一、GDI簡介
1）什麼是裝置上下文
2）裝置上下文型別
3）常見的GDI物件
4）windows座標系
5）GDI繪圖步驟
1）獲取DC的3種方法
2）PAINTSTRUCT結構
3）BeginPaint函式
4）EndPaint函式
5）GetDC函式
6）GetWindowDC函式
7）三種方式的區別
8）程式碼例項
#include<windows.h>
//自定義的視窗過程
LRESULT CALLBACK MyWindowProc(HWND hWnd, UINT Msg,
WPARAM wParam, LPARAM lParam)
{
switch (Msg)
{
case WM_DESTROY:
PostQuitMessage(0);//可以使GetMessage返回0
return 0;
case WM_PAINT:
{
//1.使用BeginPaint，它能將無效區域變成有效（如果存在無效區域，系統會一直髮送WM_PAINT）
/*PAINTSTRUCT ps;
HDC hdc = BeginPaint(hWnd, &ps);
TextOut(hdc, 0, 0, L"你好啊！", lstrlen(L"你好啊！"));
EndPaint(hWnd, &ps);*/
//2.使用GetDC獲取客戶區DC，它並不能將無效區域變成有效,所以WM_PAINT一直髮送，文字一直閃爍
/*
HDC hdc = GetDC(hWnd);
TextOut(hdc, 0, 0, L"你好啊！", lstrlen(L"你好啊！"));
ReleaseDC(hWnd, hdc);
//return 0; //去掉之後交給預設DefWindowProc處理WM_PAINT訊息，會呼叫BeginPaint，EndPaint
*/
}
break;
case WM_NCPAINT:
{
//3.獲取整個視窗的DC，包括標題欄，工具條等
HDC hdc = GetWindowDC(hWnd);
RECT r = {0,0,400,20};
HBRUSH brh = CreateSolidBrush(RGB(255, 0, 0));
FillRect(hdc, &r, brh);
DeleteObject(brh);
ReleaseDC(hWnd, hdc);//釋放掉DC
return true;
}break;
}
return DefWindowProc(hWnd, Msg, wParam, lParam);
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nShowCmd)
{
//1.註冊視窗類
WNDCLASS wnd;
wnd.cbClsExtra = 0;
wnd.cbWndExtra = 0;
wnd.hbrBackground = (HBRUSH)(GetStockObject(GRAY_BRUSH));//背景色
wnd.hCursor = LoadCursor(NULL, IDC_ARROW);//游標
wnd.hIcon = LoadIcon(NULL, IDI_APPLICATION);//圖示
//wnd.lpfnWndProc = DefWindowProc;//預設視窗過程函式，用於處理訊息
wnd.lpfnWndProc = MyWindowProc;//自定義的視窗過程函式
wnd.lpszClassName = L"MrHuang";//視窗類名
wnd.lpszMenuName = NULL;//選單資源名稱
wnd.style = CS_HREDRAW | CS_DBLCLKS;//視窗類、樣式
wnd.hInstance = hInstance;//例項控制代碼
RegisterClass(&wnd);
//建立視窗(返回之前傳送WM_CREATE)
HWND hWnd = CreateWindow(L"MrHuang", L"第一個視窗程式",
WS_OVERLAPPEDWINDOW, 100, 100, 400, 400, NULL, NULL, hInstance, NULL);
//顯示視窗
ShowWindow(hWnd, nShowCmd);
//更新視窗(傳送WM_PAINT)
UpdateWindow(hWnd);
//訊息迴圈（收到WM_QUIT訊息退出）
MSG msg;
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);//翻譯訊息
DispatchMessage(&msg);//分發訊息到視窗過程
}
}
1）建立畫筆
2）選擇一個物件到資料上下文
3）畫直線
4）畫矩形
5）建立畫刷
6）DeleteObject函式
7）GetStockObject函式
8）畫橢圓
9）畫餅圖
10）寫入字串
11）SetBkColor函式
12）SetBkMode函式
13）DrawText函式
14）SetTextAlign函式
15）程式碼例項
①繪製直線、矩形、橢圓、餅圖
#include<windows.h>
//自定義的視窗過程
LRESULT CALLBACK MyWindowProc(HWND hWnd, UINT Msg,
WPARAM wParam, LPARAM lParam)
{
switch (Msg)
{
case WM_DESTROY:
PostQuitMessage(0);//可以使GetMessage返回0
return 0;
case WM_PAINT:
{
PAINTSTRUCT ps;
//獲取裝置上下文控制代碼
HDC hdc = BeginPaint(hWnd, &ps);
//建立畫筆
HPEN hPen = CreatePen(PS_DASHDOT, 1, RGB(255, 0, 0));
