Data commit

Task/Bitmap-Write-a-PPM-file/BBC-BASIC/bitmap-write-a-ppm-file.basic

@@ -0,0 +1,30 @@
+      Width% = 200
+      Height% = 200
+
+      VDU 23,22,Width%;Height%;8,16,16,128
+      *display c:\lena
+
+      f% = OPENOUT("c:\lena.ppm")
+      IF f%=0 ERROR 100, "Failed to open output file"
+      BPUT #f%, "P6"
+      BPUT #f%, "# Created using BBC BASIC"
+      BPUT #f%, STR$(Width%) + " " +STR$(Height%)
+      BPUT #f%, "255"
+
+      FOR y% = Height%-1 TO 0 STEP -1
+        FOR x% = 0 TO Width%-1
+          rgb% = FNgetpixel(x%,y%)
+          BPUT #f%, rgb% >> 16
+          BPUT #f%, (rgb% >> 8) AND &FF
+          BPUT #f%, rgb% AND &FF
+        NEXT
+      NEXT y%
+      CLOSE#f%
+
+      END
+
+      DEF FNgetpixel(x%,y%)
+      LOCAL col%
+      col% = TINT(x%*2,y%*2)
+      SWAP ?^col%,?(^col%+2)
+      = col%