[PATCH weston v2 08/20] compositor: add weston_matrix_transform_rect() and use it where appropriate

[Giulio Camuffo]

Just a nitpick below:

2014-10-16 18:55 GMT+03:00 Derek Foreman <derekf at osg.samsung.com>:
> New function that transforms a pixman_box32_t rectangle by a matrix.
>
> Since pixman rectangles are represented by 2 corners, non-90 degree
> rotations can't be properly represented.  This function gives the
> axis aligned rectangle that encloses the rotated rectangle.
>
> We use this for matrix_transform_region() and weston_matrix_transform_rect(),
> simplifying them and allowing them to work for non 90 degree rotations.
> ---
>  src/compositor.c | 96 ++++++++++++++++++++++++++++----------------------------
>  src/compositor.h |  4 +++
>  2 files changed, 52 insertions(+), 48 deletions(-)
>
> diff --git a/src/compositor.c b/src/compositor.c
> index e45dd62..7c0f050 100644
> --- a/src/compositor.c
> +++ b/src/compositor.c
> @@ -654,6 +654,50 @@ weston_view_to_global_float(struct weston_view *view,
>         }
>  }
>
> +WL_EXPORT pixman_box32_t
> +weston_matrix_transform_rect(struct weston_matrix *matrix,
> +                            pixman_box32_t rect)

The function name doesn't imply it returns an axis aligned bounding
box. Maybe something like "weston_matrix_rect_to_transformed_aabb"
would be better?

> +{
> +       int i;
> +       pixman_box32_t out;
> +
> +       /* since pixman regions are defined by two corners we have
> +        * to be careful with rotations that aren't multiples of 90.
> +        * We need to take all four corners of the region and rotate
> +        * them, then construct the largest possible two corner
> +        * rectangle from the result.
> +        */
> +       struct weston_vector corners[4] = {
> +               {{rect.x1, rect.y1, 0, 1}},
> +               {{rect.x2, rect.y1, 0, 1}},
> +               {{rect.x1, rect.y2, 0, 1}},
> +               {{rect.x2, rect.y2, 0, 1}},
> +       };
> +
> +       for (i = 0; i < 4; i++) {
> +               weston_matrix_transform(matrix, &corners[i]);
> +               corners[i].f[0] /= corners[i].f[3];
> +               corners[i].f[1] /= corners[i].f[3];
> +       }
> +
> +       out.x1 = floor(corners[0].f[0]);
> +       out.y1 = floor(corners[0].f[1]);
> +       out.x2 = ceil(corners[0].f[0]);
> +       out.y2 = ceil(corners[0].f[1]);
> +
> +       for (i = 1; i < 4; i++) {
> +               if (floor(corners[i].f[0]) < out.x1)
> +                       out.x1 = floor(corners[i].f[0]);
> +               if (floor(corners[i].f[1]) < out.y1)
> +                       out.y1 = floor(corners[i].f[1]);
> +               if (ceil(corners[i].f[0]) > out.x2)
> +                       out.x2 = ceil(corners[i].f[0]);
> +               if (ceil(corners[i].f[1]) > out.y2)
> +                       out.y2 = ceil(corners[i].f[1]);
> +       }
> +       return out;
> +}
> +
>  WL_EXPORT void
>  weston_transformed_coord(int width, int height,
>                          enum wl_output_transform transform,
> @@ -747,38 +791,8 @@ weston_matrix_transform_region(pixman_region32_t *dest,
>         if (!dest_rects)
>                 return;
>
> -       for (i = 0; i < nrects; i++) {
> -               struct weston_vector vec1 = {{
> -                       src_rects[i].x1, src_rects[i].y1, 0, 1
> -               }};
> -               weston_matrix_transform(matrix, &vec1);
> -               vec1.f[0] /= vec1.f[3];
> -               vec1.f[1] /= vec1.f[3];
> -
> -               struct weston_vector vec2 = {{
> -                       src_rects[i].x2, src_rects[i].y2, 0, 1
> -               }};
> -               weston_matrix_transform(matrix, &vec2);
> -               vec2.f[0] /= vec2.f[3];
> -               vec2.f[1] /= vec2.f[3];
> -
> -               if (vec1.f[0] < vec2.f[0]) {
> -                       dest_rects[i].x1 = floor(vec1.f[0]);
> -                       dest_rects[i].x2 = ceil(vec2.f[0]);
> -               } else {
> -                       dest_rects[i].x1 = floor(vec2.f[0]);
> -                       dest_rects[i].x2 = ceil(vec1.f[0]);
> -               }
> -
> -
> -               if (vec1.f[1] < vec2.f[1]) {
> -                       dest_rects[i].y1 = floor(vec1.f[1]);
> -                       dest_rects[i].y2 = ceil(vec2.f[1]);
> -               } else {
> -                       dest_rects[i].y1 = floor(vec2.f[1]);
> -                       dest_rects[i].y2 = ceil(vec1.f[1]);
> -               }
> -       }
> +       for (i = 0; i < nrects; i++)
> +               dest_rects[i] = weston_matrix_transform_rect(matrix, src_rects[i]);
>
>         pixman_region32_clear(dest);
>         pixman_region32_init_rects(dest, dest_rects, nrects);
> @@ -939,22 +953,8 @@ WL_EXPORT pixman_box32_t
>  weston_surface_to_buffer_rect(struct weston_surface *surface,
>                               pixman_box32_t rect)
>  {
> -       struct weston_buffer_viewport *vp = &surface->buffer_viewport;
> -       float xf, yf;
> -
> -       /* first transform box coordinates if the scaler is set */
> -       scaler_surface_to_buffer(surface, rect.x1, rect.y1, &xf, &yf);
> -       rect.x1 = floorf(xf);
> -       rect.y1 = floorf(yf);
> -
> -       scaler_surface_to_buffer(surface, rect.x2, rect.y2, &xf, &yf);
> -       rect.x2 = floorf(xf);
> -       rect.y2 = floorf(yf);
> -
> -       return weston_transformed_rect(surface->width_from_buffer,
> -                                      surface->height_from_buffer,
> -                                      vp->buffer.transform, vp->buffer.scale,
> -                                      rect);
> +       return weston_matrix_transform_rect(&surface->surface_to_buffer_matrix,
> +                                           rect);
>  }
>
>  WL_EXPORT void
> diff --git a/src/compositor.h b/src/compositor.h
> index b15eb01..79b5190 100644
> --- a/src/compositor.h
> +++ b/src/compositor.h
> @@ -1453,6 +1453,10 @@ int
>  module_init(struct weston_compositor *compositor,
>             int *argc, char *argv[]);
>
> +pixman_box32_t
> +weston_matrix_transform_rect(struct weston_matrix *matrix,
> +                            pixman_box32_t rect);
> +
>  void
>  weston_transformed_coord(int width, int height,
>                          enum wl_output_transform transform,
> --
> 2.1.1
>
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