//將筆選入到裝置上下文(使用這支筆)
SelectObject(hdc, hPen);
//1.畫直線(兩個點)
MoveToEx(hdc, 100, 100, NULL);
LineTo(hdc, 200, 100);
//建立畫刷
HBRUSH hBsh = CreateSolidBrush(RGB(0, 255, 0));
//將畫刷選入到裝置上下文(使用這支畫刷)
SelectObject(hdc, hBsh);
//2.畫矩形(正方形)
Rectangle(hdc, 200, 200, 400, 400);
//獲取透明畫刷
HGDIOBJ hBsh2 =GetStockObject(NULL_BRUSH);
SelectObject(hdc, hBsh2);
Rectangle(hdc, 100, 100, 200, 150);
//3.畫橢圓（圓形）
Ellipse(hdc, 200, 200, 400, 400);
Ellipse(hdc, 100, 100, 200, 150);
//4.畫餅圖
/*
//餅圖產生的步驟分解
Ellipse(hdc, 500, 100, 800, 400);
//從圓心到第一個點的連線
MoveToEx(hdc, 650, 250, NULL);
LineTo(hdc,1000, 300);
//從圓心到第二個點的連線
MoveToEx(hdc, 650, 250, NULL);
LineTo(hdc, 400, 400);
*/
Pie(hdc, 500, 100, 800, 400, 1000, 300,400, 400);
//刪除GDI物件
DeleteObject(hPen);
DeleteObject(hBsh);
EndPaint(hWnd, &ps);
}
break;
}
return DefWindowProc(hWnd, Msg, wParam, lParam);
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nShowCmd)
{
//1.註冊視窗類
WNDCLASS wnd;
wnd.cbClsExtra = 0;
wnd.cbWndExtra = 0;
wnd.hbrBackground = (HBRUSH)(GetStockObject(GRAY_BRUSH));//背景色
wnd.hCursor = LoadCursor(NULL, IDC_ARROW);//游標
wnd.hIcon = LoadIcon(NULL, IDI_APPLICATION);//圖示
//wnd.lpfnWndProc = DefWindowProc;//預設視窗過程函式，用於處理訊息
wnd.lpfnWndProc = MyWindowProc;//自定義的視窗過程函式
wnd.lpszClassName = L"MrHuang";//視窗類名
wnd.lpszMenuName = NULL;//選單資源名稱
wnd.style = CS_HREDRAW | CS_DBLCLKS;//視窗類、樣式
wnd.hInstance = hInstance;//例項控制代碼
RegisterClass(&wnd);
//建立視窗(返回之前傳送WM_CREATE)
HWND hWnd = CreateWindow(L"MrHuang", L"第一個視窗程式",
WS_OVERLAPPEDWINDOW, 100, 100, 1000, 700, NULL, NULL, hInstance, NULL);
//顯示視窗
ShowWindow(hWnd, nShowCmd);
//更新視窗(傳送WM_PAINT)
UpdateWindow(hWnd);
//訊息迴圈（收到WM_QUIT訊息退出）
MSG msg;
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);//翻譯訊息
DispatchMessage(&msg);//分發訊息到視窗過程
}
}
②寫入字串
#include<windows.h>
//自定義的視窗過程
LRESULT CALLBACK MyWindowProc(HWND hWnd, UINT Msg,
WPARAM wParam, LPARAM lParam)
{
switch (Msg)
{
case WM_DESTROY:
PostQuitMessage(0);//可以使GetMessage返回0
return 0;
case WM_PAINT:
{
PAINTSTRUCT ps;
//獲取裝置上下文控制代碼
HDC hdc = BeginPaint(hWnd, &ps);
//改變文字的背景色
SetBkColor(hdc, RGB(255, 0, 0));
//設定文字背景模式
SetBkMode(hdc, TRANSPARENT);//透明
//設定文字的顏色
SetTextColor(hdc, RGB(255, 0, 0));
//設定文字的參考點
SetTextAlign(hdc, TA_TOP);
//1.介面上畫文字
TextOut(hdc,250, 200, L"你好啊，這是畫的文字！", lstrlen(L"你好啊，這是畫的文字！"));
//2.在矩形範圍中畫文字
RECT r = {250,400,300,500};
Rectangle(hdc, r.left, r.top, r.right, r.bottom);
DrawText(hdc, L"你好啊，這是畫的文字！", lstrlen(L"你好啊，這是畫的文字！")
, &r, DT_BOTTOM|DT_SINGLELINE);
EndPaint(hWnd, &ps);
