Adding limited font style support

src/main/java/com/miraisolutions/xlconnect/CellStyle.java

@@ -49,4 +49,14 @@ public interface CellStyle {
     void setFillPattern(FillPatternType bg);
 
     void setWrapText(boolean wrap);
+
+    void setFontBold(boolean bold);
+
+    void setFontName(String name);
+
+    void setFontItalic(boolean italic);
+
+    void setFontSize(int size);
+
+    void setFontColor(short color, byte[] rgb);
 }

src/main/java/com/miraisolutions/xlconnect/DataFormatOnlyCellStyle.java

@@ -20,11 +20,12 @@
 
 package com.miraisolutions.xlconnect;
 
-import com.miraisolutions.xlconnect.data.DataType;
+import java.util.EnumMap;
+
 import org.apache.poi.ss.usermodel.BorderStyle;
 import org.apache.poi.ss.usermodel.FillPatternType;
 
-import java.util.EnumMap;
+import com.miraisolutions.xlconnect.data.DataType;
 
 /**
  * Marker cell style used to specify that a cell style
@@ -96,6 +97,30 @@ public void setWrapText(boolean wrap) {
         throw new UnsupportedOperationException();
     }
 
+    public void setFontBold(boolean bold) {
+        throw new UnsupportedOperationException();
+    }
+
+    public void setFontName(String name) {
+        throw new UnsupportedOperationException();
+    }
+
+    public void setFontItalic(boolean italic) {
+        throw new UnsupportedOperationException();
+    }
+
+    public void setFontUnderline(byte underlineType) {
+        throw new UnsupportedOperationException();
+    }
+
+    public void setFontSize(int size) {
+        throw new UnsupportedOperationException();
+    }
+
+    public void setFontColor(short color, byte[] rgb) {
+        throw new UnsupportedOperationException();
+    }
+
     public static DataFormatOnlyCellStyle get(DataType type) {
         DataFormatOnlyCellStyle cs;
         if (instances.containsKey(type))

src/main/java/com/miraisolutions/xlconnect/HCellStyle.java

@@ -90,6 +90,24 @@ public void setWrapText(boolean wrap) {
         cellStyle.setWrapText(wrap);
     }
 
+    public void setFontBold(boolean bold) {
+        throw new UnsupportedOperationException("Font operations are not supported in HCellStyle.");
+    }
+    public void setFontName(String name) {
+        throw new UnsupportedOperationException("Font operations are not supported for SSCellStyle.");
+    }
+
+    public void setFontItalic(boolean italic) {
+        throw new UnsupportedOperationException("Font operations are not supported for SSCellStyle.");
+    }
+
+    public void setFontSize(int size) {
+        throw new UnsupportedOperationException("Font operations are not supported for SSCellStyle.");
+    }
+    public void setFontColor(short color, byte[] rgb) {
+        throw new UnsupportedOperationException("Font color is not supported for HCellStyle.");
+    }
+
     public static HCellStyle create(HSSFWorkbook workbook, String name) {
         HSSFCellStyle cellStyle = workbook.createCellStyle();
         if (name != null) cellStyle.setUserStyleName(name);

src/main/java/com/miraisolutions/xlconnect/SSCellStyle.java

@@ -25,6 +25,7 @@
 import org.apache.poi.ss.usermodel.DataFormat;
 import org.apache.poi.ss.usermodel.FillPatternType;
 
+
 public final class SSCellStyle implements CellStyle {
 
     org.apache.poi.ss.usermodel.Workbook workbook;
@@ -91,4 +92,24 @@ public void setWrapText(boolean wrap) {
     public static void set(Cell c, SSCellStyle cs) {
         c.setCellStyle(cs.cellStyle);
     }
+
+    public void setFontBold(boolean bold) {
+        throw new UnsupportedOperationException("Font operations are not supported in HCellStyle.");
+    }
+
+    public void setFontName(String name) {
+        throw new UnsupportedOperationException("Font operations are not supported for SSCellStyle.");
+    }
+
+    public void setFontItalic(boolean italic) {
+        throw new UnsupportedOperationException("Font operations are not supported for SSCellStyle.");
+    }
+
+    public void setFontSize(int size) {
+        throw new UnsupportedOperationException("Font operations are not supported for SSCellStyle.");
+    }
+    public void setFontColor(short color, byte[] rgb) {
+        throw new UnsupportedOperationException("Font color is not supported for SSCellStyle.");
+    }
+
 }

