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| author | Rodrigo Vivi <[email protected]> | 2018-07-23 09:13:12 -0700 | 
|---|---|---|
| committer | Rodrigo Vivi <[email protected]> | 2018-07-23 09:13:12 -0700 | 
| commit | c74a7469f97c0f40b46e82ee979f9fb1bb6e847c (patch) | |
| tree | f2690a1a916b73ef94657fbf0e0141ae57701825 /Documentation/media/uapi/v4l/selection-api-intro.rst | |
| parent | 6f15a7de86c8cf2dc09fc9e6d07047efa40ef809 (diff) | |
| parent | 500775074f88d9cf5416bed2ca19592812d62c41 (diff) | |
Merge drm/drm-next into drm-intel-next-queued
We need a backmerge to get DP_DPCD_REV_14 before we push other
i915 changes to dinq that could break compilation.
Signed-off-by: Rodrigo Vivi <[email protected]>
Diffstat (limited to 'Documentation/media/uapi/v4l/selection-api-intro.rst')
| -rw-r--r-- | Documentation/media/uapi/v4l/selection-api-intro.rst | 28 | 
1 files changed, 28 insertions, 0 deletions
| diff --git a/Documentation/media/uapi/v4l/selection-api-intro.rst b/Documentation/media/uapi/v4l/selection-api-intro.rst new file mode 100644 index 000000000000..09ca93f91bf7 --- /dev/null +++ b/Documentation/media/uapi/v4l/selection-api-intro.rst @@ -0,0 +1,28 @@ +.. -*- coding: utf-8; mode: rst -*- + +************ +Introduction +************ + +Some video capture devices can sample a subsection of a picture and +shrink or enlarge it to an image of arbitrary size. Next, the devices +can insert the image into larger one. Some video output devices can crop +part of an input image, scale it up or down and insert it at an +arbitrary scan line and horizontal offset into a video signal. We call +these abilities cropping, scaling and composing. + +On a video *capture* device the source is a video signal, and the +cropping target determine the area actually sampled. The sink is an +image stored in a memory buffer. The composing area specifies which part +of the buffer is actually written to by the hardware. + +On a video *output* device the source is an image in a memory buffer, +and the cropping target is a part of an image to be shown on a display. +The sink is the display or the graphics screen. The application may +select the part of display where the image should be displayed. The size +and position of such a window is controlled by the compose target. + +Rectangles for all cropping and composing targets are defined even if +the device does supports neither cropping nor composing. Their size and +position will be fixed in such a case. If the device does not support +scaling then the cropping and composing rectangles have the same size. |