GDI мерцает при анимации растрового изображения

Я пытаюсь удалить мерцание из моей растровой анимации в GDI. Это радужная анимация. Анимация выполняется плавно, но растровые кнопки мерцают.

Я попробовал InvalidateRect(), но мерцание все равно происходит. Вот мой урезанный код. ImageData — это значение пикселя моего статического растрового изображения радуги. Я анимирую его, перемещая все элементы в их следующее положение.

#include <Windows.h>
#include <iostream>
#include <deque>
#include <vector>

HDC hdcMem;
HBITMAP hbmMem;
HANDLE hOld;
PAINTSTRUCT ps;
HDC hdc;
HBITMAP Membitmap;

int WIDTH = 350;
int HEIGHT = 500;

std::deque<int> imageData =
    {0xFB017D, 0xFB0278, 0xFB017D, 0xFC0280, 0xFB027A, 0xFB027A, 0xFB017C, 0xFA0175, 0xFC026E, 0xFC026C, 0xFC036B, 0xFC0266,
     0xFC0263, 0xFC015E, 0xFC025B, 0xFB015A, 0xFB0351, 0xFB0351, 0xFC014E, 0xFC024C, 0xFC0249, 0xFC0146, 0xFC0242, 0xFC0241, 0xFD0237, 0xFD0237, 0xFD0237, 0xFD0235, 0xFD0132, 0xFD022D, 0xFD0329, 0xFC0226, 0xFC0228, 0xFC0323, 0xFC021D, 0xFC0319, 0xFE0219, 0xFD0116, 0xFD0213, 0xFC020E, 0xFC020C, 0xFC030B, 0xFB0206, 0xFB0304, 0xFB0303, 0xF90403, 0xF90304, 0xF90306, 0xFD0002, 0xFE0606, 0xFB0905, 0xF90C04, 0xFC1005, 0xFD1104, 0xFB1404, 0xFC1906, 0xF81A03, 0xFB2004, 0xFB2203, 0xFA2402, 0xFA2805, 0xF82A05, 0xF82D04, 0xFB3204, 0xFB3705, 0xF93A06, 0xFA3D06, 0xFC3F05, 0xFF4105, 0xFE4203, 0xFC4604, 0xFB4A06, 0xFB5106, 0xFC5207, 0xFB5406, 0xFC5707, 0xFB5904, 0xFB5B03, 0xFC5D02, 0xFC5E03, 0xFC6303, 0xFB6504, 0xFC6804, 0xFB6E04, 0xFC7205, 0xFC7605, 0xFC7905, 0xFD7A04, 0xF97B02, 0xFC7E03, 0xFB8102, 0xFB8402, 0xFC8A05, 0xFC8C04, 0xFA8F03, 0xFD9204, 0xFB9703, 0xFC9804, 0xFC9A03, 0xFC9D03, 0xFBA103, 0xFCA603, 0xFDAA06, 0xFEAD06, 0xFBAE06, 0xFDB306, 0xFDB805, 0xFCBC05, 0xFBBD06, 0xFAC005, 0xFCC304, 0xFEC502, 0xFACC05, 0xFBCD05, 0xFBD007, 0xFDD305, 0xFAD403, 0xFAD703, 0xF9DA03, 0xFBDC05, 0xFDE104, 0xFAE202, 0xF8E703, 0xFBED06, 0xFDEF06, 0xFCEE05, 0xFAF005, 0xFAF307, 0xFAF503, 0xF8F603, 0xF7F605, 0xF2F504, 0xF0F505, 0xEDF605, 0xECF703, 0xEBF904, 0xE6FC06, 0xE1F903, 0xDDF904, 0xDCFC05, 0xD7FB05, 0xD4FC06, 0xD3FB05, 0xCEF801, 0xCEF703, 0xCCF803, 0xC8FA05, 0xC2FA03, 0xBEFA04, 0xBAFA05, 0xB6FB04, 0xB3F902, 0xB4FA04, 0xB3F903, 0xB0FA03, 0xADFB05, 0xAAFC06,
