#pragma once

class CDrawImg
{
public:
	CDrawImg(HWND wnd)
	{
		m_hbrush = CreateSolidBrush(RGB(0, 0, 0));
		pBmpInfo = (BITMAPINFO *)chBmpBuf;
		pBmpInfo->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
		pBmpInfo->bmiHeader.biPlanes = 1;
		pBmpInfo->bmiHeader.biCompression = BI_RGB;
		for (int i = 0; i < 256; i++)
		{
			pBmpInfo->bmiColors[i].rgbBlue = i;
			pBmpInfo->bmiColors[i].rgbGreen = i;
			pBmpInfo->bmiColors[i].rgbRed = i;
			pBmpInfo->bmiColors[i].rgbReserved = i;
		}
		GetClientRect(wnd, wrect);
		hdc = GetDC(wnd);
	}
	void Draw(int width, int height, int channels, uchar* data)
	{
		pBmpInfo->bmiHeader.biWidth = width;
		pBmpInfo->bmiHeader.biHeight = height;
		pBmpInfo->bmiHeader.biBitCount = 8 * channels;

		FillRect(hdc, wrect, m_hbrush);
		int DesX = 0;
		int DesY = wrect.Height();
		int DesWidth = wrect.Width();
		int DesHeight = wrect.Height();
		double ratio = width / (double)height;
		int WidthRequest = ratio * wrect.Height();
		int HeightRequest = wrect.Width() / ratio;
		if (wrect.Width() < WidthRequest)
		{
			DesHeight = DesWidth / ratio;
			DesY = (wrect.Height() - DesHeight) / 2 + DesHeight;
		}
		else if (wrect.Height() < HeightRequest)
		{
			DesWidth = DesHeight * ratio;
			DesX = (wrect.Width() - DesWidth) / 2;
		}
		::SetStretchBltMode(hdc, COLORONCOLOR);
		::StretchDIBits(hdc,
			DesX, DesY, DesWidth, -DesHeight,
			0, 0, width, height,
			data, pBmpInfo,
			DIB_RGB_COLORS, SRCCOPY);
	}
private:
	char           chBmpBuf[2048];
	BITMAPINFO     *pBmpInfo;
	CRect wrect;
	HDC hdc;
	HBRUSH m_hbrush;
};