Feat/rasterizer update 21

This feature update adds logging to the current implementation of the rendering package. It also includes minor refactorings in the FunctionalRenderingBase and ImageRasterizer. (No changes in functionality) Please review.

src/main/java/de/tudresden/inf/mci/brailleplot/rendering/AbstractCanvas.java

@@ -3,6 +3,8 @@ package de.tudresden.inf.mci.brailleplot.rendering;
 import de.tudresden.inf.mci.brailleplot.configparser.Format;
 import de.tudresden.inf.mci.brailleplot.configparser.Printer;
 import de.tudresden.inf.mci.brailleplot.printabledata.PrintableData;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -15,6 +17,8 @@ import java.util.ListIterator;
  */
 public abstract class AbstractCanvas {
 
+    private final Logger mLogger = LoggerFactory.getLogger(this.getClass());
+
     Printer mPrinter;
     Format mFormat;
 
@@ -23,23 +27,31 @@ public abstract class AbstractCanvas {
     List<PrintableData> mPageContainer;
 
     AbstractCanvas(final Printer printer, final Format format) throws InsufficientRenderingAreaException {
+
+        mLogger.trace("Creating new canvas");
+
         mPrinter = printer;
         mFormat = format;
         mPageContainer = new ArrayList<>();
 
         readConfig();
+
     }
 
     private void readConfig() throws InsufficientRenderingAreaException {
 
+        mLogger.trace("Reading general printer and format configuration for printing area calculation");
+
         // New approach using a box model:
 
         // Create a page box
         int pageWidth = mFormat.getProperty("page.width").toInt();
         int pageHeight = mFormat.getProperty("page.height").toInt();
         Rectangle pageBox = new Rectangle(0, 0, pageWidth, pageHeight);
+        mLogger.trace("Determined page box: {}", pageBox);
 
         // Create a margin box
+        mLogger.trace("Cropping edges by defined margins:");
         int marginTop = mFormat.getProperty("margin.top").toInt();
         int marginLeft = mFormat.getProperty("margin.left").toInt();
         int marginBottom = mFormat.getProperty("margin.bottom").toInt();
@@ -53,6 +65,7 @@ public abstract class AbstractCanvas {
         } catch (Rectangle.OutOfSpaceException e) {
             throw new InsufficientRenderingAreaException("The sum of the defined margins is bigger than the page size.", e);
         }
+        mLogger.trace("Determined margin box: {}", marginBox);
 
         // Create a constraint box
         double constraintTop = mPrinter.getProperty("constraint.top").toDouble();
@@ -69,8 +82,10 @@ public abstract class AbstractCanvas {
             constraintWidth = Integer.MAX_VALUE;
         }
         Rectangle constraintBox = new Rectangle(constraintLeft, constraintTop, constraintWidth, constraintHeight);
+        mLogger.trace("Determined constraint box: {}", constraintBox);
 
         mPrintableArea = calculatePrintingArea(marginBox, constraintBox);
+        mLogger.info("The calculated available printing area equals: {}", mPrintableArea);
 
     }