Creating Our Control

The SimpleButtonCreate function will allow the user to create the SimpleButton control directly with this function. The parameters for SimpleButtonCreate are hWndParent, lpszText, xpos, ypos, controlwidth, controlheight, dwResourceID, and finally dwStyle. This is more or less typical for creating a control with CreateWindowEx and as such we try to keep our function as similar to that as we can, so that it is easier for the end user to use.

Most of the parameters of the SimpleButtonCreate function are self-explanatory: the width, height, position of the control, the text to display, the parent handle of our child control and the resource id number associated with the control.

The dwStyle parameter gives us a number of options to allow us or the user to tailor the control to our requirements, based on the styles we define for its usage. Unfortunately their isn't much in the microsoft documentation to indicate what values we can pass to the dwStyle parameter apart from the standard windows defined ones: WS_BORDER, WS_VISIBLE, WS_CHILD etc

The most useful information I came across that explains the dwStyle flags parameter of CreateWindowEx is from Raymond Chen's old new thing blog

The low 16 bits of the dwStyle parameter are defined by the implementer of the window class (by the person who calls RegisterClass)

That means we have 0x0 - 0xFFFF reserved for defining styles for our controls - 65535 possible values or 16 values if we require bitmasked unique values (1111111111111111). And we can incorporate the standard style flags as well if we so desire (WS_BORDER, WS_VISIBLE etc). So our SimpleButton styles we will use are:

; SimpleButton Button Styles:
SBBS_CENTER             EQU 0h  ; Align text centrally
SBBS_LEFT               EQU 1h  ; Align text to the left of the button
SBBS_HAND               EQU 2h  ; Show a hand when mouse moves over button.
SBBS_PUSHBUTTON         EQU 4h  ; Simulate button movement when clicked.
SBBS_AUTOSTATE          EQU 8h  ; Automatically toggle state when clicked.

; SimpleButton Edge (Border) Styles:
SBES_NONE               EQU 0
SBES_LEFT               EQU 1
SBES_TOP                EQU 2
SBES_BOTTOM             EQU 4
SBES_RIGHT              EQU 8

So our SimpleButtonCreate function is just a wrapper to register the control if not already registered and a call to CreateWindowEx to create it, returning the handle to the newly created control in eax. Also we check with the dwStyle parameter which flags are passed to SimpleButtonCreate, to ensure for example that WS_CHILD and WS_VISIBLE is included and any other flags we might want as well. This check is also performed in the _SB_Init procedure in case our SimpleButton control was created via a dialog resource. Of course you are free to define how you want your control to behave at creation and what flags if any you want to force to be included or even excluded from use.

Here is our SimpleButtonCreate function:

; SimpleButtonCreate - Returns handle in eax of newly created control or NULL
SimpleButtonCreate PROC PRIVATE hWndParent:DWORD, lpszText:DWORD, xpos:DWORD, /
                                ypos:DWORD, controlwidth:DWORD, controlheight:DWORD, /
                                dwResourceID:DWORD, dwStyle:DWORD
    LOCAL hinstance:DWORD
    LOCAL hControl:DWORD
    LOCAL dwNewStyle:DWORD

    Invoke GetModuleHandle, NULL
    mov hinstance, eax

    Invoke SimpleButtonRegister ; register our control if its not already registered.

    mov eax, dwStyle
    mov dwNewStyle, eax
        or dwNewStyle, WS_CHILD or WS_VISIBLE or WS_CLIPCHILDREN

    Invoke CreateWindowEx, NULL, Addr SimpleButtonClass, lpszText, dwNewStyle, xpos, /
                           ypos, controlwidth, controlheight, hWndParent, / 
                           dwResourceID, hinstance, NULL
SimpleButtonCreate ENDP

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