duplo.nut

   function writeRGBString(tpixel, color)
   {
       local r = color[0] * BYTESPERCOLOR;
       local g = color[1] * BYTESPERCOLOR;
       local b = color[2] * BYTESPERCOLOR;
       tpixel.writestring(bits.slice(g, g+BYTESPERCOLOR));
       tpixel.writestring(bits.slice(r, r+BYTESPERCOLOR));
       tpixel.writestring(bits.slice(b, b+BYTESPERCOLOR));    
   }

   function writePixel(p, color) 
   {
       frame.seek(p*BYTESPERPIXEL);
       writeRGBString(frame, color);
   }

   // Clears the frame buffer (with an optional color)
   // but does not write it to the pixel strip
   // color is an array of the form [r, g, b]
   function clearFrame(color = null) 
   {
       local colorString = clearString;
       if (color) 
       {
           // Get the color string
           colorString = blob(BYTESPERPIXEL);
           writeRGBString(colorString, color);
       }        

       frame.seek(0);
       for (local p = 0; p < frameSize; p++) frame.writestring(colorString.tostring());
           frame.writen(0x00,'c');
   }