vncencoder.cpp

realvnc是一个非常流行的远程控制程序

//  Copyright (C) 2002-2003 RealVNC Ltd. All Rights Reserved.
//  Copyright (C) 1999 AT&T Laboratories Cambridge. All Rights Reserved.
//
//  This file is part of the VNC system.
//
//  The VNC system is free software; you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation; either version 2 of the License, or
//  (at your option) any later version.
//
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with this program; if not, write to the Free Software
//  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
//  USA.
//
// If the source code for the VNC system is not available from the place 
// whence you received this file, check http://www.uk.research.att.com/vnc or contact
// the authors on [e-mail] for information on obtaining it.


// vncEncoder - Object used to encode data for RFB

#include "vncEncoder.h"
#include "vncBuffer.h"

// Pixel format used internally when the client is palette-based & server is truecolour

static const rfbPixelFormat BGR233Format = {
    8, 8, 0, 1, 7, 7, 3, 0, 3, 6
};

// The base (RAW) encoder class

vncEncoder::vncEncoder()
{
	ZeroMemory(&m_remoteformat, sizeof(m_remoteformat));
	ZeroMemory(&m_localformat, sizeof(m_localformat));
	ZeroMemory(&m_transformat, sizeof(m_transformat));
	m_transtable = NULL;
	m_localpalette = NULL;
	m_bytesPerRow = 0;
}

vncEncoder::~vncEncoder()
{
	if (m_transtable != NULL)
	{
		free(m_transtable);
		m_transtable = NULL;
	}
	if (m_localpalette != NULL)
	{
		free(m_localpalette);
		m_localpalette = NULL;
	}
}

void
vncEncoder::Init()
{
}

UINT
vncEncoder::RequiredBuffSize(UINT width, UINT height)
{
	return sz_rfbFramebufferUpdateRectHeader +
		(width * height * m_remoteformat.bitsPerPixel)/8;
}

UINT
vncEncoder::NumCodedRects(const rfb::Rect &rect)
{
	return 1;
}

// Translate a rectangle
inline void
vncEncoder::Translate(BYTE *source, BYTE *dest, const rfb::Rect &rect)
{
	// Calculate where in the source rectangle to read from
	BYTE *sourcepos = (BYTE *)(source + (m_bytesPerRow * rect.tl.y)+(rect.tl.x * (m_localformat.bitsPerPixel / 8)));

	// Call the translation function
	(*m_transfunc) (m_transtable,
					&m_localformat,
					&m_transformat,
					(char *)sourcepos,
					(char *)dest,
					m_bytesPerRow,
					rect.br.x-rect.tl.x,
					rect.br.y-rect.tl.y
					);
}

// Encode a rectangle
inline UINT
vncEncoder::EncodeRect(BYTE *source, BYTE *dest, const rfb::Rect &rect)
{
	// Create the header for the update in the destination area
	rfbFramebufferUpdateRectHeader *surh = (rfbFramebufferUpdateRectHeader *)dest;
	surh->r.x = (CARD16) rect.tl.x;
	surh->r.y = (CARD16) rect.tl.y;
	surh->r.w = (CARD16) (rect.br.x-rect.tl.x);
	surh->r.h = (CARD16) (rect.br.y-rect.tl.y);
	surh->r.x = Swap16IfLE(surh->r.x);
	surh->r.y = Swap16IfLE(surh->r.y);
	surh->r.w = Swap16IfLE(surh->r.w);
	surh->r.h = Swap16IfLE(surh->r.h);
	surh->encoding = Swap32IfLE(rfbEncodingRaw);

	// Translate the data in place in the output buffer
	Translate(source, dest + sz_rfbFramebufferUpdateRectHeader, rect);

	// Return the buffer size
	return sz_rfbFramebufferUpdateRectHeader +
		((rect.br.x-rect.tl.x)*(rect.br.y-rect.tl.y)*m_remoteformat.bitsPerPixel) / 8;
}

BOOL
vncEncoder::GetRemotePalette(RGBQUAD *quadlist, UINT ncolours)
{
	vnclog.Print(LL_INTINFO, VNCLOG("remote palette data requested\n"));

