apps/window_server/Renderer_vesa.cpp

   1 #include "Renderer_vesa.h"
   2 #include "assert.h"
   3 #include <win/Color.h>
   4
   5 #define MIN(a, b) ((a) < (b) ? (a) : (b))
   6
   7 const color555 kCursorBits555 [] = {
   8         0x7fff,0x7fff,0x00,0x00,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,
   9         0x7fff,0x7fff,0x7fff,0x7fff,0x00,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,
  10         TRANS555COLOR,0x7fff,0x7fff,0x7fff,0x7fff,0x00,0x00,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,
  11         TRANS555COLOR,0x7fff,0x7fff,0x7fff,0x7fff,0x7fff,0x7fff,0x00,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,
  12         TRANS555COLOR,TRANS555COLOR,0x7fff,0x7fff,0x7fff,0x7fff,0x7fff,0x7fff,0x7fff,0x00,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,
  13         TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,0x7fff,0x7fff,0x7fff,0x7fff,0x7fff,0x7fff,0x7fff,0x00,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,
  14         TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,0x7fff,0x7fff,0x7fff,0x7fff,0x7fff,0x7fff,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,
  15         TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,0x7fff,0x7fff,0x7fff,0x7fff,0x00,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,
  16         TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,0x7fff,0x7fff,0x7fff,TRANS555COLOR,0x7fff,0x00,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,
  17         TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,0x7fff,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,0x7fff,0x00,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,
  18         TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,0x7fff,0x00,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,
  19         TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,0x7fff,0x00,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,
  20         TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,0x7fff,0x00,TRANS555COLOR,TRANS555COLOR,
  21         TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,0x7fff,0x00,TRANS555COLOR,
  22         TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,0x7fff,TRANS555COLOR,
  23         TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR,TRANS555COLOR
  24 };
  25
  26 const color565 kCursorBits565 [] = {
  27         0xffff,0xffff,0x00,0x00,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,
  28         0xffff,0xffff,0xffff,0xffff,0x00,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,
  29         TRANS565COLOR,0xffff,0xffff,0xffff,0xffff,0x00,0x00,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,
  30         TRANS565COLOR,0xffff,0xffff,0xffff,0xffff,0xffff,0xffff,0x00,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,
  31         TRANS565COLOR,TRANS565COLOR,0xffff,0xffff,0xffff,0xffff,0xffff,0xffff,0xffff,0x00,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,
  32         TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,0xffff,0xffff,0xffff,0xffff,0xffff,0xffff,0xffff,0x00,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,
  33         TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,0xffff,0xffff,0xffff,0xffff,0xffff,0xffff,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,
  34         TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,0xffff,0xffff,0xffff,0xffff,0x00,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,
  35         TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,0xffff,0xffff,0xffff,TRANS565COLOR,0xffff,0x00,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,
  36         TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,0xffff,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,0xffff,0x00,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,
  37         TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,0xffff,0x00,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,
  38         TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,0xffff,0x00,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,
  39         TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,0xffff,0x00,TRANS565COLOR,TRANS565COLOR,
  40         TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,0xffff,0x00,TRANS565COLOR,
  41         TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,0xffff,TRANS565COLOR,
  42         TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR,TRANS565COLOR
  43 };
  44
  45 const color888 kCursorBits888 [] = {
  46         0xffffff,0xffffff,0x00,0x00,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,
  47         0xffffff,0xffffff,0xffffff,0xffffff,0x00,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,
  48         TRANS888COLOR,0xffffff,0xffffff,0xffffff,0xffffff,0x00,0x00,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,
  49         TRANS888COLOR,0xffffff,0xffffff,0xffffff,0xffffff,0xffffff,0xffffff,0x00,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,
  50         TRANS888COLOR,TRANS888COLOR,0xffffff,0xffffff,0xffffff,0xffffff,0xffffff,0xffffff,0xffffff,0x00,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,
