References ▼
The GRADIENTDLGPARAMS structure provides information used to initialize the dialog box created by the L_DlgGetGradient function. After the user closes the dialog box, this structure is updated with information about the user's selections.
typedef struct _GRADIENTDLGPARAMS{L_UINT uStructSize;pBITMAPHANDLE pBitmap;L_UINT uStyle;COLORREF crStart;COLORREF crEnd;L_UINT uSteps;L_UINT32 uDlgFlags;LTCOMMDLGHELPCB pfnHelpCallback;L_VOID *pHelpCallBackUserData;} GRADIENTDLGPARAMS,* LPGRADIENTDLGPARAMS;
Size of this structure, in bytes. Use the sizeof operator to calculate this value.
Pointer to the bitmap handle that references the bitmap used for preview or processing.
The gradient style. For a list of possible values, refer to Effect Gradient Styles.
The starting color of the gradient. You can specify a COLORREF value, such as the return value of the Windows RGB macro, or you can use the PALETTEINDEX macro to specify a palette color.
The ending color of the gradient. You can specify a COLORREF value, such as the return value of the Windows RGB macro, or you can use the PALETTEINDEX macro to specify a palette color.
The number of steps in the gradient.
User interface flags for this dialog, which determines the layout and action of the dialog. Possible values are:
| Value | Meaning |
|---|---|
| DLG_GRADIENT_SHOW_CONTEXTHELP | [0x00000001] dialog should contain a context sensitive help icon. |
| DLG_GRADIENT_SHOW_PREVIEW | [0x00000002] show a preview of the image in the dialog. The pBitmap member of this structure should contain a valid bitmap. |
| DLG_GRADIENT_AUTOPREVIEW | [0x00000004] auto preview when options change |
| DLG_GRADIENT_STARTCOLOR | [0x00000008] start color is an option |
| DLG_GRADIENT_ENDCOLOR | [0x00000010] end color is an option |
| DLG_GRADIENT_STEPS | [0x00000020] gradient steps is an option |
| DLG_GRADIENT_NO_TREEVIEW | [0x00000040] DO NOT use TreeView |
| DLG_GRADIENT_CLASS_LINEAR | [0x00000080] linear gradients are an option |
| DLG_GRADIENT_CLASS_ANGULAR | [0x00000100] angular gradients are an option |
| DLG_GRADIENT_CLASS_RECTANGULAR | [0x00000200] rectangular gradients are an option |
| DLG_GRADIENT_CLASS_ELLIPTICAL | [0x00000400] elliptical gradients are an option |
| DLG_GRADIENT_CLASS_CONICAL | [0x00000800] conical gradients are an option |
Pointer to an optional help callback function. If you do not wish to provide help to this dialog, use NULL as the value of this parameter. To provide help to this dialog, use the function pointer as the value of this parameter. The callback function must adhere to the prototype described in LTCOMMDLGHELPCB.
Void pointer that you can use to pass one or more additional parameters that the callback function needs. To use this feature, assign a value to a variable or create a structure that contains as many fields as you need. Then, in this parameter, pass the address of the variable or structure, casting it to L_VOID *. The callback function, which receives the address in its own pHelpCallBackUserData parameter, can cast it to a pointer of the appropriate data type to access your variable or structure. If the additional parameters are not needed, you can pass NULL in this parameter.