Using API (CreateWindowEx) - My First Window

[tarka]

Having struggled to achieve my first simple (well it is in VB6) objective, I thought it might be of interest and help to other newbies like me.

Objective - To produce a window that -
   1. Has a fixed size (Height & Width)
   2. Is centered on the screen
   3. Includes a custom icon
   4. Omits the MINIMIZE & MAXIMIZE buttons
   5. Is not resizable

Process
   1. Run Prostart.exe (Located in \MASM32)
   2. Use the following settings -
      Use Toolbar    - Unchecked
      Use Statusbar   - Unchecked
      Project File Name   - Prg01
      Window Title   - Prg01
      Manual Size      - Checked
      Width      - 300
      Height      - 250
      Use Fixed Border   - Unchecked
      Code Options   - ALL Unchecked

   3  Set the path for the output using "Set Target Dir"
       
   4  Select the "Create Project" button & then select "Yes" on the "Build" dialog

   5  NOTE - If MASM32 is not in the root directory you will get the following error.
      This assumes that you have already entered the revised paths in prostart.ini

           Prg01.inc(15) : Fatal error A1000: cannot open file : \masm32\macros\macros.asm

      This can be corrected by changing the path on line 15 of Prg01.inc
      and rerunning "makeit.bat"

   6. At this point we have code that satisfies the first two objectives.

   7. To achieve the third objective a custom 16x16 .ico file was produced using IcoFX.exe.
      (This is available as freeware from "http://icofx.ro/"

   8. To Install the new Icon.
      Copy new Icon file (ADir_Icon.ico) to Prg01 Directory
      Change "rsrc.rc" resource definition file from -
         500 ICON MOVEABLE PURE LOADONCALL DISCARDABLE "Prg01.ico"
      to -
         500 ICON MOVEABLE PURE LOADONCALL DISCARDABLE "ADir_Icon.ico"
      Run Makeit.bat to recompile program
      Execute Prg01.exe {new Icon now present in Caption Bar}

   9. To remove the Minimize & Maximize Buttons from the Form we need to change the sub-class

      A review of the "CreateWindowEx" API call shows that the buttons are controlled by dwstyle.
      The existing program uses the constant WS_OVERLAPPEDWINDOW 0x00CF0000
      This value is the equivalent of the following.

         = WS_CAPTION    0x00C00000
         + WS_SYSMENU    0x00080000
         + WS_SIZEBOX    0x00040000
         + WS_MINIMIZEBOX   0x00020000
         + WS_MAXIMIZEBOX   0x00010000

      The revised value required to remove MINIMIZEBOX & MAXIMIZEBOX is 0x00CC0000

   10 This is implemented as follows
      
      Add an item to the .data section in Prg01.inc

         PrgWinSty dd 0

       Add the following code in the start section after the global variables and immediately before "Call Main"

         push    eax          
         mov    eax, 0CC0000h
         mov    PrgWinSty, eax
         pop    eax                  

       Change the following code in "Main proc"

                     invoke CreateWindowEx,WS_EX_LEFT,
                                               ADDR szClassName,
                                               ADDR szDisplayName,
                                               WS_OVERLAPPEDWINDOW,
                                               Wtx,Wty,Wwd,Wht,
                                               NULL,NULL,
                                               hInstance,NULL
      To
                      invoke CreateWindowEx,WS_EX_LEFT,
                                               ADDR szClassName,
                                               ADDR szDisplayName,
                                               PrgWinSty,
                                               Wtx,Wty,Wwd,Wht,
                                               NULL,NULL,
                                               hInstance,NULL               
   
      Run "makeit.bat" to recompile and run Prg01.exe to see the revised form.
      (Objective 3 & 4 have now been achieved)

   11 The final step of preventing resizing is now easy, all that is required is to change the
      PrgWinSty value to 0C80000h and recompile.

All the original objectives have now been achieved, and it demonstrates how changing the constant values included in dwstyle will affect the form attributes created by "CreateWindowEx"

You will also be able to experiment with other form elements by changing the selected options in prostart.exe


Cheers

Tarka