Graphics gurus... simple graph with PBDLL?

[Wayne Diamond]

Ive created a very simple yet effective graph with VB6 that Id like to use in my PB apps, but graphics in PBDLL seem to be so different than in VB6 so I'm getting nowhere
My graph is very easy to build, just start a new VB project and add just two controls - one picturebox (Autoredraw=True, Forecolor=Green, ScaleMode=Pixels, ScaleWidth=110, ScaleWidth=80), and a Timer.
Add this code to the project, and press F5 to start. It will show randomly created values, I think it looks kinda neat considering there's not much behind it

Dim GraphValue(100) As Integer  'Can display up to 100 different values
 
Private Sub Form_Load()
On Error Resume Next
For I = 1 To 100
 GraphValue(I) = 0
Next I
Timer1.Interval = 200
End Sub
 
Private Sub Timer1_Timer()
Dim NextVal As Integer
Picture1.Cls
'Move all values down 1 (visually all pixels move left 1)
For I = 2 To 100
 GraphValue(I - 1) = GraphValue(I)
Next I
Randomize
GraphValue(100) = CInt(Rnd * 70)  'Picture1 is only 70 pixels high
For I = 2 To 100
 Picture1.Line (I - 1, 70 - GraphValue(I - 1))-(I, 70 - GraphValue(I))
Next I
End Sub

I want to do this with pure PB code only, no 3rd party DLLs


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[Jules Marchildon]

wayne;
the output looks like my last ecg print out. i'm no graphics guru, but i can point you to this
article that should start you in the right direction...

'message [url="http://www.powerbasic.com/support/pbforums/showthread.php?t=22937"]http://www.powerbasic.com/support/pbforums/showthread.php?t=22937[/url] 
'forum:  source code
'topic:  primitive chart recorder
'name:   iain johnstone, member
'date:   february 27, 2001 11:53 am

'-------------------------------------------------------------------------------
'
'   chart.bas for pb/dll
'   iain johnstone.
'
'   an experiment to create a chart recorder
'   sine wave data generated as demo (plus square wave, random noise and fundamental plus octave sine
wave)
'   select wave form in drawtrace
'   all variations and adaptations are up to you!
'
'   on switches, click on black dots by numbers
'   on pen zero, drag black circle around.
'   let me know if you remove the flicker in drawtrace
'
'   it would be interesting to see how big this would be in c or vb.
'   though i am not suggesting anybody tries!
'-------------------------------------------------------------------------------

regards,
jules

[Peter Lameijn]

Simple but nice example... (translation of VB a VB example)

#Compile Exe
#Include "win32api.inc

%IMAGEBOX    = %WM_USER + 1024
%TIMERID1    = %WM_USER + 1025
%PWIDTH      = 250
%PHEIGHT     = 150
%PGRID       = 25
%TINTERVAL   = 100

Global Counter As Long, OldY As Long, hDCh As Long, hDC As Long, hPenB As Long, hPenC As Long
Global hDlg As Long, hTimer As Long, hImg As Long, NewY As Long, hPenBg As Long

CallBack Function CbMain () As Long
  Local lRet As Long, lCnt As Long
  Local ps As PAINTSTRUCT
  Static hMapBmp As Long, hMapBmpOld As Long, hMemDC As Long, _
         hPenOld As Long, rectA As RECT, rectD As RECT

  Select Case CbMsg
    Case %WM_INITDIALOG
      hPenB  = CreatePen(%PS_SOLID, 0, Rgb(250,250,  0))
      hPenC  = CreatePen(%PS_SOLID, 0, Rgb(200,  0,  0))
      hPenBg = CreatePen(%PS_SOLID, 0, Rgb(  0,  0,  0))
      rectA.nTop = 0 : rectA.nLeft = 0 : rectA.nRight = %PWIDTH : rectA.nBottom = %PHEIGHT
      hDC = GetDC(%HWND_DESKTOP)
      hMemDC = CreateCompatibleDC (hDC)
      hMapBmp = CreateCompatibleBitmap (hDC, %PWIDTH, %PHEIGHT )
      hMapBmpOld = SelectObject( hMemDC, hMapBmp )
      Call ReleaseDC(%HWND_DESKTOP, hDC)
      hPenOld = SelectObject( hMemDC, hPenB )
      PatBlt hMemDC, 0, 0, %PWIDTH, %PHEIGHT, %WHITENESS
      rectD.nTop = 5 : rectD.nLeft = 5
      MapDialogRect hdlg, rectD
      rectD.nTop  = rectD.nTop  + 3
      rectD.nLeft = rectD.nLeft + 3

    Case %WM_TIMER
      ScrollDC hMemDC, -1, 0, rectA, rectA, ByVal %NULL, ByVal %NULL
      OldY = Sin(0.15*Counter)*(%PHEIGHT\2 -1)+%PHEIGHT\2
      Incr Counter
      NewY = Sin(0.15*Counter)*(%PHEIGHT\2 -1)+%PHEIGHT\2
      If Counter Mod %PGRID = 0 Then
        SelectObject hMemDC, hPenC
      Else
        SelectObject hMemDC, hPenBg
      End If
      MoveToex hMemDC, %PWIDTH-3, 2, ByVal 0
      LineTo   hMemDC, %PWIDTH-3, 150
      For lCnt = %PGRID To %PGRID * (%PHEIGHT \ %PGRID) Step %PGRID
        SetPixel hMemDC, %PWIDTH-3, lCnt, Rgb(200,0,0)
      Next
      SelectObject hMemDC, hPenB
      MoveToEx hMemDC, %PWIDTH-3, OldY, ByVal 0
      LineTo   hMemDC, %PWIDTH-3, NewY
      InvalidateRect hDlg, ByVal 0, 0

    Case %WM_PAINT
      hDc = BeginPaint(hDlg, Ps)
      lRet = BitBlt (hDC, rectD.nLeft, rectD.nTop, %PWIDTH, %PHEIGHT, hMemDC, 0, 0, %SRCCOPY)
      EndPaint hDlg, ps

    Case %WM_DESTROY
      SelectObject hMemDC, hPenOld
      SelectObject hMemDC, hMapBmpOld
      DeleteObject hMapBmp
      DeleteDC hMemDC
      DeleteObject hPenB
      DeleteObject hPenC
      DeleteObject hPenBg
  End Select
End Function

Function PbMain () As Long
  Local lRet As Long
  Dialog New 0, "Dynamically scrolling graph",,,182,120, %WS_SYSMENU Or %WS_VISIBLE To hDlg
  hTimer = SetTimer (hDlg,%TIMERID1,10,ByVal %Null)
  Control Add Label, hDlg, %IMAGEBOX,"",5,5,%PWIDTH  * 0.68, %PHEIGHT * 0.64, _
                     %SS_BITMAP Or %SS_BLACKRECT, %WS_EX_CLIENTEDGE
  Control Handle hDlg, %IMAGEBOX To hImg
  Dialog Show Modal hDlg Call CbMain
End Function

------------------
Peter.
mailto[email protected][email protected]</A>

[Borje Hagsten]

Best teacher is many samples. Here is PB version of asked VB code:

#COMPILE EXE
#INCLUDE "WIN32API.INC"
 
%ID_IMAGE1 = %WM_USER + 10
%ID_TIMER  = %WM_USER + 20
%INTERVAL  = 200
 
GLOBAL ihWnd AS LONG
GLOBAL GraphValue() AS LONG
 
DECLARE CALLBACK FUNCTION DlgCallback()
 
'¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤
' Main entance
'¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤
FUNCTION PBMAIN
  LOCAL hDlg AS LONG
  DIALOG NEW 0, "Draw demo",,, 204, 58, %WS_CAPTION OR %WS_SYSMENU TO hDlg
 
  CONTROL ADD BUTTON,   hDlg, %IDCANCEL, "E&xit",  150, 40, 50, 14
  CONTROL ADD LABEL, hDlg, %ID_IMAGE1, "", 4, 4, 140, 50,, %WS_EX_CLIENTEDGE
  CONTROL HANDLE hDlg, %ID_IMAGE1 TO ihWnd
 
  DIALOG SHOW MODAL hDlg CALL DlgCallback
END FUNCTION
 
'¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤
' Main dialog's callback procedure
'¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤
CALLBACK FUNCTION DlgCallback()
  SELECT CASE CBMSG
    CASE %WM_INITDIALOG
       LOCAL I AS LONG, rc AS RECT, hPen AS LONG, hBrush AS LONG, hBrushOld AS LONG
       LOCAL hDC AS LONG, memDC AS LONG, hBit AS LONG
       STATIC hTimer AS LONG : REDIM GraphValue(100)
 
       hTimer = SetTimer(CBHNDL, %ID_TIMER, %INTERVAL, 0) 'create timer
 
    CASE %WM_DESTROY
       IF hTimer THEN KillTimer CBHNDL, hTimer      'destroy timer
 
     CASE %WM_TIMER
        IF CBWPARAM = %ID_TIMER THEN
           GetClientRect ihWnd, rc             'draw area
           hDC = GetDC(ihWnd)                  'get label's device context
           memDC = CreateCompatibleDC(hDC)     'create compatible memDC for smoother action
           hbit  = CreateCompatibleBitmap(hDC, rc.nRight, rc.nBottom) 'and bitmap
           hbit = SelectObject(memDC, hbit)    'select bitmap into DC
 
           'CLS
           hBrush    = GetSysColorBrush(%COLOR_WINDOW) 'this is the background color
           hBrushOld = SelectObject(memDC, hBrush)     'select new brush into DC, old is returned
           FillRect memDC, rc, hBrush                  'paint background
           SelectObject memDC, OldhBrush               'select old brush back into memDC
 
           'Move all values down 1 (visually all pixels move left 1)
           For I = 2 To 100
              GraphValue(I - 1) = GraphValue(I)
           Next I
           Randomize
           GraphValue(100) = CLNG(Rnd * 70)
 
           'PICTURE1.LINE
           hPen = CreatePen(%PS_SOLID, 1, RGB(0,127,0))   'create green pen to draw with
           hPen = SelectObject(memDC, hPen)               'select it into memDC
           For I = 2 To 100
              MoveTo memDC, I - 1, 70 - GraphValue(I - 1) 'move into position
              LineTo memDC, I, 70 - GraphValue(I)         'draw line to..
           Next I
           DeleteObject SelectObject(memDC, hPen)         'select old pen backl, delete new
 
           BitBlt hDC, 0, 0, rc.nRight, rc.nBottom, memDC, 0, 0, %SRCCOPY 'copy all to label
 
           DeleteObject SelectObject(memDC, hbit)          'clean up to avoid memory leaks
           DeleteDC memDC
           ReleaseDC ihWnd, hDC
        END IF
 
     CASE %WM_COMMAND : IF CBCTL = %IDCANCEL THEN DIALOG END CBHNDL
 
  END SELECT
 
END FUNCTION

------------------
Okay, Windows GDI is easy to make mistakes with. Added hBrushOld to
WM_TIMER event, so proper brush is used and selected back into memDC..


[This message has been edited by Borje Hagsten (edited August 03, 2001).]

[Wayne Diamond]

Fwaarrrrrr, thanks! Its a rainy Friday night here in Perth so I'm staying in to play with graphics (for the first time), I'll go through those samples now as soon as I get a bourbon and coke.
Cheers!

[3 minutes, 1 bourbon and coke later]
Borje, strewth - thats virtually an exact copy of my demo, very impressed!! Thankyou so much for that, I find it a lot easier to learn PB when Ive got a direct VB sample to compare it, I'll be cooking with gas now

Peter, thats also very cool - I love the scrolling grid behind the graph line, very nice

Have a good night!


[This message has been edited by Wayne Diamond (edited August 03, 2001).]

[Russ Srole]

Check out Graphix Toolkit. It makes this stuff pretty easy.

Russ Srole

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