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* Copyright (C) 2002 RealVNC Ltd. All Rights Reserved.
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* Copyright (C) 2003 Sun Microsystems, Inc.
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* This is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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* This software is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this software; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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* Before including this file, you must define a number of CPP macros.
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* BPP should be 8, 16 or 32 depending on the bits per pixel.
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* GET_IMAGE_INTO_BUF should be some code which gets a rectangle of pixel data
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* into the given buffer. EXTRA_ARGS can be defined to pass any other
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* arguments needed by GET_IMAGE_INTO_BUF.
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* Note that the buf argument to ZRLE_ENCODE needs to be at least one pixel
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* bigger than the largest tile of pixel data, since the ZRLE encoding
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* algorithm writes to the position one past the end of the pixel data.
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#include <zrleoutstream.h>
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#include <zrlepalettehelper.h>
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/* __RFB_CONCAT2 concatenates its two arguments. __RFB_CONCAT2E does the same
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but also expands its arguments if they are macros */
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#ifndef __RFB_CONCAT2E
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#define __RFB_CONCAT2(a,b) a##b
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#define __RFB_CONCAT2E(a,b) __RFB_CONCAT2(a,b)
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#define PIXEL_T __RFB_CONCAT2E(zrle_U,BPP)
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#define zrleOutStreamWRITE_PIXEL __RFB_CONCAT2E(zrleOutStreamWriteOpaque,CPIXEL)
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#define ZRLE_ENCODE __RFB_CONCAT2E(zrleEncode,CPIXEL)
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#define ZRLE_ENCODE_TILE __RFB_CONCAT2E(zrleEncodeTile,CPIXEL)
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#define PIXEL_T __RFB_CONCAT2E(zrle_U,BPP)
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#define zrleOutStreamWRITE_PIXEL __RFB_CONCAT2E(zrleOutStreamWriteOpaque,BPP)
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#define ZRLE_ENCODE __RFB_CONCAT2E(zrleEncode,BPP)
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#define ZRLE_ENCODE_TILE __RFB_CONCAT2E(zrleEncodeTile,BPP)
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static const int bitsPerPackedPixel[] = {
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0, 1, 2, 2, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4
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static zrlePaletteHelper paletteHelper;
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#endif /* ZRLE_ONCE */
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static void ZRLE_ENCODE_TILE (PIXEL_T* data, int w, int h, zrleOutStream* os);
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static void ZRLE_ENCODE (int x, int y, int w, int h,
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zrleOutStream* os, void* buf
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for (ty = y; ty < y+h; ty += rfbZRLETileHeight) {
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int tx, th = rfbZRLETileHeight;
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if (th > y+h-ty) th = y+h-ty;
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for (tx = x; tx < x+w; tx += rfbZRLETileWidth) {
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int tw = rfbZRLETileWidth;
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if (tw > x+w-tx) tw = x+w-tx;
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GET_IMAGE_INTO_BUF(tx,ty,tw,th,buf);
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ZRLE_ENCODE_TILE((PIXEL_T*)buf, tw, th, os);
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zrleOutStreamFlush(os);
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static void ZRLE_ENCODE_TILE (PIXEL_T* data, int w, int h, zrleOutStream* os)
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/* First find the palette and the number of runs */
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zrlePaletteHelper *ph;
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int singlePixels = 0;
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PIXEL_T* end = ptr + h * w;
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*end = ~*(end-1); /* one past the end is different so the while loop ends */
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zrlePaletteHelperInit(ph);
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while (*++ptr == pix) ;
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zrlePaletteHelperInsert(ph, pix);
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/* Solid tile is a special case */
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zrleOutStreamWriteU8(os, 1);
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zrleOutStreamWRITE_PIXEL(os, ph->palette[0]);
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// Try to work out whether to use RLE and/or a palette. We do this by
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// estimating the number of bytes which will be generated and picking the
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// method which results in the fewest bytes. Of course this may not result
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// in the fewest bytes after compression...
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estimatedBytes = w * h * (BPPOUT/8); // start assuming raw
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plainRleBytes = ((BPPOUT/8)+1) * (runs + singlePixels);
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if (plainRleBytes < estimatedBytes) {
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estimatedBytes = plainRleBytes;
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if (ph->size < 128) {
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int paletteRleBytes = (BPPOUT/8) * ph->size + 2 * runs + singlePixels;
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if (paletteRleBytes < estimatedBytes) {
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estimatedBytes = paletteRleBytes;
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int packedBytes = ((BPPOUT/8) * ph->size +
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w * h * bitsPerPackedPixel[ph->size-1] / 8);
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if (packedBytes < estimatedBytes) {
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estimatedBytes = packedBytes;
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if (!usePalette) ph->size = 0;
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zrleOutStreamWriteU8(os, (useRle ? 128 : 0) | ph->size);
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for (i = 0; i < ph->size; i++) {
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zrleOutStreamWRITE_PIXEL(os, ph->palette[i]);
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PIXEL_T* end = ptr + w * h;
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while (*ptr == pix && ptr < end)
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len = ptr - runStart;
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if (len <= 2 && usePalette) {
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int index = zrlePaletteHelperLookup(ph, pix);
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zrleOutStreamWriteU8(os, index);
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zrleOutStreamWriteU8(os, index);
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int index = zrlePaletteHelperLookup(ph, pix);
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zrleOutStreamWriteU8(os, index | 128);
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zrleOutStreamWRITE_PIXEL(os, pix);
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zrleOutStreamWriteU8(os, 255);
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zrleOutStreamWriteU8(os, len);
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assert (ph->size < 17);
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bppp = bitsPerPackedPixel[ph->size-1];
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for (i = 0; i < h; i++) {
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PIXEL_T* eol = ptr + w;
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PIXEL_T pix = *ptr++;
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zrle_U8 index = zrlePaletteHelperLookup(ph, pix);
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byte = (byte << bppp) | index;
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zrleOutStreamWriteU8(os, byte);
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zrleOutStreamWriteU8(os, byte);
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for (ptr = data; ptr < data+w*h; ptr++) {
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zrleOutStreamWRITE_PIXEL(os, *ptr);
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zrleOutStreamWriteBytes(os, (zrle_U8 *)data, w*h*(BPP/8));
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#undef zrleOutStreamWRITE_PIXEL
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#undef ZRLE_ENCODE_TILE