sw-vsync

Graphics and Screen4.0 (8.x)Screen Graphics Subsystem Developer's GuideAPIProgrammingUtilities

Display software-rasterized content

Syntax:

sw-vsync   [-bg_rbga=background_color]
           [-display=display_id]
           [-format=pixel_format]
           [-frame-limit=frames]
           [-grid]
           [-interval=swap_interval]
           [-nbuffers=count]
           [-pipeline=pipeline]
           [-pos=x,y]
           [-size=widthxheight]
           [-transparency=transparency_mode]
           [-zorder=zorder]

Runs on:

QNX OS

Options:

-bg_rbga=background_color

Set the color and alpha compenent specified by background_color as the background color for the window. The color and alpha component are set using a comma-separated list of integers that consists of the red, green, and blue values of the color, followed by the alpha component. For example, use this string: 0xff,0xff,0x0,0xff, to set the background to yellow and opaque (which is the default).

-display=display_id

Specify which display the window will appear on by using display_id. You can specify display_id as one of the following:

an integer that identifies the display
an ID string that identifies the name of the display (id_string)

Whether by integer or by string, the display that you specify using display_id must be one of the displays that you've configured in the display subsections of the winmgr section in your configuration file (e.g., graphics.conf).

If you don't have any display subsections configured, or if you don't specify the display option, then sw-vsync uses the default display.

-format=pixel_format

Set the pixel format, as a string, of the window (default is the pixel format assigned by Screen Graphics Subsystem). The pixel format can be one of the following strings:

rgba8888
rgbx8888
rgba5551
rgbx5551
rgb565

-frame-limit=frames

Limit the number of frames rendered to the value specified by frame_limit (integer). By default, sw-vsync assumes an unlimited number of frames.

-grid

Display grid lines (40 x 40 pixel).

-interval=swap_interval

Set the swap interval, as an integer (default is 1). The swap interval is the minimum number of vsync periods between image updates.

-nbuffers=count

Set the number of window buffers to be created for rendering. The default is 1.

-pipeline=pipeline_id

Set the pipeline as specified by pipeline_id (integer). If you don't specify this option, sw-vsync uses the pipeline of the framebuffer.

If you use this option, Screen applies the SCREEN_USAGE_OVERLAY usage flag and uses the pipeline specified by pipeline_id.

-pos=x,y

Set the position, using integer x and y coordinates of the viewport (default is 0, 0).

-size=widthxheight

Set the size as specified, using integer values for width and height, of the viewport. The default size is fullscreen.

-transparency=transparency_mode

Set the transparency mode of the window. Valid transparency modes are:


Transparency mode	Description
none	Default mode; result is an opaque window
test	Destination pixels are replaced by source pixels; pixels may be opaque or fully transparent
src	Destination pixels are replaced by source pixels, including the alpha channel; window will be blended with contents underneath it

-zorder=zorder

Set the z-order specified by zorder, as an integer, of the window. A z-order of 0 is used if this option isn't specified.

Description:

The sw-vsync binary is a command-line tool that can be used to confirm that screen is running, and software rendering can be used.

To run sw-vsync:

Ensure that screen is running.
Run sw-vsync from a shell.

Examples:

# sw-vsync

Page updated: August 11, 2025