描述

 

Draws a sequence of connected B閦ier splines.

 

C++ Syntax

 

 

FreeBASIC 语法

 

 

参数

 

pPen

 

[in] Pointer to a pen that is used to draw the B閦ier splines.

 

pts

 

[in] Pointer to an array of PointF objects that specify the starting, ending, and control points of the B閦ier splines.

 

count

 

[in]整数,指定的点的数组元素个数.

 

返回值

 

如果该方法成功,则返回Ok,这是对Status枚举元素.

如果这个方法失败,它返回一个枚举的其他元素的Status.

 

备注

 

A B閦ier spline does not pass through its control points. The control points act as magnets, pulling the curve in certain directions to influence the way a B閦ier spline bends. Each B閦ier spline requires a starting point and an ending point. Each ending point is the starting point for the next B閦ier spline.

 

引用文件

 

CGpBitmap.inc (include CGdiPlus.inc)

 

示例

 

' ========================================================================================

' The following example draws a pair of B閦ier curves.

' ========================================================================================

SUB Example_DrawBeziers (BYVAL hdc AS HDC)

 

  ' // Create a graphics object from the window device context

  DIM graphics AS CGpGraphics = hdc

  ' // Get the DPI scaling ratio

  DIM rxRatio AS SINGLE = graphics.GetDpiX / 96

  DIM ryRatio AS SINGLE = graphics.GetDpiY / 96

  ' // Set the scale transform

  graphics.ScaleTransform(rxRatio, ryRatio)

 

  ' // Define a Pen object and an array of PointF objects.

  DIM greenPen AS CGpPen = GDIP_ARGB(255, 0, 255, 0)

  DIM startPoint AS GpPointF : startPoint.x = 100.0 : startPoint.y = 100.0

  DIM ctrlPoint1 AS GpPointF : ctrlPoint1.x = 200.0 : ctrlPoint1.y = 50.0

  DIM ctrlPoint2 AS GpPointF : ctrlPoint2.x = 400.0 : ctrlPoint2.y = 10.0

  DIM endPoint1  AS GpPointF : endPoint1.x  = 500.0 : endPoint1.y  = 100.0

  DIM ctrlPoint3 AS GpPointF : ctrlPoint3.x = 600.0 : ctrlPoint3.y = 200.0

  DIM ctrlPoint4 AS GpPointF : ctrlPoint4.x = 700.0 : ctrlPoint4.y = 400.0

  DIM endPoint2  AS GpPointF : endPoint2.x  = 500.0 : endPoint2.y  = 500.0

 

  DIM curvePoints(6) AS GpPointF

  curvePoints(0) = startPoint

  curvePoints(1) = ctrlPoint1

  curvePoints(2) = ctrlPoint2

  curvePoints(3) = endPoint1

  curvePoints(4) = ctrlPoint3

  curvePoints(5) = ctrlPoint4

  curvePoints(6) = endPoint2

 

  ' // Draw the Bezier curves.

  graphics.DrawBeziers(@greenPen, @curvePoints(0), 7)

 

  ' // Draw the control and end points.

  DIM redBrush AS CGpSolidBrush = GDIP_ARGB(255, 255, 0, 0)

  graphics.FillEllipse(@redBrush, 100 - 5, 100 - 5, 10, 10)

  graphics.FillEllipse(@redBrush, 500 - 5, 100 - 5, 10, 10)

  graphics.FillEllipse(@redBrush, 500 - 5, 500 - 5, 10, 10)

  DIM blueBrush AS CGpSolidBrush = GDIP_ARGB(255, 0, 0, 255)

  graphics.FillEllipse(@blueBrush, 200 - 5, 50 - 5, 10, 10)

  graphics.FillEllipse(@blueBrush, 400 - 5, 10 - 5, 10, 10)

  graphics.FillEllipse(@blueBrush, 600 - 5, 200 - 5, 10, 10)

  graphics.FillEllipse(@blueBrush, 700 - 5, 400 - 5, 10, 10)

 

END SUB

' ========================================================================================