Data commit

Task/Grayscale-image/BBC-BASIC/grayscale-image.basic

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+      Width% = 200
+      Height% = 200
+
+      VDU 23,22,Width%;Height%;8,16,16,128
+      *display c:\lena
+
+      FOR y% = 0 TO Height%-1
+        FOR x% = 0 TO Width%-1
+          rgb% = FNgetpixel(x%,y%)
+          r% = rgb% >> 16
+          g% = (rgb% >> 8) AND &FF
+          b% = rgb% AND &FF
+          l% = INT(0.3*r% + 0.59*g% + 0.11*b% + 0.5)
+          PROCsetpixel(x%,y%,l%,l%,l%)
+        NEXT
+      NEXT y%
+      END
+
+      DEF PROCsetpixel(x%,y%,r%,g%,b%)
+      COLOUR 1,r%,g%,b%
+      GCOL 1
+      LINE x%*2,y%*2,x%*2,y%*2
+      ENDPROC
+
+      DEF FNgetpixel(x%,y%)
+      LOCAL col%
+      col% = TINT(x%*2,y%*2)
+      SWAP ?^col%,?(^col%+2)
+      = col%