使用路徑

本節包含程式碼範例，可讓使用者使用 [選擇字型] 對話方塊) 選取特定點大小 (的) 字型、使用以這個字型繪製的文字來選取裁剪路徑 (，然後檢視裁剪至文字的結果。

此程式碼範例用來建立出現在 剪輯路徑中的圖例。

CHOOSEFONT cf;          // common dialog box font structure  
LOGFONT lf;             // logical font structure  
HFONT hfont;            // new logical font handle  
HFONT hfontOld;         // original logical font handle  
HDC hdc;                // display DC handle  
int nXStart, nYStart;   // drawing coordinates  
RECT rc;                // structure for painting window  
SIZE sz;                // structure that receives text extents  
double aflSin[90];      // sine of 0-90 degrees  
double aflCos[90];      // cosine of 0-90 degrees  
double flRadius,a;      // radius of circle  
int iMode;              // clipping mode  
HRGN hrgn;              // clip region handle  
 
LRESULT APIENTRY MainWndProc( 
    HWND hwnd,                // window handle  
    UINT message,             // type of message  
    WPARAM wParam,            // additional information  
    LPARAM lParam)            // additional information  
 
{ 
 
    PAINTSTRUCT ps; 
 
    switch (message) 
    { 
        case WM_PAINT: 
            hdc = BeginPaint(hwnd, &ps); 
            EndPaint(hwnd, &ps); 
            break; 
 
        case WM_COMMAND:     // command from app's menu  
            switch (wParam) 
            { 
                case IDM_VANISH:  // erases client area  
                    hdc = GetDC(hwnd); 
                    GetClientRect(hwnd, &rc); 
                    FillRect(hdc, &rc, GetStockObject(WHITE_BRUSH)); 
                    ReleaseDC(hwnd, hdc); 
                    break; 
 
                case IDM_AND: // sets clip mode to RGN_AND  
                    iMode = RGN_AND; 
                    break; 
 
                case IDM_COPY: // sets clip mode to RGN_COPY  
                    iMode = RGN_COPY; 
                    break; 
 
                case IDM_DIFF: // sets clip mode to RGN_DIFF  
                    iMode = RGN_DIFF; 
                    break; 
 
                case IDM_OR: // sets clip mode to RGN_OR  
                    iMode = RGN_OR; 
                    break; 
 
                case IDM_XOR: // sets clip mode to RGN_XOR  
                    iMode = RGN_XOR; 
                    break; 
 
                case IDM_CLIP_PATH: 
 
                    // Retrieve a cached DC for the window.  
 
                    hdc = GetDC(hwnd); 
 
                    // Use the font requested by the user in the  
                    // Choose Font dialog box to create a logical 
                    // font, then select that font into the DC.  
 
                    hfont = CreateFontIndirect(cf.lpLogFont); 
                    hfontOld = SelectObject(hdc, hfont); 
 
                    // Retrieve the dimensions of the rectangle  
                    // that surrounds the text.  
 
                    GetTextExtentPoint32(hdc, "Clip Path", 9, &sz); 
 
                    // Set a clipping region using the rect that  
                    // surrounds the text.  
 
                    hrgn = CreateRectRgn(nXStart, nYStart, 
                        nXStart + sz.cx, 
                        nYStart + sz.cy); 
 
                    SelectClipRgn(hdc, hrgn); 
 
                    // Create a clip path using text drawn with  
                    // the user's requested font.  
 
                    BeginPath(hdc); 
                    TextOut(hdc, nXStart, nYStart, "Clip Path", 9); 
                    EndPath(hdc); 
                    SelectClipPath(hdc, iMode); 
 
                    // Compute the sine of 0, 1, ... 90 degrees.  
                    for (i = 0; i < 90; i++) 
                    { 
                        aflSin[i] = sin( (((double)i) / 180.0) 
                                    * 3.14159); 
                    } 
 
                    // Compute the cosine of 0, 1,... 90 degrees.  
                    for (i = 0; i < 90; i++) 
                    { 
                        aflCos[i] = cos( (((double)i) / 180.0) 
                                    * 3.14159); 
                    } 
 
                    // Set the radius value.  
 
                    flRadius = (double)(2 * sz.cx); 
 
                    // Draw the 90 rays extending from the  
                    // radius to the edge of the circle.  
 
                    for (i = 0; i < 90; i++) 
                    { 
                        MoveToEx(hdc, nXStart, nYStart, 
                           (LPPOINT) NULL); 
                        LineTo(hdc, nXStart + ((int) (flRadius 
                            * aflCos[i])), 
                               nYStart + ((int) (flRadius 
                            * aflSin[i]))); 
                    } 
 
                    // Reselect the original font into the DC.  
 
                    SelectObject(hdc, hfontOld); 
 
                    // Delete the user's font.  
 
                    DeleteObject(hfont); 
 
                    // Release the DC.  
 
                    ReleaseDC(hwnd, hdc); 
 
                    break; 
 
 
                case IDM_FONT: 
 
                    // Initialize necessary members.  
 
                    cf.lStructSize = sizeof (CHOOSEFONT); 
                    cf.hwndOwner = hwnd; 
                    cf.lpLogFont = &lf; 
                    cf.Flags = CF_SCREENFONTS | CF_EFFECTS; 
                    cf.rgbColors = RGB(0, 255, 255); 
                    cf.nFontType = SCREEN_FONTTYPE; 
 
                    // Display the Font dialog box, allow the user  
                    // to choose a font, and render text in the  
                    // window with that selection.  
 
                    if (ChooseFont(&cf)) 
                    { 
                        hdc = GetDC(hwnd); 
                        hfont = CreateFontIndirect(cf.lpLogFont); 
                        hfontOld = SelectObject(hdc, hfont); 
                        crOld = SetTextColor(hdc, cf.rgbColors); 
                        TextOut(hdc, nXStart, nYStart, 
                            "Clip Path", 9); 
                        SetTextColor(hdc, crOld); 
                        SelectObject(hdc, hfontOld); 
                        DeleteObject(hfont); 
                        ReleaseDC(hwnd, hdc); 
                    } 
 
                    break; 
 
                default: 
                    return DefWindowProc(hwnd, message, wParam, 
                        lParam); 
            } 
            break; 
 
        case WM_DESTROY:    // window is being destroyed  
            PostQuitMessage(0); 
            break; 
 
        default: 
            return DefWindowProc(hwnd, message, wParam, lParam); 
    } 
    return 0; 
}