Parameters hdc Handle to the destination device context. pVertex Pointer to an array of TRIVERTEX structures that each define a triangle vertex. dwNumVertex Number of vertices. pMesh Array of GRADIENT_TRIANGLE structures in triangle mode, or an array of GRADIENT_RECT structures in rectangle mode. dwNumMesh The number of elements (triangles or rectangles) in pMesh. dwMode Specifies gradient fill mode. This parameter can contain one of the following values. Value Meaning GRADIENT_FILL_RECT_H In this mode, two endpoints describe a rectangle. The rectangle is defined to have a constant color (specified by the TRIVERTEX structure) for the left and right edges. GDI interpolates the color from the top to bottom edge and fills the interior. GRADIENT_FILL_RECT_V In this mode, two endpoints describe a rectangle. The rectangle is defined to have a constant color (specified by the TRIVERTEX structure) for the top and bottom edges. GDI interpolates the color from the top to bottom edge and fills the interior. GRADIENT_FILL_TRIANGLE In this mode, an array of TRIVERTEX structures is passed to GDI along with a list of array indexes that describe separate triangles. GDI performs linear interpolation between triangle vertices and fills the interior. Drawing is done directly in 24- and 32-bit-per-pixel modes. Dithering is performed in 16-, 8.4-, and 1-bit-per-pixel mode. Return Values If the function succeeds, the return value is TRUE.If the function fails, the return value is FALSE.Windows NT: To get extended error information, callGetLastError.Res To add smooth shading to a triangle, call the GradientFill function with the three triangle endpoints. GDI will linearly interpolate and fill the triangle. To add smooth shading to a rectangle, call GradientFill with the upper-left and lower-right coordinates of the rectangle. There are two shading modes used when drawing a rectangle. In horizontal mode, the rectangle is shaded from left to right. In vertical mode, the rectangle is shaded from top to bottom. The GradientFill function uses a mesh method to specify the endpoints of the object to draw. All vertices are passed to GradientFill in the pVertex array. The pMesh parameter specifies how these vertices are connected to form an object. When filling a rectangle, pMesh points to an array of GRADIENT_RECT structures. Each GRADIENT_RECT structure specifies the index of two vertices in the pVertex array. These two vertices form the upper-left and lower-right boundary of one rectangle. In the case of filling a triangle, pMesh points to an array of GRADIENT_TRIANGLE structures. Each GRADIENT_TRIANGLE structure specifies the index of three vertices in the pVertex array. These three vertices form one triangle. In order to simplify hardware acceleration, this routine is not required to be pixel-perfect in the triangle interior. For more information, see Smooth Shading, Drawing a Shaded Triangle, and Drawing a Shaded Rectangle. QuickInfo Windows NT: Requires version 5.0 or later. Windows: Requires Windows 98 or later. Windows CE: Unsupported. Header: Declared in wingdi.h. Import Library: Included as a resource in msimg32.dll.GRADIENT_RECT [This is preliminary documentation and subject to change.] The GRADIENT_RECT structure specifies the index of two vertices in the pVertex array. These two vertices form the upper-left and lower-right boundaries of a rectangle.typedef struct _GRADIENT_RECT { ULONG UpperLeft; ULONG LowerRight; }GRADIENT_RECT, *PGRADIENT_RECT,*LPGRADIENT_RECT;
Members UpperLeft Specifies the upper-left corner of a rectangle. LowerRight Specifies the lower-right corner of a rectangle. Res The GRADIENT_RECT structure contains the values used in the dwMode parameter of the GradientFill function. For related GradientFill structures, see GRADIENT_TRIANGLE and TRIVERTEX.For an example of the use of this structure, see Drawing a Shaded Rectangle. QuickInfo Windows NT: Requires version 5.0 or later. Windows: Requires Windows 98 or later. Windows CE: Unsupported. Header: Declared in wingdi.h. GRADIENT_TRIANGLE [This is preliminary documentation and subject to change.] The GRADIENT_TRIANGLE structure specifies the index of three vertices in the pVertex array. These three vertices form one triangle. typedef struct _GRADIENT_TRIANGLE { ULONG Vertex1; ULONG Vertex2; ULONG Vertex3; }GRADIENT_TRIANGLE,*PGRADIENT_TRIANGLE,*LPGRADIENT_TRIANGLE;
Members Vertex1 First point of the triangle where sides intersect. Vertex2 Second point of the triangle where sides intersect. Vertex3 Third point of the triangle where sides intersect. Res The GRADIENT_TRIANGLE structure contains the values used in the dwMode parameter of the GradientFill function. For related GradientFill structures, see GRADIENT_RECT and TRIVERTEX.For an example of this function, see Drawing a Shaded Triangle. QuickInfo Windows NT: Requires version 5.0 or later. Windows: Requires Windows 98 or later. Windows CE: Unsupported. Header: Declared in wingdi.h. TRIVERTEX [This is preliminary documentation and subject to change.] The TRIVERTEX structure contains color information and position information. typedef USHORT COLOR16; typedef struct _TRIVERTEX { LONG x; Long y; COLOR16 Red; COLOR16 Green; COLOR16 Blue; COLOR16 Alpha; }TRIVERTEX,*PTRIVERTEX,*LPTRIVERTEX;
