Property Structures & Constants

Note that in the WM_CREATE message of the main processing function _SB_WndProc, I use two structures for defining the variables that I will use in the control internally and externally (named _SIMPLEBUTTON_PROPERTIES and SIMPLEBUTTON_PROPERTIES), although they aren't used directly by most controls, instead I opt to use constant values that are offsets into the allocated memory.

For example, the internal variables structure I use is defined as such:

_SIMPLEBUTTON_PROPERTIES   STRUCT
    dwEnabledState         DD ?
    dwMouseOver            DD ?
    dwSelectedState        DD ?
    dwMouseDown            DD ?
_SIMPLEBUTTON_PROPERTIES   ENDS

with the internal variables (or properties) used, defined as constants:

@SimpleButtonEnabledState  EQU 0
@SimpleButtonMouseOver     EQU 4
@SimpleButtonSelectedState EQU 8
@SimpleButtonMouseDown     EQU 12

So the memory block that the four internal variables are stored in, starts at offset 0 for the first one, offset 4 for the next and so on (assuming all variables are dword values of course). We will see later on getting and setting these internal and external variables using the helper functions: __GetIntProperty, __SetIntProperty, __GetExtProperty and __SetExtProperty.

The external properties and structure (SIMPLEBUTTON_PROPERTIES)) is defined similarly in the SimpleButton.inc file for the end-user. Typically the end-user wont make use of the structure directly, its just added as a convienance - mainly for the use by the developer. It is easier to use SIZEOF structurename to pass to the __AllocMemProperties function to determine the size of memory to allocate for our control's properties.

Here is the list of external properties constants that we define for the end-user:

@SimpleButtonTextFont            EQU 0  ; hFont
@SimpleButtonTextColor           EQU 4  ; Colorref
@SimpleButtonTextColorAlt        EQU 8  ; Colorref
@SimpleButtonTextColorSel        EQU 12 ; Colorref
@SimpleButtonTextColorSelAlt     EQU 16 ; Colorref
@SimpleButtonTextColorDisabled   EQU 20 ; Colorref
@SimpleButtonBackColor           EQU 24 ; Colorref
@SimpleButtonBackColorAlt        EQU 28 ; Colorref
@SimpleButtonBackColorSel        EQU 32 ; Colorref
@SimpleButtonBackColorSelAlt     EQU 36 ; Colorref
@SimpleButtonBackColorDisabled   EQU 40 ; Colorref
@SimpleButtonBorderColor         EQU 44 ; Colorref
@SimpleButtonBorderColorAlt      EQU 48 ; Colorref
@SimpleButtonBorderColorSel      EQU 52 ; Colorref
@SimpleButtonBorderColorSelAlt   EQU 56 ; Colorref
@SimpleButtonBorderColorDisabled EQU 60 ; Colorref
@SimpleButtonBorderStyle         EQU 64 ; Border Style Flags