diff options
Diffstat (limited to 'Documentation/linux_tv/media/v4l/selection-api-006.rst')
| -rw-r--r-- | Documentation/linux_tv/media/v4l/selection-api-006.rst | 102 |
1 files changed, 51 insertions, 51 deletions
diff --git a/Documentation/linux_tv/media/v4l/selection-api-006.rst b/Documentation/linux_tv/media/v4l/selection-api-006.rst index 54b769e2fd73..b2ac12f2e3d4 100644 --- a/Documentation/linux_tv/media/v4l/selection-api-006.rst +++ b/Documentation/linux_tv/media/v4l/selection-api-006.rst @@ -12,17 +12,17 @@ Examples .. code-block:: c :caption: Example 1.15. Resetting the cropping parameters - struct v4l2_selection sel = { - .type = V4L2_BUF_TYPE_VIDEO_CAPTURE, - .target = V4L2_SEL_TGT_CROP_DEFAULT, - }; - ret = ioctl(fd, VIDIOC_G_SELECTION, &sel); - if (ret) - exit(-1); - sel.target = V4L2_SEL_TGT_CROP; - ret = ioctl(fd, VIDIOC_S_SELECTION, &sel); - if (ret) - exit(-1); + struct v4l2_selection sel = { + .type = V4L2_BUF_TYPE_VIDEO_CAPTURE, + .target = V4L2_SEL_TGT_CROP_DEFAULT, + }; + ret = ioctl(fd, VIDIOC_G_SELECTION, &sel); + if (ret) + exit(-1); + sel.target = V4L2_SEL_TGT_CROP; + ret = ioctl(fd, VIDIOC_S_SELECTION, &sel); + if (ret) + exit(-1); Setting a composing area on output of size of *at most* half of limit placed at a center of a display. @@ -31,26 +31,26 @@ placed at a center of a display. .. code-block:: c :caption: Example 1.16. Simple downscaling - struct v4l2_selection sel = { - .type = V4L2_BUF_TYPE_VIDEO_OUTPUT, - .target = V4L2_SEL_TGT_COMPOSE_BOUNDS, - }; - struct v4l2_rect r; - - ret = ioctl(fd, VIDIOC_G_SELECTION, &sel); - if (ret) - exit(-1); - /* setting smaller compose rectangle */ - r.width = sel.r.width / 2; - r.height = sel.r.height / 2; - r.left = sel.r.width / 4; - r.top = sel.r.height / 4; - sel.r = r; - sel.target = V4L2_SEL_TGT_COMPOSE; - sel.flags = V4L2_SEL_FLAG_LE; - ret = ioctl(fd, VIDIOC_S_SELECTION, &sel); - if (ret) - exit(-1); + struct v4l2_selection sel = { + .type = V4L2_BUF_TYPE_VIDEO_OUTPUT, + .target = V4L2_SEL_TGT_COMPOSE_BOUNDS, + }; + struct v4l2_rect r; + + ret = ioctl(fd, VIDIOC_G_SELECTION, &sel); + if (ret) + exit(-1); + /* setting smaller compose rectangle */ + r.width = sel.r.width / 2; + r.height = sel.r.height / 2; + r.left = sel.r.width / 4; + r.top = sel.r.height / 4; + sel.r = r; + sel.target = V4L2_SEL_TGT_COMPOSE; + sel.flags = V4L2_SEL_FLAG_LE; + ret = ioctl(fd, VIDIOC_S_SELECTION, &sel); + if (ret) + exit(-1); A video output device is assumed; change ``V4L2_BUF_TYPE_VIDEO_OUTPUT`` for other devices @@ -59,23 +59,23 @@ for other devices .. code-block:: c :caption: Example 1.17. Querying for scaling factors - struct v4l2_selection compose = { - .type = V4L2_BUF_TYPE_VIDEO_OUTPUT, - .target = V4L2_SEL_TGT_COMPOSE, - }; - struct v4l2_selection crop = { - .type = V4L2_BUF_TYPE_VIDEO_OUTPUT, - .target = V4L2_SEL_TGT_CROP, - }; - double hscale, vscale; - - ret = ioctl(fd, VIDIOC_G_SELECTION, &compose); - if (ret) - exit(-1); - ret = ioctl(fd, VIDIOC_G_SELECTION, &crop); - if (ret) - exit(-1); - - /* computing scaling factors */ - hscale = (double)compose.r.width / crop.r.width; - vscale = (double)compose.r.height / crop.r.height; + struct v4l2_selection compose = { + .type = V4L2_BUF_TYPE_VIDEO_OUTPUT, + .target = V4L2_SEL_TGT_COMPOSE, + }; + struct v4l2_selection crop = { + .type = V4L2_BUF_TYPE_VIDEO_OUTPUT, + .target = V4L2_SEL_TGT_CROP, + }; + double hscale, vscale; + + ret = ioctl(fd, VIDIOC_G_SELECTION, &compose); + if (ret) + exit(-1); + ret = ioctl(fd, VIDIOC_G_SELECTION, &crop); + if (ret) + exit(-1); + + /* computing scaling factors */ + hscale = (double)compose.r.width / crop.r.width; + vscale = (double)compose.r.height / crop.r.height; |