	// If the local server is palette-based then call SetTranslateFunction
	// to update the palette-to-truecolour mapping:
	if (!m_localformat.trueColour)
	{
		if (!SetTranslateFunction())
			return FALSE;
	}

	// If the client is truecolour then don't fill in the palette buffer...
	if (m_remoteformat.trueColour)
		return FALSE;

	// If the server is truecolour then fake BGR233
	if (m_localformat.trueColour)
	{
		// Fake BGR233...
		vnclog.Print(LL_INTINFO, VNCLOG("generating BGR233 palette data\n"));

		int ncolours = 1 << m_transformat.bitsPerPixel;
		if (m_localpalette != NULL)
			free(m_localpalette);
		m_localpalette = (char *)malloc(ncolours * sizeof(RGBQUAD));
		
		if (m_localpalette != NULL)
		{
			RGBQUAD *colour = (RGBQUAD *)m_localpalette;

			for (int i=0; i<ncolours; i++)
			{
				colour[i].rgbBlue = (((i >> m_transformat.blueShift) & m_transformat.blueMax) * 255) / m_transformat.blueMax;
				colour[i].rgbRed = (((i >> m_transformat.redShift) & m_transformat.redMax) * 255) / m_transformat.redMax;
				colour[i].rgbGreen = (((i >> m_transformat.greenShift) & m_transformat.greenMax) * 255) / m_transformat.greenMax;
			}
		}
	}
	else
	{
		// Set up RGBQUAD rfbPixelFormat info
		vnclog.Print(LL_INTINFO, VNCLOG("generating 8-bit palette data\n"));

		rfbPixelFormat remote;
		remote.trueColour = TRUE;
		remote.bitsPerPixel = 32;
		remote.depth = 24;
		remote.bigEndian = FALSE;
		remote.redMax = remote.greenMax = remote.blueMax = 255;
		remote.redShift = 16;
		remote.greenShift = 8;
		remote.blueShift = 0;

		// We get the ColourMapSingleTableFns procedure to handle retrieval of the
		// palette for us, to avoid replicating the code!
		(*rfbInitColourMapSingleTableFns[remote.bitsPerPixel / 16])
			(&m_localpalette, &m_localformat, &remote);
	}

	// Did we create some palette info?
	if (m_localpalette == NULL)
	{
		vnclog.Print(LL_INTERR, VNCLOG("failed to obtain colour map data!\n"));
		return FALSE;
	}

	// Copy the data into the RGBQUAD buffer
	memcpy(quadlist, m_localpalette, ncolours*sizeof(RGBQUAD));

	return TRUE;
}

BOOL
vncEncoder::SetTranslateFunction()
{
	vnclog.Print(LL_INTINFO, VNCLOG("settranslatefunction called\n"));

	// By default, the actual format translated to matches the client format
	m_transformat = m_remoteformat;

    // Check that bits per pixel values are valid

    if ((m_transformat.bitsPerPixel != 8) &&
		(m_transformat.bitsPerPixel != 16) &&
		(m_transformat.bitsPerPixel != 32))
    {
		vnclog.Print(LL_CONNERR,
			VNCLOG("only 8, 16 or 32 bits supported remotely - %d requested\n"),
			m_transformat.bitsPerPixel
			);

		return FALSE;
    }
	
    if ((m_localformat.bitsPerPixel != 8) &&
		(m_localformat.bitsPerPixel != 16) &&
		(m_localformat.bitsPerPixel != 32))
    {
		vnclog.Print(LL_CONNERR,
			VNCLOG("only 8, 16 or 32 bits supported locally - %d in use\n"),
			m_localformat.bitsPerPixel
			);

		return FALSE;
    }

	if (!m_transformat.trueColour && (m_transformat.bitsPerPixel != 8))
	{
		vnclog.Print(LL_CONNERR, VNCLOG("only 8-bit palette format supported remotely\n"));
		return FALSE;
	}
	if (!m_localformat.trueColour && (m_localformat.bitsPerPixel != 8))
	{
		vnclog.Print(LL_CONNERR, VNCLOG("only 8-bit palette format supported locally\n"));
		return FALSE;
	}

