Busy Developers' Guide to HSSF FeaturesBusy Developers' Guide to Features
Want to use HSSF read and write spreadsheets in a hurry? This guide is for you. If you're after
more in-depth coverage of the HSSF user-API please consult the HOWTO
guide as it contains actual descriptions of how to use this stuff.
Index of Features
How to create a new workbook
How to create a sheet
How to create cells
How to create date cells
Working with different types of cells
Aligning cells
Working with borders
Fills and color
Merging cells
Working with fonts
Custom colors
Reading and writing
Use newlines in cells.
Create user defined data formats.
Fit Sheet to One Page
Set print area for a sheet.
Set page numbers on the footer of a sheet.
Shift rows.
Set a sheet as selected.
Set the zoom magnification for a sheet.
Create split and freeze panes.
Repeating rows and columns.
Headers and Footers.
Drawing Shapes.
Styling Shapes.
Shapes and Graphics2d.
Outlining.
FeaturesNew 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");
// Create a row and put some cells in it. Rows are 0 based.
HSSFRow row = sheet.createRow((short)0);
// Create a cell and put a value in it.
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");
// Create a row and put some cells in it. Rows are 0 based.
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
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.
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.
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...)
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.
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:
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.
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: