draw a line in a graphic control???

[Mike Schneider]

Hi guys,

I'm a real newbie, coming from the PBCC side of things. I am trying to write my first program with PB9, and it's not going well.

All the program does is draw a line in a graphic control. Alas, it's not drawing the line.

Can someone look at this and enlighten me?

Thanks,

Mike...

#COMPILE EXE
#DIM ALL
%usemacros = 1
#INCLUDE "win32api.inc"
#INCLUDE "commctrl.inc"
#INCLUDE "PBForms.Inc"

'constants
%idd_dialog1 = 101
%idc_button1 = 1001
%idc_graphic1 = 1002

GLOBAL hDlg AS DWORD
GLOBAL mylabel AS STRING
GLOBAL hParent AS DWORD
GLOBAL hWin AS DWORD

'declarations
DECLARE CALLBACK FUNCTION showDialog1proc()
DECLARE FUNCTION ShowDialog1(BYVAL hParent AS DWORD) AS LONG

'main entry point
FUNCTION PBMAIN () AS LONG
    'PBFormsInitComCtrls (%icc_win95_classes or %icc_date_classes or_
    '%icc_internet_classes)

    showDialog1 %HWND_DESKTOP
END FUNCTION

'callbacks
CALLBACK FUNCTION ShowDialog1Proc()
'LOCAL hDlg AS DWORD
LOCAL hWin AS DWORD
    SELECT CASE AS LONG CBMSG
        CASE %WM_COMMAND
            SELECT CASE AS LONG CBCTL
            CASE %idc_button1
                IF CBCTLMSG = %BN_CLICKED OR CBCTLMSG = 1 THEN
                    'mylabel$ =  "hDlg = " + str$(hDlg)
                    'msgbox mylabel$
                    
                    'drawline
                    GRAPHIC ATTACH hDlg, %idc_graphic1
                    GRAPHIC COLOR %RED, RGB(0,0,191)
                    GRAPHIC LINE (10,-10)-(50,-50)
                END IF
            END SELECT
    END SELECT
END FUNCTION


'dialogs
FUNCTION showdialog1(BYVAL hParent AS DWORD) AS LONG
    LOCAL Rslt AS LONG
'    LOCAL hDlg AS DWORD

    DIALOG NEW hParent, "Dialog1",384,184,201,121,%WS_POPUP OR %WS_SYSMENU OR _
    %WS_BORDER OR %WS_DLGFRAME OR %DS_MODALFRAME, TO hDlg
    CONTROL ADD BUTTON, hDlg, %IDC_BUTTON1, "Button1",68,90,75,20
    CONTROL ADD GRAPHIC, hDlg, %idc_graphic1, "", 50,10,100,75,%WS_BORDER
    

    DIALOG SHOW MODAL hDlg, CALL showDialog1Proc TO Rslt


    FUNCTION = Rslt
END FUNCTION

[Peter Jinks]

Hi Mike,

You're drawing your line outside of the graphic control:

GRAPHIC LINE (10,-10)-(50,-50)

Those Y-coordinates are negative. Change to:

GRAPHIC LINE (10,10)-(50,50)

and you'll see it.

Regards,

Pete.

[Mike Schneider]

Ah finally, thanks Pete.

Next problem... I removed the global variables and went back to the local variables, like my examples showed. Now it doesn't work again.

Is hDlg supposed to be local or global?

Mike...

#COMPILE EXE
#DIM ALL
%usemacros = 1
#INCLUDE "win32api.inc"
#INCLUDE "commctrl.inc"
#INCLUDE "PBForms.Inc"

'constants
%idd_dialog1 = 101
%idc_button1 = 1001
%idc_graphic1 = 1002

'GLOBAL hDlg AS DWORD
'GLOBAL mylabel AS STRING
'GLOBAL hParent AS DWORD
'GLOBAL hWin AS DWORD

'declarations
DECLARE CALLBACK FUNCTION showDialog1proc()
DECLARE FUNCTION ShowDialog1(BYVAL hParent AS DWORD) AS LONG

'main entry point
FUNCTION PBMAIN () AS LONG
    'PBFormsInitComCtrls (%icc_win95_classes or %icc_date_classes or_
    '%icc_internet_classes)

    showDialog1 %HWND_DESKTOP
END FUNCTION

'callbacks
CALLBACK FUNCTION ShowDialog1Proc()
LOCAL hDlg AS DWORD
LOCAL hWin AS DWORD
    SELECT CASE AS LONG CBMSG
        CASE %WM_COMMAND
            SELECT CASE AS LONG CBCTL
            CASE %idc_button1
                IF CBCTLMSG = %BN_CLICKED OR CBCTLMSG = 1 THEN
                    'mylabel$ =  "hDlg = " + str$(hDlg)
                    'msgbox mylabel$

                    'drawline
                    GRAPHIC ATTACH hDlg, %idc_graphic1
                    GRAPHIC COLOR %RED, RGB(0,0,191)
                    GRAPHIC LINE (10,10)-(50,50)
                END IF
            END SELECT
    END SELECT
END FUNCTION


'dialogs
FUNCTION showdialog1(BYVAL hParent AS DWORD) AS LONG
    LOCAL Rslt AS LONG
    LOCAL hDlg AS DWORD

    DIALOG NEW hParent, "Dialog1",384,184,201,121,%WS_POPUP OR %WS_SYSMENU OR _
    %WS_BORDER OR %WS_DLGFRAME OR %DS_MODALFRAME, TO hDlg
    CONTROL ADD BUTTON, hDlg, %IDC_BUTTON1, "Button1",68,90,75,20
    CONTROL ADD GRAPHIC, hDlg, %idc_graphic1, "", 50,10,100,75,%WS_BORDER


    DIALOG SHOW MODAL hDlg, CALL showDialog1Proc TO Rslt


    FUNCTION = Rslt
END FUNCTION

[Gary Beene]

Mike,

Use CB.HNDL to access the dialog handle in the Callback function.

Or, keep hDlg as Global. That's that way I prefer.

[Rodney Hicks]

Change this line

GRAPHIC ATTACH hDlg, %idc_graphic1

to this

GRAPHIC ATTACH CB.HNDL, %idc_graphic1

comment out the LOCAL hDlg as DWORD

Posting same as Gary, same advice regarding the CB.HNDL.

[Gary Beene]

Also, Mike,

In gbSnippets, there's an example app with several graphics controls - multiple ways to use it, including lines. It's snippet gbs_00089.

Here's a copy in case you're interested.

'Compilable Example:
'The following compilable code demonstrates a dialog with muiltiple graphic controls,
'a resource file, and an imagelist, Various commands to load/size images in the graphic
'controls are used, as well as some basic drawing commands are demonstrated.
'The Dialog Callback response to a mouse click is demonstrated.
'Controls can also have a Callback function of their own.

#Compile Exe
#Dim All
#Include "Win32API.inc"
#Resource "gbsnippets.pbr"
Global hDlg As Dword, hLst As Dword, hTemp As Dword
Global style&, extstyle&
Function PBMain() As Long
Dialog New Pixels, 0, "Graphic Control Test",300,300,450,380, %WS_SysMenu, 0 To hDlg

'create imagelist  w,h,depth,size
ImageList New Icon 16,16,32,3 To hLst
ImageList Add Icon hLst, "x"
ImageList Add Icon hLst, "y"
ImageList Add Icon hLst, "check"

'create graphic control - various frames
Control Add Graphic, hDlg, 301,"", 10,10,30,30, %WS_Visible Or %SS_Sunken
Control Add Graphic, hDlg, 302,"", 50,10,30,30, %WS_Visible Or %WS_DlgFrame
Control Add Graphic, hDlg, 303,"", 90,10,30,30, %WS_Visible Or %WS_Border

