modules/video_filter/rotate.c: add pf_video_mouse input filter

Add input rotation for mouse events in the rotate video filter.

Previously the rotate video filter would not rotate mouse events,
which would cause confusion if another video filter taking mouse
input was chained before rotate (e.g. zoom, puzzle, etc), and
clicks headed for those in-filter actions would have to go to
their pre-rotated positions in order for VLC to accept them.

Signed-off-by: Thomas Guillem <thomas@gllm.fr>

modules/video_filter/rotate.c

@@ -35,6 +35,7 @@
 #include <vlc_common.h>
 #include <vlc_plugin.h>
 #include <vlc_filter.h>
+#include <vlc_mouse.h>
 #include <vlc_picture.h>
 #include "filter_picture.h"
 #include "../control/motionlib.h"
@@ -44,6 +45,8 @@
  *****************************************************************************/
 static int  Create    ( filter_t * );
 
+static int Mouse( filter_t *p_filter, vlc_mouse_t *p_mouse,
+                  const vlc_mouse_t *p_old );
 static picture_t *FilterPacked( filter_t *, picture_t * );
 VIDEO_FILTER_WRAPPER_CLOSE(Filter, Destroy)
 
@@ -118,7 +121,7 @@ static void fetch_trigo( filter_sys_t *sys, int *i_sin, int *i_cos )
 
 static const struct vlc_filter_operations packed_filter_ops =
 {
-    .filter_video = FilterPacked, .close = Destroy,
+    .filter_video = FilterPacked, .video_mouse = Mouse, .close = Destroy,
 };
 
 /*****************************************************************************
@@ -198,6 +201,41 @@ static void Destroy( filter_t *p_filter )
     free( p_sys );
 }
 
+/*****************************************************************************
+ *
+ *****************************************************************************/
+static int Mouse( filter_t *p_filter, vlc_mouse_t *p_mouse,
+                  const vlc_mouse_t *p_old )
+{
+    VLC_UNUSED( p_old );
+
+    const video_format_t *p_fmt = &p_filter->fmt_out.video;
+    filter_sys_t *p_sys = p_filter->p_sys;
+
+    const int i_x = p_mouse->i_x;
+    const int i_y = p_mouse->i_y;
+
+    if( p_sys->p_motion != NULL )
+    {
+        int i_angle = motion_get_angle( p_sys->p_motion );
+        store_trigo( p_sys, i_angle / 20.f );
+    }
+
+    int i_sin, i_cos;
+    fetch_trigo( p_sys, &i_sin, &i_cos );
+
+    p_mouse->i_x = ( p_fmt->i_visible_width >> 1 );
+    p_mouse->i_y = ( p_fmt->i_visible_height >> 1 );
+
+    const int i_rx = ( i_x - p_mouse->i_x );
+    const int i_ry = ( i_y - p_mouse->i_y );
+
+    p_mouse->i_x += ( ( i_rx * i_cos - i_ry * i_sin )>> 12 );
+    p_mouse->i_y += ( ( i_rx * i_sin + i_ry * i_cos )>> 12 );
+
+    return VLC_SUCCESS;
+}
+
 /*****************************************************************************
  *
  *****************************************************************************/