	// Now choose the translation function to use

	// We don't do remote palettes unless they're 8-bit
    if (!m_transformat.trueColour)
	{
		// Is the local format the same?
		if (!m_localformat.trueColour &&
			(m_localformat.bitsPerPixel == m_transformat.bitsPerPixel))
		{
			// Yes, so don't do any encoding
			vnclog.Print(LL_INTINFO, VNCLOG("no encoding required - both 8-bit palettized\n"));

			m_transfunc = rfbTranslateNone;

			// The first time the client sends an update, it will call
			// GetRemotePalette to get the palette information required
			return TRUE;
		}
		else if (m_localformat.trueColour)
		{
			// Local side is truecolour, remote is palettized
			vnclog.Print(LL_INTINFO, VNCLOG("local truecolour, remote palettized.  using BGR233 palette\n"));

			// Fill out the translation table as if writing to BGR233
			m_transformat = BGR233Format;

			// Continue on down to the main translation section
		}
		else
		{
			// No, so not supported yet...
			vnclog.Print(LL_CONNERR, VNCLOG("unknown local pixel format in use!\n"));
			return FALSE;
		}
	}

	// REMOTE FORMAT IS TRUE-COLOUR

	// Handle 8-bit palette-based local data
	if (!m_localformat.trueColour)
	{
		// 8-bit palette to truecolour...

		// Yes, so pick the right translation function!
		vnclog.Print(LL_INTINFO, VNCLOG("using 8-bit colourmap to truecolour translation\n"));

		m_transfunc = rfbTranslateWithSingleTableFns
			[m_localformat.bitsPerPixel / 16]
			[m_transformat.bitsPerPixel / 16];

		(*rfbInitColourMapSingleTableFns[m_transformat.bitsPerPixel / 16])
			(&m_transtable, &m_localformat, &m_transformat);
		return m_transtable != NULL;
	}

	// If we reach here then we're doing truecolour to truecolour

	// Are the formats identical?
    if (PF_EQ(m_transformat,m_localformat))
	{
		// Yes, so use the null translation function
		vnclog.Print(LL_INTINFO, VNCLOG("no translation required\n"));

		m_transfunc = rfbTranslateNone;

		return TRUE;
    }

	// Is the local display a 16-bit one
    if (m_localformat.bitsPerPixel == 16)
	{
		// Yes, so use a single lookup-table
		vnclog.Print(LL_INTINFO, VNCLOG("single LUT used\n"));

		m_transfunc = rfbTranslateWithSingleTableFns
			[m_localformat.bitsPerPixel / 16]
			[m_transformat.bitsPerPixel / 16];

		(*rfbInitTrueColourSingleTableFns[m_transformat.bitsPerPixel / 16])
			(&m_transtable, &m_localformat, &m_transformat);
    }
	else
	{
		// No, so use three tables - one for each of R, G, B.
		vnclog.Print(LL_INTINFO, VNCLOG("triple LUT used\n"));

		m_transfunc = rfbTranslateWithRGBTablesFns
			[m_localformat.bitsPerPixel / 16]
			[m_transformat.bitsPerPixel / 16];

		(*rfbInitTrueColourRGBTablesFns[m_transformat.bitsPerPixel / 16])
			(&m_transtable, &m_localformat, &m_transformat);
    }

	return m_transtable != NULL;
}

BOOL
vncEncoder::SetLocalFormat(rfbPixelFormat &pixformat, int width, int height)
{
	// Work out the bytes per row at the local end - useful
	m_bytesPerRow = width * pixformat.bitsPerPixel/8;

	// Save the pixel format
	m_localformat = pixformat;
	return SetTranslateFunction();
}

BOOL
vncEncoder::SetRemoteFormat(rfbPixelFormat &pixformat)
{
	// Save the client pixel format
	m_remoteformat = pixformat;

	return SetTranslateFunction();
}