Did I mention I hate math [grin]... ok...so here we go so far... I am passing a variable diameter of the arc ($d), the total number of widgets possible ($n), and the number of current widgets ($x)

so let's say $d = 100 $n = 100 $x = 50 $perc = $x / $n (0.50 or 50 %) degree conversion = # * (180/M_PI) asin($perc) converted to degrees = 30 acos($perc) converted to degrees = 60 my arc runs from 180 deg. to 360/0 degree, or left to right, pointing upwards (upside down U). i guess I am not getting my head around the numbers...is there anywhere on the net that has a good thorough description about a process like this? Thx. mike > -----Original Message----- > From: Darren Gamble [mailto:[EMAIL PROTECTED]] > Sent: Friday, May 31, 2002 11:40 AM > To: 'Michael Geier'; Php-General > Subject: RE: [PHP] gd project question > > > Good day, > > Wow, a high school math question. > > You should use asin() and acos() of the angle to get the y and x > differentials, respectively. Multiply the result by the size of > the needle. > > This assumes that your guage is oriented horizontally, and the > needle sweeps > from right to left, pointing upwards. Adjust the sign or switch the > functions around if your gauge is different. > > Note that the functions operate in radians (2*pi radians == 360 degrees). > > ============================ > Darren Gamble > Planner, Regional Services > Shaw Cablesystems GP > 630 - 3rd Avenue SW > Calgary, Alberta, Canada > T2P 4L4 > (403) 781-4948 > > > > -----Original Message----- > > From: Michael Geier [mailto:[EMAIL PROTECTED]] > > Sent: Friday, May 31, 2002 9:18 AM > > To: Php-General > > Subject: [PHP] gd project question > > > > > > I have the following issue: > > > > I am making a "gas guage" based on a percentage. > > ie. > > - a 180 degree arc is created > > - the range will be 0 to n (undetermined ammount) > > - there will be x number of entries > > - the needle will pount to a a percentage > > for (int)floor((x / n) * 100) > > > > The issue is, I have the starting pt for the needle > > (imagefilledarc > > needs the center of the 'circle' as the starting pt, > > which is where > > the needle will start too), but how would I get the x|y > > coordinates > > for the end of the needle based on a perentage of a half-circle > > (180 degree arc)? > > > > Appreciate any clues or ideas. > > > > --- > > Michael Geier > > > > > > -- > > PHP General Mailing List (http://www.php.net/) > > To unsubscribe, visit: http://www.php.net/unsub.php > > > > -- > PHP General Mailing List (http://www.php.net/) > To unsubscribe, visit: http://www.php.net/unsub.php > -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php