[RESOLVED] Displaying a Clock in a PictureBox Problem. Displayed Time Not Exactly Right

[Hassan Basri]

Hello everybody,

I have a picturebox in which I draw a circle. I then display the time in clock format by moving 3 line objects using the following code. LH is the Hour hand, LM is the minute hand and LS is the seconds hand.

In general the code works for most times however for certain times it doesn't look right. For example 10:35 will look more like 11:35.

Anybody have an idea how to fix this, is there more precise positioning of the clock hands? Thanks for any help.

LH.X1 = picClock.ScaleWidth / 2
LH.Y1 = picClock.ScaleHeight / 2

LM.X1 = picClock.ScaleWidth / 2
LM.Y1 = picClock.ScaleHeight / 2

LS.X1 = picClock.ScaleWidth / 2
LS.Y1 = picClock.ScaleHeight / 2

LH.X2 = 0.65 * (picClock.ScaleWidth / 2) * Cos(PI / 180 * (30 * intTotalHours - 90)) + LH.X1
LH.Y2 = 0.65 * (picClock.ScaleHeight / 2) * Sin(PI / 180 * (30 * intTotalHours - 90)) + LH.Y1

LM.X2 = 0.85 * (picClock.ScaleWidth / 2) * Cos(PI / 180 * (6 * intMinute - 90)) + LH.X1
LM.Y2 = 0.85 * (picClock.ScaleHeight / 2) * Sin(PI / 180 * (6 * intMinute - 90)) + LH.Y1

LS.X2 = 0.9 * (picClock.ScaleHeight / 2) * Cos(PI / 180 * (6 * intSecond - 90)) + LH.X1
LS.Y2 = 0.9 * (picClock.ScaleHeight / 2) * Sin(PI / 180 * (6 * intSecond - 90)) + LH.Y1

[Logophobic]

While the second hand might tick forward each second, the hour and minute hands should move continuously. This means you need to calculate the angles for the hour an minute hands to at least the nearest second.

For the angle of the hour hand, calculate the number of seconds elapsed since midnight/noon and divide by 43200 (the number of seconds in a 12-hour period). This tells you what percentage of one complete rotation is complete. Multiply by 360 to get the angle in degrees, or multiply by 2*pi for radians, which you need for the trig functions.

For the angle of the minute hand, calculate the number of seconds elapsed since the beginning of the hour and divide by 3600. As above, multiply by 360 for angle in degrees, or by 2*pi for radians.

Private Sub Timer1_Timer()
  Const pi = 3.1415926535898
  Dim HAngle As Double
  Dim MAngle As Double
  Dim SAngle As Double
  Dim H As Integer
  Dim M As Integer
  Dim S As Integer
  
  Label1.Caption = Now
  H = Hour(Now)
  M = Minute(Now)
  S = Second(Now)
  
  LH.X1 = picClock.ScaleWidth / 2
  LH.Y1 = picClock.ScaleHeight / 2
  
  LM.X1 = picClock.ScaleWidth / 2
  LM.Y1 = picClock.ScaleHeight / 2
  
  LS.X1 = picClock.ScaleWidth / 2
  LS.Y1 = picClock.ScaleHeight / 2
  
  HAngle = pi * (3600 * H + 60 * M + S) / 21600 - pi / 2
  LH.X2 = 0.65 * (picClock.ScaleWidth / 2) * Cos(HAngle) + LH.X1
  LH.Y2 = 0.65 * (picClock.ScaleHeight / 2) * Sin(HAngle) + LH.Y1
  
  MAngle = pi * (60 * M + S) / 1800 - pi / 2
  LM.X2 = 0.85 * (picClock.ScaleWidth / 2) * Cos(MAngle) + LH.X1
  LM.Y2 = 0.85 * (picClock.ScaleHeight / 2) * Sin(MAngle) + LH.Y1
  
  SAngle = pi * S / 30 - pi / 2
  LS.X2 = 0.9 * (picClock.ScaleHeight / 2) * Cos(SAngle) + LH.X1
  LS.Y2 = 0.9 * (picClock.ScaleHeight / 2) * Sin(SAngle) + LH.Y1
End Sub

[Hassan Basri]

Thank you for your code Logophobic. I tried it in the application, it seems to work correctly for times that are between the hours of 1 to 8 (both am and pm) however 9 to 12 it is incorrect.

[westconn1]

to fix an overflow problem change this line

HAngle = pi * (CLng(3600) * H + 60 * M + S) / 21600 - pi / 2

then seems to work right

[Hassan Basri]

to fix an overflow problem change this line

HAngle = pi * (CLng(3600) * H + 60 * M + S) / 21600 - pi / 2

then seems to work right

Thanks westconn1, that fixed the problem.