CDC::BeginPath
デバイス コンテキストのパス ブラケットを開きます。
BOOL BeginPath();
戻り値
正常終了した場合は 0 以外を返します。それ以外の場合は 0 を返します。
解説
パス ブラケットを開いた後のアプリケーションは、パスにあるポイントを定義する GDI 描画の関数を呼び出すことができます。アプリケーションは EndPath のメンバー関数を呼び出してオープン パス ブラケットを閉じることができます。アプリケーションが BeginPathを呼び出す場合、前のパスが破棄されます。
パスのポイントを定義する描画の関数の一覧については、Windows SDK の BeginPath を参照してください。
使用例
// This implementation uses GDI paths to draw the outline of
// some text in a TrueType font. The path is used to record the way
// the TrueType font would be drawn. Then, the function uses the data
// returned from CDC::GetPath() to draw the font--without filling it.
void CDCView::DrawPath(CDC* pDC)
{
// Describe a 24-point truetype font of normal weight
LOGFONT lf;
memset(&lf, 0, sizeof(lf));
lf.lfHeight = -MulDiv(24, pDC->GetDeviceCaps(LOGPIXELSY), 72);
lf.lfWeight = FW_NORMAL;
lf.lfOutPrecision = OUT_TT_ONLY_PRECIS;
// create and select it
CFont newFont;
if (!newFont.CreateFontIndirect(&lf))
return;
CFont* pOldFont = pDC->SelectObject(&newFont);
// use a path to record how the text was drawn
pDC->BeginPath();
pDC->TextOut(10, 10, _T("Outline this!"));
pDC->EndPath();
// Find out how many points are in the path. Note that
// for long strings or complex fonts, this number might be
// gigantic!
int nNumPts = pDC->GetPath(NULL, NULL, 0);
if (nNumPts == 0)
return;
// Allocate memory to hold points and stroke types from
// the path.
LPPOINT lpPoints = NULL;
LPBYTE lpTypes = NULL;
try
{
lpPoints = new POINT[nNumPts];
lpTypes = new BYTE[nNumPts];
}
catch (CException* pe)
{
delete [] lpPoints;
lpPoints = NULL;
delete [] lpTypes;
lpTypes = NULL;
pe->Delete();
}
if (lpPoints == NULL || lpTypes == NULL)
return;
// Now that we have the memory, really get the path data.
nNumPts = pDC->GetPath(lpPoints, lpTypes, nNumPts);
// If it worked, draw the lines. Windows 98 doesn't support
// the PolyDraw API, so we use our own member function to do
// similar work. If you're targeting only later versions of
// Windows, you can use the PolyDraw() API and avoid the
// COutlineView::PolyDraw() member function.
if (nNumPts != -1)
pDC->PolyDraw(lpPoints, lpTypes, nNumPts);
// Release the memory we used
delete [] lpPoints;
delete [] lpTypes;
// Put back the old font
pDC->SelectObject(pOldFont);
return;
}
必要条件
ヘッダー: afxwin.h