Support Padding, borders, and margin for MulticolRenderer

DEVSIX-7604

Author: guustysebie

layout/src/main/java/com/itextpdf/layout/element/MulticolContainer.java

@@ -22,10 +22,8 @@ This file is part of the iText (R) project.
  */
 package com.itextpdf.layout.element;
 
-import com.itextpdf.layout.renderer.MulticolRenderer;
 import com.itextpdf.layout.renderer.IRenderer;
-
-import java.util.Map;
+import com.itextpdf.layout.renderer.MulticolRenderer;
 
 /**
  * represents a container of the column objects.
@@ -39,17 +37,6 @@ public MulticolContainer() {
         super();
     }
 
-    /**
-     * Copies all properties of {@link MulticolContainer} to its child elements.
-     */
-    public void copyAllPropertiesToChildren() {
-        for (final IElement child : this.getChildren()) {
-            for (final Map.Entry<Integer, Object> entry : this.properties.entrySet()) {
-                child.setProperty(entry.getKey(), entry.getValue());
-            }
-        }
-    }
-
     @Override
     protected IRenderer makeNewRenderer() {
         return new MulticolRenderer(this);

layout/src/main/java/com/itextpdf/layout/renderer/AbstractRenderer.java

@@ -1793,6 +1793,7 @@ protected Rectangle applyMargins(Rectangle rect, UnitValue[] margins, boolean re
 
     /**
      * Returns margins of the renderer
+     * [0] - top; [1] - right; [2] - bottom; [3] - left
      *
      * @return a {@code float[]} margins of the renderer
      */
@@ -1802,6 +1803,7 @@ protected UnitValue[] getMargins() {
 
     /**
      * Returns paddings of the renderer
+     * [0] - top; [1] - right; [2] - bottom; [3] - left
      *
      * @return a {@code float[]} paddings of the renderer
      */
@@ -1815,7 +1817,7 @@ protected UnitValue[] getPaddings() {
      * @param rect     a rectangle paddings will be applied on.
      * @param paddings the paddings to be applied on the given rectangle
      * @param reverse  indicates whether paddings will be applied
-     *                 inside (in case of false) or outside (in case of false) the rectangle.
+     *                 inside (in case of false) or outside (in case of true) the rectangle.
      * @return a {@link Rectangle border box} of the renderer
      */
     protected Rectangle applyPaddings(Rectangle rect, UnitValue[] paddings, boolean reverse) {

layout/src/main/java/com/itextpdf/layout/renderer/MulticolRenderer.java

@@ -23,11 +23,13 @@ This file is part of the iText (R) project.
 package com.itextpdf.layout.renderer;
 
 import com.itextpdf.kernel.geom.Rectangle;
+import com.itextpdf.layout.borders.Border;
 import com.itextpdf.layout.element.MulticolContainer;
 import com.itextpdf.layout.layout.LayoutArea;
 import com.itextpdf.layout.layout.LayoutContext;
 import com.itextpdf.layout.layout.LayoutResult;
 import com.itextpdf.layout.properties.Property;
+import com.itextpdf.layout.properties.UnitValue;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -38,7 +40,7 @@ This file is part of the iText (R) project.
 public class MulticolRenderer extends AbstractRenderer {
 
     private static final int MAX_RELAYOUT_COUNT = 4;
-    private static final float ZERO_DELTA = 0.0001f;
+    private static final float ZERO_DELTA = 0.0001F;
 
     private BlockRenderer elementRenderer;
     private int columnCount;
@@ -54,22 +56,19 @@ public MulticolRenderer(MulticolContainer modelElement) {
         super(modelElement);
     }
 
-    @Override
-    public IRenderer getNextRenderer() {
-        logWarningIfGetNextRendererNotOverridden(MulticolRenderer.class, this.getClass());
-        return new MulticolRenderer((MulticolContainer) modelElement);
-    }
-
     /**
      * {@inheritDoc}
      */
     @Override
     public LayoutResult layout(LayoutContext layoutContext) {
-        ((MulticolContainer) this.getModelElement()).copyAllPropertiesToChildren();
         this.setProperty(Property.TREAT_AS_CONTINUOUS_CONTAINER, Boolean.TRUE);
-        final Rectangle initialBBox = layoutContext.getArea().getBBox();
+        final Rectangle actualBBox = layoutContext.getArea().getBBox().clone();
+        applyPaddings(actualBBox, false);
+        applyBorderBox(actualBBox, false);
+        applyMargins(actualBBox, false);
+
         columnCount = (int) this.<Integer>getProperty(Property.COLUMN_COUNT);
-        columnWidth = initialBBox.getWidth() / columnCount;
+        columnWidth = actualBBox.getWidth() / columnCount;
         if (this.elementRenderer == null) {
             // initialize elementRenderer on first layout when first child represents renderer of element which
             // should be layouted in multicol, because on the next layouts this can have multiple children
@@ -85,7 +84,7 @@ public LayoutResult layout(LayoutContext layoutContext) {
 
         approximateHeight = prelayoutResult.getOccupiedArea().getBBox().getHeight() / columnCount;
 
