KAY

New Workbook
HSSFWorkbook wb = new HSSFWorkbook();
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
New Sheet
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet1 = wb.createSheet("new sheet");
HSSFSheet sheet2 = wb.createSheet("second sheet");
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
Creating Cells
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");

// 创造一个行并放一些单元格，行是从0开始的
HSSFRow row = sheet.createRow((short)0);
// 创造一个单元格并放入值
HSSFCell cell = row.createCell((short)0);
cell.setCellValue(1);

// Or do it on one line.
row.createCell((short)1).setCellValue(1.2);
row.createCell((short)2).setCellValue("This is a string");
row.createCell((short)3).setCellValue(true);

// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
Creating Date Cells
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");
HSSFRow row = sheet.createRow((short)0);

// Create a cell and put a date value in it. The first cell is not styled
// as a date.
HSSFCell cell = row.createCell((short)0);
cell.setCellValue(new Date());

// we style the second cell as a date (and time). It is important to
// create a new cell style from the workbook otherwise you can end up
// modifying the built in style and effecting not only this cell but other cells.
HSSFCellStyle cellStyle = wb.createCellStyle();
cellStyle.setDataFormat(HSSFDataFormat.getBuiltinFormat("m/d/yy h:mm"));
cell = row.createCell((short)1);
cell.setCellValue(new Date());
cell.setCellStyle(cellStyle);

// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
Working with different types of cells
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");
HSSFRow row = sheet.createRow((short)2);
row.createCell((short) 0).setCellValue(1.1);
row.createCell((short) 1).setCellValue(new Date());
row.createCell((short) 2).setCellValue("a string");
row.createCell((short) 3).setCellValue(true);
row.createCell((short) 4).setCellType(HSSFCell.CELL_TYPE_ERROR);

// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
Demonstrates various alignment options
public static void main(String[] args)
throws IOException
{
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");
HSSFRow row = sheet.createRow((short) 2);
createCell(wb, row, (short) 0, HSSFCellStyle.ALIGN_CENTER);
createCell(wb, row, (short) 1, HSSFCellStyle.ALIGN_CENTER_SELECTION);
createCell(wb, row, (short) 2, HSSFCellStyle.ALIGN_FILL);
createCell(wb, row, (short) 3, HSSFCellStyle.ALIGN_GENERAL);
createCell(wb, row, (short) 4, HSSFCellStyle.ALIGN_JUSTIFY);
createCell(wb, row, (short) 5, HSSFCellStyle.ALIGN_LEFT);
createCell(wb, row, (short) 6, HSSFCellStyle.ALIGN_RIGHT);

// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();

}

/**
* Creates a cell and aligns it a certain way.
*
* @param wb the workbook
* @param row the row to create the cell in
* @param column the column number to create the cell in
* @param align the alignment for the cell.
*/
private static void createCell(HSSFWorkbook wb, HSSFRow row, short column, short align)
{
HSSFCell cell = row.createCell(column);
cell.setCellValue("Align It");
HSSFCellStyle cellStyle = wb.createCellStyle();
cellStyle.setAlignment(align);
cell.setCellStyle(cellStyle);
}
Working with borders
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");

// Create a row and put some cells in it. Rows are 0 based.
HSSFRow row = sheet.createRow((short) 1);

// Create a cell and put a value in it.
HSSFCell cell = row.createCell((short) 1);
cell.setCellValue(4);

// Style the cell with borders all around.
HSSFCellStyle style = wb.createCellStyle();
style.setBorderBottom(HSSFCellStyle.BORDER_THIN);
style.setBottomBorderColor(HSSFColor.BLACK.index);
style.setBorderLeft(HSSFCellStyle.BORDER_THIN);
style.setLeftBorderColor(HSSFColor.GREEN.index);
style.setBorderRight(HSSFCellStyle.BORDER_THIN);
style.setRightBorderColor(HSSFColor.BLUE.index);
style.setBorderTop(HSSFCellStyle.BORDER_MEDIUM_DASHED);
style.setTopBorderColor(HSSFColor.BLACK.index);
cell.setCellStyle(style);

// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
Fills and colors
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");

// Create a row and put some cells in it. Rows are 0 based.
HSSFRow row = sheet.createRow((short) 1);

// Aqua background 浅绿色
HSSFCellStyle style = wb.createCellStyle();
style.setFillBackgroundColor(HSSFColor.AQUA.index);
style.setFillPattern(HSSFCellStyle.BIG_SPOTS);
HSSFCell cell = row.createCell((short) 1);
cell.setCellValue("X");
cell.setCellStyle(style);

// Orange "foreground", foreground being the fill foreground not the font color.
style = wb.createCellStyle();
style.setFillForegroundColor(HSSFColor.ORANGE.index);
style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
cell = row.createCell((short) 2);
cell.setCellValue("X");
cell.setCellStyle(style);

// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
Merging cells
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");

HSSFRow row = sheet.createRow((short) 1);
HSSFCell cell = row.createCell((short) 1);
cell.setCellValue("This is a test of merging");

sheet.addMergedRegion(new Region(1,(short)1,1,(short)2));

// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
Working with fonts
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");

// Create a row and put some cells in it. Rows are 0 based.
HSSFRow row = sheet.createRow((short) 1);

// Create a new font and alter it.
HSSFFont font = wb.createFont();
font.setFontHeightInPoints((short)24);
font.setFontName("Courier New");
font.setItalic(true);
font.setStrikeout(true);

// Fonts are set into a style so create a new one to use.
HSSFCellStyle style = wb.createCellStyle();
style.setFont(font);

// Create a cell and put a value in it.
HSSFCell cell = row.createCell((short) 1);
cell.setCellValue("This is a test of fonts");
cell.setCellStyle(style);

// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
Custom colors
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet();
HSSFRow row = sheet.createRow((short) 0);
HSSFCell cell = row.createCell((short) 0);
cell.setCellValue("Default Palette");

//apply some colors from the standard palette,
// as in the previous examples.
//we'll use red text on a lime background

HSSFCellStyle style = wb.createCellStyle();
style.setFillForegroundColor(HSSFColor.LIME.index);
style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);

HSSFFont font = wb.createFont();
font.setColor(HSSFColor.RED.index);
style.setFont(font);

cell.setCellStyle(style);

//save with the default palette
FileOutputStream out = new FileOutputStream("default_palette.xls");
wb.write(out);
out.close();

//now, let's replace RED and LIME in the palette
// with a more attractive combination
// (lovingly borrowed from freebsd.org)

cell.setCellValue("Modified Palette");

//creating a custom palette for the workbook
HSSFPalette palette = wb.getCustomPalette();

//replacing the standard red with freebsd.org red
palette.setColorAtIndex(HSSFColor.RED.index,
(byte) 153, //RGB red (0-255)
(byte) 0, //RGB green
(byte) 0 //RGB blue
);
//replacing lime with freebsd.org gold
palette.setColorAtIndex(HSSFColor.LIME.index, (byte) 255, (byte) 204, (byte) 102);

//save with the modified palette
// note that wherever we have previously used RED or LIME, the
// new colors magically appear
out = new FileOutputStream("modified_palette.xls");
wb.write(out);
out.close();
Reading and Rewriting Workbooks
POIFSFileSystem fs =
new POIFSFileSystem(new FileInputStream("workbook.xls"));
HSSFWorkbook wb = new HSSFWorkbook(fs);
HSSFSheet sheet = wb.getSheetAt(0);
HSSFRow row = sheet.getRow(2);
HSSFCell cell = row.getCell((short)3);
if (cell == null)
cell = row.createCell((short)3);
cell.setCellType(HSSFCell.CELL_TYPE_STRING);
cell.setCellValue("a test");

// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
Using newlines in cells
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet s = wb.createSheet();
HSSFRow r = null;
HSSFCell c = null;
HSSFCellStyle cs = wb.createCellStyle();
HSSFFont f = wb.createFont();
HSSFFont f2 = wb.createFont();

cs = wb.createCellStyle();

cs.setFont( f2 );
//Word Wrap MUST be turned on
cs.setWrapText( true );

r = s.createRow( (short) 2 );
r.setHeight( (short) 0x349 );
c = r.createCell( (short) 2 );
c.setCellType( HSSFCell.CELL_TYPE_STRING );
c.setCellValue( "Use \n with word wrap on to create a new line" );
c.setCellStyle( cs );
s.setColumnWidth( (short) 2, (short) ( ( 50 * 8 ) / ( (double) 1 / 20 ) ) );

FileOutputStream fileOut = new FileOutputStream( "workbook.xls" );
wb.write( fileOut );
fileOut.close();Data Formats
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("format sheet");
HSSFCellStyle style;
HSSFDataFormat format = wb.createDataFormat();
HSSFRow row;
HSSFCell cell;
short rowNum = 0;
short colNum = 0;

row = sheet.createRow(rowNum++);
cell = row.createCell(colNum);
cell.setCellValue(11111.25);
style = wb.createCellStyle();
style.setDataFormat(format.getFormat("0.0"));
cell.setCellStyle(style);

row = sheet.createRow(rowNum++);
cell = row.createCell(colNum);
cell.setCellValue(11111.25);
style = wb.createCellStyle();
style.setDataFormat(format.getFormat("#,##0.0000"));
cell.setCellStyle(style);

FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
Fit Sheet to One Page
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("format sheet");
HSSFPrintSetup ps = sheet.getPrintSetup();

sheet.setAutobreaks(true);

ps.setFitHeight((short)1);
ps.setFitWidth((short)1);

// Create various cells and rows for spreadsheet.

FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
Set Print Area
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("Sheet1");
wb.setPrintArea(0, "$A$1:$C$2");
//sets the print area for the first sheet
//Alternatively:
//wb.setPrintArea(0, 0, 1, 0, 0) is equivalent to using the name reference (See the JavaDocs for more details)

// Create various cells and rows for spreadsheet.

FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();


Set Page Numbers on Footer
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("format sheet");
HSSFFooter footer = sheet.getFooter()

footer.setRight( "Page " + HSSFFooter.page() + " of " + HSSFFooter.numPages() );

// Create various cells and rows for spreadsheet.

FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
Using the Convenience Functions
The convenience functions live in contrib and provide utility features such as setting borders around merged regions and changing style attributes without explicitly creating new styles.

HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet1 = wb.createSheet( "new sheet" );

// Create a merged region
HSSFRow row = sheet1.createRow( (short) 1 );
HSSFRow row2 = sheet1.createRow( (short) 2 );
HSSFCell cell = row.createCell( (short) 1 );
cell.setCellValue( "This is a test of merging" );
Region region = new Region( 1, (short) 1, 4, (short) 4 );
sheet1.addMergedRegion( region );

// Set the border and border colors.
final short borderMediumDashed = HSSFCellStyle.BORDER_MEDIUM_DASHED;
HSSFRegionUtil.setBorderBottom( borderMediumDashed,
region, sheet1, wb );
HSSFRegionUtil.setBorderTop( borderMediumDashed,
region, sheet1, wb );
HSSFRegionUtil.setBorderLeft( borderMediumDashed,
region, sheet1, wb );
HSSFRegionUtil.setBorderRight( borderMediumDashed,
region, sheet1, wb );
HSSFRegionUtil.setBottomBorderColor(HSSFColor.AQUA.index, region, sheet1, wb);
HSSFRegionUtil.setTopBorderColor(HSSFColor.AQUA.index, region, sheet1, wb);
HSSFRegionUtil.setLeftBorderColor(HSSFColor.AQUA.index, region, sheet1, wb);
HSSFRegionUtil.setRightBorderColor(HSSFColor.AQUA.index, region, sheet1, wb);

