ioctl VIDIOC_G_CROP, VIDIOC_S_CROP &manvol; VIDIOC_G_CROP VIDIOC_S_CROP Get or set the current cropping rectangle int ioctl int fd int request struct v4l2_crop *argp int ioctl int fd int request const struct v4l2_crop *argp fd &fd; request VIDIOC_G_CROP, VIDIOC_S_CROP argp To query the cropping rectangle size and position applications set the type field of a v4l2_crop structure to the respective buffer (stream) type and call the VIDIOC_G_CROP ioctl with a pointer to this structure. The driver fills the rest of the structure or returns the &EINVAL; if cropping is not supported. To change the cropping rectangle applications initialize the type and &v4l2-rect; substructure named c of a v4l2_crop structure and call the VIDIOC_S_CROP ioctl with a pointer to this structure. The driver first adjusts the requested dimensions against hardware limits, &ie; the bounds given by the capture/output window, and it rounds to the closest possible values of horizontal and vertical offset, width and height. In particular the driver must round the vertical offset of the cropping rectangle to frame lines modulo two, such that the field order cannot be confused. Second the driver adjusts the image size (the opposite rectangle of the scaling process, source or target depending on the data direction) to the closest size possible while maintaining the current horizontal and vertical scaling factor. Finally the driver programs the hardware with the actual cropping and image parameters. VIDIOC_S_CROP is a write-only ioctl, it does not return the actual parameters. To query them applications must call VIDIOC_G_CROP and &VIDIOC-G-FMT;. When the parameters are unsuitable the application may modify the cropping or image parameters and repeat the cycle until satisfactory parameters have been negotiated. When cropping is not supported then no parameters are changed and VIDIOC_S_CROP returns the &EINVAL;. &cs-str; &v4l2-buf-type; type Type of the data stream, set by the application. Only these types are valid here: V4L2_BUF_TYPE_VIDEO_CAPTURE, V4L2_BUF_TYPE_VIDEO_OUTPUT, V4L2_BUF_TYPE_VIDEO_OVERLAY, and custom (driver defined) types with code V4L2_BUF_TYPE_PRIVATE and higher. &v4l2-rect; c Cropping rectangle. The same co-ordinate system as for &v4l2-cropcap; bounds is used. &return-value; EINVAL Cropping is not supported.