As promised, Peter's solution is a step up, and there are some important improvements, including:
- the use of a structure to contain the parameters for each ring the program draws
(Peter wanted more control than a loop provides) - more sophisticated trigonometry
- the use of a Panel component to contain the graphics
Peter's solution is also integrated into a larger program so it won't run without the rest of his design, and there are a few undefined terms in it. But it's still very worth studying to understand GDI+. Here's his solution in his own words ...
First I defined a structure ...
Public Structure MapStructure
Dim PenColor As Color ' Color to draw the circle
Dim PenWidth As Integer ' Width of pen
Dim CenterX As Single ' X coordinate of center
Dim CenterY As Single ' Y coordinate of center
Dim CircleSize As Integer ' Size of circle
Dim Visible As Boolean ' True if this circle is to be plotted, False if not
Dim Fill As Boolean ' True if this circle is to be filled, False if not
End Structure
... and a suitably global variable ...
Private ShowLines As Boolean
' True if show the non-adjacent connections
' False otherwise
Then I declared an array
Public MapArray(MaxRoom) _
As MapStructure
I computed the semi-constant stuff once, in the following loop. (Note the use of an old FORTRAN trick: 4*Atan(1) = PI, so I can reduce your computation of SegAngle to a much simpler expression)
SegAngle = Math.Atan(1) / 4
Radius = ((panMap.Height + panMap.Width) / 4) - 80
For I = 0 To MaxRoom
RadAngle = I * SegAngle
With MapArray(I)
.PenWidth = 3
.CenterX = Radius * (1 + Math.Sin(RadAngle)) + 60
.CenterY = Radius * (1 - Math.Cos(RadAngle)) + 60
.CircleSize = 46
End With
Next I
The "variable" information in MapArray is computed here:
Private Sub ReadMap()
Dim I As Integer
Dim J As Integer
Dim LocalColorNumber As Integer
Dim LowerLimit As Integer
Dim Upperlimit As Integer
panMap.Visible = True
If GameObject(Nou.Map, Obj.Value) > 0 Then
For I = 0 To MaxRoom
With MapArray(I)
.PenColor = ColorList(2 + FNRanNr(13)).Value
.Visible = True
.Fill = ((I Mod 2) = 0)
End With
Next I
ShowLines = False
Else
If GameObject(Nou.Chxlrth, Obj.Location) = Obj.Carried Then
LowerLimit = 0
Upperlimit = MaxRoom
Else
LowerLimit = CurLocation - 3 * (Magic + 1)
If LowerLimit < 0 Then LowerLimit = 0
Upperlimit = CurLocation + 3 * (Magic + 1)
If Upperlimit > MaxRoom Then Upperlimit = MaxRoom
End If
For I = 0 To MaxRoom
With MapArray(I)
If ((I >= LowerLimit) AndAlso (I <= Upperlimit)) Then
.Visible = True
If I = CurLocation Then
LocalColorNumber = 12
' Bright red for present location
Else
LocalColorNumber = 4
' Otherwise, dark red
End If
For J = 0 To MaxWall
If Math.Abs( _
Room(I, J, Roo.RoomNr)) = CurLocation Then
LocalColorNumber -= 2
' Make color green if connection in
' some dimension to current location
Exit For
End If
Next J
.PenColor = ColorList(LocalColorNumber).Value
.Fill = (I <= (-1 - TruePath))
Else
.Visible = False
End If
End With
Next I
ShowLines = True
End If
Call panMap.Refresh()
End Sub
