fsleyes.gl.glmask

This module provides the GLMask class, which implements functionality for rendering an Image overlay as a binary mask.

class fsleyes.gl.glmask.GLMask(image, overlayList, displayCtx, canvas, threedee)

Bases: fsleyes.gl.glimageobject.GLImageObject

The GLMask class encapsulates logic to render an Image instance as a binary mask in OpenGL.

When created, a GLMask instance assumes that the provided Image instance has a Display.overlayType of mask, and that its associated Display instance contains a MaskOpts instance, containing mask-specific display properties.

Textures

A GLMask will use up to two textures:

• An ImageTexture for storing the 3D image data. This texture is bound to texture unit 0.

• A RenderTexture, used for edge filtering if necessary. This texture will be bound to texture unit 1.

2D rendering

On 2D canvases, A GLMask is rendered similarly to a GLVolume - a 2D slice is taken through the 3D image texture. If the MaskOpts.outline property is active, this slice is rendered to an off-screen texture, which is then passed through an edge filter (see the filters module).

Version dependent modules

The GLMask class makes use of the functions defined in the gl14.glmask_funcs or the gl21.glmask_funcs modules, which provide OpenGL version specific details for rendering.

These version dependent modules must provide the following functions:

init(GLMask)	Perform any necessary initialisation.
destroy(GLMask)	Perform any necessary cleanup
compileShaders(GLMask)	(Re-)compile the shader program
updateShaderState(GLMask)	Update the shader program state
draw2D(GLMask, ...)	Draw a slice of the image
drawAll(GLMask, ...)	Draw multiple slices of the image

__init__(image, overlayList, displayCtx, canvas, threedee)

Create a GLMask.

Parameters

• image – The Image instance.

• overlayList – The OverlayList

• displayCtx – The DisplayContext managing the scene.

• canvas – The canvas doing the drawing.

• threedee – 2D or 3D rendering

destroy()

Must be called when this GLMask is no longer needed. Destroys the ImageTexture.

ready()

Returns True if this GLMask is ready to be drawn, False otherwise.

textureReady()

Returns True if the imageTexture is ready to be used, False otherwise.

updateShaderState(*args, **kwargs)

Calls gl14.gllabel_funcs.updateShaderState() or gl21.gllabel_funcs.updateShaderState(), and Notifier.notify(). Uses idle.idleWhen() to ensure that they don’t get called until ready() returns True.

addDisplayListeners()

Adds a bunch of listeners to the Display object, and the associated MaskOpts instance, which define how the mask image should be displayed.

removeDisplayListeners()

Removes all the listeners added by addDisplayListeners().

refreshImageTexture()

Makes sure that the ImageTexture, used to store the Image data, is up to date.

getColour()

Prepares and returns the mask colour for use in the fragment shader.

getThreshold()

Prepares and returns the mask thresholds for use in the fragment shader.

preDraw(xform=None, bbox=None)

Binds the ImageTexture and calls the version-dependent preDraw function.

draw2D(zpos, axes, xform=None, bbox=None)

Calls the version-dependent draw2D function, then applies the edge filter if necessary.

drawAll(axes, zposes, xforms)

Calls the version-dependent drawAll function, then applies the edge filter if necessary.

draw3D(*args, **kwargs)

Does nothing.

postDraw(xform=None, bbox=None)

Unbinds the ImageTexture.

_GLMask__imageSyncChanged(*a)

Called when the NiftiOpts.volume property is synchronised or un-synchronised. Calls refreshImageTexture() and updateShaderState().

_GLMask__imageTextureChanged(*a)

Called when the image texture data has changed. Triggers a refresh.

_GLMask__interpChanged(*a)

Called when the MaskOpts.interpolation changes. Updates the image texture.

_GLMask__volumeChanged(*a)

Called when the NiftiOpts.volume changes. Updates the image texture.

__module__ = 'fsleyes.gl.glmask'