On Sun, 05. Jul 13:28, Omar Emara wrote:
> This patch adds a select_region option to the xcbgrab input device.
> If set to 1, the user will be prompted to select the grabbing area
> graphically by clicking and dragging. A rectangle will be drawn to
> mark the grabbing area. A single click with no dragging will select
> the whole screen. The option overwrites the video_size, grab_x, and
> grab_y options if set by the user.
>
> For testing, just set the select_region option as follows:
>
> ffmpeg -f x11grab -select_region 1 -i :0.0 output.mp4
>
> The drawing happens directly on the root window using standard rubber
> banding techniques, so it is very efficient and doesn't depend on any
> X extensions or compositors.
>
> Signed-off-by: Omar Emara <m...@omaremara.dev>
> ---
> doc/indevs.texi | 7 +++
> libavdevice/xcbgrab.c | 129 ++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 136 insertions(+)
>
> diff --git a/doc/indevs.texi b/doc/indevs.texi
> index 6f5afaf344..b5df111801 100644
> --- a/doc/indevs.texi
> +++ b/doc/indevs.texi
> @@ -1478,6 +1478,13 @@ ffmpeg -f x11grab -framerate 25 -video_size cif -i
> :0.0+10,20 out.mpg
> @subsection Options
>
> @table @option
> +@item select_region
> +Specify whether to select the grabbing area graphically using the pointer.
> +A value of @code{1} prompts the user to select the grabbing area graphically
> +by clicking and dragging. A single click with no dragging will select the
> +whole screen. This option overwrites the @var{video_size}, @var{grab_x},
> +and @var{grab_y} options. Default value is @code{0}.
> +
> @item draw_mouse
> Specify whether to draw the mouse pointer. A value of @code{0} specifies
> not to draw the pointer. Default value is @code{1}.
> diff --git a/libavdevice/xcbgrab.c b/libavdevice/xcbgrab.c
> index 6f6b2dbf15..c5adb33b00 100644
> --- a/libavdevice/xcbgrab.c
> +++ b/libavdevice/xcbgrab.c
> @@ -22,6 +22,7 @@
> #include "config.h"
>
> #include <stdlib.h>
> +#include <string.h>
> #include <xcb/xcb.h>
>
> #if CONFIG_LIBXCB_XFIXES
> @@ -69,6 +70,7 @@ typedef struct XCBGrabContext {
> int show_region;
> int region_border;
> int centered;
> + int select_region;
>
> const char *framerate;
>
> @@ -92,6 +94,7 @@ static const AVOption options[] = {
> { "centered", "Keep the mouse pointer at the center of grabbing region
> when following.", 0, AV_OPT_TYPE_CONST, { .i64 = -1 }, INT_MIN, INT_MAX, D,
> "follow_mouse" },
> { "show_region", "Show the grabbing region.", OFFSET(show_region),
> AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, D },
> { "region_border", "Set the region border thickness.",
> OFFSET(region_border), AV_OPT_TYPE_INT, { .i64 = 3 }, 1, 128, D },
> + { "select_region", "Select the grabbing region graphically using the
> pointer.", OFFSET(select_region), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, D },
> { NULL },
> };
>
> @@ -668,6 +671,124 @@ static void setup_window(AVFormatContext *s)
> draw_rectangle(s);
> }
>
> +#define CROSSHAIR_CURSOR 34
> +
> +static xcb_rectangle_t rectangle_from_corners(xcb_point_t *corner_a,
> + xcb_point_t *corner_b)
> +{
> + xcb_rectangle_t rectangle;
> + rectangle.x = FFMIN(corner_a->x, corner_b->x);
> + rectangle.y = FFMIN(corner_a->y, corner_b->y);
> + rectangle.width = FFABS(corner_a->x - corner_b->x);
> + rectangle.height = FFABS(corner_a->y - corner_b->y);
> + return rectangle;
> +}
> +
> +static int select_region(AVFormatContext *s)
> +{
> + XCBGrabContext *c = s->priv_data;
> + xcb_connection_t *connection = c->conn;
> + xcb_screen_t *screen = c->screen;
> +
> + int ret = 0;
> + int done = 0;
> + int was_pressed = 0;
> + xcb_cursor_t cursor;
> + xcb_font_t cursor_font;
> + xcb_point_t press_position;
