2 files changed, 112 insertions, 0 deletions

diff --git a/ws2015/eip/blaetter/05/Histogramm.java b/ws2015/eip/blaetter/05/Histogramm.java
new file mode 100644
index 0000000..87e6b4e
--- /dev/null
+++ b/ws2015/eip/blaetter/05/Histogramm.java
@@ -0,0 +1,111 @@
+import java.awt.Rectangle;
+import java.awt.Color;
+import java.awt.Point;
+
+class Histogramm {
+
+    public static final int SPACING = 1;
+    public static final int MIN_BAR_WIDTH = 2;
+    public static final int HEIGHT = 480;
+    public static final int LABEL_HEIGHT = 12;
+    public static final int MIN_WIDTH = 640;
+
+    public static final Color COLD = Color.blue;
+    public static final Color HOT = Color.red;
+    
+    public static void main(String[] args)
+    {
+        if (args.length < 2)
+            {
+                System.err.println("Need at least two arguments");
+                System.exit(2);
+            }
+
+        String input = "";
+        for (int i = 1; i < args.length; i++)
+            input += args[i];
+
+        char[] alphabet = args[0].toCharArray();
+        // We convert to char[] instead of byte[] in order to be unicode aware
+
+        graph(alphabet, makeRelative(countOccurences(alphabet, input)));
+        // Why can’t we have nice things? Like function composition?
+    }
+
+    public static double[] makeRelative (int[] counts)
+    {
+        double[] relativeCounts = new double[counts.length];
+        int max = 0;
+
+        // I'm sure there's a library function for this but I was too lazy to look
+        for (int c : counts)
+            if (c > max)
+                max = c;
+
+        for (int i = 0; i < counts.length; i++)
+            relativeCounts[i] = ((double) counts[i]) / max;
+        
+        return relativeCounts;
+    }
+    
+    public static void graph(char[] alphabet, double[] counts)
+    {
+        int minWidth = MIN_BAR_WIDTH * (counts.length) + SPACING * (counts.length - 1);
+        int width = Math.max(minWidth, MIN_WIDTH);
+
+        int barWidth = (width - SPACING * (counts.length - 1)) / counts.length;
+        
+        GraphicsWindow gw = new GraphicsWindow(width, HEIGHT);
+        gw.setText("Histogramm");
+
+        int x = 0;
+
+        for (int i = 0; i < counts.length; i++)
+            {
+                int height = (int) (counts[i] * HEIGHT);
+                Point corner = new Point(x, HEIGHT - height);
+                Rectangle bar = new Rectangle(corner.x, corner.y, barWidth, height);
+                boolean labelAbove = height <= LABEL_HEIGHT;
+
+                
+                gw.setColor(color(counts[i]));
+                gw.fill(bar);
+                gw.setColor(labelAbove ? Color.black : Color.white);
+                gw.drawStringAt(String.format("%c", alphabet[i]), new Point(corner.x, corner.y + (labelAbove ? -5 : LABEL_HEIGHT)));
+
+                x += SPACING + barWidth;
+            }
+
+        gw.mouseClick();
+        System.exit(0);
+    }
+
+    public static Color color(double c)
+    {
+        double r, g, b;
+        r = HOT.getRed() * c + COLD.getRed() * (1 - c);
+        g = HOT.getGreen() * c + COLD.getGreen() * (1 - c);
+        b = HOT.getBlue() * c + COLD.getBlue() * (1 - c);
+        return new Color((int) r, (int) g, (int) b);
+    }
+
+    public static int[] countOccurences(char[] alphabet, String input)
+    {
+        int[] count = new int[alphabet.length];
+
+        for (int i = 0; i < alphabet.length; i++)
+            count[i] = 0;
+        
+        for (char c : input.toCharArray())
+            for (int i = 0; i < alphabet.length; i++)
+                if (alphabet[i] == c)
+                    count[i]++;
+        
+        /* We could skip right to the next input character as soon as we
+         * find a match but this implementation supports multiple occurences
+         * of a char in the alphabet (inefficiently)
+         */
+
+        return count;
+    }
+}
diff --git a/ws2015/eip/blaetter/05/manifest b/ws2015/eip/blaetter/05/manifest
index 0573ab5..b858ad4 100644
--- a/ws2015/eip/blaetter/05/manifest
+++ b/ws2015/eip/blaetter/05/manifest
@@ -1 +1,2 @@
+Histogramm.java
 H5-2.pdf
\ No newline at end of file