// Shows some usages of HSSFCellUtil
HSSFCellStyle style = wb.createCellStyle();
style.setIndention((short)4);
HSSFCellUtil.createCell(row, 8, "This is the value of the cell", style);
HSSFCell cell2 = HSSFCellUtil.createCell( row2, 8, "This is the value of the cell");
HSSFCellUtil.setAlignment(cell2, wb, HSSFCellStyle.ALIGN_CENTER);

// Write out the workbook
FileOutputStream fileOut = new FileOutputStream( "workbook.xls" );
wb.write( fileOut );
fileOut.close();
Shift rows up or down on a sheet
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("row sheet");

// Create various cells and rows for spreadsheet.

// Shift rows 6 - 11 on the spreadsheet to the top (rows 0 - 5)
sheet.shiftRows(5, 10, -5);

FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
Set a sheet as selected
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("row sheet");
sheet.setSelected(true);

// Create various cells and rows for spreadsheet.

FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
Set the zoom magnification
The zoom is expressed as a fraction. For example to express a zoom of 75% use 3 for the numerator and 4 for the denominator.

HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet1 = wb.createSheet("new sheet");
sheet1.setZoom(3,4); // 75 percent magnification
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
Splits and freeze panes
There are two types of panes you can create; freeze panes and split panes.

A freeze pane is split by columns and rows. You create a freeze pane using the following mechanism:

sheet1.createFreezePane( 3, 2, 3, 2 );

The first two parameters are the columns and rows you wish to split by. The second two parameters indicate the cells that are visible in the bottom right quadrant.

Split pains appear differently. The split area is divided into four separate work area's. The split occurs at the pixel level and the user is able to adjust the split by dragging it to a new position.

Split panes are created with the following call:

sheet2.createSplitPane( 2000, 2000, 0, 0, HSSFSheet.PANE_LOWER_LEFT );

The first parameter is the x position of the split. This is in 1/20th of a point. A point in this case seems to equate to a pixel. The second parameter is the y position of the split. Again in 1/20th of a point.

The last parameter indicates which pane currently has the focus. This will be one of HSSFSheet.PANE_LOWER_LEFT, PANE_LOWER_RIGHT, PANE_UPPER_RIGHT or PANE_UPPER_LEFT.

HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet1 = wb.createSheet("new sheet");
HSSFSheet sheet2 = wb.createSheet("second sheet");
HSSFSheet sheet3 = wb.createSheet("third sheet");
HSSFSheet sheet4 = wb.createSheet("fourth sheet");

// Freeze just one row
sheet1.createFreezePane( 0, 1, 0, 1 );
// Freeze just one column
sheet2.createFreezePane( 1, 0, 1, 0 );
// Freeze the columns and rows (forget about scrolling position of the lower right quadrant).
sheet3.createFreezePane( 2, 2 );
// Create a split with the lower left side being the active quadrant
sheet4.createSplitPane( 2000, 2000, 0, 0, HSSFSheet.PANE_LOWER_LEFT );

FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
Repeating rows and columns
It's possible to set up repeating rows and columns in your printouts by using the setRepeatingRowsAndColumns() function in the HSSFWorkbook class.

This function Contains 5 parameters. The first parameter is the index to the sheet (0 = first sheet). The second and third parameters specify the range for the columns to repreat. To stop the columns from repeating pass in -1 as the start and end column. The fourth and fifth parameters specify the range for the rows to repeat. To stop the columns from repeating pass in -1 as the start and end rows.

HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet1 = wb.createSheet("new sheet");
HSSFSheet sheet2 = wb.createSheet("second sheet");

// Set the columns to repeat from column 0 to 2 on the first sheet
wb.setRepeatingRowsAndColumns(0,0,2,-1,-1);
// Set the the repeating rows and columns on the second sheet.
wb.setRepeatingRowsAndColumns(1,4,5,1,2);

FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
Headers and Footers
Example is for headers but applies directly to footers.

HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");

HSSFHeader header = sheet.getHeader();
header.setCenter("Center Header");
header.setLeft("Left Header");
header.setRight(HSSFHeader.font("Stencil-Normal", "Italic") +
HSSFHeader.fontSize((short) 16) + "Right w/ Stencil-Normal Italic font and size 16");

FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
Drawing Shapes
POI supports drawing shapes using the Microsoft Office drawing tools. Shapes on a sheet are organized in a hiearchy of groups and and shapes. The top-most shape is the patriarch. This is not visisble on the sheet at all. To start drawing you need to call createPatriarch on the HSSFSheet class. This has the effect erasing any other shape information stored in that sheet. By default POI will leave shape records alone in the sheet unless you make a call to this method.

To create a shape you have to go through the following steps:

Create the patriarch.
Create an anchor to position the shape on the sheet.
Ask the patriarch to create the shape.
Set the shape type (line, oval, rectangle etc...)
Set any other style details converning the shape. (eg: line thickness, etc...)
HSSFPatriarch patriarch = sheet.createDrawingPatriarch();
a = new HSSFClientAnchor( 0, 0, 1023, 255, (short) 1, 0, (short) 1, 0 );
HSSFSimpleShape shape1 = patriarch.createSimpleShape(a1);
shape1.setShapeType(HSSFSimpleShape.OBJECT_TYPE_LINE);
Text boxes are created using a different call:

HSSFTextbox textbox1 = patriarch.createTextbox(
new HSSFClientAnchor(0,0,0,0,(short)1,1,(short)2,2));
textbox1.setString(new HSSFRichTextString("This is a test") );
It's possible to use different fonts to style parts of the text in the textbox. Here's how:

HSSFFont font = wb.createFont();
font.setItalic(true);
font.setUnderline(HSSFFont.U_DOUBLE);
HSSFRichTextString string = new HSSFRichTextString("Woo!!!");
string.applyFont(2,5,font);
textbox.setString(string );
Just as can be done manually using Excel, it is possible to group shapes together. This is done by calling createGroup() and then creating the shapes using those groups.

It's also possible to create groups within groups.

Warning
Any group you create should contain at least two other shapes or subgroups.
Here's how to create a shape group:

// Create a shape group.
HSSFShapeGroup group = patriarch.createGroup(
new HSSFClientAnchor(0,0,900,200,(short)2,2,(short)2,2));

// Create a couple of lines in the group.
HSSFSimpleShape shape1 = group.createShape(new HSSFChildAnchor(3,3,500,500));
shape1.setShapeType(HSSFSimpleShape.OBJECT_TYPE_LINE);
( (HSSFChildAnchor) shape1.getAnchor() ).setAnchor((short)3,3,500,500);
HSSFSimpleShape shape2 = group.createShape(new HSSFChildAnchor((short)1,200,400,600));
shape2.setShapeType(HSSFSimpleShape.OBJECT_TYPE_LINE);
If you're being observant you'll noticed that the shapes that are added to the group use a new type of anchor: the HSSFChildAnchor. What happens is that the created group has it's own coordinate space for shapes that are placed into it. POI defaults this to (0,0,1023,255) but you are able to change it as desired. Here's how:

myGroup.setCoordinates(10,10,20,20); // top-left, bottom-right
If you create a group within a group it's also going to have it's own coordinate space.

Styling Shapes
By default shapes can look a little plain. It's possible to apply different styles to the shapes however. The sorts of things that can currently be done are:

Change the fill color.
Make a shape with no fill color.
Change the thickness of the lines.
Change the style of the lines. Eg: dashed, dotted.
Change the line color.
Here's an examples of how this is done:

HSSFSimpleShape s = patriarch.createSimpleShape(a);
s.setShapeType(HSSFSimpleShape.OBJECT_TYPE_OVAL);
s.setLineStyleColor(10,10,10);
s.setFillColor(90,10,200);
s.setLineWidth(HSSFShape.LINEWIDTH_ONE_PT * 3);
s.setLineStyle(HSSFShape.LINESTYLE_DOTSYS);
Shapes and Graphics2d
While the native POI shape drawing commands are the recommended way to draw shapes in a shape it's sometimes desirable to use a standard API for compatibility with external libraries. With this in mind we created some wrappers for Graphics and Graphics2d.

