Add smart row wrapping and cleanup table drawing

src/main/java/be/quodlibet/boxable/DefaultRowWrappingFunction.java

@@ -0,0 +1,64 @@
+package be.quodlibet.boxable;
+
+import org.apache.pdfbox.pdmodel.PDPage;
+
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * This Wrapping function allows you to create advanced table layouts by hiding borders,
+ * without braking them on pagebreaks. e.g.:
+ * ┌────┬──────┬──────┐
+ * ├────┼──────┤      │
+ * ├────┼──────┤      │
+ * ├────┼──────┤      │
+ * ├────┼──────┤      │
+ * ├────┼──────┤      │
+ * └────┴──────┴──────┘
+ * <p>
+ * is not broken between pages
+ */
+public class DefaultRowWrappingFunction implements RowWrappingFunction {
+
+
+    @Override
+    public <T extends PDPage> int[] getWrappableRows(List<Row<T>> rows) {
+        int[] wrapableRows = new int[rows.size()];
+        wrapableRows[0] = 0;
+        int j = 1;
+        for (int i = 1; i < rows.size(); i++) {
+            Row<?> row = rows.get(i);
+            if (isProperTableRowStart(row)) {
+                wrapableRows[j++] = i;
+            }
+        }
+        return Arrays.copyOf(wrapableRows, j);
+    }
+
+    /*
+     * Checks if this is a proper start of a table row,
+     * i.e. every cell is visibly closed by a border on top or has no sides anyway.
+     *
+     * allowed:
+     * "┌────┐", "      "
+     * not allowed:
+     * "│    │", "│     ","     │"
+     * */
+    private boolean isProperTableRowStart(Row<?> row) {
+        if (row.getCells().isEmpty()) {
+            return true;
+        }
+        boolean previousClosed = false;
+        for (Cell<?> cell : row.getCells()) {
+
+            if (cell.getTopBorder() == null && (cell.getLeftBorder() != null && !previousClosed)) {
+                return false;
+            }
+            previousClosed = cell.getTopBorder() != null;
+        }
+        Cell<?> lastCell = row.getCells().get(row.getCells().size() - 1);
+
+        return lastCell.getTopBorder() != null || (lastCell.getRightBorder() == null);
+    }
+
+}

src/main/java/be/quodlibet/boxable/Row.java

@@ -22,6 +22,7 @@ public class Row<T extends PDPage> {
 	private boolean headerRow = false;
 	float height;
 	private float lineSpacing = 1;
+	private float wrapHeight = -1;
 
 	Row(Table<T> table, List<Cell<T>> cells, float height) {
 		this.table = table;
@@ -285,4 +286,32 @@ public float getLineSpacing() {
 	public void setLineSpacing(float lineSpacing) {
 		this.lineSpacing = lineSpacing;
 	}
+
+
+	/**
+	 * Finds out, taking restricted row wrapping into account, how much vertical space this row,
+	 * together with all un-wrappable rows that follow, will take.
+	 *
+	 * @return wrapHeight
+	 */
+	public float getWrapHeight() {
+		return table.calcWrapHeight(this);
+	}
+
+	protected void setWrapHeight(float wrapHeight) {
+		this.wrapHeight = wrapHeight;
+	}
+
+	protected float getSavedWrapHeight() {
+		return this.wrapHeight;
+	}
+
+	public boolean hasBottomBorder() {
+		for (Cell<T> cell : cells) {
+			if (cell.getBottomBorder() == null) {
+				return false;
+			}
+		}
+		return !cells.isEmpty();
+	}
 }

src/main/java/be/quodlibet/boxable/RowWrappingFunction.java

@@ -0,0 +1,19 @@
+package be.quodlibet.boxable;
+
+import org.apache.pdfbox.pdmodel.PDPage;
+
+import java.util.List;
+
+/**
+ * This interface allows you to specify where in the table page breaks may be inserted.
+ */
+public interface RowWrappingFunction {
+
+
+	/**
+	 * Allows you to specify at which indexes rows that can be moved to the next page are.
+	 * @param rows list of rows to consider
+	 * @return indexes of rows that may be moved to the next page, if the current page is full
+	 */
+	<T extends PDPage> int[] getWrappableRows(List<Row<T>> rows);
+}

src/main/java/be/quodlibet/boxable/Table.java

@@ -1,4 +1,3 @@
-
 /*
  Quodlibet.be
  */
@@ -56,6 +55,8 @@ public abstract class Table<T extends PDPage> {
 
     private PageProvider<T> pageProvider;
 
