CreatePen

MSDN中这样写到：：

The CreatePen function creates a logical pen that has the specified style, width, and color. The pen can subsequently be selected into a device context and used to draw lines and curves.

HPEN CreatePen(
  int fnPenStyle,    // pen style
  int nWidth,        // pen width
  COLORREF crColor   // pen color
);

Parameters

fnPenStyle

[in] Specifies the pen style. It can be any one of the following values.

Value	Meaning
PS_SOLID	The pen is solid.
PS_DASH	The pen is dashed. This style is valid only when the pen width is one or less in device units.
PS_DOT	The pen is dotted. This style is valid only when the pen width is one or less in device units.
PS_DASHDOT	The pen has alternating dashes and dots. This style is valid only when the pen width is one or less in device units.
PS_DASHDOTDOT	The pen has alternating dashes and double dots. This style is valid only when the pen width is one or less in device units.
PS_NULL	The pen is invisible.
PS_INSIDEFRAME	The pen is solid. When this pen is used in any GDI drawing function that takes a bounding rectangle, the dimensions of the figure are shrunk so that it fits entirely in the bounding rectangle, taking into account the width of the pen. This applies only to geometric pens.

nWidth

[in] Specifies the width of the pen, in logical units. If nWidth is zero, the pen is a single pixel wide, regardless of the current transformation.

CreatePen returns a pen with the specified width bit with the PS_SOLID style if you specify a width greater than one for the following styles: PS_DASH, PS_DOT, PS_DASHDOT, PS_DASHDOTDOT.

crColor

[in] Specifies a color reference for the pen color. To generate a COLORREF structure, use the RGB macro.

Return Values

If the function succeeds, the return value is a handle that identifies a logical pen.

If the function fails, the return value is NULL.

Windows NT/2000/XP: To get extended error information, call GetLastError.

Remarks

After an application creates a logical pen, it can select that pen into a device context by calling the SelectObject function. After a pen is selected into a device context, it can be used to draw lines and curves.

If the value specified by the nWidth parameter is zero, a line drawn with the created pen always is a single pixel wide regardless of the current transformation.

If the value specified by nWidth is greater than 1, the fnPenStyle parameter must be PS_NULL, PS_SOLID, or PS_INSIDEFRAME.

If the value specified by nWidth is greater than 1 and fnPenStyle is PS_INSIDEFRAME, the line associated with the pen is drawn inside the frame of all primitives except polygons and polylines.

If the value specified by nWidth is greater than 1, fnPenStyle is PS_INSIDEFRAME, and the color specified by the crColor parameter does not match one of the entries in the logical palette, the system draws lines by using a dithered color. Dithered colors are not available with solid pens.

When you no longer need the pen, call the DeleteObject function to delete it.

ICM: No color management is done at creation. However, color management is performed when the pen is selected into an ICM-enabled device context.

Example Code

For an example, see Creating Colored Pens and Brushes.

Requirements

  Windows NT/2000/XP: Included in Windows NT 3.1 and later.   Windows 95/98/Me: Included in Windows 95 and later.   Header: Declared in Wingdi.h; include Windows.h.   Library: Use Gdi32.lib.

See Also

Pens Overview, Pen Functions, CreatePenIndirect, COLORREF, DeleteObject, ExtCreatePen, GetObject, RGB, SelectObject

参数	类型及说明
nPenStyle	Long，指定画笔样式，可以是下述常数之一
	PS_SOLID	画笔画出的是实线
	PS_DASH	画笔画出的是虚线（nWidth必须是1）
	PS_DOT	画笔画出的是点线（nWidth必须是1）
	PS_DASHDOT	画笔画出的是点划线（nWidth必须是1）
	PS_DASHDOTDOT	画笔画出的是点-点-划线（nWidth必须是1）
	PS_NULL	画笔不能画图
	PS_INSIDEFRAME	画笔在由椭圆、矩形、圆角矩形、饼图以及弦等生成的封闭对象框中画图。如指定的准确RGB颜色不存在，就进行抖动处理
nWidth	Long，以逻辑单位表示的画笔的宽度
crColor	Long，画笔的RGB颜色
注解
一旦不再需要画笔，记得用DeleteObject函数将其删除