viewporter Module¶
WpViewport¶
-
class
pywayland.protocol.viewporter.
WpViewport
¶ Crop and scale interface to a
WlSurface
An additional interface to a
WlSurface
object, which allows the client to specify the cropping and scaling of the surface contents.This interface works with two concepts: the source rectangle (src_x, src_y, src_width, src_height), and the destination size (dst_width, dst_height). The contents of the source rectangle are scaled to the destination size, and content outside the source rectangle is ignored. This state is double- buffered, and is applied on the next
WlSurface.commit()
.The two parts of crop and scale state are independent: the source rectangle, and the destination size. Initially both are unset, that is, no scaling is applied. The whole of the current
WlBuffer
is used as the source, and the surface size is as defined inWlSurface.attach()
.If the destination size is set, it causes the surface size to become dst_width, dst_height. The source (rectangle) is scaled to exactly this size. This overrides whatever the attached
WlBuffer
size is, unless theWlBuffer
is NULL. If theWlBuffer
is NULL, the surface has no content and therefore no size. Otherwise, the size is always at least 1x1 in surface local coordinates.If the source rectangle is set, it defines what area of the
WlBuffer
is taken as the source. If the source rectangle is set and the destination size is not set, then src_width and src_height must be integers, and the surface size becomes the source rectangle size. This results in cropping without scaling. If src_width or src_height are not integers and destination size is not set, the bad_size protocol error is raised when the surface state is applied.The coordinate transformations from buffer pixel coordinates up to the surface-local coordinates happen in the following order: 1. buffer_transform (
WlSurface.set_buffer_transform()
) 2. buffer_scale (WlSurface.set_buffer_scale()
) 3. crop and scale (WpViewport
.set*) This means, that the source rectangle coordinates of crop and scale are given in the coordinates after the buffer transform and scale, i.e. in the coordinates that would be the surface- local coordinates if the crop and scale was not applied.If src_x or src_y are negative, the bad_value protocol error is raised. Otherwise, if the source rectangle is partially or completely outside of the non-NULL
WlBuffer
, then the out_of_buffer protocol error is raised when the surface state is applied. A NULLWlBuffer
does not raise the out_of_buffer error.The x, y arguments of
WlSurface.attach()
are applied as normal to the surface. They indicate how many pixels to remove from the surface size from the left and the top. In other words, they are still in the surface-local coordinate system, just like dst_width and dst_height are.If the
WlSurface
associated with theWpViewport
is destroyed, allWpViewport
requests except ‘destroy’ raise the protocol error no_surface.If the
WpViewport
object is destroyed, the crop and scale state is removed from theWlSurface
. The change will be applied on the nextWlSurface.commit()
.-
destroy
() → 'None'¶ Request – opcode 0 (attached to
Resource
instance)Remove scaling and cropping from the surface
The associated wl_surface’s crop and scale state is removed. The change is applied on the next
WlSurface.commit()
.
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set_source
(x: 'float', y: 'float', width: 'float', height: 'float') → 'None'¶ Request – opcode 1 (attached to
Resource
instance)Set the source rectangle for cropping
Set the source rectangle of the associated
WlSurface
. SeeWpViewport
for the description, and relation to theWlBuffer
size.If all of x, y, width and height are -1.0, the source rectangle is unset instead. Any other set of values where width or height are zero or negative, or x or y are negative, raise the bad_value protocol error.
The crop and scale state is double-buffered state, and will be applied on the next
WlSurface.commit()
.Parameters: - x (ArgumentType.Fixed) – source rectangle x
- y (ArgumentType.Fixed) – source rectangle y
- width (ArgumentType.Fixed) – source rectangle width
- height (ArgumentType.Fixed) – source rectangle height
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set_destination
(width: 'int', height: 'int') → 'None'¶ Request – opcode 2 (attached to
Resource
instance)Set the surface size for scaling
Set the destination size of the associated
WlSurface
. SeeWpViewport
for the description, and relation to theWlBuffer
size.If width is -1 and height is -1, the destination size is unset instead. Any other pair of values for width and height that contains zero or negative values raises the bad_value protocol error.
The crop and scale state is double-buffered state, and will be applied on the next
WlSurface.commit()
.Parameters: - width (ArgumentType.Int) – surface width
- height (ArgumentType.Int) – surface height
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WpViewporter¶
-
class
pywayland.protocol.viewporter.
WpViewporter
¶ Surface cropping and scaling
The global interface exposing surface cropping and scaling capabilities is used to instantiate an interface extension for a
WlSurface
object. This extended interface will then allow cropping and scaling the surface contents, effectively disconnecting the direct relationship between the buffer and the surface size.-
destroy
() → 'None'¶ Request – opcode 0 (attached to
Resource
instance)Unbind from the cropping and scaling interface
Informs the server that the client will not be using this protocol object anymore. This does not affect any other objects,
WpViewport
objects included.
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get_viewport
(surface: 'WlSurface') → 'Proxy[WpViewport]'¶ Request – opcode 1 (attached to
Resource
instance)Extend surface interface for crop and scale
Instantiate an interface extension for the given
WlSurface
to crop and scale its content. If the givenWlSurface
already has aWpViewport
object associated, the viewport_exists protocol error is raised.Parameters: surface ( WlSurface
) – the surfaceReturns: WpViewport
– the new viewport interface id
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