     0xA2FA05, 0x9EF904, 0x9CFB07, 0x98FA05, 0x94F802, 0x92F703, 0x8FF903, 0x8DFB06, 0x89FB06, 0x84FA04, 0x82FA03, 0x83FB06, 0x7DF905, 0x77F905, 0x77FA06, 0x77FA08, 0x73F906, 0x6EFA03, 0x6AFB02, 0x6AFA04, 0x68F802, 0x68FA04, 0x63F904, 0x5DF703, 0x58F804, 0x56FA05, 0x52FA04, 0x53F903, 0x4DF903, 0x4AFA04, 0x47F905, 0x47F905, 0x45F806, 0x3FF902, 0x3BF901, 0x3BFC05, 0x36FA02, 0x32F803, 0x2EF804, 0x2CF906, 0x27F904, 0x27F904, 0x26FA05, 0x1FFB03, 0x1CFB04, 0x18FA03, 0x14FA04, 0x10FA05, 0x0CFA04, 0x0CFA04, 0x0BFB04, 0x04F904, 0x04F904, 0x04F904, 0x04F904, 0x04F904, 0x04F904, 0x04F904, 0x04F904, 0x03FA0B, 0x03FA0B, 0x03FA0D, 0x04FA0F, 0x04FA13, 0x03FA15, 0x04FA19, 0x04FA1B, 0x02F922, 0x03FA23, 0x03FA27, 0x03F92A, 0x04F92F, 0x05FA33, 0x04FA37, 0x04F939, 0x05F93F, 0x06FA42, 0x05FA43, 0x05FA47, 0x04FB4B, 0x04FA4F, 0x04FA51, 0x05FA54, 0x04FA57, 0x04FA57, 0x04FA5B, 0x03FB5D, 0x03FA61, 0x03FA65, 0x04FA67, 0x04FA69, 0x04F96D, 0x04F96E, 0x04F970, 0x04F976, 0x04F97A, 0x05F980, 0x04F982, 0x04F984, 0x05F988, 0x07FB8A, 0x05FB8E, 0x03FA8F, 0x03FA92, 0x04FB93, 0x06FB96, 0x06FB96, 0x05FA9B, 0x05FA9F, 0x03FAA1, 0x04FAA5, 0x04F9A9, 0x04FBAC, 0x04FBAC, 0x04FBAC, 0x04FBB5, 0x04FBB7, 0x04FAB9, 0x04FABB, 0x04F8C2, 0x05F9C5, 0x03F9C6, 0x03F9C8, 0x04F9CE, 0x02F7CC, 0x05F7CF, 0x06F7D4, 0x03F6D8, 0x04F8DE, 0x05F8E4, 0x02F7E5, 0x03F8E7, 0x03F8E7, 0x03F8E9, 0x03F7ED, 0x04F7F1, 0x04F6F7, 0x04F6FA, 0x03F4FB, 0x05F1FF, 0x02EEFC, 0x05EEFD, 0x04E9FC, 0x05E8FB, 0x06E7FD,
     0x04E1FB, 0x05E2FC, 0x06DDF9, 0x02D6FE, 0x01D5FA, 0x04D6F7, 0x04D1FE, 0x05CEF8, 0x06CBF6, 0x03C4FD, 0x05C2FC, 0x02BEFB, 0x03BCFC, 0x05BBFD, 0x04B5FB, 0x03B1FA, 0x04B0FC, 0x04AEFC, 0x02ABFC, 0x04ABFC, 0x03AAFB, 0x03A7FC, 0x04A4FC, 0x049FFC, 0x059BFC, 0x0498FC, 0x0592FE, 0x028FFB, 0x038BFB, 0x0389FC, 0x0586FD, 0x0482FB, 0x057FFC, 0x057FFE, 0x057CFE, 0x0277FB, 0x0474FC, 0x0671FD, 0x056BFC, 0x0468FC, 0x0468FE, 0x0466FF, 0x0361FE, 0x035BFB, 0x0659FD, 0x0354FB, 0x0354FD, 0x0654FE, 0x034FFA, 0x064EFA, 0x054AFD, 0x0446FC, 0x0343FC, 0x0442F9, 0x053FF8, 0x043BF7, 0x0338FA, 