Consider min and max container's heights while processing line's cross size

DEVSIX-5178

Author: ars18wrw

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

@@ -102,8 +102,9 @@ public static List<List<FlexItemInfo>> calculateChildrenRectangles(Rectangle fle
             mainSize = layoutBox.getWidth();
         }
         // We need to have crossSize only if its value is definite.
-        // The calculation differs from width calculation because if width isn't definite, parent's width shall be taken
-        Float crossSize = flexContainerRenderer.retrieveMinHeight();
+        Float crossSize = flexContainerRenderer.retrieveHeight();
+        Float minCrossSize = flexContainerRenderer.retrieveMinHeight();
+        Float maxCrossSize = flexContainerRenderer.retrieveMaxHeight();
 
         determineFlexBasisAndHypotheticalMainSizeForFlexItems(flexItemCalculationInfos, (float) mainSize);
 
@@ -130,7 +131,8 @@ public static List<List<FlexItemInfo>> calculateChildrenRectangles(Rectangle fle
         determineHypotheticalCrossSizeForFlexItems(lines);
 
         // 8. Calculate the cross size of each flex line.
-        List<Float> lineCrossSizes = calculateCrossSizeOfEachFlexLine(lines, isSingleLine, crossSize);
+        List<Float> lineCrossSizes =
+                calculateCrossSizeOfEachFlexLine(lines, isSingleLine, minCrossSize, crossSize, maxCrossSize);
 
         // TODO DEVSIX-5003 min/max height calculations are not supported
         // If the flex container is single-line, then clamp the line’s cross-size to be within
@@ -409,7 +411,7 @@ static void determineHypotheticalCrossSizeForFlexItems(List<List<FlexItemCalcula
     }
 
     static List<Float> calculateCrossSizeOfEachFlexLine(List<List<FlexItemCalculationInfo>> lines,
-                                                        boolean isSingleLine, Float crossSize) {
+            boolean isSingleLine, Float minCrossSize, Float crossSize, Float maxCrossSize) {
         List<Float> lineCrossSizes = new ArrayList<>();
         if (isSingleLine && crossSize != null && !lines.isEmpty()) {
             lineCrossSizes.add((float) crossSize);
@@ -435,6 +437,17 @@ static List<Float> calculateCrossSizeOfEachFlexLine(List<List<FlexItemCalculatio
                     }
                     flexLinesCrossSize = Math.max(0, largestHypotheticalCrossSize);
                 }
+                
+                // 3. If the flex container is single-line, then clamp the line’s cross-size to be
+                // within the container’s computed min and max cross sizes
+                if (isSingleLine && !lines.isEmpty()) {
+                    if (null != minCrossSize) {
+                        flexLinesCrossSize = Math.max((float) minCrossSize, flexLinesCrossSize);
+                    }
+                    if (null != maxCrossSize) {
+                        flexLinesCrossSize = Math.min((float) maxCrossSize, flexLinesCrossSize);
+                    }
+                }
                 lineCrossSizes.add(flexLinesCrossSize);
             }
         }

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

@@ -31,16 +31,8 @@ This file is part of the iText (R) project.
 import com.itextpdf.layout.Document;
 import com.itextpdf.layout.Style;
 import com.itextpdf.layout.borders.SolidBorder;
-import com.itextpdf.layout.element.AreaBreak;
-import com.itextpdf.layout.element.Div;
-import com.itextpdf.layout.element.FlexContainer;
-import com.itextpdf.layout.element.IElement;
-import com.itextpdf.layout.element.Image;
-import com.itextpdf.layout.element.List;
-import com.itextpdf.layout.element.Paragraph;
-import com.itextpdf.layout.element.Table;
-import com.itextpdf.layout.property.Background;
 import com.itextpdf.layout.property.AlignmentPropertyValue;
+import com.itextpdf.layout.property.Background;
 import com.itextpdf.layout.property.JustifyContent;
 import com.itextpdf.layout.property.ListNumberingType;
 import com.itextpdf.layout.property.OverflowPropertyValue;
@@ -50,13 +42,15 @@ This file is part of the iText (R) project.
 import com.itextpdf.test.annotations.LogMessage;
 import com.itextpdf.test.annotations.LogMessages;
 import com.itextpdf.test.annotations.type.IntegrationTest;
+
+import java.io.IOException;
+import java.util.Arrays;
 import org.junit.Assert;
 import org.junit.BeforeClass;
 import org.junit.Test;
 import org.junit.experimental.categories.Category;
 import org.junit.runner.RunWith;
 import org.junit.runners.Parameterized;
-
 import java.io.IOException;
 import java.util.Arrays;
 
