/*
* corre.c
*
* Routines to implement Compact Rise-and-Run-length Encoding (CoRRE). This
* code is based on krw's original javatel rfbserver.
*/
/*
* Copyright (C) 2002 RealVNC Ltd.
* OSXvnc Copyright (C) 2001 Dan McGuirk <mcguirk@incompleteness.net>.
* Original Xvnc code Copyright (C) 1999 AT&T Laboratories Cambridge.
* 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.
*/
#include <rfb/rfb.h>
/*
* cl->beforeEncBuf contains pixel data in the client's format.
* cl->afterEncBuf contains the RRE encoded version. If the RRE encoded version is
* larger than the raw data or if it exceeds cl->afterEncBufSize then
* raw encoding is used instead.
*/
static int subrectEncode8(rfbClientPtr cl, uint8_t *data, int w, int h);
static int subrectEncode16(rfbClientPtr cl, uint16_t *data, int w, int h);
static int subrectEncode32(rfbClientPtr cl, uint32_t *data, int w, int h);
static uint32_t getBgColour(char *data, int size, int bpp);
static rfbBool rfbSendSmallRectEncodingCoRRE(rfbClientPtr cl, int x, int y,
int w, int h);
/*
* rfbSendRectEncodingCoRRE - send an arbitrary size rectangle using CoRRE
* encoding.
*/
rfbBool
rfbSendRectEncodingCoRRE(rfbClientPtr cl,
int x,
int y,
int w,
int h)
{
if (h > cl->correMaxHeight) {
return (rfbSendRectEncodingCoRRE(cl, x, y, w, cl->correMaxHeight) &&
rfbSendRectEncodingCoRRE(cl, x, y + cl->correMaxHeight, w,
h - cl->correMaxHeight));
}
if (w > cl->correMaxWidth) {
return (rfbSendRectEncodingCoRRE(cl, x, y, cl->correMaxWidth, h) &&
rfbSendRectEncodingCoRRE(cl, x + cl->correMaxWidth, y,
w - cl->correMaxWidth, h));
}
rfbSendSmallRectEncodingCoRRE(cl, x, y, w, h);
return TRUE;
}
/*
* rfbSendSmallRectEncodingCoRRE - send a small (guaranteed < 256x256)
* rectangle using CoRRE encoding.
*/
static rfbBool
rfbSendSmallRectEncodingCoRRE(rfbClientPtr cl,
int x,
int y,
int w,
int h)
{
rfbFramebufferUpdateRectHeader rect;
rfbRREHeader hdr;
int nSubrects;
int i;
char *fbptr = (cl->scaledScreen->frameBuffer + (cl->scaledScreen->paddedWidthInBytes * y)
+ (x * (cl->scaledScreen->bitsPerPixel / 8)));
int maxRawSize = (cl->scaledScreen->width * cl->scaledScreen->height
* (cl->format.bitsPerPixel / 8));
if (cl->beforeEncBufSize < maxRawSize) {
cl->beforeEncBufSize = maxRawSize;
if (cl->beforeEncBuf == NULL)
cl->beforeEncBuf = (char *)malloc(cl->beforeEncBufSize);
else
cl->beforeEncBuf = (char *)realloc(cl->beforeEncBuf, cl->beforeEncBufSize);
}
if (cl->afterEncBufSize < maxRawSize) {
cl->afterEncBufSize = maxRawSize;
if (cl->afterEncBuf == NULL)
cl->afterEncBuf = (char *)malloc(cl->afterEncBufSize);
else
cl->afterEncBuf = (char *)realloc(cl->afterEncBuf, cl->afterEncBufSize);
}
(*cl->translateFn)(cl->translateLookupTable,&(cl->screen->serverFormat),
&cl->format, fbptr, cl->beforeEncBuf,
cl->scaledScreen->paddedWidthInBytes, w, h);
switch (cl->format.bitsPerPixel) {
case 8:
nSubrects = subrectEncode8(cl, (uint8_t *)cl->beforeEncBuf, w, h);
break;
case 16:
nSubrects = subrectEncode16(cl, (uint16_t *)cl->beforeEncBuf, w, h);
break;
case 32:
nSubrects = subrectEncode32(cl, (uint32_t *)cl->beforeEncBuf, w, h);
break;
default:
rfbLog("getBgColour: bpp %d?\n",cl->format.bitsPerPixel);
return FALSE;
}
if (nSubrects < 0) {
/* RRE encoding was too large, use raw */
return rfbSendRectEncodingRaw(cl, x, y, w, h);
}
rfbStatRecordEncodingSent(cl,rfbEncodingCoRRE,
sz_rfbFramebufferUpdateRectHeader + sz_rfbRREHeader + cl->afterEncBufLen,
sz_rfbFramebufferUpdateRectHeader + w * h * (cl->format.bitsPerPixel / 8));
if (cl->ublen + sz_rfbFramebufferUpdateRectHeader + sz_rfbRREHeader
> UPDATE_BUF_SIZE)
{
if (!rfbSendUpdateBuf(cl))
return FALSE;
}
rect.r.x = Swap16IfLE(x);
rect.r.y = Swap16IfLE(y);
rect.r.w = Swap16IfLE(w);
rect.r.h = Swap16IfLE(h);
rect.encoding = Swap32IfLE(rfbEncodingCoRRE);
memcpy(&cl->updateBuf[cl->ublen], (char *)&rect,
sz_rfbFramebufferUpdateRectHeader);
cl->ublen += sz_rfbFramebufferUpdateRectHeader;
hdr.nSubrects = Swap32IfLE(nSubrects);
memcpy(&cl->updateBuf[cl->ublen], (char *)&hdr, sz_rfbRREHeader);
cl->ublen += sz_rfbRREHeader;
for (i = 0; i < cl->afterEncBufLen;) {
int bytesToCopy = UPDATE_BUF_SIZE - cl->ublen;
if (i + bytesToCopy > cl->afterEncBufLen) {
bytesToCopy = cl->afterEncBufLen - i;
}
memcpy(&cl->updateBuf[cl->ublen], &cl->afterEncBuf[i], bytesToCopy);
cl->ublen += bytesToCopy;
i += bytesToCopy;
if (cl->ublen == UPDATE_BUF_SIZE) {
if (!rfbSendUpdateBuf(cl))
return FALSE;
}
}
return TRUE;
}
/*
* subrectEncode() encodes the given multicoloured rectangle as a background
* colour overwritten by single-coloured rectangles. It returns the number
* of subrectangles in the encoded buffer, or -1 if subrect encoding won't
* fit in the buffer. It puts the encoded rectangles in cl->afterEncBuf. The
* single-colour rectangle partition is not optimal, but does find the biggest
* horizontal or vertical rectangle top-left anchored to each consecutive
* coordinate position.