0x0536FF, 0x0734FF, 0x0530FB, 0x042DFB, 0x0528FC, 0x0223FA, 0x0521FE, 0x0720FF, 0x051DFD, 0x0517FD, 0x0415FB, 0x0412FB, 0x030FFB, 0x040DFC, 0x0509FE, 0x0406FB, 0x0203FB, 0x0201FC, 0x0402FD, 0x0601FD, 0x0600FE, 0x0302FD, 0x0402FD, 0x0801FC, 0x0B02FD, 0x0E02FA, 0x1502FC, 0x1A01FD, 0x1C01FC, 0x1C02FB, 0x2003FD, 0x2303FC, 0x2601FC, 0x2A01FB, 0x2B02FC, 0x2C02FC, 0x3001FD, 0x3201FB, 0x3801FC, 0x3A02FB, 0x3E03FD, 0x4202F9, 0x4601FC, 0x4A02FC, 0x4D02FD, 0x4D02FB, 0x4E02FA, 0x5202F7, 0x5501F7, 0x5B00FB, 0x5E02FB, 0x6303FB, 0x6502FB, 0x6701FA, 0x6802FB, 0x6B02FC, 0x6A01FC, 0x6C02FC, 0x7002FB, 0x7502FD, 0x7B02FD, 0x8002FC, 0x8401FC, 0x8602FD, 0x8902FE, 0x8D02FD, 0x8D02FD, 0x8F03FC, 0x9102FC, 0x9402FB, 0x9801FC, 0x9B02FB, 0x9E03FD, 0xA302FD, 0xA500FA, 0xAC03FE, 0xAC02FB, 0xAE01FB, 0xB203FC, 0xB500FB, 0xBC02FD, 0xBD00FC, 0xC001FE, 0xC403FE, 0xC502FC, 0xC602FA, 0xCA02FB, 0xCD02FA,
     0xCD02FA, 0xD402FB, 0xD702FC, 0xD902FD, 0xDD02FC, 0xE102FB, 0xE402FC, 0xE802FB, 0xEC01FC, 0xED00FC, 0xF202F9, 0xF601FE, 0xF602F7, 0xF600FF, 0xF703F8, 0xFA02F9, 0xFD02F0, 0xFD02F0, 0xFD02F0, 0xFC01EE, 0xFC01EF, 0xFD03DF, 0xFC02E0, 0xFC02E0, 0xFC02DE, 0xFD03D9, 0xFC02D8, 0xFB03CD, 0xFD02CE, 0xFD02CD, 0xFD03C7, 0xFD01C6, 0xFC02BC, 0xFC02BE, 0xFB01BA, 0xFB02B4, 0xFD02B3, 0xFD02B3, 0xFC01B2, 0xFC02AE, 0xFC02AC, 0xFC01A8, 0xFC02A4, 0xFC02A1, 0xFC039F, 0xFC039F, 0xFB029E, 0xFC0298, 0xFB0294, 0xFC018F, 0xFC018E, 0xFB0278, 0xFB0083, 0xFB017C, 0xFC0377, 0xFB0081, 0xFB017C, 0xFB0373, 0xFA007B, 0xFC026E, 0xFC026C, 0xFC036B, 0xFC0266, 0xFC0263, 0xFC015E, 0xFC025B, 0xFB015A, 0xFB0351, 0xFB0351, 0xFC014E, 0xFC024C, 0xFC0249, 0xFC0146, 0xFC0242, 0xFC0241, 0xFD0237, 0xFD0237, 0xFD0237, 0xFD0235, 0xFD0132, 0xFD022D, 0xFD0329, 0xFC0226, 0xFC0228, 0xFC0323, 0xFC021D, 0xFC0319, 0xFE0219, 0xFD0116, 0xFD0213, 0xFC020E, 0xFC020C, 0xFC030B, 0xFB0206, 0xFB0304, 0xFB0303, 0xF90403, 0xF90304, 0xF90306, 0xFD0002, 0xFE0606, 0xFB0905, 0xF90C04, 0xFC1005, 0xFD1104, 0xFB1404, 0xFC1906, 0xFB1A04, 0xFD2005, 0xFC2304, 0xFB2503, 0xFA2805, 0xFA2C07, 0xFA2F06, 0xFE3507, 0xF93503, 0xF93704, 0xF83B04, 0xFB3E04, 0xFD4104, 0xFB4202, 0xFB4503, 0xFA4905, 0xF64C01, 0xF84E03, 0xF85103, 0xF95404, 0xFA5803, 0xFB5B03, 0xFD5E03, 0xFD5F04, 0xFC6303, 0xFB6504, 0xFC6804, 0xFB6E04, 0xFC7205, 0xFC7605, 0xFC7905, 0xFC7903, 0xFA7C03, 0xFD7F04, 0xFC8203, 0xFB8402, 0xFB8904, 0xFC8C04,
