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发信人: bloom (├┝┞┟┠┢┣�), 信区: VB
标  题: API函数使用手册之 AngleArc(转载)
发信站: 哈工大紫丁香 (2000年09月07日18:35:00 星期四), 转信

【以下文字转载自 cnTemp 讨论区】
【原文由 catchy 所发表】
发信人: espn (小楼一夜听春雨), 信区: VisualBasic
发信站: BBS 水木清华站 (Wed Mar 29 20:32:32 2000)

Declare Function AngleArc Lib "gdi32.dll" (ByVal hdc As Long, ByVal x
As Long, ByVal y As Long, ByVal dwRadius As Long, ByVal eStartAngle As
Single, ByVal eSweepAngle As Single) As Long

Platforms: Win NT

AngleArc draws a circular arc on a graphics-capable device. The circle
that the arc is drawn on is determined by its center and radius. The
starting and ending points of the arc are determined by angle measures
in degrees (o). 0o is due right, 90o is due up, 180o is due left, and
270o is due down. Of course, any other angle measures can be used. The
arc is drawn in the direction determined by SetArcDirection and using
the device's current drawing color. The function returns 1 if
successful, or 0 if an error occured.

hdc
The device context of the device to draw the arc on.
x
The x coordinate of the center of the circle.
y
The y coordinate of the center of the circle.
dwRadius
The radius of the circle.
eStartAngle
The angle (in degrees) identifying the starting point of the arc.
eSweepAngle
The angle (in degrees) identifying the ending point of the arc.
Example:

' Draw an arc formed by the upper half of a circle (from 0 to 180
' degrees counterclockwise).  The circle is centered at (100, 150) and
has a radius
' of 50.  The arc is drawn in red on the window Form1.
Dim retval As Long  ' return value

Form1.ForeColor = RGB(255, 0, 0)  ' set the drawing color to red
' Make sure arcs are drawn going counterclockwise
retval = SetArcDirection(Form1.hDC, AD_COUNTERCLOCKWISE)
' Draw the arc
retval = AngleArc(Form1.hDC, 100, 150, 50, 0, 180)

--
Standing on the bridge that crosses
The river that goes out to the sea,
The wind is full of a thousand voices
They pass by the bridge and me...

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