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/* Copyright (C) 2002-2005 RealVNC Ltd. All Rights Reserved.
*
* This 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 software 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 software; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
* USA.
*/
//
// RRE encoding function.
//
// This file is #included after having set the following macros:
// BPP - 8, 16 or 32
//
// The data argument to RRE_ENCODE contains the pixel data, and it writes the
// encoded version to the given OutStream. If the encoded version exceeds w*h
// it aborts and returns -1, otherwise it returns the number of subrectangles.
//
#include <rdr/OutStream.h>
namespace rfb {
// CONCAT2E concatenates its arguments, expanding them if they are macros
#ifndef CONCAT2E
#define CONCAT2(a,b) a##b
#define CONCAT2E(a,b) CONCAT2(a,b)
#endif
#define PIXEL_T rdr::CONCAT2E(U,BPP)
#define WRITE_PIXEL CONCAT2E(writeOpaque,BPP)
#define RRE_ENCODE CONCAT2E(rreEncode,BPP)
int RRE_ENCODE (PIXEL_T* data, int w, int h, rdr::OutStream* os, PIXEL_T bg);
int RRE_ENCODE (void* data, int w, int h, rdr::OutStream* os)
{
// Find the background colour - count occurrences of up to 4 different pixel
// values, and choose the one which occurs most often.
const int nCols = 4;
PIXEL_T pix[nCols];
int count[nCols] = { 0, };
PIXEL_T* ptr = (PIXEL_T*)data;
PIXEL_T* end = ptr + w*h;
while (ptr < end) {
int i;
for (i = 0; i < nCols; i++) {
if (count[i] == 0)
pix[i] = *ptr;
if (pix[i] == *ptr) {
count[i]++;
break;
}
}
if (i == nCols) break;
ptr++;
}
int bg = 0;
for (int i = 1; i < nCols; i++)
if (count[i] > count[bg]) bg = i;
// Now call the function to do the encoding.
return RRE_ENCODE ((PIXEL_T*)data, w, h, os, pix[bg]);
}
int RRE_ENCODE (PIXEL_T* data, int w, int h, rdr::OutStream* os, PIXEL_T bg)
{
int oldLen = os->length();
os->WRITE_PIXEL(bg);
int nSubrects = 0;
for (int y = 0; y < h; y++)
{
int x = 0;
while (x < w) {
if (*data == bg) {
x++;
data++;
continue;
}
// Find horizontal subrect first
PIXEL_T* ptr = data+1;
PIXEL_T* eol = data+w-x;
while (ptr < eol && *ptr == *data) ptr++;
int sw = ptr - data;
ptr = data + w;
int sh = 1;
while (sh < h-y) {
eol = ptr + sw;
while (ptr < eol)
if (*ptr++ != *data) goto endOfHorizSubrect;
ptr += w - sw;
sh++;
}
endOfHorizSubrect:
// Find vertical subrect
int vh;
for (vh = sh; vh < h-y; vh++)
if (data[vh*w] != *data) break;
if (vh != sh) {
ptr = data+1;
int vw;
for (vw = 1; vw < sw; vw++) {
for (int i = 0; i < vh; i++)
if (ptr[i*w] != *data) goto endOfVertSubrect;
ptr++;
}
endOfVertSubrect:
// If vertical subrect bigger than horizontal then use that.
if (sw*sh < vw*vh) {
sw = vw;
sh = vh;
}
}
nSubrects++;
os->WRITE_PIXEL(*data);
os->writeU16(x);
os->writeU16(y);
os->writeU16(sw);
os->writeU16(sh);
if (os->length() > oldLen + w*h) return -1;
ptr = data+w;
PIXEL_T* eor = data+w*sh;
while (ptr < eor) {
eol = ptr + sw;
while (ptr < eol) *ptr++ = bg;
ptr += w - sw;
}
x += sw;
data += sw;
}
}
return nSubrects;
}
#undef PIXEL_T
#undef WRITE_PIXEL
#undef RRE_ENCODE
}
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