Support collapsing margins for flex container

DEVSIX-5137

Author: Eugene Bochilo

src/main/java/com/itextpdf/html2pdf/attach/impl/DefaultHtmlProcessor.java

@@ -220,10 +220,6 @@ public List<com.itextpdf.layout.element.IElement> processElements(INode root) {
         for (IPropertyContainer propertyContainer : bodyDiv.getChildren()) {
             if (propertyContainer instanceof com.itextpdf.layout.element.IElement) {
                 setConvertedRootElementProperties(body.getStyles(), context, propertyContainer);
-                // TODO DEVSIX-5087 remove this when working on a ticket
-                if (((IElement) propertyContainer).getRenderer() instanceof FlexContainerRenderer) {
-                    propertyContainer.setProperty(Property.COLLAPSING_MARGINS, null);
-                }
                 elements.add((com.itextpdf.layout.element.IElement) propertyContainer);
             }
         }

src/main/java/com/itextpdf/html2pdf/css/apply/impl/DisplayFlexTagCssApplier.java

@@ -61,7 +61,6 @@ public void apply(ProcessorContext context, IStylesContainer stylesContainer, IT
         if (container != null) {
             FlexApplierUtil.applyFlexContainerProperties(stylesContainer.getStyles(), container);
             //TODO DEVSIX-5087 remove these lines when working on a ticket
-            container.setProperty(Property.COLLAPSING_MARGINS, null);
             container.deleteOwnProperty(Property.FLOAT);
             container.deleteOwnProperty(Property.CLEAR);
             container.deleteOwnProperty(Property.OVERFLOW_X);

src/main/java/com/itextpdf/html2pdf/css/apply/util/FlexApplierUtil.java

@@ -71,6 +71,7 @@ private FlexApplierUtil() {
      */
     public static void applyFlexItemProperties(Map<String, String> cssProps, ProcessorContext context,
             IPropertyContainer element) {
+        element.setProperty(Property.COLLAPSING_MARGINS, null);
         final String flexGrow = cssProps.get(CommonCssConstants.FLEX_GROW);
         if (flexGrow != null) {
             final Float flexGrowValue = CssDimensionParsingUtils.parseFloat(flexGrow);

src/test/java/com/itextpdf/html2pdf/css/DisplayFlexTest.java

@@ -27,6 +27,7 @@ This file is part of the iText (R) project.
 import com.itextpdf.html2pdf.HtmlConverter;
 import com.itextpdf.html2pdf.attach.impl.layout.HtmlPageBreak;
 import com.itextpdf.html2pdf.attach.impl.layout.form.element.TextArea;
+import com.itextpdf.io.LogMessageConstant;
 import com.itextpdf.layout.element.Div;
 import com.itextpdf.layout.element.IElement;
 import com.itextpdf.layout.element.Image;
@@ -35,6 +36,8 @@ This file is part of the iText (R) project.
 import com.itextpdf.layout.property.Property;
 import com.itextpdf.layout.property.UnitValue;
 import com.itextpdf.layout.renderer.FlexContainerRenderer;
+import com.itextpdf.test.annotations.LogMessage;
+import com.itextpdf.test.annotations.LogMessages;
 import com.itextpdf.test.annotations.type.IntegrationTest;
 
 import java.io.FileInputStream;
@@ -323,9 +326,6 @@ public void tempDisablePropertiesTest() throws IOException {
         Assert.assertFalse(elements.get(0).hasProperty(Property.OVERFLOW_Y));
         Assert.assertFalse(elements.get(0).hasProperty(Property.FLOAT));
         Assert.assertFalse(elements.get(0).hasProperty(Property.CLEAR));
-
-        Assert.assertTrue(elements.get(0).hasProperty(Property.COLLAPSING_MARGINS));
-        Assert.assertNull(elements.get(0).<Object>getProperty(Property.COLLAPSING_MARGINS));
     }
 
     @Test
@@ -362,7 +362,6 @@ public void flexItemPropertiesTest() throws IOException {
     }
 
     @Test
-    // TODO DEVSIX-5137	flex: support margin collapse
     public void flexGrowTest() throws IOException, InterruptedException {
         String name = "flexGrow";
         convertToPdfAndCompare(name, SOURCE_FOLDER, DESTINATION_FOLDER);
@@ -395,7 +394,6 @@ public void floatAtFlexItemNestedTest() throws IOException, InterruptedException
     }
 
     @Test
-    // TODO DEVSIX-5135 flex item with nested floating element processed incorrectly
     public void flexContainerHeightTest() throws IOException, InterruptedException {
         convertToPdfAndCompare("flexContainerHeight", SOURCE_FOLDER, DESTINATION_FOLDER);
     }
@@ -426,7 +424,6 @@ public void flexAlignItemsStretchTest() throws IOException, InterruptedException
     }
 
