ImageDrawArc

Description

Draws a circular or elliptical arc.

Returns

Nothing.

Category

Image functions

Function syntax

ImageDrawArc(name, x, y, width, height, startAngle, arcAngle [, filled])

See also

ImageDrawCubicCurve, ImageDrawOval, ImageDrawQuadraticCurve, ImageSetAntialiasing, ImageSetDrawingColor, ImageSetDrawingStroke, IsImageFile

History

ColdFusion 8: Added this function.

Parameters

Parameter

Description

name

Required. The ColdFusion image on which this operation is performed.

x

Required. The x coordinate of the upper-left corner of the arc.

y

Required. The y coordinate of the upper-left corner of the arc.

width

Required. The width of the arc.

height

Required. The height of the arc.

startAngle

Required. The beginning angle in degrees.

arcAngle

Required. The angular extent of the arc, relative to the start angle.

filled

Optional. Specify whether the arc is filled:

  • yes: The arc is filled with the specified drawing color.

  • no: Only the outline of the arc is drawn (default).

Usage

The resulting arc begins at startAngle and extends for arcAngle degrees. Degrees start at 0 in the three o’clock position. A positive value indicates a counter-clockwise rotation; a negative value indicates a clockwise rotation.

The center of the arc is the center of the rectangle whose origin is (x,y) and whose size is specified by the width and height parameters.

The angles are specified relative to the non-square extents of the bounding rectangle so that 45 degrees always falls on the line from the center of the ellipse to the upper-right corner of the bounding rectangle. As a result, if the bounding rectangle is noticeably longer on one axis than the other, the angles to the start and end of the arc segment are skewed farther along the longer axis of the bounds.

If the filled parameter is set to yes, the area inside the oval is filled with the current drawing color.

Use the ImageSetDrawingColor and ImageSetDrawingStroke functions to specify the color and line attributes of the arc. Use the ImageSetAntialiasing function to improve the quality of the rendered image.

Example

<!--- This example shows how to use the ImageNew function to create a blank 
ColdFusion image that is 250 pixels wide and 180 pixels high. ---> 
<cfset myImage=ImageNew("",250,320)> 
<!--- Set the drawing color for the arc to orange. ---> 
<cfset ImageSetDrawingColor(myImage,"orange")> 
<!--- Turn on antialiasing to improve image quality. ---> 
<cfset ImageSetAntialiasing(myImage,"on")> 
<!--- Draw an enclosed orange arc starting at the coordinate (5,5). ---> 
<cfset ImageDrawArc(myImage,5,5,200,300,100,100,"yes")> 
<!--- Display the image in a browser. ---> 
<cfimage action="writeToBrowser" source="#myImage#">