I am trying to create a pie chart that shows the minimum balance of an account in relation to the actual balance of the account.

My problem is i can't figure out how to get this percentage into actual coordinates.

I am using 0,0 as my starting left point and 100,100 as my ending right point of the pie chart.

So if the numbers were $25 minimum $100 balance, how could i convert that into pie chart points?

I dont have math book with me, but there are formulas to calculate starting and ending points of the pie. In your example, 25% would be simple, cause no big calculations are necessary.

Pie Me.hdc, 0, 0, 100, 100, 100, 50, 50, 0

I have attached an graphics example (drawn by me   ) of how pie API works, so oyu can understand it better (x1,y1)-(x2,y2) are left-top/right-bottom coordinaters of rectangle, (Sx,Sy) - starting point of the pie (Ex,Ey) ending point of the pie.

[Edited by Goran on 04-05-2004 at 05:39 PM GMT]

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By the way, similar thing you can do with Circle command, I have made you a code that will show you the idea:

Private Sub DrawPie(Percent As Single) Const pi = 3.141592654 Dim ratio As Single     Me.Cls     ratio = (10 / 8 - Percent / 100)     If ratio > 1 Then ratio = ratio - 1          Circle (2500, 2500), 1000, , -2 * pi * ratio, -pi / 2 End Sub

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Thank you very much for the help.

I worked out an approximation that works pretty good...

dblBal = (minBalance / AcctBalance) * 100 If dblBal <= 25 Then     X1 = dblBal * 2     Y1 = 0     X2 = 0     Y2 = dblBal * 2     XX1 = 0     YY1 = dblBal * 2     XX2 = dblBal * 2     YY2 = 0 End If If dblBal > 25 And dblBal <= 50 Then     X1 = dblBal     Y1 = 0     X2 = dblBal     Y2 = dblBal * 2     XX1 = dblBal     YY1 = dblBal * 2     XX2 = dblBal     YY2 = 0 End If If dblBal > 50 And dblBal <= 75 Then     X1 = dblBal * 0.667     Y1 = 0     X2 = dblBal * 1.333     Y2 = dblBal * 0.667     XX1 = dblBal * 1.333     YY1 = dblBal * 0.667     XX2 = dblBal * 0.667     YY2 = 0 End If If dblBal > 75 And dblBal <= 99 Then     X1 = dblBal * 1.143     Y1 = 0     X2 = dblBal * 1.143     Y2 = dblBal * 0.571     XX1 = dblBal * 1.143     YY1 = dblBal * 0.571     XX2 = dblBal * 1.143     YY2 = 0 End If If dblBal = 100 Then     X1 = 50     Y1 = 0     X2 = 50     Y2 = 0 End If

Here is my teachers reply to this problem...

quote:

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This looks to be a kind of approximation.  The problem is it's a linear approximation of a curve.  I think for the purposes of this pie chart it should work out okay--the visual appearance of the chart will be close enough for its purpose.  However, if you want to get exact about it, here's the right approach as I remember it.  Let's suppose that the percentage is between 0 and 12.5%, and we want our wedge to be in the upper part of the right side of the pie.  That means that the angle of our pie piece is between 0 and 45 degrees, right?  If you place the whole pie in a square that's the same size, then if we extend the lines on the side of the pie piece they would make a right triangle when they met the line on the right side of the square.  We need both points where these lines would meet the square.  One is fixed, it's halfway up the right side.  The other's the trick.  But since we have a right triangle, we just use the tangent function, which gives us the ratio of the opposite side to the adjacent side.  The adjacent side's length is just the radius of the circle, and we can get the angle by dividing 100 percentage points into 360 degrees.  That gives us the length of the opposite side which tells us where to place that other point.

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Yes, your teacher is right. He was explaining yoo how to determine your second line of the pie, since first line is not changing. And as I said, there is a math formula, but I cant recall how it goes, and your teacher was giving you a clue how to implement this function (as he says it is tangent function which is used on right triangle). You would have to look in a math book and find this funciton in order to implement it in your code.

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