     0xF98E02, 0xFC9103, 0xFB9703, 0xFC9804, 0xFC9A03, 0xFC9D03, 0xFBA103, 0xFCA603, 0xFCA905, 0xFDAC05, 0xFBAE06, 0xFDB306, 0xFDB805, 0xFCBC05, 0xFBBD06, 0xFBBF05, 0xFCC304, 0xFEC502, 0xF8CA03, 0xFACC04, 0xFBD007, 0xFCD204, 0xFAD403, 0xFBD804, 0xFADB04, 0xFCDD06, 0xFDE104, 0xFAE202, 0xF8E703, 0xFBED06, 0xFDEF06, 0xFBED04, 0xF9EF04, 0xF9F206, 0xFAF503, 0xF8F603, 0xF7F605, 0xF2F504, 0xF0F505, 0xEDF605, 0xECF703, 0xEAF803, 0xE5FB05, 0xE0F802, 0xDDF904, 0xDBFB04, 0xD6FA04, 0xD3FB05, 0xD2FA04, 0xCEF801, 0xCFF804, 0xCDF904, 0xC7F904, 0xC1F902, 0xBDF903, 0xBAFA05, 0xB6FB04, 0xB5FA03, 0xB4FA04, 0xB2FA03, 0xAFF902, 0xACFA04, 0xA9FB05, 0xA1F904, 0x9EF904, 0x9BFA06, 0x98FA05, 0x94F802, 0x92F703, 0x8FF903, 0x8DFB06, 0x89FB06, 0x84FA04, 0x84FA04, 0x82FA05, 0x7CF804, 0x77F905, 0x76F905, 0x76F907, 0x73F906, 0x6DF902, 0x6AFB02, 0x6AFA04, 0x68F802, 0x67F903, 0x63F904, 0x5CF602, 0x58F804, 0x56FA05, 0x52FA04, 0x54FA04, 0x4DF903, 0x4AFA04, 0x47F905, 0x46F804, 0x43F906, 0x40FA03, 0x3CFA02, 0x3BFC05, 0x36FA02, 0x32F803, 0x2EF804, 0x2CF906, 0x27F904, 0x27F904, 0x25F904, 0x1FFB03, 0x1CFB04, 0x18FA03, 0x14FA04, 0x10FA05, 0x0CFA04, 0x0CFA04, 0x0BFB04, 0x04F904, 0x04F904, 0x04F904, 0x04F904, 0x04F904, 0x04F904, 0x04F904, 0x04F904, 0x03FA0B, 0x03FA0B, 0x03FA0D, 0x04FA0F, 0x04FA13, 0x03FA15, 0x04FA19, 0x04FA1B, 0x02F922, 0x03FA23, 0x03FA27, 0x03F92A, 0x04F92F, 0x05FA33, 0x04FA37, 0x04F939, 0x05F93F, 0x06FA42, 0x05FA43, 0x05FA47, 0x04FB4B, 0x04FA4F, 0x04FA51,
     0x05FA54, 0x04FB55, 0x04FA57, 0x04FA59, 0x03FB5D, 0x03FA61, 0x03FA65, 0x04FA69, 0x04FA6B, 0x04F970, 0x04F96D, 0x04F779, 0x04FA73, 0x04F783, 0x05F97D, 0x04F889, 0x04F886, 0x04F887, 0x06FA89, 0x05FB8E, 0x03FA8F, 0x03FA92, 0x04FB93, 0x06FB96, 0x05FA95, 0x05FA9B, 0x05FA9D, 0x03FAA1, 0x04FAA5, 0x04F9A9, 0x04FBAC, 0x04FBAC, 0x04FBAD, 0x04FBB5, 0x04FBB7, 0x04FABB, 0x04FBB7, 0x04F8C5, 0x05F9C3, 0x03F9C6, 0x03F9C8, 0x04F9CE, 0x02F7CC, 0x05F7CF, 0x06F7D4, 0x03F6D8, 0x04F8DE, 