Colors and Background Patterns
Microsoft Excel can set the foreground (outline) and background (fill) colors of cells and background patterns.
Aspose.Cells also supports these features in a flexible manner. In this topic, we learn to use these features using Aspose.Cells.
Setting Colors and Background Patterns
Aspose.Cells provides a class, Workbook that represents a Microsoft Excel file. The Workbook class contains a Worksheets collection that allows access to each worksheet in the Excel file. A worksheet is represented by the Worksheet class. The Worksheet class provides a Cells collection. Each item in the Cells collection represents an object of the Cell class.
The Cell has the GetStyle and SetStyle methods that are used to get and set a cell’s formatting. The Style class provides properties for setting the foreground and background colors of the cells. Aspose.Cells provides a BackgroundType enumeration that contains a set of pre-defined types of background patterns which are given below.
|DiagonalCrosshatch||Represents diagonal crosshatch pattern|
|DiagonalStripe||Represents diagonal stripe pattern|
|Gray6||Represents 6.25% gray pattern|
|Gray12||Represents 12.5% gray pattern|
|Gray25||Represents 25% gray pattern|
|Gray50||Represents 50% gray pattern|
|Gray75||Represents 75% gray pattern|
|HorizontalStripe||Represents horizontal stripe pattern|
|None||Represents no background|
|ReverseDiagonalStripe||Represents reverse diagonal stripe pattern|
|Solid||Represents solid pattern|
|ThickDiagonalCrosshatch||Represents thick diagonal crosshatch pattern|
|ThinDiagonalCrosshatch||Represents thin diagonal crosshatch pattern|
|ThinDiagonalStripe||Represents thin diagonal stripe pattern|
|ThinHorizontalCrosshatch||Represents thin horizontal crosshatch pattern|
|ThinHorizontalStripe||Represents thin horizontal stripe pattern|
|ThinReverseDiagonalStripe||Represents thin reverse diagonal stripe pattern|
|ThinVerticalStripe||Represents thin vertical stripe pattern|
|VerticalStripe||Represents vertical stripe pattern|
In the example below, the foreground color of the A1 cell is set but A2 is configured to have both foreground and background colors with a vertical stripe background pattern.
Important to Know
- To set a cell’s foreground or background color, use the Style object’s ForegroundColor or BackgroundColor properties. Both properties will take effect only if the Style object’s Pattern property is configured.
- The ForegroundColor property sets the cell’s shade color. The Pattern property specifies the type of background pattern used for the foreground or background color. Aspose.Cells provides an enumeration, BackgroundType. that contains a set of pre-defined types of background patterns.
- If you select BackgroundType.None value from the BackgroundType enumeration, the foreground color is not applied. Likewise, the background color is not applied if you select the BackgroundType.None or BackgroundType.Solid values.
- When retrieving cell’s shading/fill color, if Style.Pattern is BackgroundType.None, Style.ForegroundColor will return Color.Empty.
Applying Gradient Fill Effects
Colors and Palette
A palette is the number of colors available for use in creating an image. The use of a standardized palette in a presentation allows the user to create a consistent look. Each Microsoft Excel (97-2003) file has a palette of 56 colors that can be applied to cells, fonts, gridlines, graphic objects, fills and lines in a chart.
With Aspose.Cells it is possible not only to use the palette’s existing colors but also custom colors. Before using a custom color, add it to the palette first.
This topic discusses how to add custom colors to the palette.
Adding Custom Colors to Palette
Aspose.Cells supports Microsoft Excel’s 56 color palette. To use a custom color that is not defined in the palette, add the color to the palette.
Aspose.Cells provides a class, Workbook, that represents a Microsoft Excel file. The Workbook class provides a ChangePalette method that takes the following parameters to add a custom color to modify the palette:
- Custom Color, the custom color to be added.
- Index, the index of the color in the palette that the custom color will replace. Should be between 0-55.
The example below adds a custom color (Orchid) to the palette before applying it on a font.