Data commit

Task/Greyscale-bars-Display/FreeBASIC/greyscale-bars-display.basic

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+' version 01-09-2017
+'    compile with: fbc -s console
+' or compile with: fbc -s gui
+' hit any key to stop
+
+Dim As UInteger d, blocks, blocksize, ps, col, h, w, x, y1, y2
+
+ScreenInfo w, h
+' create display size window, 8bit color (palette), no frame
+ScreenRes w, h, 8,, 8
+
+For x = 0 To 255        ' create grayscale palette for
+    Palette x, x, x, x  ' the window we just opened
+Next
+
+h = h \ 4 : y2 = h -1
+
+If w Mod 64 <> 0 Then w -= (w Mod 64)
+blocks = 8 : blocksize = w \ 8
+
+For ps = 1 To 4
+    For x = 0 To blocks -1
+        col = 255 * x \ (blocks -1)              ' from black to white
+        If (ps And 1) = 0 Then col = 255 - col   ' from white to black
+        Line (x * blocksize, y1) - (((x +1) * blocksize) -1, y2), col, bf
+    Next
+    y1 += h : y2 += h
+    blocks *= 2 : blocksize \= 2
+Next
+
+' empty keyboard buffer
+While Inkey <> "" : Wend
+
+Sleep
+End