0x05F8E4, 0x02F7E5, 0x03F8E7, 0x03F8E7, 0x03F8E9, 0x03F7ED, 0x04F7F1, 0x04F6F7, 0x04F6FA, 0x03F4FB, 0x05F1FE, 0x02EEFB, 0x05EEFD, 0x04E9FC, 0x05E8FB, 0x06E7FD, 0x04E1FB, 0x05E2FC, 0x06DDF9, 0x02D6FE, 0x02D6FB, 0x05D7F8, 0x04D1FE, 0x05CEF8, 0x06CBF6, 0x03C4FD, 0x05C2FC, 0x02BEFB, 0x03BCFC, 0x05BBFD, 0x04B5FB, 0x03B1FA, 0x04B0FC, 0x04AEFC, 0x02ABFC, 0x04ABFC, 0x03AAFB, 0x03A7FC, 0x03A3FB, 0x049FFC, 0x049AFB, 0x0498FC, 0x0592FE, 0x028FFB, 0x038BFB, 0x0389FC, 0x0586FD, 0x0482FB, 0x047EFB, 0x047EFD, 0x057CFE, 0x0277FB, 0x0474FC, 0x0671FD, 0x056BFC, 0x0468FC, 0x0468FE, 0x0466FF, 0x0361FE, 0x035BFB, 0x0659FD, 0x0354FB, 0x0354FD, 0x0654FE, 0x034FFA, 0x064EFA, 0x054AFD, 0x0446FC, 0x0343FC, 0x0442F9, 0x043EF7, 0x043BF7, 0x0338FA, 0x0536FD, 0x0633FE, 0x042FFA, 0x042DFB, 0x0528FC, 0x0223FA, 0x0420FD, 0x061FFF, 0x041CFC, 0x0517FD, 0x0415FB, 0x0412FB, 0x0410FC, 0x040DFC, 0x0509FE, 0x0507FC, 0x0203FB, 0x0201FC, 0x0402FD, 0x0601FD, 0x0600FE, 0x0302FD, 0x0402FD, 0x0801FC, 0x0B02FD,
     0x0E02FA, 0x1502FC, 0x1A01FD, 0x1C01FC, 0x1C02FB, 0x2003FD, 0x2303FC, 0x2601FC, 0x2A01FB, 0x2B02FC, 0x2C02FC, 0x3001FD, 0x3201FB, 0x3801FC, 0x3A02FB, 0x3E03FD, 0x4201FB, 0x4601FC, 0x4A02FC, 0x4D02FD, 0x4D02FB, 0x4E02FA, 0x5202F7, 0x5501F7, 0x5B00FB, 0x5E02FB, 0x6303FB, 0x6502FB, 0x6701FA, 0x6802FB, 0x6B02FC, 0x6A01FC, 0x6C02FC, 0x7002FB, 0x7502FD, 0x7B02FD, 0x8002FC, 0x8401FC, 0x8602FD, 0x8902FE, 0x8D02FD, 0x8D02FD, 0x8F03FC, 0x9102FC, 0x9402FB, 0x9801FC, 0x9B02FB, 0x9E03FD, 0xA302FD, 0xA500FA, 0xAC03FE, 0xAC02FB, 0xAE01FB, 0xB203FC, 0xB500FB, 0xBC02FD, 0xBD00FC, 0xC001FE, 0xC403FE, 0xC502FC, 0xC602FA, 0xCA02FB, 0xCD02FA, 0xCD02FA, 0xD402FB, 0xD702FC, 0xD902FD, 0xDD02FC, 0xE102FB, 0xE402FC, 0xE802FB, 0xEC01FC, 0xED00FC, 0xF202F9, 0xF601FE, 0xF603F5, 0xF601FF, 0xF704F6, 0xFA02F9, 0xFD02F0, 0xFD02ED, 0xFD01F4, 0xFC00F3, 0xFC04DF, 0xFD00F1, 0xFC03DB, 0xFC03DB, 0xFC01E2, 0xFD02DD, 0xFC03CF, 0xFB01D5, 0xFD02CB, 0xFD03C9, 0xFD02CE, 0xFD03BD, 0xFC01C0, 0xFC02BE, 0xFB01BA, 0xFB02B4, 0xFD02B3, 0xFD02B3, 0xFC01B2, 0xFC02AE, 0xFC02AC, 0xFC01A9, 0xFC01A6, 0xFC02A1, 0xFC039F, 0xFC039F, 0xFB029C, 0xFC0298, 0xFB0294, 0xFC018F, 0xFC018E};