src/main/java/com/miraisolutions/xlconnect/XCellStyle.java

@@ -24,11 +24,26 @@
 import org.apache.poi.ss.usermodel.DataFormat;
 import org.apache.poi.ss.usermodel.FillPatternType;
 import org.apache.poi.xssf.model.StylesTable;
-import org.apache.poi.xssf.usermodel.*;
+import org.apache.poi.xssf.usermodel.DefaultIndexedColorMap;
+import org.apache.poi.xssf.usermodel.IndexedColorMap;
+import org.apache.poi.xssf.usermodel.XSSFCell;
+import org.apache.poi.xssf.usermodel.XSSFCellStyle;
+import org.apache.poi.xssf.usermodel.XSSFColor;
+import org.apache.poi.xssf.usermodel.XSSFFont;
+import org.apache.poi.xssf.usermodel.XSSFWorkbook;
 import org.apache.poi.xssf.usermodel.extensions.XSSFCellAlignment;
 import org.apache.poi.xssf.usermodel.extensions.XSSFCellBorder;
 import org.apache.poi.xssf.usermodel.extensions.XSSFCellFill;
-import org.openxmlformats.schemas.spreadsheetml.x2006.main.*;
+import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTBorder;
+import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTBorderPr;
+import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTCellAlignment;
+import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTCellStyle;
+import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTCellStyles;
+import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTFill;
+import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTPatternFill;
+import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTXf;
+import org.openxmlformats.schemas.spreadsheetml.x2006.main.STBorderStyle;
+import org.openxmlformats.schemas.spreadsheetml.x2006.main.STPatternType;
 
 /**
  * This class uses parts from
@@ -311,6 +326,113 @@ public void setFillForegroundColor(short fg) {
         setFillForegroundColor(clr);
     }
 
