Greyscale bars/Display: Difference between revisions

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 '''[http://www.cogier.com/gambas/GreyScale.png Click here for image of the output]'''
+=={{header|Go}}==
+{{libheader|Go Graphics}}
+{{trans|Java}}
+<lang go>package main
+import (
+    "github.com/fogleman/gg"
+    "math"
+)
+func greyBars(dc *gg.Context) {
+    run := 0
+    colorComp := 0.0 // component of the color
+    for colCount := 8; colCount < 128; colCount *= 2 {
+        // by this gap we change the background color
+        colorGap := 255.0 / float64(colCount-1)
+        colWidth := float64(dc.Width() / colCount)
+        colHeight := float64(dc.Height() / 4)
+        // switches color directions with each iteration of for loop
+        if run%2 == 0 {
+            colorComp = 0.0
+        } else {
+            colorComp = 255.0
+            colorGap = -colorGap
+        }
+        xstart, ystart := 0.0, colHeight*float64(run)
+        for i := 0; i < colCount; i++ {
+            icolor := int(math.Round(colorComp)) // round to nearer integer
+            dc.SetRGB255(icolor, icolor, icolor)
+            dc.DrawRectangle(xstart, ystart, colWidth, colHeight)
+            dc.Fill()
+            xstart += colWidth
+            colorComp += colorGap
+        }
+        run++
+    }
+}
+func main() {
+    dc := gg.NewContext(640, 320)
+    greyBars(dc)
+    dc.SavePNG("greybars.png")
+}</lang>
+{{out}}
+<pre>
+Image similar to R entry (first image)
+</pre>
 =={{header|Haskell}}==