ApplicationSettings.RasterExportTransparencyColor Property (Visio)
Determines the transparency color that is applied to the exported image when you call the Export method of the Master, Page, Selection, or Shape object to export the specified object to a GIF or PNG file. Read/write.
expression An expression that returns an ApplicationSettings object.
Microsoft Visio ignores this setting if RasterExportUseTransparencyColor is False.
The value of the RasterExportTransparencyColor property must be a valid OLE_COLOR color. The default is RGB(255,255,255), which means that Visio applies a white transparency color on export.
For any given session of Microsoft Visio, when the RasterExportTransparencyColor property value is set, either programmatically or in the user interface, the setting then becomes the new default for the remainder of the session. However, it is not persisted to the next session.
The setting of the RasterExportTransparencyColor property corresponds to the transparency color selected in the GIF Output Options or PNG Output Options dialog box. (Click the File tab, click Save As, in the Save as type list, select Graphics Interchange Format (*.gif) or Portable Network Graphics (*.png), and then click Save.)