void CycleColors()
{
    int lastElement = imageData.back(); // Save the last element
    imageData.pop_back();               // Remove the last element
    imageData.push_front(lastElement);  // Insert the last element at the front
}

void rainbow(HDC hdc, int x, int y, int IMAGE_WIDTH)
{
    BITMAPINFOHEADER bmih = {0};
    bmih.biSize = sizeof(BITMAPINFOHEADER);
    bmih.biWidth = IMAGE_WIDTH;
    bmih.biHeight = -1;
    bmih.biPlanes = 1;
    bmih.biBitCount = 32;
    bmih.biCompression = BI_RGB;
    bmih.biSizeImage = 0;
    bmih.biXPelsPerMeter = 15;
    bmih.biYPelsPerMeter = 5;

    BITMAPINFO dbmi = {0};
    dbmi.bmiHeader = bmih;

    std::vector<int> imageDataVector(imageData.begin(), imageData.end());

    StretchDIBits(hdc, x, y, IMAGE_WIDTH, 1,
                  0, 0, IMAGE_WIDTH, 1,
                  reinterpret_cast<const void *>(imageDataVector.data()), &dbmi, 0, SRCCOPY);
}

// main function
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lparam);
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow)
{
    TCHAR appname[] = TEXT("Template");
    WNDCLASS wndclass;
    MSG msg;
    HWND hwnd;

    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = 0;
    wndclass.hbrBackground = NULL;
    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wndclass.hInstance = hInstance;
    wndclass.lpfnWndProc = WndProc;
    wndclass.lpszClassName = appname;
    wndclass.lpszMenuName = NULL;
    wndclass.style = CS_HREDRAW | CS_VREDRAW;

