morphlcd.ctl

串口通讯。上位机实例.提供了良好的界面。对初学者很有参考性

'*************************************************************************
'* displays the value stored in the .Value property.  The 'ForceDisplay' *
'* parameter is used to force a redisplay when a property is changed.    *
'*************************************************************************

   Dim sMainValue     As String    ' non-exponential, main value.
   Dim sExponentValue As String    ' up to n_NumDigitsExp long exponent (including sign).
   Dim IsBase10       As Boolean   ' not using this function return value now.

'  just in case, so exponent "E" and hex digits get processed correctly.
   sValue = UCase(sValue)

'  a catch for if there isn't a 0 in front of the decimal separator in a
'  fractional value.  (That won't happen if control is used correctly.)
   If Left(sValue, 1) = "." Then
      sValue = "0" & sValue
   End If

'  determine the color brush to use when displaying the value.
   If Val(sValue) < 0 Then

'     value is negative; use negative value color brushes.
      CurrentLitColorBrush = LCDLitColorBrushNeg
      CurrentBurnInColorBrush = LCDBurnInColorBrushNeg

'     a word about the PreviousNegative stuff... Normally individual display digits are drawn
'     only if the digit has changed from the previous displayed digit in the same position.
'     This saves a great deal of time in my timing tests.  However, when the sign is changed
'     when a new value is displayed, we have to force a redraw of every digit, even if they're
'     the same as in previous display.  That way a displayed value can't be a mishmash of
'     positive and negative value colors.
      If Not PreviousNegative Then
         PreviousMainValue = String(m_NumDigits, "X")
         PreviousExponentValue = String(m_NumDigitsExp, "X")
      End If
      PreviousNegative = True

   Else

'     value is positive; use regular (positive number) color brushes.
      CurrentLitColorBrush = LCDLitColorBrush
      CurrentBurnInColorBrush = LCDBurnInColorBrush

      If PreviousNegative Then
         PreviousMainValue = String(m_NumDigits, "X")
         PreviousExponentValue = String(m_NumDigitsExp, "X")
      End If
      PreviousNegative = False

   End If

'  separate possible exponent from overall value.
   IsBase10 = SeparateMainValueAndExponent(sValue, sMainValue, sExponentValue)

'  display the main value, and also the exponent if permitted by the ShowExponent property.
   DisplayMainValue sMainValue, ForceDisplay
   If m_ShowExponent Then
      DisplayExponentValue sExponentValue, ForceDisplay
   End If

End Sub

Private Function SeparateMainValueAndExponent(ByVal sValue As String, ByRef sMainValue As String, ByRef ExponentValue As String) As Boolean

'*************************************************************************
'* if it's an exponential base-10 number, separates the exponent and the *
'* main value.  Otherwise returns the value and spaces for exponent.     *
'*************************************************************************

   Dim ExpPos       As Long      ' position in value of exponent symbols E+ or E-.
   Dim ExponentSign As String    ' what sign the exponent is (+ or -).

   If InStr(sValue, "E+") > 0 Or InStr(sValue, "E-") > 0 Then

'     since we see an "E" followed by a "+" or "-" we know it's the base-10
'     exponent "E", not hex "E".  Separate the main value and exponent.
      ExpPos = InStr(sValue, "E+")
      If ExpPos = 0 Then
         ExpPos = InStr(sValue, "E-")
      End If
      sMainValue = Left(sValue, ExpPos - 1)
      ExponentSign = Mid(sValue, ExpPos + 1, 1)
      ExponentValue = Right(sValue, Len(sValue) - ExpPos - 1)

'     grab appropriate part of exponent depending on whether
'     we're displaying calculation result exponent or seconds.
      If InStr(sValue, ":") = 0 Then
         ExponentValue = Right(String(m_NumDigitsExp - 1, "0") & ExponentValue, m_NumDigitsExp - 1)
      Else
         ExponentValue = Right(String(m_NumDigitsExp - 1, "0") & ExponentValue, m_NumDigitsExp)
      End If
      If ExponentSign = "-" Then
         ExponentValue = ExponentSign & ExponentValue
      Else
         ExponentValue = " " & ExponentValue
      End If
      SeparateMainValueAndExponent = True

   Else

'     could be hex, or a non-exponential decimal value.  Just return the original value.
      sMainValue = sValue
      ExponentValue = String(m_NumDigitsExp, " ")

   End If

End Function

Private Sub DisplayMainValue(strValue As String, ByVal ForceDisplay As Boolean)

'*************************************************************************
'* displays non-exponent portion of value stored in .Value property.     *
'*************************************************************************

   Dim s            As String    ' right-justified version of value.
   Dim i            As Long      ' loop variable.
   Dim CurrentDigit As String    ' the current digit being displayed.

