Update documentation and implementations of bounding box calculations. Rename functions to fit their behavior

This commit is contained in:
Mario Hüttel 2019-11-16 15:54:56 +01:00
parent e7f0f904e8
commit 2b0e2095e6
3 changed files with 96 additions and 17 deletions

View File

@ -145,7 +145,7 @@ static void calculate_path_miter_points(struct vector_2d *a, struct vector_2d *b
vector_2d_subtract(m2, m2, &v_vec);
}
void bounding_box_calculate_path_box(GList *vertices, double thickness,
void bounding_box_update_with_path(GList *vertices, double thickness,
conv_generic_to_vector_2d_t conv_func, union bounding_box *box)
{
GList *vertex_iterator;
@ -191,24 +191,40 @@ void bounding_box_update_point(union bounding_box *destination, conv_generic_to_
destination->vectors.upper_right.y = MAX(destination->vectors.upper_right.y, point.y);
}
/**
* @brief Apply transformations onto bounding box.
* @param scale Scaling factor
* @param rotation_deg Roation of bounding box around the origin in degrees (counterclockwise)
* @param flip_at_x Flip the boundig box on the x axis before rotating.
* @param box Bounding box the operations should be applied to.
*/
void bounding_box_get_all_points(struct vector_2d *points, union bounding_box *box)
{
if (!points || !box)
return;
points[0].x = box->vectors.lower_left.x;
points[0].y = box->vectors.lower_left.y;
points[1].x = box->vectors.upper_right.x;
points[1].y = box->vectors.lower_left.y;
points[2].x = box->vectors.upper_right.x;
points[2].y = box->vectors.upper_right.y;
points[3].x = box->vectors.lower_left.x;
points[3].y = box->vectors.upper_right.y;
}
void bounding_box_apply_transform(double scale, double rotation_deg, bool flip_at_x, union bounding_box *box)
{
int i;
struct vector_2d input_points[4];
/* Due to linearity, the order of the operations does not matter.
* flip must be applied before rotation as defined by the GDS format
*/
for (i = 0; i < 2; i++) {
box->vector_array[i].y *= (flip_at_x ? -1 : 1);
vector_2d_rotate(&box->vector_array[i], rotation_deg * M_PI / 180);
vector_2d_scale(&box->vector_array[i], scale);
if (!box)
return;
bounding_box_get_all_points(input_points, box);
/* Reset box */
bounding_box_prepare_empty(box);
for (i = 0; i < 4; i++) {
input_points[i].y *= (flip_at_x ? -1 : 1);
vector_2d_rotate(&input_points[i], rotation_deg * M_PI / 180.0);
vector_2d_scale(&input_points[i], scale);
bounding_box_update_point(box, NULL, &input_points[i]);
}
}

View File

@ -63,7 +63,7 @@ static void update_box_with_gfx(union bounding_box *box, struct gds_graphics *gf
* Please be aware if paths are the outmost elements of your cell.
* You might end up with a completely wrong calculated cell size.
*/
bounding_box_calculate_path_box(gfx->vertices, gfx->width_absolute,
bounding_box_update_with_path(gfx->vertices, gfx->width_absolute,
(conv_generic_to_vector_2d_t)&convert_gds_point_to_2d_vector,
&current_box);
break;

View File

@ -46,12 +46,75 @@ union bounding_box {
typedef void (*conv_generic_to_vector_2d_t)(void *, struct vector_2d *);
/**
* @brief Calculate bounding box of polygon
* @param vertices List of vertices that describe the polygon
* @param conv_func Conversion function to convert vertices to vector_2d structs.
* @param box Box to write to. This box is not updated! All previous data is discarded
*/
void bounding_box_calculate_polygon(GList *vertices, conv_generic_to_vector_2d_t conv_func, union bounding_box *box);
/**
* @brief Update an exisitng bounding box with another one.
* @param destination Target box to update
* @param update Box to update the target with
*/
void bounding_box_update_box(union bounding_box *destination, union bounding_box *update);
/**
* @brief Prepare an empty bounding box.
*
* Updating this specially prepared box, results in a bounding box that is the same size as the update
*
* @param box Box to preapre
*/
void bounding_box_prepare_empty(union bounding_box *box);
/**
* @brief Update bounding box with a point
* @param destination Bounding box to update
* @param conv_func Conversion function to convert \p pt to a vector_2d. May be NULL
* @param pt Point to update bounding box with
*/
void bounding_box_update_point(union bounding_box *destination, conv_generic_to_vector_2d_t conv_func, void *pt);
/**
* @brief Return all four corner points of a bounding box
* @param[out] points Array of 4 vector_2d structs that has to be allocated by the caller
* @param box Bounding box
*/
void bounding_box_get_all_points(struct vector_2d *points, union bounding_box *box);
/**
* @brief Apply transformations onto bounding box.
*
* All corner points of the bounding \f$ \vec{P_i} \f$ box are transformed to output points \f$ \vec{P_o} \f$ by:
*
* \f$ \vec{P_o} = s \cdot \begin{pmatrix}\cos\left(\phi\right) & -\sin\left(\phi\right)\\ \sin\left(\phi\right) & \cos\left(\phi\right)\end{pmatrix} \cdot \begin{pmatrix} 1 & 0 \\ 0 & -1^{m} \end{pmatrix} \cdot \vec{P_i} \f$, with:
*
* * \f$s\f$: Scale
* * \f$m\f$: 1, if flipped_at_x is True, else 0
* * \f$\phi\f$: Rotation angle in radians. The conversion degrees => radians is done internally
*
* The result is the bounding box generated around all output points
*
* @param scale Scaling factor
* @param rotation_deg Rotation of bounding box around the origin in degrees (counterclockwise)
* @param flip_at_x Flip the boundig box on the x axis before rotating.
* @param box Bounding box the operations should be applied to.
* @note Keep in mind, that this bounding boxy is actually the bounding box of the rotated boundig box and not the object itself.
* It might be too big.
*/
void bounding_box_apply_transform(double scale, double rotation_deg, bool flip_at_x, union bounding_box *box);
void bounding_box_calculate_path_box(GList *vertices, double thickness, conv_generic_to_vector_2d_t conv_func, union bounding_box *box);
/**
* @brief Calculate the bounding box of a path and update the given bounding box
* @param vertices Vertices the path is made up of
* @param thickness Thisckness of the path
* @param conv_func Conversion function for vertices to vector_2d structs
* @param box Bounding box to write results in.
*/
void bounding_box_update_with_path(GList *vertices, double thickness, conv_generic_to_vector_2d_t conv_func, union bounding_box *box);
#endif /* _BOUNDING_BOX_H_ */