-        List<IRenderer> container = balanceContentAndLayoutColumns(layoutContext);
+        List<IRenderer> container = balanceContentAndLayoutColumns(layoutContext, actualBBox);
 
         this.occupiedArea = calculateContainerOccupiedArea(layoutContext);
         this.setChildRenderers(container);
@@ -97,19 +96,38 @@ public LayoutResult layout(LayoutContext layoutContext) {
         return result;
     }
 
-    private List<IRenderer> balanceContentAndLayoutColumns(LayoutContext prelayoutContext) {
+    @Override
+    public IRenderer getNextRenderer() {
+        logWarningIfGetNextRendererNotOverridden(MulticolRenderer.class, this.getClass());
+        return new MulticolRenderer((MulticolContainer) modelElement);
+    }
+
+    private float safelyRetrieveFloatProperty(int property) {
+        final Object value = this.<Object>getProperty(property);
+        if (value instanceof UnitValue) {
+            return ((UnitValue) value).getValue();
+        }
+        if (value instanceof Border) {
+            return ((Border) value).getWidth();
+        }
+        return 0F;
+    }
+
+    private List<IRenderer> balanceContentAndLayoutColumns(LayoutContext prelayoutContext, Rectangle actualBBox) {
         Float additionalHeightPerIteration = null;
-        List<IRenderer> container = new ArrayList<>();
+        final List<IRenderer> container = new ArrayList<>();
         int counter = MAX_RELAYOUT_COUNT;
         while (counter-- > 0) {
-            IRenderer overflowRenderer = layoutColumnsAndReturnOverflowRenderer(prelayoutContext, container);
+            final IRenderer overflowRenderer = layoutColumnsAndReturnOverflowRenderer(prelayoutContext, container,
+                    actualBBox);
             if (overflowRenderer == null) {
                 return container;
             }
             if (additionalHeightPerIteration == null) {
                 LayoutResult overflowResult = overflowRenderer.layout(
                         new LayoutContext(new LayoutArea(1, new Rectangle(columnWidth, INF))));
-                additionalHeightPerIteration = overflowResult.getOccupiedArea().getBBox().getHeight() / MAX_RELAYOUT_COUNT;
+                additionalHeightPerIteration =
+                        overflowResult.getOccupiedArea().getBBox().getHeight() / MAX_RELAYOUT_COUNT;
             }
             if (Math.abs(additionalHeightPerIteration.floatValue()) <= ZERO_DELTA) {
                 return container;
@@ -119,10 +137,22 @@ private List<IRenderer> balanceContentAndLayoutColumns(LayoutContext prelayoutCo
         return container;
     }
 
+
     private LayoutArea calculateContainerOccupiedArea(LayoutContext layoutContext) {
         LayoutArea area = layoutContext.getArea().clone();
-        area.getBBox().setHeight(approximateHeight);
-        Rectangle initialBBox = layoutContext.getArea().getBBox();
+        float totalHeight = approximateHeight;
+
+        totalHeight += safelyRetrieveFloatProperty(Property.PADDING_BOTTOM);
+        totalHeight += safelyRetrieveFloatProperty(Property.PADDING_TOP);
+        totalHeight += safelyRetrieveFloatProperty(Property.MARGIN_BOTTOM);
+        totalHeight += safelyRetrieveFloatProperty(Property.MARGIN_TOP);
+        totalHeight += safelyRetrieveFloatProperty(Property.BORDER_BOTTOM);
+        totalHeight += safelyRetrieveFloatProperty(Property.BORDER_TOP);
+        final float TOP_AND_BOTTOM = 2;
+        totalHeight += safelyRetrieveFloatProperty(Property.BORDER) * TOP_AND_BOTTOM;
+
+        area.getBBox().setHeight(totalHeight);
+        final Rectangle initialBBox = layoutContext.getArea().getBBox();
         area.getBBox().setY(initialBBox.getY() + initialBBox.getHeight() - area.getBBox().getHeight());
         return area;
     }
@@ -134,16 +164,20 @@ private BlockRenderer getElementsRenderer() {
         return (BlockRenderer) getChildRenderers().get(0);
     }
 
