changes

ext.lisp

@@ -0,0 +1,11 @@
+
+;; start is the intended function to load this ext.lisp file
+;; I use `(save-image 'start)` 
+(defun start () (load-package "ext.lisp"))
+
+;; Quick shorthand 
+(defun dir () (directory))
+
+(defun file-read (filename) (with-sd-card (str filename) (read str)))
+(defun file-append (filename data) (with-sd-card (str filename 2) (print data str)))
+(defun file-write (filename data) (with-sd-card (str filename 2) (print data str)))

extensions.ino

@@ -3,6 +3,62 @@
 */
   
 // Definitions
+void SDWriteTwo (File file, uint16_t word) {
+  file.write(word & 0xFF); file.write((word >> 8) & 0xFF);
+}
+
+
+object *fn_savescreen (object *args, object *env) {
+  (void) env;
+  #if defined(sdcardsupport)
+  object *arg = checkstring(first(args));
+  sd_begin();
+  File file;
+  char buffer[BUFFERSIZE];
+  file = SD.open(MakeFilename(arg, buffer), FILE_WRITE);
+  if (!file) error2(PSTR("problem saving to SD card or invalid filename"));
+  uint16_t width = 320, height = 240;
+  file.write('B'); file.write('M');          // BMP
+  SDWriteInt(file, 14+40+width*height*2);    // File size in bytes
+  SDWriteInt(file, 0);
+  SDWriteInt(file, 14+40);                   // Offset to image data from start
+  // Image header: 40 bytes
+  SDWriteInt(file, 40);                      // Header size
+  SDWriteInt(file, width);                   // Image width
+  SDWriteInt(file, height);                  // Image height
+  SDWriteTwo(file, 1);   // Planes
+  SDWriteTwo(file, 16); // Bits per pixel
+  SDWriteInt(file, 0);                       // Compression (none)
+  SDWriteInt(file, 0);                       // Image size (0 for uncompressed)
+  SDWriteInt(file, 0);                       // Preferred X resolution (ignore)
+  SDWriteInt(file, 0);                       // Preferred Y resolution (ignore)
+  SDWriteInt(file, 0);                       // Colour map entries (ignore)
+  SDWriteInt(file, 0);                       // Important colours (ignore)
+  // Image data: width * height * 2 bytes
+  for (int y=height-1; y>=0; y--) {
+    int line = y/Leading, row = y%Leading;
+    for (int x=0; x<width; x++) {
+      int column = x/6, col = x%6;
+      char c = 0; bool bit;
+      if (column < Columns) c = ScrollBuf[column][(line+Scroll) % Lines];
+      if (col>=5 || row>=8) bit = 0;
+      else bit = font[(c & 0x7f)*5 + col] >> row & 1;
+      uint16_t rgb;
+      if (c & 0x80 && row<8) {
+        if (bit) rgb = COLOR_BLACK; else rgb = COLOR_GREEN;
+      } else {
+        if (bit) rgb = COLOR_WHITE; else rgb = COLOR_BLACK;
+      }
+      uint16_t data = (rgb & 0xFFC0)>>1 | (rgb & 0x1F); // Convert to 555 format
+      SDWriteTwo(file, data);
+    }
+  }
+  file.close();
+  #endif
+  return nil;
+}
+
+
 object *fn_sym_def (object *args, object *env) {
   (void) env;
   object *obj = first(args);
@@ -26,17 +82,19 @@ object *fn_sym_def (object *args, object *env) {
 
 // Symbol names
 const char string_sym_def[] PROGMEM = "symbol-def";
-
+const char stringsavescreen[] PROGMEM = "save-screen";
 
 // Documentation strings
 const char doc_sym_def[] PROGMEM = "(symbol-def symbol [str])\n"
 "Prints the definition of a symbol (variable or function) defined in ulisp using the pretty printer."
 "If str is specified it prints to the specified stream. It returns no value.";
 
+const char docsavescreen[] PROGMEM = "(save-screen filename)\n"
+"Saves an image of the text screen as a BMP file on the SD card.";
 
 // Symbol lookup table
 const tbl_entry_t lookup_table2[] PROGMEM = {
-
+  { stringsavescreen, fn_savescreen, 0211, docsavescreen },
   { string_sym_def, fn_sym_def, 0212, doc_sym_def }
 };