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CPen::CPen

Constructs a CPen object.

CPen( ); 
CPen( 
   int nPenStyle, 
   int nWidth, 
   COLORREF crColor  
); 
CPen( 
   int nPenStyle, 
   int nWidth, 
   const LOGBRUSH* pLogBrush, 
   int nStyleCount = 0, 
   const DWORD* lpStyle = NULL  
);

nPenStyle

Specifies the pen style. This parameter in the first version of the constructor can be one of the following values:

  • PS_SOLID   Creates a solid pen.

  • PS_DASH   Creates a dashed pen. Valid only when the pen width is 1 or less, in device units.

  • PS_DOT   Creates a dotted pen. Valid only when the pen width is 1 or less, in device units.

  • PS_DASHDOT   Creates a pen with alternating dashes and dots. Valid only when the pen width is 1 or less, in device units.

  • PS_DASHDOTDOT   Creates a pen with alternating dashes and double dots. Valid only when the pen width is 1 or less, in device units.

  • PS_NULL   Creates a null pen.

  • PS_INSIDEFRAME   Creates a pen that draws a line inside the frame of closed shapes produced by the Windows GDI output functions that specify a bounding rectangle (for example, the Ellipse, Rectangle, RoundRect, Pie, and Chord member functions). When this style is used with Windows GDI output functions that do not specify a bounding rectangle (for example, the LineTo member function), the drawing area of the pen is not limited by a frame.

The second version of the CPen constructor specifies a combination of type, style, end cap, and join attributes. The values from each category should be combined by using the bitwise OR operator (|). The pen type can be one of the following values:

  • PS_GEOMETRIC   Creates a geometric pen.

  • PS_COSMETIC   Creates a cosmetic pen.

    The second version of the CPen constructor adds the following pen styles for nPenStyle:

  • PS_ALTERNATE   Creates a pen that sets every other pixel. (This style is applicable only for cosmetic pens.)

  • PS_USERSTYLE   Creates a pen that uses a styling array supplied by the user.

    The end cap can be one of the following values:

  • PS_ENDCAP_ROUND   End caps are round.

  • PS_ENDCAP_SQUARE   End caps are square.

  • PS_ENDCAP_FLAT   End caps are flat.

    The join can be one of the following values:

  • PS_JOIN_BEVEL   Joins are beveled.

  • PS_JOIN_MITER   Joins are mitered when they are within the current limit set by the SetMiterLimit function. If the join exceeds this limit, it is beveled.

  • PS_JOIN_ROUND   Joins are round.

nWidth

Specifies the width of the pen.

  • For the first version of the constructor, if this value is 0, the width in device units is always 1 pixel, regardless of the mapping mode.

  • For the second version of the constructor, if nPenStyle is PS_GEOMETRIC, the width is given in logical units. If nPenStyle is PS_COSMETIC, the width must be set to 1.

crColor

Contains an RGB color for the pen.

pLogBrush

Points to a LOGBRUSH structure. If nPenStyle is PS_COSMETIC, the lbColor member of the LOGBRUSH structure specifies the color of the pen and the lbStyle member of the LOGBRUSH structure must be set to BS_SOLID. If nPenStyle is PS_GEOMETRIC, all members must be used to specify the brush attributes of the pen.

nStyleCount

Specifies the length, in doubleword units, of the lpStyle array. This value must be zero if nPenStyle is not PS_USERSTYLE.

lpStyle

Points to an array of doubleword values. The first value specifies the length of the first dash in a user-defined style, the second value specifies the length of the first space, and so on. This pointer must be NULL if nPenStyle is not PS_USERSTYLE.

If you use the constructor with no arguments, you must initialize the resulting CPen object with the CreatePen, CreatePenIndirect, or CreateStockObject member functions.

If you use the constructor that takes arguments, then no further initialization is necessary. The constructor with arguments can throw an exception if errors are encountered, while the constructor with no arguments will always succeed.

// Create a solid red pen of width 2.
CPen myPen1(PS_SOLID, 2, RGB(255,0,0));

// Create a geometric pen.
LOGBRUSH logBrush;
logBrush.lbStyle = BS_SOLID;
logBrush.lbColor = RGB(0,255,0);
CPen myPen2(PS_DOT|PS_GEOMETRIC|PS_ENDCAP_ROUND, 2, &logBrush);

Header: afxwin.h

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