-    private IRenderer layoutColumnsAndReturnOverflowRenderer(LayoutContext preLayoutContext, List<IRenderer> container) {
+    private IRenderer layoutColumnsAndReturnOverflowRenderer(LayoutContext preLayoutContext,
+            List<IRenderer> container, Rectangle actualBBox) {
         container.clear();
-        Rectangle initialBBox = preLayoutContext.getArea().getBBox();
+
+        final Rectangle initialBBox = actualBBox.clone();
         IRenderer renderer = elementRenderer;
         for (int i = 0; i < columnCount && renderer != null; i++) {
             LayoutArea tempArea = preLayoutContext.getArea().clone();
             tempArea.getBBox().setWidth(columnWidth);
             tempArea.getBBox().setHeight(approximateHeight);
             tempArea.getBBox().setX(initialBBox.getX() + columnWidth * i);
-            tempArea.getBBox().setY(initialBBox.getY() + initialBBox.getHeight() - tempArea.getBBox().getHeight());
+            tempArea.getBBox().setY(initialBBox.getY() + initialBBox.getHeight() - tempArea.getBBox()
+                    .getHeight());
+
             LayoutContext columnContext = new LayoutContext(tempArea, preLayoutContext.getMarginsCollapseInfo(),
                     preLayoutContext.getFloatRendererAreas(), preLayoutContext.isClippedHeight());
 

layout/src/test/java/com/itextpdf/layout/element/MulticolContainerTest.java

@@ -36,14 +36,13 @@ This file is part of the iText (R) project.
 import com.itextpdf.test.ExtendedITextTest;
 import com.itextpdf.test.annotations.type.IntegrationTest;
 
+import java.io.IOException;
 import java.util.function.Consumer;
 import org.junit.Assert;
 import org.junit.BeforeClass;
 import org.junit.Test;
 import org.junit.experimental.categories.Category;
 
-import java.io.IOException;
-
 @Category(IntegrationTest.class)
 public class MulticolContainerTest extends ExtendedITextTest {
     public static final String SOURCE_FOLDER = "./src/test/resources/com/itextpdf/layout/MulticolContainerTest/";
@@ -170,6 +169,45 @@ public void continuousColumContainerParagraphAll() throws IOException, Interrupt
         });
     }
 
+    @Test
+    public void continuousColumContainerParagraphAllChildStart() throws IOException, InterruptedException {
+        executeTest("continuousColumContainerParagraphAllChildStart", new MulticolContainer(), ctx -> {
+            ctx.setProperty(Property.COLUMN_COUNT, 3);
+            ctx.setBackgroundColor(DEFAULT_BACKGROUND_COLOR);
+            ctx.setBorder(DEFAULT_BORDER);
+            ctx.setMarginTop(DEFAULT_MARGIN);
+            ctx.setPaddingTop(DEFAULT_PADDING);
+            ctx.setMarginBottom(DEFAULT_MARGIN);
+            ctx.setPaddingBottom(DEFAULT_PADDING);
+            Paragraph paragraph = new Paragraph(generateLongString(300));
+            paragraph.setBorder(new SolidBorder(ColorConstants.RED, 2));
+            paragraph.setMarginTop(200);
+            paragraph.setPaddingTop(40);
+            paragraph.setBackgroundColor(ColorConstants.PINK);
+            ctx.add(paragraph);
+        });
+    }
+
+    @Test
+    public void continuousColumContainerParagraphAllChildEnd() throws IOException, InterruptedException {
+        executeTest("continuousColumContainerParagraphAllChildEnd", new MulticolContainer(), ctx -> {
+            ctx.setProperty(Property.COLUMN_COUNT, 3);
+            ctx.setBackgroundColor(DEFAULT_BACKGROUND_COLOR);
+            ctx.setBorder(DEFAULT_BORDER);
+            ctx.setMarginTop(DEFAULT_MARGIN);
+            ctx.setPaddingTop(DEFAULT_PADDING);
+            ctx.setMarginBottom(DEFAULT_MARGIN);
+            ctx.setPaddingBottom(DEFAULT_PADDING);
+            Paragraph paragraph = new Paragraph(generateLongString(300));
+            paragraph.setBorder(new SolidBorder(ColorConstants.RED, 2));
+            paragraph.setMarginBottom(200);
+            paragraph.setPaddingBottom(40);
+            paragraph.setBackgroundColor(ColorConstants.PINK);
+            ctx.add(paragraph);
+        });
+    }
+
+
     @Test
     public void continuousColumContainerParagraphOverflowShouldShow() throws IOException, InterruptedException {
         executeTest("continuousColumContainerParagraphOverflowShouldShow", new MulticolContainer(), ctx -> {