222 lines
9.6 KiB
Plaintext
222 lines
9.6 KiB
Plaintext
README
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^^^^^^
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This directory contains tiny graphics support for NuttX. The contents of this directory
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are only build if CONFIG_NX is defined in the NuttX configuration file.
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Contents
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^^^^^^^^
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Roadmap
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Related Header Files
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Directories
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Installing New Fonts
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Configuration Settings
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Roadmap
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^^^^^^^
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This directory holds NuttX graphic packages. Not all of these packages are implemented
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at the present, but here is the longer term roadmap:
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NxWidgets - NxWidgets is a higher level, C++, object-oriented library for object-
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oriented access to graphics "widgets." NxWidgets is provided as a separate
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package. NxWidgets is built on top of the core NuttX graphics subsystem,
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but is not a part of the core graphics subsystems.
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NXTOOLKIT - A set of C graphics tools that provide higher-level window drawing
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operations. The toolkit can be used for window-oriented graphics
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without NxWidgets and is built on top of NX.
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NXFONTS - A set of C graphics tools for presenting (bitmap) font images.
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NX - The tiny NuttX windowing system. This includes the small-footprint
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multi-user implementation (NXMU as described below). NX can be used
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without NxWidgets and without NXTOOLKIT for raw access to window memory.
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NXGLIB - Low level graphics utilities and direct framebuffer rendering logic.
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NX is built on top of NXGLIB.
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NxTerm - NxTerm is a write-only character device that is built on top of
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an NX window. This character device can be used to provide stdout
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and stderr and, hence, can provide the output side of NuttX console.
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Related Header Files
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^^^^^^^^^^^^^^^^^^^^
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include/nuttx/nx/nxglib.h -- Describes the NXGLIB C interfaces
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include/nuttx/nx/nx.h -- Describes the NX C interfaces
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include/nuttx/nx/nxtk.h -- Describe the NXTOOLKIT C interfaces
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include/nuttx/nx/nxfont.h -- Describe sthe NXFONT C interfaces
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Directories
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^^^^^^^^^^^
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The graphics capability consist both of components internal to the RTOS
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and of user-callable interfaces. In the NuttX kernel mode build there are
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some components of the graphics subsystem are callable in user mode and other
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components that are internal to the RTOS. This directory, nuttx/graphics,
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contains only those components that are internal to the RTOS.
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User callable functions must, instead, be part of a library that can be
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linked against user applications. This user callable interfaces are
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provided in sub-directories under nuttx/libs/libnx.
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libs/libnx/nx
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Client application callable interfaces.
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graphics/nxglib
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libs/libnx/nxglib
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The NuttX tiny graphics library. The directory contains generic utilities
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support operations on primitive graphics objects and logic to rasterize directly
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into a framebuffer. It has no concept of windows (other than the one, framebuffer
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window).
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graphics/nxbe
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This is the "back-end" of a tiny windowing system. It contains most
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of the important window management logic: clipping, window controls,
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window drawing, etc. Currently, the NXserver is the only "front-end"
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(Historically, there was a single user front-end, NXSU, but that front-
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end no longer exists).
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graphics/nxmu
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libs/libnx/nxmu
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This is the NX multi user "front end". When combined with the generic
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"back-end" (nxbe), it implements a multi-threaded, multi-user windowing
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system. The files in this directory present the window APIs described in
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include/nuttx/nx/nx.h. The multi-user front-end includes the NX graphics
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server that executes on its own thread; multiple graphics clients then
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communicate with the server via a POSIX message queue to serialize window
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operations from many threads. The multi-user front-end is selected
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automatically.
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libs/libnx/nxfonts
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This is where the NXFONTS implementation resides. This is a relatively low-
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level set of charset set/glyph management APIs. See include/nuttx/nx/nxfonts.h
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libs/libnx/nxtk
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This is where the NXTOOLKIT implementation resides. This toolkit is built on
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top of NX and works with either the single-user or multi-user NX version. See
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include/nuttx/nx/nxtk.h
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apps/grahpics/nxwidgets
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The NxWidgets code is provided as a separate package located outside of the
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NuttX source tree (probably at this location).
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Installing New Fonts
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^^^^^^^^^^^^^^^^^^^^
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[Refer to nuttx/libs/libnx/nxfonts/README.txt]
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Configuration Settings
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^^^^^^^^^^^^^^^^^^^^^^
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General NX Settings
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-------------------
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CONFIG_NX
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Enables overall support for graphics library and NX
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CONFIG_NX_NPLANES
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Some YUV color formats requires support for multiple planes, one for each
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color component. Unless you have such special hardware, this value should be
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undefined or set to 1.
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CONFIG_NX_WRITEONLY
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Define if the underlying graphics device does not support read operations.
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Automatically defined if CONFIG_NX_LCDDRIVER and CONFIG_LCD_NOGETRUN are
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defined.
