Common Question 36

How do I implement background bitmaps and/or gradients?

Within the demo, see examples 023, 024, and print example 127.

To enable background bitmaps and/or gradients, BitmapGradientMode must be set to TRUE and the DeskColor, GraphBackColor, or TableBackColor must be set to 1 (.NET Color.Empty).

Note: .NET Developers use Color.Empty in replace of setting a color to value 1.

Next, the following properties are used to describe the bitmaps and or gradients:

Graph and Scientific Graph Objects can use WorkingAxis to control the above properties on a per axis basis. This allows different bitmaps and/or gradients per axis.

Setting DeskColor, GraphBackColor, and TableBackColor to 1

Setting a background color to 1 (.NET Color.Empty) tells ProEssentials that the background is transparent. The background must be designated as transparent so that normal RGB color fills are disabled.

For example, you can set set DeskBmpFilename and DeskBmpStyle to apply a background bitmap to the desk area of the control. You would also normally set DeskColor to 1 (.NET: Color.Empty). However, you could also set GraphBackColor to 1 (.NET Color.Empty) which would cause the desk areas background bitmap to also show behind the charting/axis area. Thus, the entire controls background would show the desk areas bitmap.

Predefined Bitmaps and Gradients

The ProEssentials DLL has built-in bitmaps and predefined gradients which can be invoked with the QuickStyle property. Be sure to set BitmapGradientMode to TRUE before setting QuickStyle.

You can also utilize the predefined bitmaps by supplying the text "1700" through "1710" for any BMP filename. This loads the corresponding bitmap resource included within the DLL. These internal bitmaps are included as part of the QuickStyle mechanism but you may find them useful for your own unique purposes. These bitmaps are small and are designed to be tiled by setting DeskBmpStyle, GraphBmpStyle, and/or TableBmpStyle to PEBS_TILED_BITBLT.