DOCUMENT:Q190180  07-AUG-1998  [vbwin]
TITLE   :PRB: Value of the Point Function Does Not Match Set Color
PRODUCT :Microsoft Visual Basic for Windows
PROD/VER:WINDOWS:4.0,5.0,6.0
OPER/SYS:WINDOWS
KEYWORDS:

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The information in this article applies to:

 - Microsoft Visual Basic Learning, Professional, and Enterprise Editions
   for Windows, versions 5.0, 6.0
 - Microsoft Visual Basic Standard, Professional, and Enterprise Editions,
   16-bit and 32-bit, for Windows, version 4.0
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SYMPTOMS
========

When using the Visual Basic Point function to determine the color of the
specified point, the RGB color value returned does not always match the
region's color as set by the developer at design-time. Consequently, direct
comparisons between a given point's color and a color property setting
should be avoided because the values may not always agree.

CAUSE
=====

This problem is typically the result of one of the following situations:

1. The developer has set the color value for a property to a system color
   (such as., &H80000001) instead of a valid RGB color value. The Point
   method will always return an RGB value.

2. The color value has been set to a color that is not within the range of
   valid colors for the video hardware (or display settings) on an end
   user's system. Such colors are typically translated to the nearest
   matching color based on the available system palette. This means that
   you can never guarantee that the Point function will exactly match the
   developer's chosen design-time color value.

RESOLUTION
==========

The only way to guarantee that a value returned from the Point function is
the color setting chosen by the developer is to set a variable at run-time
to a known point that contains the correct color, and use this value during
comparisons. For example, if you know that coordinate 100,100 always
contains the FillColor then you can set a variable to Point(100,100), and
then use this variable when comparing a given point's color to the
FillColor, as follows:

   ActualFillColor = Point(100, 100)
   If ActualFillColor = Point(x, y) Then
      ' Do some code ...
   End If

STATUS
======

This behavior is by design.

MORE INFORMATION
================

Steps to Reproduce Behavior
---------------------------

1. Start a new Standard EXE project in Visual Basic. Form1 is created by
   default.

2. Add a Label, Label1, and a Shape control, Shape1, to Form1.

3. Add the following code to Form1's module:

      Private Sub Form_Load()
         Label1.Caption = "Test Color"
         Shape1.FillStyle = 0 'Solid
         Shape1.FillColor = &H8000000D 'System Color
      End Sub

      Private Sub Form_MouseMove(Button As Integer, Shift As Integer, _
                                 X As Single, Y As Single)
         Dim Color As Long
         Color = Me.Point(X, Y)
         If Color = Shape1.FillColor Then
            Label1.Caption = "Mouse is over the shape!"
         Else
            Label1.Caption = "Mouse is Not over the shape!"
         End If
      End Sub

4. Run the program by hitting the F5 key or choosing Start from the Run
   menu. Move the mouse over the form. Note that the label never
   indicates that the mouse is over the shape. To correct the problem, you
   need to compare the MouseMove point value to a known point value.

5. Stop the project and replace Form1's MouseMove event with this code:

      Private Sub Form_MouseMove(Button As Integer, Shift As Integer, _
                                 X As Single, Y As Single)
         Dim ActualFillColor As Long
         Dim Color As Long
         ActualFillColor = Me.Point(Shape1.Left + 10, Shape1.Top + 10)
         Color = Me.Point(X, Y)
         If Color = ActualFillColor Then
            Label1.Caption = "Mouse is over the shape!"
         Else
            Label1.Caption = "Mouse is Not over the shape!"
         End If
      End Sub

6. Run the program by pressing the F5 key. Note that now when you move the
   mouse over the form, the label correctly shows when the mouse is over
   the shape.

Additional query words: kbDSupport kbDSD kbVBp kbVBp400 kbVBp500 kbVBp600
kbNoKeyWord
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Version           : WINDOWS:4.0,5.0,6.0
Platform          : WINDOWS
Issue type        : kbprb

=============================================================================

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