+
+public void setFontBold(boolean bold) {
+    cloneAndModifyFont((font) -> font.setBold(bold));
+}
+
+public void setFontName(String name) {
+    cloneAndModifyFont((font) -> font.setFontName(name));
+}
+
+public void setFontItalic(boolean italic) {
+    cloneAndModifyFont((font) -> font.setItalic(italic));
+}
+
+public void setFontColor(short color, byte[] rgb) {
+    StylesTable stylesTable = workbook.getStylesSource();
+    CTXf xf = getXf();
+
+    // Store existing fill and border properties so we don't lose them
+    long oldFillId = xf.getFillId();
+    boolean oldApplyFill = xf.getApplyFill();
+    long oldBorderId = xf.getBorderId();
+    boolean oldApplyBorder = xf.getApplyBorder();
+    long oldNumFmtId = xf.getNumFmtId();
+    boolean oldApplyNumberFormat = xf.getApplyNumberFormat();
+
+    // Alignment and other properties could also be preserved if needed
+    CTCellAlignment oldAlignment = null;
+    if (xf.isSetAlignment()) {
+        oldAlignment = (CTCellAlignment) xf.getAlignment().copy();
+    }
+
+    int currentFontId = (int) xf.getFontId();
+    XSSFFont currentFont = workbook.getFontAt(currentFontId);
+
+    // Create a new font to isolate changes without affecting defaults
+    XSSFFont newFont = workbook.createFont();
+    copyFontProperties(currentFont, newFont);
+
+    // Apply custom color if RGB is given, otherwise use indexed color
+    if (rgb != null) {
+        XSSFColor customColor = new XSSFColor(rgb, stylesTable.getIndexedColors());
+        newFont.setColor(customColor);
+    } else {
+        newFont.setColor(color);
+    }
+
+    // Store the new font and update the style
+    int newFontIndex = stylesTable.putFont(newFont);
+    xf.setFontId(newFontIndex);
+    xf.setApplyFont(true);
+    getCoreXf().setFontId(newFontIndex);
+
+    // Restore the previously saved style attributes so they are not overwritten
+    xf.setFillId(oldFillId);
+    xf.setApplyFill(oldApplyFill);
+    xf.setBorderId(oldBorderId);
+    xf.setApplyBorder(oldApplyBorder);
+    xf.setNumFmtId(oldNumFmtId);
+    xf.setApplyNumberFormat(oldApplyNumberFormat);
+
+    if (oldAlignment != null) {
+        xf.setAlignment(oldAlignment);
+    }
+}
+
+public void setFontSize(int size) {
+    cloneAndModifyFont((font) -> font.setFontHeightInPoints((short) size));
+}
+
+private void cloneAndModifyFont(java.util.function.Consumer<XSSFFont> fontModifier) {
+    StylesTable stylesTable = workbook.getStylesSource();
+    int currentFontId = (int) getXf().getFontId();
+    XSSFFont oldFont = workbook.getFontAt(currentFontId);
+
+    // Create a brand new font to avoid modifying any existing shared font
+    XSSFFont newFont = workbook.createFont();
+
+    // Copy properties from the old font
+    copyFontProperties(oldFont, newFont);
+
+    // Apply the requested modification (bold, italic, name, color, size, etc.)
+    fontModifier.accept(newFont);
+
+    // Add the newly created font to the styles table and update the style
+    int newFontIndex = stylesTable.putFont(newFont);
+    CTXf xf = getXf();
+    xf.setFontId(newFontIndex);
+    xf.setApplyFont(true);
+    getCoreXf().setFontId(newFontIndex);
+}
+
+private void copyFontProperties(XSSFFont source, XSSFFont target) {
+    target.setFontName(source.getFontName());
+    target.setFontHeightInPoints(source.getFontHeightInPoints());
+    target.setBold(source.getBold());
+    target.setItalic(source.getItalic());
+    target.setUnderline(source.getUnderline());
+    target.setStrikeout(source.getStrikeout());
+
+    XSSFColor color = source.getXSSFColor();
+    if (color != null) {
+        target.setColor(color);
+    } else {
+        target.setColor(source.getColor());
+    }
+}
+
     public void setFillPattern(FillPatternType fp) {
         CTFill ct = getCTFill();
         CTPatternFill ptrn = ct.isSetPatternFill() ? ct.getPatternFill() : ct.addNewPatternFill();
@@ -373,6 +495,7 @@ public static XCellStyle create(XSSFWorkbook workbook, String name) {
 
         return new XCellStyle(workbook, xfSize - 1, styleXfSize - 1);
     }
+
 
     /**
      * Used for querying user-named cell styles (style xf only).

src/main/java/com/miraisolutions/xlconnect/integration/r/RCellStyleWrapper.java

@@ -20,10 +20,11 @@
 
 package com.miraisolutions.xlconnect.integration.r;
 
-import com.miraisolutions.xlconnect.CellStyle;
 import org.apache.poi.ss.usermodel.BorderStyle;
 import org.apache.poi.ss.usermodel.FillPatternType;
 
+import com.miraisolutions.xlconnect.CellStyle;
+
 public final class RCellStyleWrapper {
 
     final CellStyle cellStyle;
@@ -76,4 +77,23 @@ public void setFillPattern(int bg) {
     public void setWrapText(boolean wrap) {
         cellStyle.setWrapText(wrap);
     }
+
+    public void setFontBold(boolean bold) {
+        cellStyle.setFontBold(bold);
+    }
+
+    public void setFontName(String name) {
+        cellStyle.setFontName(name);
+    }
+
+    public void setFontItalic(boolean italic) {
+        cellStyle.setFontItalic(italic);
+    }
+
+    public void setFontSize(int size) {
+        cellStyle.setFontSize(size);
+    }
+    public void setFontColor(int indexedColor, byte[] rgb) {
+        cellStyle.setFontColor((short) indexedColor, rgb);
+    }
 }