GdipGetNearestColor

// gdiplus.dll
#include <windows.h>

Status GdipGetNearestColor(
    GpGraphics* graphics,
    DWORD* argb
);

<DllImport("gdiplus.dll", ExactSpelling:=True)>
Public Shared Function GdipGetNearestColor(
    graphics As IntPtr,   ' GpGraphics* in/out
    ByRef argb As UInteger   ' DWORD* in/out
) As Integer
End Function

' graphics : GpGraphics* in/out
' argb : DWORD* in/out
Declare PtrSafe Function GdipGetNearestColor Lib "gdiplus" ( _
    ByVal graphics As LongPtr, _
    ByRef argb As Long) As Long
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

GdipGetNearestColor = ctypes.windll.gdiplus.GdipGetNearestColor
GdipGetNearestColor.restype = ctypes.c_int
GdipGetNearestColor.argtypes = [
    ctypes.c_void_p,  # graphics : GpGraphics* in/out
    ctypes.POINTER(wintypes.DWORD),  # argb : DWORD* in/out
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('gdiplus.dll')
GdipGetNearestColor = Fiddle::Function.new(
  lib['GdipGetNearestColor'],
  [
    Fiddle::TYPE_VOIDP,  # graphics : GpGraphics* in/out
    Fiddle::TYPE_VOIDP,  # argb : DWORD* in/out
  ],
  Fiddle::TYPE_INT)

#[link(name = "gdiplus")]
extern "system" {
    fn GdipGetNearestColor(
        graphics: *mut GpGraphics,  // GpGraphics* in/out
        argb: *mut u32  // DWORD* in/out
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("gdiplus.dll")]
public static extern int GdipGetNearestColor(IntPtr graphics, ref uint argb);
"@
$api = Add-Type -MemberDefinition $sig -Name 'gdiplus_GdipGetNearestColor' -Namespace Win32 -PassThru
# $api::GdipGetNearestColor(graphics, argb)

#uselib "gdiplus.dll"
#func global GdipGetNearestColor "GdipGetNearestColor" sptr, sptr
; GdipGetNearestColor varptr(graphics), varptr(argb)   ; 戻り値は stat
; graphics : GpGraphics* in/out -> "sptr"
; argb : DWORD* in/out -> "sptr"
; ※HSP3.7は #func のため戻り値はシステム変数 stat に格納されます。

#uselib "gdiplus.dll"
#cfunc global GdipGetNearestColor "GdipGetNearestColor" var, var
; res = GdipGetNearestColor(graphics, argb)
; graphics : GpGraphics* in/out -> "var"
; argb : DWORD* in/out -> "var"
; ※出力/バッファ引数は var 方式(変数を直接渡す)。varptr 方式にも切替可。

; Status GdipGetNearestColor(GpGraphics* graphics, DWORD* argb)
#uselib "gdiplus.dll"
#cfunc global GdipGetNearestColor "GdipGetNearestColor" var, var
; res = GdipGetNearestColor(graphics, argb)
; graphics : GpGraphics* in/out -> "var"
; argb : DWORD* in/out -> "var"
; ※出力/バッファ引数は var 方式(変数を直接渡す)。varptr 方式にも切替可。

import (
	"golang.org/x/sys/windows"
	"unsafe"
)

var (
	gdiplus = windows.NewLazySystemDLL("gdiplus.dll")
	procGdipGetNearestColor = gdiplus.NewProc("GdipGetNearestColor")
)

// graphics (GpGraphics* in/out), argb (DWORD* in/out)
r1, _, err := procGdipGetNearestColor.Call(
	uintptr(graphics),
	uintptr(argb),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // Status

function GdipGetNearestColor(
  graphics: Pointer;   // GpGraphics* in/out
  argb: Pointer   // DWORD* in/out
): Integer; stdcall;
  external 'gdiplus.dll' name 'GdipGetNearestColor';

result := DllCall("gdiplus\GdipGetNearestColor"
    , "Ptr", graphics   ; GpGraphics* in/out
    , "Ptr", argb   ; DWORD* in/out
    , "Int")   ; return: Status

●GdipGetNearestColor(graphics, argb) = DLL("gdiplus.dll", "int GdipGetNearestColor(void*, void*)")
# 呼び出し: GdipGetNearestColor(graphics, argb)
# graphics : GpGraphics* in/out -> "void*"
# argb : DWORD* in/out -> "void*"
# なでしこ1は32bit・ANSI(Shift_JIS)。文字列=char*(ANSI)、ポインタ/ハンドル=void*(4byte)。