*
* The coding scheme is simply [<bgcolour><subrect><subrect>...] where each
* <subrect> is [<colour><x><y><w><h>].
*/
#define DEFINE_SUBRECT_ENCODE(bpp) \
static int \
subrectEncode##bpp(rfbClientPtr client, uint##bpp##_t *data, int w, int h) { \
uint##bpp##_t cl; \
rfbCoRRERectangle subrect; \
int x,y; \
int i,j; \
int hx=0,hy,vx=0,vy; \
int hyflag; \
uint##bpp##_t *seg; \
uint##bpp##_t *line; \
int hw,hh,vw,vh; \
int thex,they,thew,theh; \
int numsubs = 0; \
int newLen; \
uint##bpp##_t bg = (uint##bpp##_t)getBgColour((char*)data,w*h,bpp); \
\
*((uint##bpp##_t*)client->afterEncBuf) = bg; \
\
client->afterEncBufLen = (bpp/8); \
\
for (y=0; y<h; y++) { \
line = data+(y*w); \
for (x=0; x<w; x++) { \
if (line[x] != bg) { \
cl = line[x]; \
hy = y-1; \
hyflag = 1; \
for (j=y; j<h; j++) { \
seg = data+(j*w); \
if (seg[x] != cl) {break;} \
i = x; \
while ((seg[i] == cl) && (i < w)) i += 1; \
i -= 1; \
if (j == y) vx = hx = i; \
if (i < vx) vx = i; \
if ((hyflag > 0) && (i >= hx)) {hy += 1;} else {hyflag = 0;} \
} \
vy = j-1; \
\
/* We now have two possible subrects: (x,y,hx,hy) and (x,y,vx,vy) \
* We'll choose the bigger of the two. \
*/ \
hw = hx-x+1; \
hh = hy-y+1; \
vw = vx-x+1; \
vh = vy-y+1; \
\
thex = x; \
they = y; \
\
if ((hw*hh) > (vw*vh)) { \
thew = hw; \
theh = hh; \
} else { \
thew = vw; \
theh = vh; \
} \
\
subrect.x = thex; \
subrect.y = they; \
subrect.w = thew; \
subrect.h = theh; \
\
newLen = client->afterEncBufLen + (bpp/8) + sz_rfbCoRRERectangle; \
if ((newLen > (w * h * (bpp/8))) || (newLen > client->afterEncBufSize)) \
return -1; \
\
numsubs += 1; \
*((uint##bpp##_t*)(client->afterEncBuf + client->afterEncBufLen)) = cl; \
client->afterEncBufLen += (bpp/8); \
memcpy(&client->afterEncBuf[client->afterEncBufLen],&subrect,sz_rfbCoRRERectangle); \
client->afterEncBufLen += sz_rfbCoRRERectangle; \
\
/* \
* Now mark the subrect as done. \
*/ \
for (j=they; j < (they+theh); j++) { \
for (i=thex; i < (thex+thew); i++) { \
data[j*w+i] = bg; \
} \
} \
} \
} \
} \
\
return numsubs; \
}
DEFINE_SUBRECT_ENCODE(8)
DEFINE_SUBRECT_ENCODE(16)
DEFINE_SUBRECT_ENCODE(32)
/*
* getBgColour() gets the most prevalent colour in a byte array.
*/
static uint32_t
getBgColour(char *data, int size, int bpp)
{
#define NUMCLRS 256
static int counts[NUMCLRS];
int i,j,k;
int maxcount = 0;
uint8_t maxclr = 0;
if (bpp != 8) {
if (bpp == 16) {
return ((uint16_t *)data)[0];
} else if (bpp == 32) {
return ((uint32_t *)data)[0];
} else {
rfbLog("getBgColour: bpp %d?\n",bpp);
return 0;
}
}
for (i=0; i<NUMCLRS; i++) {
counts[i] = 0;
}
for (j=0; j<size; j++) {
k = (int)(((uint8_t *)data)[j]);
if (k >= NUMCLRS) {
rfbLog("getBgColour: unusual colour = %d\n", k);
return 0;
}
counts[k] += 1;
if (counts[k] > maxcount) {
maxcount = counts[k];
maxclr = ((uint8_t *)data)[j];
}
}
return maxclr;
}