    // check this window class is registered or not
    if (!RegisterClass(&wndclass))
    {
        MessageBox(NULL, TEXT("Window class is not registered"), TEXT("Error...."), MB_ICONERROR);
        return 0;
    }

    hwnd = CreateWindow(appname,  // window name
                        appname,  // window text
                        WS_POPUP, // set POPUP window style for no border & controls
                        100,      // window position x
                        100,      // window position y
                        WIDTH,    // width
                        HEIGHT,   // height
                        NULL,
                        NULL,
                        hInstance,
                        NULL);

    // show & update created window
    SetTimer(hwnd, 1, 1, NULL); // Set a timer to trigger every 100ms
    ShowWindow(hwnd, SW_SHOWNORMAL);

    // get message from queue
    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return msg.wParam;
}

// WndProc function
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{

    HINSTANCE hIns;
    HWND exit_button, title;
    static int X, Y;
    LRESULT move = NULL;
    RECT rc;

    switch (message)
    {

    case WM_CREATE:
    {
        exit_button = CreateWindow(TEXT("BUTTON"), NULL, WS_CHILD | WS_VISIBLE | BS_BITMAP,
                                   250, 440, 76, 30, hwnd, (HMENU)100, hIns, 0);
        HBITMAP exitImg = (HBITMAP)LoadImageA(GetModuleHandleA(nullptr), (LPCSTR) "C:\\Users\\admin\\Documents\\test\\Resource\\Bitmap_112.bmp", IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);

        title = CreateWindow(TEXT("STATIC"), TEXT("Hello"), WS_CHILD | WS_VISIBLE, 120, 150, 120, 20, hwnd, 0, hIns, 0);
        SendMessageW(exit_button, BM_SETIMAGE, IMAGE_BITMAP, (LPARAM)exitImg);
        // SendMessageW(gen_button, BM_SETIMAGE, IMAGE_BITMAP, (LPARAM)genImg);
    }

    break;

    case WM_PAINT:
    {
        PAINTSTRUCT ps;
        GetClientRect(hwnd, &rc);
        hdc = BeginPaint(hwnd, &ps);
        hdcMem = CreateCompatibleDC(hdc);
        Membitmap = CreateCompatibleBitmap(hdc, rc.right - rc.left, rc.bottom - rc.top);
        SelectObject(hdcMem, Membitmap);

        rainbow(hdcMem, 0, 50, 300);
        BitBlt(hdc, 0, 0, rc.right - rc.left, rc.bottom - rc.top,
        hdcMem, 0, 0, SRCCOPY);
        DeleteObject(Membitmap);
        DeleteDC(hdcMem);        
        EndPaint(hwnd, &ps);
        break;
    }

    case WM_TIMER:
        CycleColors();
        InvalidateRect(hwnd, NULL, FALSE);
        return 0;
        break;

    case WM_COMMAND:

        switch (wParam)
        {
        case 100:
            PostQuitMessage(EXIT_SUCCESS);
            return 0;
        }

        break;

        // size
    case WM_SIZE:
        X = LOWORD(lParam);
        Y = HIWORD(lParam);
        break;

        // move window
    case WM_NCHITTEST:
        RECT rc;
        POINT pt;

        GetCursorPos(&pt);

        GetWindowRect(hwnd, &rc);
        rc.bottom = rc.bottom - 466;

        // if cursor position is within top layered drawn rectangle then
        // set move to HTCAPTION for moving the window from its client
        if (pt.x <= rc.right && pt.x >= rc.left && pt.y <= rc.bottom && pt.y >= rc.top)
        {
            move = DefWindowProc(hwnd, message, wParam, lParam);
            if (move == HTCLIENT)
            {
                move = HTCAPTION;
            }
        }

        return move;

        break;

    case WM_DESTROY:
        PostQuitMessage(EXIT_SUCCESS);
        return 0;
    }

    return DefWindowProc(hwnd, message, wParam, lParam);
}