     @Test
-    // TODO DEVSIX-5137	flex: support margin collapse
     public void checkboxTest() throws IOException, InterruptedException {
         convertToPdfAndCompare("checkbox", SOURCE_FOLDER, DESTINATION_FOLDER);
     }
@@ -487,6 +484,39 @@ public void smallHeightAndBigMaxHeightOnContainerAnonymousFlexItemTest() throws
                 SOURCE_FOLDER, DESTINATION_FOLDER);
     }
 
+    @Test
+    public void marginsCollapseFlexContainerAndFlexItemStretchTest() throws IOException, InterruptedException {
+        convertToPdfAndCompare("marginsCollapseFlexContainerAndFlexItemStretch", SOURCE_FOLDER, DESTINATION_FOLDER);
+    }
+
+    @Test
+    public void marginsCollapseFlexContainerAndSiblingsTest() throws IOException, InterruptedException {
+        convertToPdfAndCompare("marginsCollapseFlexContainerAndSiblings", SOURCE_FOLDER, DESTINATION_FOLDER);
+    }
+
+
+    @Test
+    @LogMessages(messages = @LogMessage(messageTemplate = LogMessageConstant.CLIP_ELEMENT))
+    public void marginsCollapseFlexContainerAndParentTest() throws IOException, InterruptedException {
+        convertToPdfAndCompare("marginsCollapseFlexContainerAndParent", SOURCE_FOLDER, DESTINATION_FOLDER);
+    }
+
+    @Test
+    public void marginsCollapseInsideFlexContainerTest() throws IOException, InterruptedException {
+        convertToPdfAndCompare("marginsCollapseInsideFlexContainer", SOURCE_FOLDER, DESTINATION_FOLDER);
+    }
+
+    @Test
+    public void marginsCollapseFlexContainerAndItsChildTest() throws IOException, InterruptedException {
+        convertToPdfAndCompare("marginsCollapseFlexContainerAndItsChild", SOURCE_FOLDER, DESTINATION_FOLDER);
+    }
+
+    @Test
+    // TODO DEVSIX-5196 Support collapsing margins for flex item's children
+    public void marginsCollapseInsideFlexItemTest() throws IOException, InterruptedException {
+        convertToPdfAndCompare("marginsCollapseInsideFlexItem", SOURCE_FOLDER, DESTINATION_FOLDER);
+    }
+
     private static void assertDiv(IElement element, String text) {
         Assert.assertTrue(element instanceof Div);
         Assert.assertEquals(1, ((Div) element).getChildren().size());

src/test/java/com/itextpdf/html2pdf/css/w3c/css_flexbox/AlignItems001Test.java

@@ -24,7 +24,6 @@ This file is part of the iText (R) project.
 
 import com.itextpdf.html2pdf.css.w3c.W3CCssTest;
 
-//TODO DEVSIX-5137 support margin collapse
 public class AlignItems001Test extends W3CCssTest {
     @Override
     protected String getHtmlFileName() {

src/test/java/com/itextpdf/html2pdf/css/w3c/css_flexbox/AlignItems002Test.java

@@ -24,7 +24,6 @@ This file is part of the iText (R) project.
 
 import com.itextpdf.html2pdf.css.w3c.W3CCssTest;
 
-//TODO DEVSIX-5137 support margin collapse
 public class AlignItems002Test extends W3CCssTest {
     @Override
     protected String getHtmlFileName() {

src/test/java/com/itextpdf/html2pdf/css/w3c/css_flexbox/AlignItems003Test.java

@@ -24,7 +24,6 @@ This file is part of the iText (R) project.
 
 import com.itextpdf.html2pdf.css.w3c.W3CCssTest;
 
-//TODO DEVSIX-5137 support margin collapse
 public class AlignItems003Test extends W3CCssTest {
     @Override
     protected String getHtmlFileName() {

src/test/java/com/itextpdf/html2pdf/css/w3c/css_flexbox/AlignItems004Test.java

@@ -25,7 +25,6 @@ This file is part of the iText (R) project.
 import com.itextpdf.html2pdf.css.w3c.W3CCssTest;
 
 //TODO DEVSIX-5096 support flex-flow property
-//TODO DEVSIX-5137 support margin collapse
 public class AlignItems004Test extends W3CCssTest {
     @Override
     protected String getHtmlFileName() {

src/test/java/com/itextpdf/html2pdf/css/w3c/css_flexbox/AlignItems005Test.java

@@ -24,7 +24,6 @@ This file is part of the iText (R) project.
 
 import com.itextpdf.html2pdf.css.w3c.W3CCssTest;
 
-//TODO DEVSIX-5137 support margin collapse
 public class AlignItems005Test extends W3CCssTest {
     @Override
     protected String getHtmlFileName() {

src/test/java/com/itextpdf/html2pdf/css/w3c/css_flexbox/AlignItems006Test.java

@@ -25,7 +25,6 @@ This file is part of the iText (R) project.
 import com.itextpdf.html2pdf.css.w3c.W3CCssTest;
 
 //TODO DEVSIX-5096 support flex-direction: column
-//TODO DEVSIX-5137 support margin collapse
 public class AlignItems006Test extends W3CCssTest {
     @Override
     protected String getHtmlFileName() {