Members x Specifies the x-coordinate, in logical units, of the upper-left corner of the rectangle. y Specifies the y-coordinate, in logical units, of the upper-left corner of the rectangle. Red Indicates color information at the point of x, y. Green Indicates color information at the point of x, y. Blue Indicates color information at the point of x, y. Alpha Indicates color information at the point of x, y. Res In the TRIVERTEX structure, x and y indicate position in the same manner as in the POINTL structure contained in the wtypes.h header file. Red, Green, Blue, and Alpha members indicate color information at the point x, y. The color information of each channel is specified as a value from 0x0000 to 0xff00. This allows higher color resolution for an object that has been split into small triangles for display. The TRIVERTEX structure contains information needed by the pVertex parameter of GradientFill. For an example of the use of this structure, see Drawing a Shaded Triangle and Drawing a Shaded Rectangle. QuickInfo Windows NT: Requires version 5.0 or later. Windows: Requires Windows 98 or later. Windows CE: Unsupported. Header: Declared in wingdi.h.
就在Form1中！ 仔细看：Private Declare Function GradientFillRect Lib "msimg32" Alias "GradientFill" (ByVal hdc As Long, pVertex As TRIVERTEX, ByVal dwNumVertex As Long, pMesh As GRADIENT_RECT, ByVal dwNumMesh As Long, ByVal dwMode As Long) As Long Private Declare Function GradientFillTri Lib "msimg32" Alias "GradientFill" (ByVal hdc As Long, pVertex As TRIVERTEX, ByVal dwNumVertex As Long, pMesh As GRADIENT_TRIANGLE, ByVal dwNumMesh As Long, ByVal dwMode As Long) As Long
http://www.dapha.net/vb/list.asp?id=260
HDC hdc,
CONST PTRIVERTEX pVertex,
DWORD dwNumVertex,
CONST PVOID pMesh,
DWORD dwNumMesh,
DWORD dwMode
);
Parameters
hdc
Handle to the destination device context.
pVertex
Pointer to an array of TRIVERTEX structures that each define a triangle vertex.
dwNumVertex
Number of vertices.
pMesh
Array of GRADIENT_TRIANGLE structures in triangle mode, or an array of GRADIENT_RECT structures in rectangle mode.
dwNumMesh
The number of elements (triangles or rectangles) in pMesh.
dwMode
Specifies gradient fill mode. This parameter can contain one of the following values. Value Meaning
GRADIENT_FILL_RECT_H In this mode, two endpoints describe a rectangle. The rectangle is defined to have a constant color (specified by the TRIVERTEX structure) for the left and right edges. GDI interpolates the color from the top to bottom edge and fills the interior.
GRADIENT_FILL_RECT_V In this mode, two endpoints describe a rectangle. The rectangle is defined to have a constant color (specified by the TRIVERTEX structure) for the top and bottom edges. GDI interpolates the color from the top to bottom edge and fills the interior.
GRADIENT_FILL_TRIANGLE In this mode, an array of TRIVERTEX structures is passed to GDI along with a list of array indexes that describe separate triangles. GDI performs linear interpolation between triangle vertices and fills the interior. Drawing is done directly in 24- and 32-bit-per-pixel modes. Dithering is performed in 16-, 8.4-, and 1-bit-per-pixel mode.
Return Values
If the function succeeds, the return value is TRUE.If the function fails, the return value is FALSE.Windows NT: To get extended error information, callGetLastError.Res
To add smooth shading to a triangle, call the GradientFill function with the three triangle endpoints. GDI will linearly interpolate and fill the triangle. To add smooth shading to a rectangle, call GradientFill with the upper-left and lower-right coordinates of the rectangle. There are two shading modes used when drawing a rectangle. In horizontal mode, the rectangle is shaded from left to right. In vertical mode, the rectangle is shaded from top to bottom. The GradientFill function uses a mesh method to specify the endpoints of the object to draw. All vertices are passed to GradientFill in the pVertex array. The pMesh parameter specifies how these vertices are connected to form an object. When filling a rectangle, pMesh points to an array of GRADIENT_RECT structures. Each GRADIENT_RECT structure specifies the index of two vertices in the pVertex array. These two vertices form the upper-left and lower-right boundary of one rectangle. In the case of filling a triangle, pMesh points to an array of GRADIENT_TRIANGLE structures. Each GRADIENT_TRIANGLE structure specifies the index of three vertices in the pVertex array. These three vertices form one triangle. In order to simplify hardware acceleration, this routine is not required to be pixel-perfect in the triangle interior. For more information, see Smooth Shading, Drawing a Shaded Triangle, and Drawing a Shaded Rectangle. QuickInfo
Windows NT: Requires version 5.0 or later.
