Views User Guides > Foundation > Portability Limitations > Non-Supported or Limited Features
Non-Supported or Limited Features
The table below gives you a list of Views features that are either partially or not supported on certain systems.
Non-supported or Limited Features 
BitPlanes
Not Supported on Microsoft Windows.
Modal mode
Not supported on Windows.
Pattern size
Microsoft Windows patterns are limited in size. You can create larger patterns, but only the upper-left corner will define the final pattern.
Transparent patterns
On Microsoft Windows, transparent patterns are available only for Microsoft Windows predefined HATCHED brushes. This means that user-defined patterns and some Views predefined patterns cannot be transparent. The list of the Views patterns built on a predefined Microsoft Windows HATCHED pattern is: dialoglr, dialogrl, horiz, vert, cross. This limitation is not applicable when using GDI+, which supports all kind of transparent brushes.
Line style
The following pattern styles are not valid when drawing lines on Microsoft Win9x: dashdot, doubledot, and longdash; these all result in the dash style. Setting the line width to a value greater than 1 causes the line pattern to disappear.
Cursor size
On Microsoft Windows, the size of the cursor is fixed and depends on the driver. When bitmaps with bad sizes are given to the IlvCursor constructor, an error message is sent. Views provides the method IlvCursor::isBad for testing the success of the creation of a cursor.
Mouse buttons
Certain types of mouse have only two buttons. In this case, the events linked to the right button are set as IlvMiddleButton. This results from the fact that, historically, the first interactors used the IlvMiddleButton and almost never the IlvRightButton. You can modify this behavior using the UseRightButton application resource.
Windows icon
The icon associated with each of the views is the same for all the views of an application.
Transparency Anti-aliasing, Gradients
Available on Windows with GDI+ and on X Window systems with Cairo.
Mutable colors
Mutable colors may only be used with the pseudo color model. The pseudo color model is an arbitrary mapping of pixel to color that depends on the screen depth and is stored in a color map (UNIX Systems) or a palette (PCs). Mutable colors do not work on direct color or on true color models.
Window opacity
Not supported on UNIX platforms.
Zoomable labels
On Windows, IlvZoomableLabel objects are implemented using Windows scalable fonts (Type1, True Type, etc.). This gives a nice rendering output (possibly with anti-aliasing and translucency) even if the text is drawn using a linear transformation (zoom, rotation, etc.). However, depending on the transformation, the size of the font may not be very accurate. This limitation is due to the fact that the Microsoft Windows system is not able to give the real size of a font.
On Unix, the behavior of Zoomable labels depends on whether the use of Xft is enabled or disabled.
*When Xft is enabled, IlvZoomableLabel objects are using FreeType fonts through Xft. This allows you to draw text with anti-aliasing, translucency, and gives a clean rendering output when the text is transformed.
*When Xft is disabled, Views uses Xlib core fonts, with no anti-aliasing and no translucency. In this case, IlvZoomableLabel objects use bitmaps that can be zoomed, rotated, and so on. This technique may give poor results (pixelation effect) depending on the zooming factor.
Strings in XOR mode
This works on X Window. Since Microsoft Windows cannot draw strings in the Xor mode, Views draws an Xor dotted rectangle that has the same size as the text. To display a real string, display an Xor label using the methods IlvPort::drawString or IlvPort::drawIString.
Published date: 05/24/2022
Last modified date: 02/24/2022