Update gsconv850.c

implemented termcap (CSI Codes) for the grayscale debug output instead of windows specific extended ASCII Codes

Works with WIndows and Linux (compiled with gcc under Linux and MSYS2 under Windows)

Author: HWR0@Proteus

gsconv850/gsconv850.c

@@ -227,8 +227,8 @@ void printHelp()
     printf("    -c,     Clean output, without banner\n");
     printf("    -H,     Shows essential data from BMP header\n");
     printf("    -t,     Show table      (0 1 2 ) - DEBUG\n");
-    printf("    -g,     Show graphics   (  %c%c%c%c) - DEBUG\n", 177, 177, 219, 219);
-    printf("    -i,     Invert graphics (%c%c%c%c  ) - DEBUG\n", 219, 219, 177, 177);
+    printf("    -g,     Show graphics   (%c[30;40m  %c[90;100m  %c[37;47m  %c[0m) - DEBUG\n", 27, 27, 27, 27);
+    printf("    -i,     Invert graphics (%c[37;47m  %c[90;100m  %c[30;40m  %c[0m) - DEBUG\n", 27,27,27,27);
     printf("    -r,     Reverse Y order\n");
     printf("    -a,     Average RGB Pixel to gray, otherwise just the red channel taken\n");
     printf("    -s,     Remove space between hex values\n");
@@ -294,8 +294,9 @@ void showBMPTable()
 void showBMPGraphics(int invColors /*colors inverted?*/)
 {
     int tmpv = 0;
-    int gray = 177;
-    int white = 219; //white = if white is foreground in terminal !
+    int esc = 27;
+    //int gray = 177;
+    //int white = 219; //white = if white is foreground in terminal !
 
     for (int y = 0; y < (fbmp.height); y++)
     {
@@ -305,20 +306,20 @@ void showBMPGraphics(int invColors /*colors inverted?*/)
             if (invColors)
                 tmpv = 2 - tmpv;
 
-            if (tmpv == 0)
+            if (tmpv == 0) //black
             {
-                printf("  ");
+                printf("%c[37;47m  ", esc);
             }
-            else if (tmpv == 1)
+            else if (tmpv == 1) //gray
             {
-                printf("%c%c", gray, gray);
+                printf("%c[90;100m  ", esc);
             }
-            else
+            else //white
             {
-                printf("%c%c", white, white);
+                printf("%c[37;47m  ", esc);
             }
         }
-        printf("\n");
+        printf("%c[0m\n",esc);
     }
 }