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common/rfb/hextileEncode.h

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+/* Copyright (C) 2002-2005 RealVNC Ltd.  All Rights Reserved.
+ * Copyright (C) 2005 Constantin Kaplinsky.  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.
+ */
+//
+// Hextile encoding function.
+//
+// This file is #included after having set the following macro:
+// BPP                - 8, 16 or 32
+
+#include <rdr/OutStream.h>
+#include <rfb/hextileConstants.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 HEXTILE_ENCODE CONCAT2E(hextileEncode,BPP)
+#define HEXTILE_ENCODE_TILE CONCAT2E(hextileEncodeTile,BPP)
+#define TEST_TILE_TYPE CONCAT2E(hextileTestTileType,BPP)
+
+int TEST_TILE_TYPE (PIXEL_T* data, int w, int h, PIXEL_T* bg, PIXEL_T* fg);
+int HEXTILE_ENCODE_TILE (PIXEL_T* data, int w, int h, int tileType,
+                         rdr::U8* encoded, PIXEL_T bg);
+
+void HEXTILE_ENCODE(rdr::OutStream* os, const PixelBuffer* pb)
+{
+  Rect t;
+  PIXEL_T buf[256];
+  PIXEL_T oldBg = 0, oldFg = 0;
+  bool oldBgValid = false;
+  bool oldFgValid = false;
+  rdr::U8 encoded[256*(BPP/8)];
+
+  for (t.tl.y = 0; t.tl.y < pb->height(); t.tl.y += 16) {
+
+    t.br.y = __rfbmin(pb->height(), t.tl.y + 16);
+
+    for (t.tl.x = 0; t.tl.x < pb->width(); t.tl.x += 16) {
+
+      t.br.x = __rfbmin(pb->width(), t.tl.x + 16);
+
+      pb->getImage(buf, t);
+
+      PIXEL_T bg = 0, fg = 0;
+      int tileType = TEST_TILE_TYPE(buf, t.width(), t.height(), &bg, &fg);
+
+      if (!oldBgValid || oldBg != bg) {
+        tileType |= hextileBgSpecified;
+        oldBg = bg;
+        oldBgValid = true;
+      }
+
+      int encodedLen = 0;
+
+      if (tileType & hextileAnySubrects) {
+
+        if (tileType & hextileSubrectsColoured) {
+          oldFgValid = false;
+        } else {
+          if (!oldFgValid || oldFg != fg) {
+            tileType |= hextileFgSpecified;
+            oldFg = fg;
+            oldFgValid = true;
+          }
+        }
+
+        encodedLen = HEXTILE_ENCODE_TILE(buf, t.width(), t.height(), tileType,
+                                         encoded, bg);
+
+        if (encodedLen < 0) {
+          pb->getImage(buf, t);
+          os->writeU8(hextileRaw);
+          os->writeBytes(buf, t.width() * t.height() * (BPP/8));
+          oldBgValid = oldFgValid = false;
+          continue;
+        }
+      }
+
+      os->writeU8(tileType);
+      if (tileType & hextileBgSpecified) os->WRITE_PIXEL(bg);
+      if (tileType & hextileFgSpecified) os->WRITE_PIXEL(fg);
+      if (tileType & hextileAnySubrects) os->writeBytes(encoded, encodedLen);
+    }
+  }
+}
+
+
+int HEXTILE_ENCODE_TILE (PIXEL_T* data, int w, int h, int tileType,
+                         rdr::U8* encoded, PIXEL_T bg)
+{
+  rdr::U8* nSubrectsPtr = encoded;
+  *nSubrectsPtr = 0;
+  encoded++;
+
+  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 endOfSubrect;
+        ptr += w - sw;
+        sh++;
+      }
+    endOfSubrect:
+
+      (*nSubrectsPtr)++;
+
+      if (tileType & hextileSubrectsColoured) {
+        if (encoded - nSubrectsPtr + (BPP/8) > w*h*(BPP/8)) return -1;
+#if (BPP == 8)
+        *encoded++ = *data;
+#elif (BPP == 16)
+        *encoded++ = ((rdr::U8*)data)[0];
+        *encoded++ = ((rdr::U8*)data)[1];
+#elif (BPP == 32)
+        *encoded++ = ((rdr::U8*)data)[0];
+        *encoded++ = ((rdr::U8*)data)[1];
+        *encoded++ = ((rdr::U8*)data)[2];
+        *encoded++ = ((rdr::U8*)data)[3];
+#endif
+      }
+
+      if (encoded - nSubrectsPtr + 2 > w*h*(BPP/8)) return -1;
+      *encoded++ = (x << 4) | y;
+      *encoded++ = ((sw-1) << 4) | (sh-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 encoded - nSubrectsPtr;
+}
+
+
+int TEST_TILE_TYPE (PIXEL_T* data, int w, int h, PIXEL_T* bg, PIXEL_T* fg)
+{
+  PIXEL_T pix1 = *data;
+  PIXEL_T* end = data + w * h;
+
+  PIXEL_T* ptr = data + 1;
+  while (ptr < end && *ptr == pix1)
+    ptr++;
+
+  if (ptr == end) {
+    *bg = pix1;
+    return 0;                   // solid-color tile
+  }
+
+  int count1 = ptr - data;
+  int count2 = 1;
+  PIXEL_T pix2 = *ptr++;
+  int tileType = hextileAnySubrects;
+
+  for (; ptr < end; ptr++) {
+    if (*ptr == pix1) {
+      count1++;
+    } else if (*ptr == pix2) {
+      count2++;
+    } else {
+      tileType |= hextileSubrectsColoured;
+      break;
+    }
+  }
+
+  if (count1 >= count2) {
+    *bg = pix1; *fg = pix2;
+  } else {
+    *bg = pix2; *fg = pix1;
+  }
+  return tileType;
+}
+
+#undef PIXEL_T
+#undef WRITE_PIXEL
+#undef HEXTILE_ENCODE
+#undef HEXTILE_ENCODE_TILE
+#undef TEST_TILE_TYPE
+}