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Diffstat (limited to 'html/en/func/lines.html')
| -rw-r--r-- | html/en/func/lines.html | 22 |
1 files changed, 13 insertions, 9 deletions
diff --git a/html/en/func/lines.html b/html/en/func/lines.html index b748391..6ba78d7 100644 --- a/html/en/func/lines.html +++ b/html/en/func/lines.html @@ -1,5 +1,5 @@ <!doctype HTML PUBLIC "-//IETF//DTD HTML//EN"> -<html> +<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office"> <head> <meta http-equiv="Content-Language" content="en-us"> @@ -64,21 +64,25 @@ canvas:fArc(xc, yc, w, h, angle1, angle2: <em>number</em>) [in Lua] canvas:wArc(xc, yc, w, h, angle1, angle2: <em>number</em>)<font><font> (WC) [in Lua]</font></font></pre> <p>Draws the arc of an ellipse aligned with the axis, using the current - foreground color and line width and style. It is drawn counter-clockwise. The + foreground color and line width and style.</p> +<p>The coordinate <b>(xc,yc)</b> defines the center of the ellipse. Dimensions <b>w</b> and <b>h</b> define the elliptic axes X and Y, respectively. </p> - <p>Angles <b>angle1</b> and <b>angle2</b>, in degrees define - the arc's beginning and end, but they are not the angle relative to the + <p>Angles <b>angle1</b> and <b>angle2</b> are in degrees and oriented + counter-clockwise. They define + the arc start and end, but they are not the angle relative to the center, except when w==h and the ellipse is reduced to a circle. The arc - starts at the point <b><b>(xc+(w/2)*cos(angle1),yc+(h/2)*sin(angle1))</b> - </b>and ends at <b>(xc+(w/2)*cos(angle2),yc+(h/2)*sin(angle2))</b>. A - complete ellipse can be drawn using 0 and 360 as the angles. </p> + starts at the point <b><b>(xc+(w/2)*cos(angle1), yc+(h/2)*sin(angle1))</b> + </b>and ends at <b>(xc+(w/2)*cos(angle2), yc+(h/2)*sin(angle2))</b>. A + complete ellipse can be drawn using 0 and 360 as the angles. If <b>angle2</b> + is less than <b>angle1</b> it will be increased by 360 until it is greater + than <b>angle1</b>. </p> <p>The angles are specified so if the size of the ellipse (w x h) is changed, its shape is preserved. So the angles relative to the center are dependent from the ellipse size. The actual angle can be obtained using <b>rangle = - atan2((h/2</b><b>)*sin(angle),(w/2)*cos(angle))</b>.</p> - <p>The angles are given in degrees. To specify the angle in radians, you can + atan2((h/2</b><b>)*sin(angle), (w/2)*cos(angle))</b>.</p> + <p>To specify the angle in radians, you can use the definition <font size="2"><strong>CD_RAD2DEG</strong></font> to multiply the value in radians before passing the angle to CD.</p> <p align="center"><font size="4">Arc Parameters<br> |