pinvoke.net: gdi32.GradientFill

Performs GDI32 based gradient fills of rectangles and triangles

GradientFill uses colors of 64 bits, i.e. 16 bits per component (16 bits each for the red, for the green, for the blue and for the alpha), so the type of R, G and B fields in the TRIVERTEX struct are ushort, and not byte.

For strongest red or/and green or/and blue or/and alpha, use ushort.MaxValue. For white color, set all R, G and B to ushort.MaxValue!

C# Signature:

[DllImport("gdi32.dll", EntryPoint = "GdiGradientFill", ExactSpelling = true)]
public static extern bool GradientFill(
    IntPtr hdc,           // handle to DC
    IntPtr pVertex,    // array of vertices
    uint dwNumVertex,     // number of vertices
    IntPtr pMesh,           // array of gradients
    uint dwNumMesh,       // size of gradient array
    GRADIENT_FILL dwMode);           // gradient fill mode

Overload

Performs GDI32 based gradient fills of rectangles only

C# Signature:

[DllImport("gdi32.dll", EntryPoint = "GdiGradientFill", ExactSpelling = true)]
public static extern bool GradientFill(
    IntPtr hdc,           // handle to DC
    TRIVERTEX[] pVertex,    // array of vertices
    uint dwNumVertex,     // number of vertices
    GRADIENT_RECT[] pMesh,    // array of gradient rectangles, that each one keeps two indices in pVertex array, to determine its bounds
    uint dwNumMesh,       // number of gradient rectangles to draw
    GRADIENT_FILL dwMode);           // Use either GRADIENT_FILL.RECT_H or GRADIENT_FILL.RECT_V. Using the value GRADIENT_FILL.TRIANGLE is wrong in this overload!

Overload

Performs GDI32 based gradient fills of triangles only

C# Signature:

[DllImport("gdi32.dll", EntryPoint = "GdiGradientFill", ExactSpelling = true)]
public static extern bool GradientFill(
    IntPtr hdc,           // handle to DC
    TRIVERTEX[] pVertex,    // array of vertices
    uint dwNumVertex,     // number of vertices
    GRADIENT_TRIANGLE[] pMesh, // array of gradient triangles, that each one keeps three indices in pVertex array, to determine its bounds
    uint dwNumMesh,       // number of gradient triangles to draw
    GRADIENT_FILL dwMode);           // Use only GRADIENT_FILL.TRIANGLE. Both values GRADIENT_FILL.RECT_H and GRADIENT_FILL.RECT_V are wrong in this overload!

VB Signature:

Declare Function GradientFill Lib "gdi32.dll" (TODO) As TODO

User-Defined Types:

Alternative Managed API:

Do you know one? Please contribute it!

Notes:

The GDI32.dll does not contain a GradientFill() function. The actual entry point is GdiGradientFill(). That's why the 'EntryPoint' attribute is present.

This method creates one entry each for rectangles and triangles. It's just a matter of convenience and error checking by the compiler.

Tips & Tricks:

Please add some!

Sample Code:

Documentation

GradientFill on MSDN