'create graphic control
style& = %WS_Visible Or %SS_Sunken Or %SS_Notify
Control Add Graphic, hDlg, 110,"", 10,50,100,100, style&
Control Add Graphic, hDlg, 120,"", 120,50,100,100, style&
Control Add Graphic, hDlg, 130,"", 230,50,100,100, style&
Control Add Graphic, hDlg, 210,"", 10,160,100,100, style&
Control Add Graphic, hDlg, 220,"", 120,160,100,100, style&
Control Add Graphic, hDlg, 230,"", 230,160,100,100, style&
Control Add Graphic, hDlg, 310,"", 10,270,100,100, style&
Control Add Graphic, hDlg, 320,"", 120,270,100,100, style&
Control Add Graphic, hDlg, 330,"", 230,270,100,100, style&

'PBR FILE
Graphic Attach hDlg, 110
Graphic Render "cowgirl", (0,0)-(100,100)    'same size (could resize)

'BMP FILE      bmpname$, (x,y)-(x2,y2) <-- dest coordinates
Graphic Attach hDlg, 120
Graphic Render "icons/cowgirl.bmp", (0,0)-(100,100) 'same size (could resize)

'IMAGELIST        (x,y), hList, index&, overlay&, style&
Graphic Attach hDlg, 130
Graphic ImageList (0,0), hLst, 1,0, %ILD_Normal
Graphic ImageList (50,50), hLst, 2,0, %ILD_Normal
Graphic ImageList (10,70), hLst, 3,0, %ILD_Normal
Graphic ImageList (70,30), hLst, 3,0, %ILD_Normal

'COPY   hSource, id&
Graphic Attach hDlg, 210           'source
Graphic Copy hDlg, 110             'copy all to 0,0
Graphic Attach hDlg, 220           'source
Graphic Copy hDlg, 110 To (20,20)  'copy all to 40,40
Graphic Attach hDlg, 230           'source
Graphic Copy hDlg, 110, (0,0)-(40,80) To (40,10) 'copy part to 40,40

'STRETCH
Graphic Attach hDlg, 310  'copy all to 0,0
Graphic Stretch hDlg, 110, (0,0)-(100,100) To _
                (0,0)-(50,50) 'copy part+shrink
Graphic Attach hDlg, 320
Graphic Stretch hDlg, 110, (0,0)-(100,100) To _
                 (0,0)-(200,200) 'copy part+expend

'DRAWING
Graphic Attach hDlg, 330
Graphic Print "Print";" here"
Graphic Color %Red
Graphic Print
Graphic Print "Now here!"
Graphic Color %Blue
Graphic Print
Graphic Print "and here!"
Graphic Ellipse (20,20)-(70,95), %Black
Graphic Ellipse (25,15)-(35,25), %Black, %Red
Graphic Line (80,10)-(50,100), %Black
Graphic Paint Border (60,75),%Green, %Black
Graphic Paint Border (60,75),%Green, %Black
Graphic Box (75,60)-(90,90),50, %White, %Red

Dialog Show Modal hDlg Call DlgProc
End Function

CallBack Function DlgProc() As Long
  If CB.Msg = %WM_Command AND CB.Ctl = 110 AND _
                    CB.Ctlmsg = %STN_Clicked Then
     MsgBox "Clicked!"
  End If
End Function

'gbs_00089

[Mike Schneider]

Thanks for the good information guys...

I'll start making the hDlg global.

The CB.HNDL thingie worked too, but I don't understand what it is or where it comes from. :confused2:

Mike...

P.S. Gary, I love your site. Do you have a tutorial for a beginner like me that tells me where to put global variables, local variables, sub routines, dialogs, constants, declares, and callbacks. Obviously, the closer it looks to PBCC, the faster I'll be able to grasp it.

I've done "Hello World" with a msgbox a thousand times, but that doesn't teach me where all the other stuff goes.

[Fred Buffington]

Mike, CB.HNDL is the current dialog handle. It will be the same as your
hDlg variable used in the DIALOG NEW statement.

I use Global hDlg (usally adding something more specific).
For example, if I am writing an Employee File maintenance dialog, I might use
hDlgEmp instead of hDlg.

The reason I use global hDlg instead of CB.HNDL (most of the time) is that I might have more than one dialog. Each of these I use a different spelling of the variable. For me, it keeps it straight which dialog I am dealing with.