+    private RowWrappingFunction rowWrappingFunction = new DefaultRowWrappingFunction();
+
     // page margins
     private final float pageTopMargin;
     private final float pageBottomMargin;
@@ -83,7 +84,7 @@ public Table(float yStart, float yStartNewPage, float pageBottomMargin, float wi
         this(yStart, yStartNewPage, 0, pageBottomMargin, width, margin, document, currentPage, drawLines, drawContent,
                 null);
     }
-  
+
     /**
      * @deprecated Use one of the constructors that pass a {@link PageProvider}
      * @param yStartNewPage Y position where possible new page of {@link Table}
@@ -223,11 +224,16 @@ public Row<T> createRow(List<Cell<T>> cells, float height) {
     public float draw() throws IOException {
         ensureStreamIsOpen();
 
+        calcWrapHeightsAndRowHeights();
+
+        // for the first row in the table, we have to draw the top border
+        removeTopBorders = false;
+
         for (Row<T> row : rows) {
             if (header.contains(row)) {
                 // check if header row height and first data row height can fit
                 // the page
-                // if not draw them on another side
+                // if not draw them on another page
                 if (isEndOfPage(getMinimumHeight())) {
                     pageBreak();
                     tableStartedAtNewPage = true;
@@ -241,17 +247,9 @@ public float draw() throws IOException {
     }
 
     private void drawRow(Row<T> row) throws IOException {
-        // row.getHeight is currently an extremely expensive function so get the value
-        // once during drawing and reuse it, since it will not change during drawing
-        float rowHeight = row.getHeight();
-
-        // if it is not header row or first row in the table then remove row's
-        // top border
-        if (row != header && row != rows.get(0)) {
-            if (!isEndOfPage(rowHeight)) {
-                row.removeTopBorders();
-            }
-        }
+        // row.getHeight is currently an extremely expensive function, so we get the value
+        // calculated in calcWrapHeightsAndRowHeights, since it will not change during drawing
+        float rowHeight = row.getLineHeight();
 
         // draw the bookmark
         if (row.getBookmark() != null) {
@@ -262,49 +260,28 @@ private void drawRow(Row<T> row) throws IOException {
             this.addBookmark(row.getBookmark());
         }
 
-        // we want to remove the borders as often as possible
-        removeTopBorders = true;
-
         // check also if we want all borders removed
         if (allBordersRemoved()) {
             row.removeAllBorders();
         }
 
-        if (isEndOfPage(rowHeight) && !header.contains(row)) {
+        if (isEndOfPage(row.getSavedWrapHeight()) && !header.contains(row)) {
 
             // Draw line at bottom of table
             endTable();
 
             // insert page break
             pageBreak();
 
-            // redraw all headers on each currentPage
-            if (!header.isEmpty()) {
-                for (Row<T> headerRow : header) {
-                    drawRow(headerRow);
-                }
-                // after you draw all header rows on next page please keep
-                // removing top borders to avoid double border drawing
-                removeTopBorders = true;
-            } else {
-                // after a page break, we have to ensure that top borders get
-                // drawn
-                removeTopBorders = false;
-            }
-        }
-        // if it is first row in the table, we have to draw the top border
-        if (row == rows.get(0)) {
+            // after a page break, we have to ensure that top borders get
+            // drawn
             removeTopBorders = false;
-        }
 
-        if (removeTopBorders) {
-            row.removeTopBorders();
-        }
+            // redraw all headers on each page
+            for (Row<T> headerRow : header) {
+                drawRow(headerRow);
+            }
 
-        // if it is header row or first row in the table, we have to draw the
-        // top border
-        if (row == rows.get(0)) {
-            removeTopBorders = false;
         }
 
         if (removeTopBorders) {
@@ -318,6 +295,9 @@ private void drawRow(Row<T> row) throws IOException {
         if (drawContent) {
             drawCellContent(row, rowHeight);
         }
+        //would be better to check line presence between rows and
+        //draw exactly what's needed between two rows in one go.
+        removeTopBorders = row.hasBottomBorder();
     }
 
