- Screen

Compensation for X Window client and server bugs
Common resources and capabilities

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# Screen

The statement

    screen name

declares a screen, where name is an arbitrary string.

A screen is totally controlled by the XposeXrecord proxy as are the other screens of the X Window server. X Window clients must connect through the proxy only. Thus, the proxy takes over total control of the X Window server.

If there are no screens defined, the xposexrecord program tries to control the screen with the display name :1.0. All screens must belong to the same X Window server (the related product XmetaX removes this restriction). If two or more screens have to be controlled, they must be configured explicitly.

The screen statement introduces sub-statements, which specify additional parameters of the screen.

The sub-statement

        display display_name

specifies the display, on which the screen has to be displayed. The display_name is formatted as usual with X11:

    [protocol/][hostname]:display_number[.screen_number]

If the protocol is not specified, the XposeXrecord proxy chooses the fastest available transport mechanism. The default value is the name of the screen.

## Common resources and capabilities

The sub-statement

        visuals
            {[+|-][class][:[depth]
            [:[number_of_significant_bits]
            [:[layer][:[transparency_type][:[transparency_value]
            [:[singleBuffered|doubleBuffered|singleOnDoubleBuffered]
            ]]]]]]}...

is used in special cases only (Common resources and capabilities). It specifies for each screen a list (Lists) of visuals presented to the X Window clients.

The sub-statement contains one or more visual specifiers. If a specifier does not fully qualify a visual (i.e. it contains one or more empty fields between the colons :) the specifier may denote multiple visuals. The individual fields specify in this order:

The class of the visual: StaticGray, GrayScale, StaticColor, PseudoColor, TrueColor, or DirectColor;

The color depth;

The number of significant bits in color specifications;

The number of the layer associated with the visual;

The kind of transparency of an overlay visual;

A value, the meaning of which depends on the kind of transparency;

The number of buffers associated with each window:

With a singleBuffered visual, all drawings go directly to the window.

With a doubleBuffered visual, drawings go mutually to one of two buffers, only one buffer is displayed.

With singleOnDoubleBuffered the XmetaX proxy simulates a single-buffered visual on a double-buffered visual.

The fields specifying layer and transparency are ignored unless the X Window server follows the SERVER_OVERLAY_VISUALS convention.

The sub-statement

        defaultVisual
            [class][:[depth]
            [:[number_of_significant_bits]
            [:[layer][:[transparency_type][:[transparency_value]
            [:[singleBuffered|doubleBuffered|singleOnDoubleBuffered]
            ]]]]]]

denotes the default visual and thus the default color model of the screen.

## GLXplus

The sub-statement

        glxPlus [on|off]

enables or disables (default) the GLXplus functionality for OpenGL hardware acceleration (Option GLXplus: Tunneling OpenGL through GLX) and introduces sub-sub-statements which further configure the option.

The sub-sub-statement

            libraryPath file_name[{:file_name}...]

specifies how to find the OpenGL library to be used. A library can be specified as a fully qualified path to a file, a fully qualified path to search for a matching library, or a file to search for in the default library search path. The first valid library found will be used. The default value of GL searches in the default library search path for a library with a name containing the string GL.

X Window clients using OpenGL have to be started through the glxPlus script.

## Pointer image zoom

The sub-statement

        pointerZoom factor

defines an integer zoom factor for all pointer images of a screen. The smoothing algorithm works best with a power of two as factor. The default value is 1. Some X Window servers clip or even distort large cursor images.

## Emulation of visuals

The option VisEmu (Options) emulates PseudoColor visuals of depths 4 and 8 on a 24 bits deep TrueColor visual. Thus it is possible to display X Window clients designed for older graphics systems of lower depths on modern hardware often supporting 24 bits depth only.

The sub-statement

      emulateVisual {PseudoColor4|PseudoColor8|none}...

enables a specific emulation or totally disables the emulation (default).

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Compensation for X Window client and server bugs
Common resources and capabilities

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2009-07-30 14:44:05 +0200