[PATCH] shell: correct position of a surface before rotating it.

[Kristian Hoegsberg]

On Wed, Mar 21, 2012 at 10:40:20PM +0100, Rafal Mielniczuk wrote:
> How to reproduce: rotate the surface to something like 45 degrees,
> resize it drastically, continue to rotate. The surface will jump
> some space and the rotation point will not be in the center
> of the surface.
> 
> Fix is to shift the surface position to match the rotation point

That works, thank you.
Kristian

> ---
>  src/shell.c |   16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/src/shell.c b/src/shell.c
> index fa51922..0983f2f 100644
> --- a/src/shell.c
> +++ b/src/shell.c
> @@ -1284,7 +1284,7 @@ rotate_binding(struct wl_input_device *device, uint32_t time,
>  		(struct weston_surface *) device->pointer_focus;
>  	struct shell_surface *surface;
>  	struct rotate_grab *rotate;
> -	GLfloat dx, dy;
> +	GLfloat dx, dy, cx, cy, cposx, cposy, dposx, dposy;
>  	GLfloat r;
>  
>  	if (base_surface == NULL)
> @@ -1334,6 +1334,20 @@ rotate_binding(struct wl_input_device *device, uint32_t time,
>  		weston_matrix_init(&surface->rotation.rotation);
>  		weston_matrix_init(&rotate->rotation);
>  	}
> +
> +	/* We need to adjust the position of the surface
> +	 * in case it was resized in a rotated state before */
> +	cx = 0.5f * surface->surface->geometry.width;
> +	cy = 0.5f * surface->surface->geometry.height;
> +	cposx = surface->surface->geometry.x + cx;
> +	cposy = surface->surface->geometry.y + cy;
> +	dposx = rotate->center.x - cposx;
> +	dposy = rotate->center.y - cposy;
> +	if (dposx != 0 || dposy != 0) {
> +		weston_surface_set_position(base_surface,
> +				base_surface->geometry.x + dposx,
> +				base_surface->geometry.y + dposy);
> +	}
>  
>  	wl_input_device_set_pointer_focus(device, NULL, time, 0, 0);
>  }
> -- 
> 1.7.9.4
>