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Working with Nodes
Node References
Primary Nodes


Canvas node is a principal Screenberry node that creates an OpenGL context window for a main server video output. It serves as a canvas on which all Screenberry image output elements such as displays and patches are composed.

Canvas Node Graph

When the Canvas node is added in the Node Graph the corresponding widget becomes accessible that allows to edit Displays and Patches associated with this canvas. The widget can be added to the workspace by selecting Window > [Canvas Name] from the main Screenberry Panel menu.

Canvas Widget

Multiple Canvas nodes can be created, but only one can be enabled for the server video output at a time. Each added Canvas node has its own corresponding widget.

Multiple Canvas nodes

For more information on editing displays and patches see the Display Editor and Patch Editor sections of this user guide.

Note: Any image source node can be connected to the Canvas node directly. In this case, it will serve as the canvas Background Image and will be fit to the size of the canvas automatically.

The Settings panel of the Canvas node offers the following control and information parameters:

Image SizeSets the width and height of the output window in pixels.
PositionSets the position of the top-left corner of the output window relative to the top-left corner of the GPU device(s) output.
FullscreenMaximizes the output window to the size of the current output device screen.
Window FrameAdds window interface elements, such as the borders, title bar and close button to the output window.
Disable Windows ExplorerDisables all Windows user interface elements such as the taskbar and other desktop items.
Quad-buffered StereoEnables frame sequential 120 FPS stereoscopic video output on Quadro graphics cards. VSync Interval should be set to 2 for 60 FPS content and 4 for 30 FPS content.
VSyncEnables vertical synchronization in the OpenGL context.
VSync IntervalSets vertical synchronization interval for the OpenGL context.
Multisample Anti-Aliasing (MSAA)Improves the appearance of rendered patch edges (makes them smoother). This anti-aliasing option only affects patches that are rendered directly to the Canvas or Display.
Always on TopSpecifies that the output window should be always above other interface windows.
Raise WindowBrings the output window above other interface windows.
OpenGL VersionSpecifies the software version of OpenGL. This parameter is set to Auto by default to automatically discover a current OpenGL software version
RendererProvides information about the graphics card in use.
Current OpenGL VersionProvides information about the current software version of OpenGL.
DisplaysProvides information about the number of Display nodes connected to the Canvas node.
PatchesProvides information about the number of Patch nodes connected to the Canvas node.
Background ImageProvides information about the image source connected to the Canvas node as a background image.
FPS Measuring
Warm Up FramesSets the number of extra frames to play before measuring the OpenGL context frame rate.
Measuring TimeSets the time interval for measuring the OpenGL context frame rate.
System Frame RateProvides information about the current system frame rate.
Actual Frame RateProvides information about the actual OpenGL context frame rate.
Target Frame RateProvides information about the set target frame rate.
VSync StatusIndicates whether vertical synchronization is enabled for the OpenGL context.
Performance Profiling
Log Frame DropsDefines threshold value as frameTime * LagMultiplier for FrameProfiler to output a LAG message.
Log Frame StatsSpecifies that frame statistics should be logged.
Frame Stats IntervalSets the interval for frame statistics logging.
Advanced Parameters
Force glFinish() UseSpecifies that glFinish() should be used.
Using glFinish()Displays that glFinish() is used.
Async Transfer ThreadsDefines the number of asynchronous OpenGL context threads for texture transfers. For this parameter to take effect, the Async Short or Async Long options for the Texture Upload mode should be selected in the node sending a video stream to the Canvas, e.g. the MediaPlayer, DeckLinkInput, DeltacastCapture, Vision, or NDIIn. In most cases, 1 or 2 threads should be sufficient. For the new Nvidia RTX cards that have 7 async copy engines the use of more threads might improve performance.
Additional Buffers for UploadSets the number of additional OpenGL buffer objects.