> + xcb_generic_event_t *event;
> + xcb_rectangle_t rectangle = {0};
> + xcb_grab_pointer_reply_t *reply;
> + xcb_grab_pointer_cookie_t cookie;
> +
> + xcb_window_t root_window = screen->root;
> + xcb_gcontext_t gc = xcb_generate_id(connection);
> + uint32_t mask = XCB_GC_FUNCTION | XCB_GC_SUBWINDOW_MODE;
> + uint32_t values[] = {XCB_GX_INVERT,
> + XCB_SUBWINDOW_MODE_INCLUDE_INFERIORS};
> + xcb_create_gc(connection, gc, root_window, mask, values);
> +
> + cursor_font = xcb_generate_id(connection);
> + xcb_open_font(connection, cursor_font, strlen("cursor"), "cursor");
> + cursor = xcb_generate_id(connection);
> + xcb_create_glyph_cursor(connection, cursor, cursor_font, cursor_font,
> + CROSSHAIR_CURSOR, CROSSHAIR_CURSOR + 1, 0, 0, 0,
> + 0xFFFF, 0xFFFF, 0xFFFF);
> + cookie = xcb_grab_pointer(connection, 0, root_window,
> + XCB_EVENT_MASK_BUTTON_PRESS |
> + XCB_EVENT_MASK_BUTTON_RELEASE |
> + XCB_EVENT_MASK_BUTTON_MOTION,
> + XCB_GRAB_MODE_ASYNC, XCB_GRAB_MODE_ASYNC,
> + root_window, cursor, XCB_CURRENT_TIME);
> +
> + if (!(reply = xcb_grab_pointer_reply(connection, cookie, NULL)) ||
> + (reply->status != XCB_GRAB_STATUS_SUCCESS)) {
reply = xcb_grab_pointer_reply(connection, cookie, NULL);
if (!reply || reply->status != XCB_GRAB_STATUS_SUCCESS) {
> + av_log(s, AV_LOG_ERROR,
> + "Failed to select region. Could not grab pointer.\n");
> + ret = AVERROR(EIO);
> + free(reply);
> + goto fail;
> + }
You need to free reply here too.
> +
> + xcb_grab_server(connection);
> + xcb_flush(connection);
There is a flush call in xcb_grab_pointer_reply(), so I don't think this one is
needed now.
> +
> + while (!done && (event = xcb_wait_for_event(connection))) {
> + switch (event->response_type & ~0x80) {
> + case XCB_BUTTON_PRESS: {
> + xcb_button_press_event_t *press = (xcb_button_press_event_t
> *)event;
> + press_position = (xcb_point_t){press->event_x, press->event_y};
> + rectangle.x = press_position.x;
> + rectangle.y = press_position.y;
> + xcb_poly_rectangle(connection, root_window, gc, 1, &rectangle);
> + was_pressed = 1;
> + break;
> + }
> + case XCB_MOTION_NOTIFY: {
> + xcb_motion_notify_event_t *motion =
> + (xcb_motion_notify_event_t *)event;
> + if (was_pressed) {
> + xcb_point_t cursor_position = {motion->event_x,
> + motion->event_y};
> + xcb_poly_rectangle(connection, root_window, gc, 1,
> + &rectangle);
> + rectangle = rectangle_from_corners(
> + &press_position, &cursor_position);
> + xcb_poly_rectangle(connection, root_window, gc, 1,
> + &rectangle);
nit:
If you rename connection to conn, some of these line breaks won't be needed.
> + }
> + break;
> + }
> + case XCB_BUTTON_RELEASE: {
> + xcb_poly_rectangle(connection, root_window, gc, 1, &rectangle);
> + done = 1;
> + break;
> + }
> + default:
> + break;
> + }
> + xcb_flush(connection);
> + free(event);
> + }
> + c->width = rectangle.width;
> + c->height = rectangle.height;
> + if (c->width && c->height) {
> + c->x = rectangle.x;
> + c->y = rectangle.y;
> + } else {
> + c->x = 0;
> + c->y = 0;
> + }
> + xcb_ungrab_server(connection);
> + xcb_ungrab_pointer(connection, XCB_CURRENT_TIME);
> +
> +fail:
> + xcb_free_cursor(connection, cursor);
> + xcb_close_font(connection, cursor_font);
> + xcb_free_gc(connection, gc);
> + return ret;
> +}
> +
> static av_cold int xcbgrab_read_header(AVFormatContext *s)
> {
> XCBGrabContext *c = s->priv_data;
> @@ -702,6 +823,14 @@ static av_cold int xcbgrab_read_header(AVFormatContext
> *s)
> return AVERROR(EIO);
> }
>
> + if (c->select_region) {
> + ret = select_region(s);
> + if (ret < 0) {
> + xcbgrab_read_close(s);
> + return ret;
> + }
> + }
> +
> ret = create_stream(s);
>
> if (ret < 0) {
Thanks,
--
Andriy
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