{
HDC
hDC; //定义设备环境句柄.
HBRUSH
hBrush; //定义画刷句柄
HPEN
hPen; //定义画笔句柄
PAINTSTRUCT
PtStr; //定义包含绘图信息的结构体变量
switch(iMessage)
{
case
WM_PAINT: //处理绘图消息.
hDC=BeginPaint(hWnd,&PtStr); //获得设备环境指针.
SetWindowOrgEx(hDC,-200,-200,NULL); //设置原点坐标为(-200,-200).
Polyline(hDC,lpSin,100); //绘制正弦曲线.
hPen=(HPEN)GetStockObject(BLACK_PEN);//设置画笔为系统预定定义的黑色画笔
hBrush=(HBRUSH)GetStockObject(DKGRAY_BRUSH);
//采用系统预定义的深灰色画刷
SelectObject(hDC,hBrush); //选入画刷.
SelectObject(hDC,hPen); //选入画笔.
lCentreX=lpSin[i].x; //圆心x坐标.
lCentreY=lpSin[i].y; //圆心y坐标.
Ellipse(hDC,lCentreX-lRadious,lCentreY-lRadious,
lCentreX+lRadious,lCentreY+lRadious); //画圆.
i++;
if(i>=100)
i=0;
DeleteObject(hPen); //删除画笔.
DeleteObject(hBrush); //删除画刷.
EndPaint(hWnd,&PtStr); //删除设备环境指针.
Sleep(100); //停0.1秒.
if(i<100)
InvalidateRect(hWnd,NULL,1); //刷新用户区.
return
0;
case
WM_DESTROY: //关闭窗口.
PostQuitMessage(0);
return
0;
default:
return(DefWindowProc(hWnd,iMessage,wParam,lParam));
}
}
编译并调试程序,
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