Solid pens| WORD EnumObj(lpDestDev, wStyle, lpCallbackFunc, lpClientData) | |||
| LPPDEVICE lpDestDev; | |||
| WORD wStyle; | |||
| FARPROC lpCallbackFunc; | |||
| LPVOID lpClientData; |
The EnumObj function enumerates the pens and brushes available on the device. GDI calls EnumObj when an application calls the EnumObjects function (GDI.71). For each object having the given style, EnumObj calls the callback function with the logical information for that object. EnumObj continues to call the callback function until there are no more objects or the callback function returns zero.
Every graphics driver must export an EnumObj function.
lpDestDev
Points to a PDEVICE or PBITMAP structure specifying the destination device or bitmap.
wStyle
Specifies whether to enumerate pens or brushes. This parameter can be one of the following values.
| Value | Meaning |
| 1 | Enumerates pens |
| 2 | Enumerates brushes |
EnumObj enumerates all objects of the given type. If there are no objects of the given type, the function must return 1.
lpCallbackFunc
Points to the user-supplied callback function.
lpClientData
Points to the user-supplied data.
The return value is the last value returned by the callback function. Otherwise, it is 1 if there are no objects of the given type.
The export ordinal for this function is 7.
The callback function has the following form:
WORD CallbackFunction(lpLogObj, lpClientData)
LPVOID lpLogObj;
LPSTR lpClientData;
| Parameter | Description |
| lpLogObj | Points to a LPEN or LBRUSH structure, depending on the wStyle parameter. |
| lpClientData | Points to the user-supplied data passed to EnumObj. |
Before calling the callback function, EnumObj must fill the LPEN or LBRUSH structure with the logical colors and other values that correspond to a given physical pen or brush.
To support some older applications (such as Microsoft Excel for versions earlier than 2.1), EnumObj specifies the 8 default EGA colors in the first 8 objects it enumerates.
| EGA color | RGB value |
| Black | 0,0,0 |
| White | 0xFF,0xFF,0xFF |
| Red | 0xFF,0,0 |
| Green | 0,0xFF,0 |
| Blue | 0,0,0xFF |
| Yellow | 0xFF,0xFF,0 |
| Magenta | 0xFF,0,0xFF |
| Cyan | 0,0xFF,0xFF |
If the driver supports additional colors, EnumObj can specify those colors in any order. Since some applications end the enumeration after the first 16 colors, the second 8 colors to enumerated should be the most desirable colors of the device.
EnumObj should enumerate solid pens before styled lines. Enumerating styled pens is optional. The function should enumerate:
Solid pens
Styled pens (optional)
Solid brushes (no dithered colors)
Hatched brushes
EnumObj does not need to specify the background colors for hatched brushes.