   ExponentFlag = False

   s = strValue

'  determine thousands separator placement, if they are to be displayed.
   If m_ShowThousandsSeparator Then
      DetermineThousandsSeparatorPlacement s
      DisplayThousandsSeparators
   End If

'  erase old decimal separator if displayed; display new one if necessary.
   ProcessDecimalSeparator s

'  erase old colon if displayed; display new one if necessary.
   ProcessColon s

'  pad the value with leading spaces.
   s = Right(Space(m_NumDigits) & s, m_NumDigits)

'  display the main value.  Only draw a digit if the particular digit being
'  drawn is different from digit the previous time value was displayed.
   Select Case m_SegmentStyle

      Case [Hexagonal]
         For i = 1 To m_NumDigits
            CurrentDigit = Mid(s, i, 1)
            If (CurrentDigit <> Mid(PreviousMainValue, i, 1)) Or ForceDisplay Then
               DisplayHexagonalSegmentDigit CurrentDigit, LCDSegment(), _
                                            DigitXPos(i - 1), m_YOffset, _
                                            m_SegmentHeight, m_SegmentWidth, _
                                            m_InterSegmentGap, DigitWidth, DigitHeight
            End If
         Next i

      Case [Trapezoidal]
         For i = 1 To m_NumDigits
            CurrentDigit = Mid(s, i, 1)
            If (CurrentDigit <> Mid(PreviousMainValue, i, 1)) Or ForceDisplay Then
               DisplayTrapezoidalSegmentDigit CurrentDigit, LCDSegment(), _
                                              DigitXPos(i - 1), m_YOffset, _
                                              m_SegmentHeight, m_SegmentWidth, _
                                              m_InterSegmentGap, DigitWidth, DigitHeight
            End If
         Next i

      Case [Rectangular]
         For i = 1 To m_NumDigits
            CurrentDigit = Mid(s, i, 1)
            If (CurrentDigit <> Mid(PreviousMainValue, i, 1)) Or ForceDisplay Then
               DisplayRectangularSegmentDigit CurrentDigit, LCDSegment(), _
                                              DigitXPos(i - 1), m_YOffset, _
                                              m_SegmentHeight, m_SegmentWidth, _
                                              m_InterSegmentGap, DigitWidth, DigitHeight
            End If
         Next i

   End Select

   UserControl.Refresh

'  save the displayed value so we know which LCD digits
'  to update the next time we need to display a value.
   PreviousMainValue = s

End Sub

Private Sub DisplayExponentValue(strValue As String, ByVal ForceDisplay As Boolean)

'*************************************************************************
'* displays exponent portion of value stored in .Value property.         *
'*************************************************************************

   Dim s            As String    ' right-justified version of exponent.
   Dim i            As Long      ' loop variable.
   Dim CurrentDigit As String    ' the current digit we're displaying.

   ExponentFlag = True

   s = Right(Space(m_NumDigitsExp) & strValue, m_NumDigitsExp)

'  display the exponent.  Only draw a digit if the particular digit being
'  drawn is different from digit the previous time value was displayed.
   Select Case m_SegmentStyleExp

      Case [Hexagonal]
         For i = 1 To m_NumDigitsExp
            CurrentDigit = Mid(s, i, 1)
            If (CurrentDigit <> Mid(PreviousExponentValue, i, 1)) Or ForceDisplay Then
               DisplayHexagonalSegmentDigit CurrentDigit, LCDSegmentExp(), _
                                            DigitXPosExp(i - 1), m_YOffsetExp, _
                                            m_SegmentHeightExp, m_SegmentWidthExp, _
                                            m_InterSegmentGapExp, DigitWidthExp, DigitHeightExp
            End If
         Next i

      Case [Trapezoidal]
         For i = 1 To m_NumDigitsExp
            CurrentDigit = Mid(s, i, 1)
            If (CurrentDigit <> Mid(PreviousExponentValue, i, 1)) Or ForceDisplay Then
               DisplayTrapezoidalSegmentDigit CurrentDigit, LCDSegmentExp(), _
                                              DigitXPosExp(i - 1), m_YOffsetExp, _
                                              m_SegmentHeightExp, m_SegmentWidthExp, _
                                              m_InterSegmentGapExp, DigitWidthExp, DigitHeightExp
            End If
         Next i

      Case [Rectangular]
         For i = 1 To m_NumDigitsExp
            CurrentDigit = Mid(s, i, 1)
            If (CurrentDigit <> Mid(PreviousExponentValue, i, 1)) Or ForceDisplay Then
               DisplayRectangularSegmentDigit CurrentDigit, LCDSegmentExp(), _
                                              DigitXPosExp(i - 1), m_YOffsetExp, _
                                              m_SegmentHeightExp, m_SegmentWidthExp, _
                                              m_InterSegmentGapExp, DigitWidthExp, DigitHeightExp
            End If
         Next i

   End Select

   UserControl.Refresh

'  save the displayed value so we know which LCD digits
'  to update the next time we need to display a value.
   PreviousExponentValue = s

End Sub

Private Sub DetermineThousandsSeparatorPlacement(ByVal sVal As String)

'*************************************************************************
'* determines which digits in the main value get a thousands separator   *
'* afterwards.  ThousandsFlag() elements that correspond to LCD digits   *
'* that need to be followed by a thousands separator are set to True.    *
'* Thanks to Redbird77 for optimizing this routine.                      *
'*************************************************************************

   Dim i    As Long      ' loop variable.
   Dim p1   As Long      ' position of first non-zero/minus sign digit.
   Dim p2   As Long      ' position of decimal separator.
   Dim sTmp As String    ' padded value.