Warning
It's important to not however before continuing that Graphics2d is a poor match to the capabilities of the Microsoft Office drawing commands. The older Graphics class offers a closer match but is still a square peg in a round hole.
All Graphics commands are issued into an HSSFShapeGroup. Here's how it's done:

a = new HSSFClientAnchor( 0, 0, 1023, 255, (short) 1, 0, (short) 1, 0 );
group = patriarch.createGroup( a );
group.setCoordinates( 0, 0, 80 * 4 , 12 * 23 );
float verticalPointsPerPixel = a.getAnchorHeightInPoints(sheet) / (float)Math.abs(group.getY2() - group.getY1());
g = new EscherGraphics( group, wb, Color.black, verticalPointsPerPixel );
g2d = new EscherGraphics2d( g );
drawChemicalStructure( g2d );
The first thing we do is create the group and set it's coordinates to match what we plan to draw. Next we calculate a reasonable fontSizeMultipler then create the EscherGraphics object. Since what we really want is a Graphics2d object we create an EscherGraphics2d object and pass in the graphics object we created. Finally we call a routine that draws into the EscherGraphics2d object.

The vertical points per pixel deserves some more explanation. One of the difficulties in converting Graphics calls into escher drawing calls is that Excel does not have the concept of absolute pixel positions. It measures it's cell widths in 'characters' and the cell heights in points. Unfortunately it's not defined exactly what type of character it's measuring. Presumably this is due to the fact that the Excel will be using different fonts on different platforms or even within the same platform.

Because of this constraint we've had to implement the concept of a verticalPointsPerPixel. This the amount the font should be scaled by when you issue commands such as drawString(). To calculate this value use the follow formula:

multipler = groupHeightInPoints / heightOfGroup
The height of the group is calculated fairly simply by calculating the difference between the y coordinates of the bounding box of the shape. The height of the group can be calculated by using a convenience called HSSFClientAnchor.getAnchorHeightInPoints().

Many of the functions supported by the graphics classes are not complete. Here's some of the functions that are known to work.

fillRect()
fillOval()
drawString()
drawOval()
drawLine()
clearRect()
Functions that are not supported will return and log a message using the POI logging infrastructure (disabled by default).

Outlining
Outlines are great for grouping sections of information together and can be added easily to columns and rows using the POI API. Here's how:

HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet1 = wb.createSheet("new sheet");

sheet1.groupRow( 5, 14 );
sheet1.groupRow( 7, 14 );
sheet1.groupRow( 16, 19 );

sheet1.groupColumn( (short)4, (short)7 );
sheet1.groupColumn( (short)9, (short)12 );
sheet1.groupColumn( (short)10, (short)11 );

FileOutputStream fileOut = new FileOutputStream(filename);
wb.write(fileOut);
fileOut.close();
To collapse (or expand) an outline use the following calls:

sheet1.setRowGroupCollapsed( 7, true );
sheet1.setColumnGroupCollapsed( (short)4, true );
The row/column you choose should contain an already created group. It can be anywhere within the group.

Images
Images are part of the drawing support. To add an image just call createPicture() on the drawing patriarch. At the time of writing the following types are supported:

PNG
JPG
DIB
It is not currently possible to read existing images and it should be noted that any existing drawings may be erased once you add a image to a sheet.

// Create the drawing patriarch. This is the top level container for
// all shapes. This will clear out any existing shapes for that sheet.
HSSFPatriarch patriarch = sheet5.createDrawingPatriarch();

HSSFClientAnchor anchor;
anchor = new HSSFClientAnchor(0,0,0,255,(short)2,2,(short)4,7);
anchor.setAnchorType( 2 );
patriarch.createPicture(anchor, loadPicture( "src/resources/logos/logoKarmokar4.png", wb ));