  51         TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,0xffffff,0xffffff,0xffffff,0xffffff,0xffffff,0xffffff,0xffffff,0x00,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,
  52         TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,0xffffff,0xffffff,0xffffff,0xffffff,0xffffff,0xffffff,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,
  53         TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,0xffffff,0xffffff,0xffffff,0xffffff,0x00,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,
  54         TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,0xffffff,0xffffff,0xffffff,TRANS888COLOR,0xffffff,0x00,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,
  55         TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,0xffffff,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,0xffffff,0x00,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,
  56         TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,0xffffff,0x00,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,
  57         TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,0xffffff,0x00,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,
  58         TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,0xffffff,0x00,TRANS888COLOR,TRANS888COLOR,
  59         TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,0xffffff,0x00,TRANS888COLOR,
  60         TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,0xffffff,TRANS888COLOR,
  61         TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR,TRANS888COLOR
  62 };
  63
  64
  65 Renderer_vesa_555::Renderer_vesa_555(char *baseAddress, int width, int height, int bytesPerRow)
  66         :       Renderer_RGB555(baseAddress, width, height, bytesPerRow)
  67 {
  68         fCursorX = width / 2;
  69         fCursorY = height / 2;
  70         DrawCursor();
  71 }
  72
  73 const unsigned kBottom = 1;
  74 const unsigned kTop = 2;
  75 const unsigned kLeft = 4;
  76 const unsigned kRight = 8;
  77
  78 #define clipmask(x, y, rect)            \
  79         ({      unsigned mask = 0;                                                              \
  80                 if (x < rect.left) mask |= kLeft;                       \
  81                 else if (x > rect.right) mask |= kRight;        \
  82                 if (y < rect.top) mask |= kTop;                 \
  83                 else if (y > rect.bottom) mask |= kBottom;      \
  84                 mask;})
  85
  86 inline int vert_intersection(int x1, int y1, int x2, int y2, int x)
  87 {
  88         return y1 + (y2 - y1) * (x - x1) / (x2 - x1);
  89 }
  90
  91 inline int horz_intersection(int x1, int y1, int x2, int y2, int y)
  92 {
  93         return x1 + (x2 - x1) * (y - y1) / (y2 - y1);
  94 }
  95
  96 void Renderer_vesa_555::DrawLine(int x1, int y1, int x2, int y2, color32 color, color_space cspace)
  97 {
  98         Rect cursorRect(fCursorX, fCursorY, fCursorX + 16 - 1, fCursorY + 16 - 1);
  99         bool invalidateCursor = true;
 100
 101         int clippedX1 = x1;
 102         int clippedY1 = y1;
 103         int clippedX2 = x2;
 104         int clippedY2 = y2;
 105         unsigned point1mask = clipmask(clippedX1, clippedY1, cursorRect);
 106         unsigned point2mask = clipmask(clippedX2, clippedY2, cursorRect);
 107         while (point1mask != 0 || point2mask != 0) {
 108                 if ((point1mask & point2mask) != 0) {
 109                         invalidateCursor = false;
 110                         break;
 111                 }
 112
 113                 unsigned  mask = point1mask ? point1mask : point2mask;
 114                 int x = 0;
 115                 int y = 0;
 116                 if (mask & kBottom) {
 117                         y = cursorRect.bottom;
 118                         x = horz_intersection(clippedX1, clippedY1, clippedX2, clippedY2, y);
 119                 } else if (mask & kTop) {
 120                         y = cursorRect.top;
 121                         x = horz_intersection(clippedX1, clippedY1, clippedX2, clippedY2, y);
 122                 } else if (mask & kRight) {
 123                         x = cursorRect.right;
 124                         y = vert_intersection(clippedX1, clippedY1, clippedX2, clippedY2, x);
 125                 } else if (mask & kLeft) {
 126                         x = cursorRect.left;
 127                         y = vert_intersection(clippedX1, clippedY1, clippedX2, clippedY2, x);
 128                 }
 129
 130                 if (point1mask) {
 131                         // Clip point 1
 132                         point1mask = clipmask(x, y, cursorRect);
 133                         clippedX1 = x;
 134                         clippedY1 = y;
 135                 } else {
 136                         // Clip point 2
 137                         point2mask = clipmask(x, y, cursorRect);
 138                         clippedX2 = x;
 139                         clippedY2 = y;
 140                 }
 141         }