}
break;
}
return DefWindowProc(hWnd, Msg, wParam, lParam);
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nShowCmd)
{
//1.註冊視窗類
WNDCLASS wnd;
wnd.cbClsExtra = 0;
wnd.cbWndExtra = 0;
wnd.hbrBackground = (HBRUSH)(GetStockObject(GRAY_BRUSH));//背景色
wnd.hCursor = LoadCursor(NULL, IDC_ARROW);//游標
wnd.hIcon = LoadIcon(NULL, IDI_APPLICATION);//圖示
//wnd.lpfnWndProc = DefWindowProc;//預設視窗過程函式，用於處理訊息
wnd.lpfnWndProc = MyWindowProc;//自定義的視窗過程函式
wnd.lpszClassName = L"MrHuang";//視窗類名
wnd.lpszMenuName = NULL;//選單資源名稱
wnd.style = CS_HREDRAW | CS_DBLCLKS;//視窗類、樣式
wnd.hInstance = hInstance;//例項控制代碼
RegisterClass(&wnd);
//建立視窗(返回之前傳送WM_CREATE)
HWND hWnd = CreateWindow(L"MrHuang", L"第一個視窗程式",
WS_OVERLAPPEDWINDOW, 100, 100, 1000, 700, NULL, NULL, hInstance, NULL);
//顯示視窗
ShowWindow(hWnd, nShowCmd);
//更新視窗(傳送WM_PAINT)
UpdateWindow(hWnd);
//訊息迴圈（收到WM_QUIT訊息退出）
MSG msg;
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);//翻譯訊息
DispatchMessage(&msg);//分發訊息到視窗過程
}
}
1）什麼是雙緩衝繪製技術
2）步驟
3）CreateCompatiableDC函式
4）CreateCompatiableBitmap函式
5）BitBlt函式
6）StretchBlt函式
7）程式碼例項
#include<windows.h>
#include<CommCtrl.h>
//自定義的視窗過程
LRESULT CALLBACK MyWindowProc(HWND hWnd, UINT Msg,
WPARAM wParam, LPARAM lParam)
{
switch (Msg)
{
case WM_DESTROY:
PostQuitMessage(0);//可以使GetMessage返回0
return 0;
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hWnd, &ps);
//1.建立相容記憶體DC,此時它的大小時1X1，很小，不能繪製
HDC hMemDC=CreateCompatibleDC(hdc);
//2.建立相容點陣圖，提供繪畫區域
HBITMAP hMemBmp = CreateCompatibleBitmap(hdc, 100, 100);
//3.把相容點陣圖選到相容記憶體DC中,此刻DC的大小與點陣圖一致，可以繪製
SelectObject(hMemDC, hMemBmp);
//4.在相容記憶體DC上進行繪圖操作
SetTextColor(hMemDC, RGB(255, 0, 0));
TextOut(hMemDC, 0, 0, L"雙緩衝技術繪製！", lstrlen(L"雙緩衝技術繪製！"));
Rectangle(hMemDC, 30, 30, 80, 80);
//5.把記憶體DC中的影像一次性畫到視窗DC上
//不拉伸
BitBlt(hdc, 0, 0, 100, 100, hMemDC, 0, 0, SRCCOPY);
//拉伸(目標矩形大於源矩形)
StretchBlt(hdc, 0, 0, 400, 400, hMemDC, 0, 0,100,100, SRCCOPY);
//壓縮(目標矩形小於源矩形)
StretchBlt(hdc, 0, 0, 50, 50, hMemDC, 0, 0, 100, 100, SRCCOPY);
//釋放資源
DeleteDC(hMemDC);
DeleteObject(hMemBmp);
EndPaint(hWnd, &ps);
}
break;
}
return DefWindowProc(hWnd, Msg, wParam, lParam);
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nShowCmd)
{
//1.註冊視窗類
WNDCLASS wnd;
wnd.cbClsExtra = 0;
wnd.cbWndExtra = 0;
wnd.hbrBackground = (HBRUSH)(GetStockObject(GRAY_BRUSH));//背景色
wnd.hCursor = LoadCursor(NULL, IDC_ARROW);//游標
wnd.hIcon = LoadIcon(NULL, IDI_APPLICATION);//圖示
//wnd.lpfnWndProc = DefWindowProc;//預設視窗過程函式，用於處理訊息
wnd.lpfnWndProc = MyWindowProc;//自定義的視窗過程函式