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CONFIG_NX_DISABLE_1BPP, CONFIG_NX_DISABLE_2BPP,
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CONFIG_NX_DISABLE_4BPP, CONFIG_NX_DISABLE_8BPP,
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CONFIG_NX_DISABLE_16BPP, CONFIG_NX_DISABLE_24BPP, and
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CONFIG_NX_DISABLE_32BPP
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NX supports a variety of pixel depths. You can save some memory by disabling
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support for unused color depths.
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CONFIG_NX_PACKEDMSFIRST
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If a pixel depth of less than 8-bits is used, then NX needs to know if the
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pixels pack from the MS to LS or from LS to MS
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CONFIG_NX_XYINPUT
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Build in support for a X/Y positional input device such as a mouse or a
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touchscreen.
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CONFIG_NX_KBD
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Build in support of keypad/keyboard input.
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CONFIG_NXTK_BORDERWIDTH
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Specifies the width of the border (in pixels) used with framed windows.
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The default is 4.
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CONFIG_NXTK_BORDERCOLOR1, CONFIG_NXTK_BORDERCOLOR2, CONFIG_NXTK_BORDERCOLOR3
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Specify the colors of the border used with framed windows.
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CONFIG_NXTK_BORDERCOLOR2 is the shadow side color and so is normally darker.
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CONFIG_NXTK_BORDERCOLOR3 is the shiny side color and so is normally brighter.
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The default is mediumdark grey, and light grey, respectively
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CONFIG_NXTK_AUTORAISE
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If set, a window will be raised to the top if the mouse position is over a
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visible portion of the window. Default: A mouse button must be clicked over
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a visible portion of the window.
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CONFIG_VNCSERVER and CONFIG_VNCCLIENT
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Enable the VNC RFB server and client, respecitively.
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Font Selections
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---------------
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[Refer to nuttx/libs/libnx/nxfonts/README.txt]
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NxTerm Configuration Settings
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--------------------------------
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CONFIG_NXTERM
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Enables building of the NxTerm driver.
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NxTerm output text/graphics options:
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CONFIG_NXTERM_BPP
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Currently, NxTerm supports only a single pixel depth. This
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configuration setting must be provided to support that single pixel depth.
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Default: The smallest enabled pixel depth. (see CONFIG_NX_DISABLE_*BPP)
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CONFIG_NXTERM_CURSORCHAR
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The bitmap code to use as the cursor. Default '_'
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CONFIG_NXTERM_MXCHARS
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NxTerm needs to remember every character written to the console so
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that it can redraw the window. This setting determines the size of some
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internal memory allocations used to hold the character data. Default: 128.
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CONFIG_NXTERM_CACHESIZE
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NxTerm supports caching of rendered fonts. This font caching is required
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for two reasons: (1) First, it improves text performance, but more
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importantly (2) it preserves the font memory. Since the NX server runs on
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a separate server thread, it requires that the rendered font memory persist
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until the server has a chance to render the font. Unfortunately, the font
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cache would be quite large if all fonts were saved. The CONFIG_NXTERM_CACHESIZE
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setting will control the size of the font cache (in number of glyphs). Only that
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number of the most recently used glyphs will be retained. Default: 16.
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NOTE: There can still be a race condition between the NxTerm driver and the
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NX task. If you every see character corruption (especially when printing
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a lot of data or scrolling), then increasing the value of CONFIG_NXTERM_CACHESIZE
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is something that you should try. Alternatively, you can reduce the size of
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CONFIG_MQ_MAXMSGSIZE which will force NxTerm task to pace the server task.
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CONFIG_NXTERM_CACHESIZE should be larger than CONFIG_MQ_MAXMSGSIZE in any event.
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CONFIG_NXTERM_LINESEPARATION
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This the space (in rows) between each row of test. Default: 0
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CONFIG_NXTERM_NOWRAP
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By default, lines will wrap when the test reaches the right hand side
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of the window. This setting can be defining to change this behavior so
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that the text is simply truncated until a new line is encountered.
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NxTerm Input options
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CONFIG_NXTERM_NXKBDIN
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Take input from the NX keyboard input callback. By default, keyboard
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input is taken from stdin (/dev/console). If this option is set, then
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the interface nxterm_kdbin() is enabled. That interface may be driven
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by window callback functions so that keyboard input *only* goes to the
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top window.
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CONFIG_NXTERM_KBDBUFSIZE
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If CONFIG_NXTERM_NXKBDIN is enabled, then this value may be used to
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define the size of the per-window keyboard input buffer. Default: 16
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CONFIG_NXTERM_NPOLLWAITERS
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The number of threads that can be waiting for read data available.
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Default: 4
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NX Multi-user options
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---------------------
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CONFIG_NX_BLOCKING
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Open the client message queues in blocking mode. In this case,
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nx_eventhandler() will not return until a message is received and processed.
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CONFIG_NX_MXSERVERMSGS and CONFIG_NX_MXCLIENTMSGS
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Specifies the maximum number of messages that can fit in the message queues.
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No additional resources are allocated, but this can be set to prevent
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flooding of the client or server with too many messages (CONFIG_PREALLOC_MQ_MSGS
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controls how many messages are pre-allocated).
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