 142
 143         if (invalidateCursor)
 144                 EraseCursor();
 145
 146         Renderer_RGB555::DrawLine(x1, y1, x2, y2, color, cspace);
 147
 148         if (invalidateCursor)
 149                 DrawCursor();
 150 }
 151
 152 void Renderer_vesa_555::FillRect(int x1, int y1, int x2, int y2, color32 color, color_space cspace)
 153 {
 154         bool invalidateCursor = false;
 155         if (Rect(x1, y1, x2, y2).Intersects(Rect(fCursorX, fCursorY, fCursorX + 16 - 1,
 156                 fCursorY + 16 - 1))) {
 157                 invalidateCursor = true;
 158                 EraseCursor();
 159         }
 160
 161         Renderer_RGB555::FillRect(x1, y1, x2, y2, color, cspace);
 162         if (invalidateCursor)
 163                 DrawCursor();
 164 }
 165
 166 void Renderer_vesa_555::Blit(int x, int y, const void *image, color_space cspace, int imageWidth,
 167     int imageHeight, int imageStrideWidth)
 168 {
 169
 170         bool invalidateCursor = false;
 171         if (Rect(x, y, x + imageWidth, y + imageHeight).Intersects(Rect(fCursorX,
 172                 fCursorY, fCursorX + 16 - 1, fCursorY + 16 - 1))) {
 173                 invalidateCursor = true;
 174                 EraseCursor();
 175         }
 176
 177         Renderer_RGB555::Blit(x, y, image, cspace, imageWidth, imageHeight, imageStrideWidth);
 178         if (invalidateCursor)
 179                 DrawCursor();
 180 }
 181
 182 void Renderer_vesa_555::StretchBlit(const Rect &imageRect, const Rect &displayRect, const void *image, color_space cspace,
 183         int imageStrideWidth)
 184 {
 185
 186         bool invalidateCursor = false;
 187         if (displayRect.Intersects(Rect(fCursorX, fCursorY, fCursorX + 16 - 1,
 188                 fCursorY + 16 - 1))) {
 189                 invalidateCursor = true;
 190                 EraseCursor();
 191         }
 192
 193         Renderer_RGB555::StretchBlit(imageRect, displayRect, image, cspace, imageStrideWidth);
 194
 195         if (invalidateCursor)
 196                 DrawCursor();
 197 }
 198
 199 void Renderer_vesa_555::CopyRect(const Rect &source, const Rect &dest)
 200 {
 201         bool invalidateCursor = false;
 202         Rect cursorRect(fCursorX, fCursorY, fCursorX + 16 - 1, fCursorY + 16 - 1);
 203         if (cursorRect.Intersects(source) || cursorRect.Intersects(dest)) {
 204                 invalidateCursor = true;
 205                 EraseCursor();
 206         }
 207
 208         Renderer_RGB555::CopyRect(source, dest);
 209         if (invalidateCursor)
 210                 DrawCursor();
 211 }
 212
 213 void Renderer_vesa_555::SetCursorPosition(int x, int  y)
 214 {
 215         EraseCursor();
 216         fCursorX = x;
 217         fCursorY = y;
 218         DrawCursor();
 219 }
 220
 221 void Renderer_vesa_555::EraseCursor()
 222 {
 223         color555 *screen_ptr = (color555 *)BufferBaseAddress() + fCursorX + fCursorY * (BufferBytesPerRow() / 2);
 224         color555 *saveBackground = fSavedBackground;
 225         int cursorDisplayWidth = MIN(16, (BufferBytesPerRow() / 2) - fCursorX);
 226         int cursorDisplayHeight = MIN(16, BufferHeight() - fCursorY);
 227         int stride = (BufferBytesPerRow() / 2) - cursorDisplayWidth;
 228
 229         for (int y = 0; y < cursorDisplayHeight; y++) {
 230                 for (int x = 0; x < cursorDisplayWidth; x++) {
 231                         if (*saveBackground != TRANS555COLOR)
 232                                 *screen_ptr = *saveBackground;
 233
 234                         screen_ptr++;
 235                         saveBackground++;
 236                 }
 237
 238                 screen_ptr += stride;
 239                 saveBackground += 16 - cursorDisplayWidth;
 240         }
 241 }
 242
 243 void Renderer_vesa_555::DrawCursor()
 244 {
 245         color555 *screen_ptr = (color555 *)BufferBaseAddress() + fCursorX + fCursorY * (BufferBytesPerRow() / 2);
 246         color555 *cursorImage = (color555 *)kCursorBits555;
 247         color555 *saveBackground = fSavedBackground;
 248         int cursorDisplayWidth = MIN(16, (BufferBytesPerRow() / 2) - fCursorX);
 249         int cursorDisplayHeight = MIN(16, BufferHeight() - fCursorY);
 250         int stride = (BufferBytesPerRow() / 2) - cursorDisplayWidth;
 251
 252         for (int y = 0; y < cursorDisplayHeight; y++) {
 253                 for (int x = 0; x < cursorDisplayWidth; x++) {
 254                         if (*cursorImage != TRANS555COLOR) {
 255                                 *saveBackground = *screen_ptr;
 256                                 *screen_ptr = *cursorImage;
 257                         } else
 258                                 *saveBackground = TRANS555COLOR;
 259
 260                         screen_ptr++;
 261                         cursorImage++;
 262                         saveBackground++;
 263                 }
 264
 265                 screen_ptr += stride;
 266                 cursorImage += 16 - cursorDisplayWidth;
 267                 saveBackground += 16 - cursorDisplayWidth;
 268         }
 269 }