Drawbacks:
probably takes more memory but i don't worry much about that in windows. Also, more variables to keep track of. If you copy and paste you may need to change these variable names each time you paste.

***Added Later***
Mike, you can learn a lot by studying the source code forum and examples included with PB9 and the downloads available from the powerbasic site

[Gary Beene]

Mike,

No, I don't have such a page. But it's a good idea. I'll generate one and let you know when it is up.

[Jeff Blakeney]

CALLBACK FUNCTION ShowDialogProc()

is a DDT version of the SDK code:

FUNCTION ShowDialogProc(Hndl AS LONG, Msg AS LONG, wParam AS LONG, lParam AS LONG) AS LONG

When you use the DDT version, PB fills in a predefined UDT with the values of those four parameters that you didn't specify in the CALLBACK FUNCTION line. This UDT is called CB so you end up with CB.HNDL, CB.MSG, CB.WPARAM and CB.LPARAM.

Sometimes those parameters also contain other useful information in their low or high words so the DDT engine also fills in other members of the UDT to make it easier to get at them.

If CB.MSG = %WM_COMMAND then

• CB.CTL is the low word of CB.WPARAM
• CB.CTLMSG is the high word of CB.WPARAM

If CB.MSG = %WM_NOTIFY then

• CB.NMHDR is set to the address of an NMHDR UDT that is passed in via CB.LPARAM
• CB.NMHWND is set to the value of NMHDR.hwndFrom
• CB.NMID is set to the value of NMHDR.idFrom
• CB.NMCODE is set to the value of NMHDR.code
• CB.NMHDR$ is a string of all twelve bytes of the NMHDR (I have no idea what this would ever be used for)

[Michael Mattias]

CB.NMHDR$ is a string of all twelve bytes of the NMHDR (I have no idea what this would ever be used for)

 LOCAL myNMHDR AS NMHDR 
      
  CASE %WM_NOTIFY 
     .....
        TYPE SET MyNmHDR = CB.NMHDR$ 
        CALL SomeFunction(MyNmHdr) 


FUNCTION SomeFunction( X AS NMHDR) 
...

MCM

[Jeff Blakeney]

Okay but what is wrong with doing this:

LOCAL myNMHDR AS NMHDR
LOCAL pTemp AS NMHDR POINTER
...
pTemp = CB.NMHDR
myNMHDR = @pTemp
lResult = SomeFunction(myNMHDR)
...
FUNCTION SomeFunction(X AS NMHDR)

Unfortunately, although CB.NMHDR is a pointer to NMHDR, you can't use myNMHDR = @CB.NMHDR but I guess that is normal. If you are using SDK style programming, you can use myNMHDR = @lParam either because the @ needs a variable defined as a pointer to work.

Here is an even simpler way:

lResult = SomeFunction(CB.NMHDR)
...
FUNCTION SomeFunction(BYVAL X AS NMHDR POINTER)
    IF @X.hwndFrom = ghDlg THEN
        ...

Or you could put a myNMHDR = @X as the first line of the function so you wouldn't need to remember to put @ at the beginning of each access to the NMHDR UDT.

[Michael Mattias]

>CB.NMHDR is a pointer to NMHDR, you can't use myNMHDR = @CB.NMHDR
==>

    CALL SomeFunction([email protected])

Assumes the "CB" UDT is defined with member "nmhdr" 'AS NMHDR PTR' but since we don't define that ourselves I guess you'll just have to try it and see what happens.

[Jeff Blakeney]

Unfortunately, that doesn't work either. I get a "Period not allowed" error at the start of the [email protected] if SomeFunction is defined as having a parameter of X AS NMHDR.

[Michael Mattias]

Well, then I guess "CB" is not a UDT, and all the 'CB.anything's are just 'reserved words.'

[Mike Schneider]

Looking forward to that page Gary.

Thanks, all you guys, for that good information! I've been downloading sample programs from powerbasic.com and looking at the samples included with the program!

Mike...