wnd.lpszClassName = L"MrHuang";//視窗類名
wnd.lpszMenuName = NULL;//選單資源名稱
wnd.style = CS_HREDRAW | CS_DBLCLKS;//視窗類、樣式
wnd.hInstance = hInstance;//例項控制代碼
RegisterClass(&wnd);
//建立視窗(返回之前傳送WM_CREATE)
HWND hWnd = CreateWindow(L"MrHuang", L"第一個視窗程式",
WS_OVERLAPPEDWINDOW, 100, 100, 400, 400, NULL, NULL, hInstance, NULL);
//顯示視窗
ShowWindow(hWnd, nShowCmd);
//更新視窗(傳送WM_PAINT)
UpdateWindow(hWnd);
//訊息迴圈（收到WM_QUIT訊息退出）
MSG msg;
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);//翻譯訊息
DispatchMessage(&msg);//分發訊息到視窗過程
}
}
1）什麼是點陣圖
2）點陣圖繪製的步驟
3）LoadImage函式
4）SetStrechBltMode函式
5）程式碼例項
#include<windows.h>
#include<CommCtrl.h>
//自定義的視窗過程
LRESULT CALLBACK MyWindowProc(HWND hWnd, UINT Msg,
WPARAM wParam, LPARAM lParam)
{
switch (Msg)
{
case WM_DESTROY:
PostQuitMessage(0);//可以使GetMessage返回0
return 0;
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hWnd, &ps);
//1.建立記憶體相容DC（1px X 1px）
HDC hMemDC = CreateCompatibleDC(hdc);
//2.載入點陣圖資源
HBITMAP hBmp= (HBITMAP)LoadImage(NULL, L"bg.bmp", IMAGE_BITMAP, 800, 800, LR_LOADFROMFILE);
//3.把點陣圖選入到相容記憶體DC
SelectObject(hMemDC, hBmp);
//新增水印
TextOut(hMemDC, 100, 100, L"亂塗亂畫", lstrlen(L"亂塗亂畫"));
//設定影像拉伸模式
//SetStretchBltMode(hdc, COLORONCOLOR);//刪除多餘畫素
SetStretchBltMode(hdc, HALFTONE);
//4.將相容DC中的影像一次性複製到視窗DC上
//BitBlt(hdc, 0, 0, 800, 800, hMemDC, 0, 0, SRCCOPY);
//完整顯示
StretchBlt(hdc, 0, 0, 400, 400, hMemDC, 0, 0, 800,800,SRCCOPY);
//5.釋放DC與點陣圖資源
DeleteObject(hBmp);
DeleteDC(hMemDC);
EndPaint(hWnd, &ps);
}
break;
}
return DefWindowProc(hWnd, Msg, wParam, lParam);
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nShowCmd)
{
//1.註冊視窗類
WNDCLASS wnd;
wnd.cbClsExtra = 0;
wnd.cbWndExtra = 0;
wnd.hbrBackground = (HBRUSH)(GetStockObject(GRAY_BRUSH));//背景色
wnd.hCursor = LoadCursor(NULL, IDC_ARROW);//游標
wnd.hIcon = LoadIcon(NULL, IDI_APPLICATION);//圖示
//wnd.lpfnWndProc = DefWindowProc;//預設視窗過程函式，用於處理訊息
wnd.lpfnWndProc = MyWindowProc;//自定義的視窗過程函式
wnd.lpszClassName = L"MrHuang";//視窗類名
wnd.lpszMenuName = NULL;//選單資源名稱
wnd.style = CS_HREDRAW | CS_DBLCLKS;//視窗類、樣式
wnd.hInstance = hInstance;//例項控制代碼
RegisterClass(&wnd);
//建立視窗(返回之前傳送WM_CREATE)
HWND hWnd = CreateWindow(L"MrHuang", L"第一個視窗程式",
WS_OVERLAPPEDWINDOW, 100, 100, 400, 400, NULL, NULL, hInstance, NULL);
//顯示視窗
ShowWindow(hWnd, nShowCmd);
//更新視窗(傳送WM_PAINT)
UpdateWindow(hWnd);
//訊息迴圈（收到WM_QUIT訊息退出）
MSG msg;
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);//翻譯訊息
DispatchMessage(&msg);//分發訊息到視窗過程
}
}
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