     /**
@@ -398,9 +378,9 @@ private void drawCellContent(Row<T> row, float rowHeight) throws IOException {
                         break;
                 }
                 imageCell.getImage().draw(document, tableContentStream, cursorX, cursorY);
-              
+
                 if (imageCell.getUrl() != null) {
-                    List<PDAnnotation> annotations = ((PDPage)currentPage).getAnnotations();
+                    List<PDAnnotation> annotations = ((PDPage) currentPage).getAnnotations();
 
                     PDBorderStyleDictionary borderULine = new PDBorderStyleDictionary();
                     borderULine.setStyle(PDBorderStyleDictionary.STYLE_UNDERLINE);
@@ -411,7 +391,7 @@ private void drawCellContent(Row<T> row, float rowHeight) throws IOException {
 
                     // Set the rectangle containing the link
                     // PDRectangle sets a the x,y and the width and height extend upwards from that!
-                    PDRectangle position = new PDRectangle(cursorX, cursorY, (float)(imageCell.getImage().getWidth()), -(float)(imageCell.getImage().getHeight()));
+                    PDRectangle position = new PDRectangle(cursorX, cursorY, (float) (imageCell.getImage().getWidth()), -(float) (imageCell.getImage().getHeight()));
                     txtLink.setRectangle(position);
 
                     // add an action
@@ -564,14 +544,14 @@ private void drawCellContent(Row<T> row, float rowHeight) throws IOException {
                             cursorY -= cell.getVerticalFreeSpace();
                             break;
                     }
-                  
+
                     if (cell.getUrl() != null) {
-                        List<PDAnnotation> annotations = ((PDPage)currentPage).getAnnotations();
+                        List<PDAnnotation> annotations = ((PDPage) currentPage).getAnnotations();
                         PDAnnotationLink txtLink = new PDAnnotationLink();
 
                         // Set the rectangle containing the link
                         // PDRectangle sets a the x,y and the width and height extend upwards from that!
-                        PDRectangle position = new PDRectangle(cursorX - 5, cursorY + 10, (float)(cell.getWidth()), -(float)(cell.getHeight()));
+                        PDRectangle position = new PDRectangle(cursorX - 5, cursorY + 10, (float) (cell.getWidth()), -(float) (cell.getHeight()));
                         txtLink.setRectangle(position);
 
                         // add an action
@@ -938,6 +918,10 @@ protected void setYStart(float yStart) {
         this.yStart = yStart;
     }
 
+    public void setRowWrappingFunction(RowWrappingFunction rowWrappingFunction) {
+        this.rowWrappingFunction = rowWrappingFunction;
+    }
+
     public boolean isDrawDebug() {
         return drawDebug;
     }
@@ -978,4 +962,33 @@ public void removeAllBorders(boolean removeAllBorders) {
         this.removeAllBorders = removeAllBorders;
     }
 
+    protected float calcWrapHeight(Row<T> tRow) {
+        int[] wrappableRows = rowWrappingFunction.getWrappableRows(rows);
+        int currentRow = rows.indexOf(tRow);
+        for (int wrappableRow : wrappableRows) {
+            if (wrappableRow > currentRow) {
+                float wrapHeight = 0;
+                for (int i = currentRow; i < wrappableRow; i++) {
+                    wrapHeight += rows.get(i).getHeight();
+                }
+                return wrapHeight;
+            }
+        }
+
+        return tRow.getHeight();
+    }
+
+    protected void calcWrapHeightsAndRowHeights() {
+        int[] wrappableRows = rowWrappingFunction.getWrappableRows(rows);
+        int prevRow = rows.size();
+        for (int i = wrappableRows.length - 1; i >= 0; i--) {
+            int wrappableRow = wrappableRows[i];
+            float height = 0;
+            for (int j = prevRow - 1; j >= wrappableRow; j--) {
+                height += rows.get(j).getHeight();
+                rows.get(j).setWrapHeight(height);
+            }
+            prevRow = wrappableRow;
+        }
+    }
 }

src/test/java/be/quodlibet/boxable/DataTableTest.java

@@ -2,7 +2,6 @@
 
 import be.quodlibet.boxable.datatable.DataTable;
 import be.quodlibet.boxable.datatable.UpdateCellProperty;
-import com.google.common.io.Files;
 import java.awt.Color;
 import java.io.File;
 import java.io.IOException;