Windows: Requires Windows 98 or later.
Windows CE: Unsupported.
Header: Declared in wingdi.h.
Import Library: Included as a resource in msimg32.dll.GRADIENT_RECT
[This is preliminary documentation and subject to change.] The GRADIENT_RECT structure specifies the index of two vertices in the pVertex array. These two vertices form the upper-left and lower-right boundaries of a rectangle.typedef struct _GRADIENT_RECT
{
ULONG UpperLeft;
ULONG LowerRight;
}GRADIENT_RECT, *PGRADIENT_RECT,*LPGRADIENT_RECT;
Members
UpperLeft
Specifies the upper-left corner of a rectangle.
LowerRight
Specifies the lower-right corner of a rectangle.
Res
The GRADIENT_RECT structure contains the values used in the dwMode parameter of the GradientFill function. For related GradientFill structures, see GRADIENT_TRIANGLE and TRIVERTEX.For an example of the use of this structure, see Drawing a Shaded Rectangle. QuickInfo
Windows NT: Requires version 5.0 or later.
Windows: Requires Windows 98 or later.
Windows CE: Unsupported.
Header: Declared in wingdi.h.
GRADIENT_TRIANGLE
[This is preliminary documentation and subject to change.] The GRADIENT_TRIANGLE structure specifies the index of three vertices in the pVertex array. These three vertices form one triangle. typedef struct _GRADIENT_TRIANGLE
{
ULONG Vertex1;
ULONG Vertex2;
ULONG Vertex3;
}GRADIENT_TRIANGLE,*PGRADIENT_TRIANGLE,*LPGRADIENT_TRIANGLE;
Members
Vertex1
First point of the triangle where sides intersect.
Vertex2
Second point of the triangle where sides intersect.
Vertex3
Third point of the triangle where sides intersect.
Res
The GRADIENT_TRIANGLE structure contains the values used in the dwMode parameter of the GradientFill function. For related GradientFill structures, see GRADIENT_RECT and TRIVERTEX.For an example of this function, see Drawing a Shaded Triangle. QuickInfo
Windows NT: Requires version 5.0 or later.
Windows: Requires Windows 98 or later.
Windows CE: Unsupported.
Header: Declared in wingdi.h.
TRIVERTEX
[This is preliminary documentation and subject to change.] The TRIVERTEX structure contains color information and position information. typedef USHORT COLOR16;
typedef struct _TRIVERTEX
{
LONG x;
Long y;
COLOR16 Red;
COLOR16 Green;
COLOR16 Blue;
COLOR16 Alpha;
}TRIVERTEX,*PTRIVERTEX,*LPTRIVERTEX;
Members
x
Specifies the x-coordinate, in logical units, of the upper-left corner of the rectangle.
y
Specifies the y-coordinate, in logical units, of the upper-left corner of the rectangle.
Red
Indicates color information at the point of x, y.
Green
Indicates color information at the point of x, y.
Blue
Indicates color information at the point of x, y.
Alpha
Indicates color information at the point of x, y.
Res
In the TRIVERTEX structure, x and y indicate position in the same manner as in the POINTL structure contained in the wtypes.h header file. Red, Green, Blue, and Alpha members indicate color information at the point x, y. The color information of each channel is specified as a value from 0x0000 to 0xff00. This allows higher color resolution for an object that has been split into small triangles for display. The TRIVERTEX structure contains information needed by the pVertex parameter of GradientFill. For an example of the use of this structure, see Drawing a Shaded Triangle and Drawing a Shaded Rectangle. QuickInfo
Windows NT: Requires version 5.0 or later.
Windows: Requires Windows 98 or later.
Windows CE: Unsupported.
Header: Declared in wingdi.h.
这个函数我用BCB试过的，效果很好，但不会用VB调用。
仔细看：Private Declare Function GradientFillRect Lib "msimg32" Alias "GradientFill" (ByVal hdc As Long, pVertex As TRIVERTEX, ByVal dwNumVertex As Long, pMesh As GRADIENT_RECT, ByVal dwNumMesh As Long, ByVal dwMode As Long) As Long
Private Declare Function GradientFillTri Lib "msimg32" Alias "GradientFill" (ByVal hdc As Long, pVertex As TRIVERTEX, ByVal dwNumVertex As Long, pMesh As GRADIENT_TRIANGLE, ByVal dwNumMesh As Long, ByVal dwMode As Long) As Long