windows で golang

山形のohisamaです。golang始めました。
窓を開くサンプルです。
ohisama/win

main.go

package main
import (
    "syscall"
    "ohisama/win"
)
var x int32
func WndProc(hWnd syscall.Handle, msg uint32, wParam, lParam uintptr) (uintptr) {
    switch msg {
    case win.WM_PAINT:
        x++
        var strMessage = "Hello"
        var ps win.PAINTSTRUCT
        hdc := win.BeginPaint(hWnd, &ps)
        for i := 0; i < 256; i++ {
            for j := 0; j < 256; j++ {
                iro := i * 256 * 256 + j
                win.SetPixelV(hdc, int32(i), int32(j), int32(iro))
            }
        }
        win.Ellipse(hdc, x,  200, 200 + x, 400)
        win.TextOut(hdc, 100, 100, strMessage, int32(len(strMessage)))
        win.EndPaint(hWnd, &ps)
        return 0
    case win.WM_COMMAND:
        return 0
    case win.WM_DESTROY:
        win.PostQuitMessage(0)
        return 0
    default:
        return win.DefWindowProc(hWnd, msg, wParam, lParam)
    }
    return 0
}
func main() {
    win.WinMain(syscall.NewCallback(WndProc))
    return
}