@@ -870,6 +864,69 @@ public void respectFlexContainersWidthTest() throws IOException, InterruptedExce
         Assert.assertNull(new CompareTool().compareByContent(outFileName, cmpFileName, destinationFolder, "diff"));
     }
 
+    @Test
+    public void flexItemsMinHeightShouldBeOverriddenTest() throws IOException, InterruptedException {
+        String outFileName = destinationFolder + "flexItemsMinHeightShouldBeOverriddenTest" + testNumber + ".pdf";
+        String cmpFileName = sourceFolder + "cmp_flexItemsMinHeightShouldBeOverriddenTest" + testNumber + ".pdf";
+        PdfDocument pdfDocument = new PdfDocument(new PdfWriter(outFileName));
+
+        Document document = new Document(pdfDocument);
+
+        Div flexContainer = createFlexContainer();
+
+        flexContainer.add(new Div().setWidth(100).setBackgroundColor(ColorConstants.BLUE).setHeight(100));
+        flexContainer.add(new Div().setWidth(100).setBackgroundColor(ColorConstants.YELLOW).setMinHeight(20));
+        document.add(flexContainer);
+
+        document.close();
+
+        Assert.assertNull(new CompareTool().compareByContent(outFileName, cmpFileName, destinationFolder, "diff"));
+    }
+
+    @Test
+    public void linesMinHeightShouldBeRespectedTest() throws IOException, InterruptedException {
+        String outFileName = destinationFolder + "linesMinHeightShouldBeRespectedTest" + testNumber + ".pdf";
+        String cmpFileName = sourceFolder + "cmp_linesMinHeightShouldBeRespectedTest" + testNumber + ".pdf";
+        PdfDocument pdfDocument = new PdfDocument(new PdfWriter(outFileName));
+
+        Document document = new Document(pdfDocument);
+
+        Div flexContainer = createFlexContainer();
+        flexContainer.setMinHeight(100);
+
+        Div child = new Div().setWidth(100).setBackgroundColor(ColorConstants.BLUE);
+        child.add(new Paragraph().setWidth(100).setBackgroundColor(ColorConstants.YELLOW));
+        flexContainer.add(child);
+
+        document.add(flexContainer);
+
+        document.close();
+
+        Assert.assertNull(new CompareTool().compareByContent(outFileName, cmpFileName, destinationFolder, "diff"));
+    }
+
+    @Test
+    public void linesMaxHeightShouldBeRespectedTest() throws IOException, InterruptedException {
+        String outFileName = destinationFolder + "linesMaxHeightShouldBeRespectedTest" + testNumber + ".pdf";
+        String cmpFileName = sourceFolder + "cmp_linesMaxHeightShouldBeRespectedTest" + testNumber + ".pdf";
+        PdfDocument pdfDocument = new PdfDocument(new PdfWriter(outFileName));
+
+        Document document = new Document(pdfDocument);
+
+        Div flexContainer = createFlexContainer();
+        flexContainer.setMaxHeight(100);
+
+        Div child = new Div().setWidth(100).setBackgroundColor(ColorConstants.BLUE).setHeight(150);
+        child.add(new Paragraph().setWidth(100).setBackgroundColor(ColorConstants.YELLOW));
+        flexContainer.add(child);
+
+        document.add(flexContainer);
+
+        document.close();
+
+        Assert.assertNull(new CompareTool().compareByContent(outFileName, cmpFileName, destinationFolder, "diff"));
+    }
+
     private Div getFlexContainer(OverflowPropertyValue overflowX, Style style) {
         FlexContainer flexContainer = createFlexContainer();
         flexContainer