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QNX Software Development Platform
QNX SDP is a cross-compiling and debugging environment, including an IDE and command-line tools, for building binary images and programs for target boards running the QNX OS 8.0.
Graphics
OpenWF Display Server User's Guide
The OpenWF Display Server (wfd-server) is a resource manager that provides applications the ability to show image buffers directly to the display controller via the OpenWF Display API.
Utilities and binaries
WFD server includes some utilities and binaries to help with calibration, debugging, and demonstrating features.
wfd-writeback
Write the contents of a port to memory

QNX Momentics IDE User's Guide
This User's Guide describes version 8.0 of the Integrated Development Environment (IDE) that's part of the QNX Tool Suite.
QNX Software Development Platform
QNX SDP is a cross-compiling and debugging environment, including an IDE and command-line tools, for building binary images and programs for target boards running the QNX OS 8.0.
- Quickstart Guide
- System Architecture
  The System Architecture guide accompanies the QNX OS and is intended for both application developers and end-users.
- OS Components & Operations
- Graphics
  - Gestures Library Reference
    The Gestures library provides gesture recognizers to detect gestures through touch events that occur when you place one or more fingers on a touch screen.
  - Image Library Reference
  - Input Events Library Reference
    The Input Events library provides the framework necessary for Screen Graphics Subsystem to communicate with your touch driver.
  - OpenWF Configuration Developer's Guide
    If you are integrating a new display, you must configure and provide the parameters of your display based on its specifications via the OpenWF Display Configuration API (Wfdcfg Library).
  - OpenWF Display Server User's Guide
    The OpenWF Display Server (wfd-server) is a resource manager that provides applications the ability to show image buffers directly to the display controller via the OpenWF Display API.
    - Before you begin
    - Introduction to the OpenWF Display Server
      The OpenWF Display Server (wfd-server) enables applications to show image buffers on the display without using Screen.
    - Configuring OpenWF Display Server
      You configure the OpenWF Display server from the wfd device 1 section of your graphics configuration (e.g., graphics.conf) file.
    - Starting wfd-server
      Screen and OpenWF Display Server share the same graphic configuration file. Ensure that Screen and its associated libraries, along with the libraries associated with the OpenWF Display Server are available on your target.
    - Utilities and binaries
      WFD server includes some utilities and binaries to help with calibration, debugging, and demonstrating features.
      - wfd-demo
        Initialize the display with a QNX logo
      - wfd-power-mode
        Set the power mode on a port
      - wfd-server-info
        Provide WFD system information
      - wfd-screenshot
        Write the contents of a port to memory and a bmp file
      - wfd-writeback
        Write the contents of a port to memory
    - wfdext.h
      QNX Extensions to OpenWF Display Specification.
  - Screen Graphics Subsystem Developer's Guide
    QNX Screen Graphics Subsystem is a graphics framework that provides all the functionality necessary to develop interactive user experiences.
  - Video Capture Developer's Guide
    The video capture framework provides applications the ability to capture frames from a video input source. These frames can be passed to a graphics component such as Screen for display.
- Programming
- System Security Guide
  The QNX System Security Guide is intended for both system integrators who are responsible for the security of a QNX OS system and developers who want to create a QNX OS resource manager free from vulnerabilities.
- Utilities & Libraries
- Migrating to QNX OS 8.0
QNX Software in the Cloud
QNX Software in the Cloud enables developers to use the QNX OS in the Amazon cloud environment.
QNX Toolkit for Visual Studio Code
This User's Guide describes the QNX^® Toolkit for Visual Studio Code. The guide introduces you to the QNX Toolkit by explaining the QNX development environment and how to build, run, and debug your QNX^® Operating System (OS) applications and systems.
QNX Hypervisor User's Guide
This User's Guide explains the QNX hypervisor architecture and provides instructions for installing and running a QNX Hypervisor system, changing system components and configuration, and using hypervisor features such as virtual devices (vdevs).
Typographical Conventions, Support, and Licensing
This section describes the typographical conventions used throughout the documentation, explains how to obtain technical support, and provides some information about licensing.

wfd-writeback

Write the contents of a port to memory

Syntax:

wfd-writeback   -ddevice_id -pport_id [options]
                [-ccount]
                [-frgba8888|rgbx8888|rgb888|rgb565|yvyu|uyvy|yuy2]
                [-hheight]
                [-ncount]
                [-q]
                [-ttimeout]
                [-wwidth]

Runs on:

QNX OS

Options:

-d device_id

Specify the device ID. Default is 2.

-p port_id

Specify the port ID. Default is 2.

-c count

Specify the number of writeback buffers to acquire. Default is 10.

-f rgba8888|rgbx8888|rgb888|rgb565|yvyu|uyvy|yuy2

Specify the writeback format. Choose from the following:

rgba8888
rgbx8888 (default)
rgb888
rgb565
yvyu
uyvy
yuy2

-h height

Specify the writeback source or destination's rectangular height. Default is 0.

-n count

Specify the number of writeback buffers. Default is 3.

-q

Run in quiet mode. Disables console logging of captured frames.

-t timeout

Specify the wait time in milliseconds to acquire an image. Where 0 is don't wait and -1 waits forever.

-w width

Specify the writeback source or destination's rectangular width. Default is 0.

Description

wfd-writeback uses the WFD server to writeback the contents of a port to memory. Ensure that writeback is supported by the WFD-driver and the writeback port enabled in the Screen configuration file.

Page updated: August 11, 2025