diff options
Diffstat (limited to 'src/sdf/ftsdf.c')
| -rw-r--r-- | src/sdf/ftsdf.c | 228 |
1 files changed, 186 insertions, 42 deletions
diff --git a/src/sdf/ftsdf.c b/src/sdf/ftsdf.c index bb8b97cb1..e0ba9a728 100644 --- a/src/sdf/ftsdf.c +++ b/src/sdf/ftsdf.c @@ -892,8 +892,8 @@ } /* This function subdivide and entire shape */ - /* into line segment such that the it doesn't */ - /* look visually different than the original */ + /* into line segment such that it doesn't */ + /* look visually different from the original */ /* curve. */ static FT_Error split_sdf_shape( SDF_Shape* shape ) @@ -933,8 +933,8 @@ { case SDF_EDGE_LINE: { - /* Just create a duplicate edge in case */ - /* it is a line. We can use the same edge */ + /* Just create a duplicate edge in case */ + /* it is a line. We can use the same edge. */ FT_CALL( sdf_edge_new( memory, &temp ) ); ft_memcpy( temp, edge, sizeof( *edge ) ); @@ -1397,10 +1397,23 @@ * computed by the corresponding `get_min_distance_' functions efficiently. * * @Input: - * [TODO] + * sdf1 :: + * First signed distance. (can be any of `a' or `b') + * + * sdf1 :: + * Second signed distance. (can be any of `a' or `b') * * @Return: - * [TODO] + * The correct signed distance, which is checked using + * the above algorithm. + * + * @Note: + * The function does not care about the actual distance, it simply + * returns the signed distance which has a larger cross product. + * So, do not call this function if the two distances are fairly + * apart. In that case simply use the signed distance with shorter + * absolute distance. + * */ static SDF_Signed_Distance resolve_corner( SDF_Signed_Distance sdf1, @@ -1420,10 +1433,23 @@ * segments. * * @Input: - * [TODO] + * line :: + * The line segment to which the shortest distance is to be + * computed. + * + * point :: + * Point from which the shortest distance is to be computed. * * @Return: - * [TODO] + * out :: + * Signed distance from the `point' to the `line'. + * + * FT_Error :: + * FreeType error, 0 means success. + * + * @Note: + * The `line' parameter must have a `edge_type' of `SDF_EDGE_LINE'. + * */ static FT_Error get_min_distance_line( SDF_Edge* line, @@ -1573,16 +1599,30 @@ * This function find the shortest distance from the `conic' bezier * curve to a given `point' and assigns it to `out'. Only use it for * conic/quadratic curves. - * [Note]: The function uses analytical method to find shortest distance - * which is faster than the Newton-Raphson's method, but has - * underflows at the moment. Use Newton's method if you can - * see artifacts in the SDF. * * @Input: - * [TODO] + * conic :: + * The conic bezier to which the shortest distance is to be + * computed. + * + * point :: + * Point from which the shortest distance is to be computed. * * @Return: - * [TODO] + * out :: + * Signed distance from the `point' to the `conic'. + * + * FT_Error :: + * FreeType error, 0 means success. + * + * @Note: + * The function uses analytical method to find shortest distance + * which is faster than the Newton-Raphson's method, but has + * underflows at the moment. Use Newton's method if you can + * see artifacts in the SDF. + * + * The `conic' parameter must have a `edge_type' of `SDF_EDGE_CONIC'. + * */ static FT_Error get_min_distance_conic( SDF_Edge* conic, @@ -1811,15 +1851,29 @@ * This function find the shortest distance from the `conic' bezier * curve to a given `point' and assigns it to `out'. Only use it for * conic/quadratic curves. - * [Note]: The function uses Newton's approximation to find the shortest - * distance, which is a bit slower than the analytical method - * doesn't cause underflow. Use is upto your needs. * * @Input: - * [TODO] + * conic :: + * The conic bezier to which the shortest distance is to be + * computed. + * + * point :: + * Point from which the shortest distance is to be computed. * * @Return: - * [TODO] + * out :: + * Signed distance from the `point' to the `conic'. + * + * FT_Error :: + * FreeType error, 0 means success. + * + * @Note: + * The function uses Newton's approximation to find the shortest + * distance, which is a bit slower than the analytical method but + * doesn't cause underflow. Use is upto your needs. + * + * The `conic' parameter must have a `edge_type' of `SDF_EDGE_CONIC'. + * */ static FT_Error get_min_distance_conic( SDF_Edge* conic, @@ -2045,15 +2099,29 @@ * This function find the shortest distance from the `cubic' bezier * curve to a given `point' and assigns it to `out'. Only use it for * cubic curves. - * [Note]: The function uses Newton's approximation to find the shortest - * distance. Another way would be to divide the cubic into conic - * or subdivide the curve into lines. * * @Input: - * [TODO] + * cubic :: + * The cubic bezier to which the shortest distance is to be + * computed. + * + * point :: + * Point from which the shortest distance is to be computed. * * @Return: - * [TODO] + * out :: + * Signed distance from the `point' to the `cubic'. + * + * FT_Error :: + * FreeType error, 0 means success. + * + * @Note: + * The function uses Newton's approximation to find the shortest + * distance. Another way would be to divide the cubic into conic + * or subdivide the curve into lines, but that is not implemented. + * + * The `cubic' parameter must have a `edge_type' of `SDF_EDGE_CUBIC'. + * */ static FT_Error get_min_distance_cubic( SDF_Edge* cubic, @@ -2296,14 +2364,24 @@ * sdf_edge_get_min_distance * * @Description: - * This function find the shortest distance from the `edge' to - * a given `point' and assigns it to `out'. + * This is a handy function which can be used to find shortest distance + * from a `point' to any type of `edge'. It checks the edge type and + * then calls the relevant `get_min_distance_' function. * * @Input: - * [TODO] + * edge :: + * An edge to which the shortest distance is to be computed. + * + * point :: + * Point from which the shortest distance is to be computed. * * @Return: - * [TODO] + * out :: + * Signed distance from the `point' to the `edge'. + * + * FT_Error :: + * FreeType error, 0 means success. + * */ static FT_Error sdf_edge_get_min_distance( SDF_Edge* edge, @@ -2349,10 +2427,24 @@ * this contour and assigns it to `out'. * * @Input: - * [TODO] + * contour :: + * A contour to which the shortest distance is to be computed. + * + * point :: + * Point from which the shortest distance is to be computed. * * @Return: - * [TODO] + * out :: + * Signed distance from the `point' to the `contour'. + * + * FT_Error :: + * FreeType error, 0 means success. + * + * @Note: + * The function does not return signed distance for each edge + * which make up the contour, it simply returns the shortest + * of all the edges. + * */ static FT_Error sdf_contour_get_min_distance( SDF_Contour* contour, @@ -2420,10 +2512,23 @@ * all the edges. * * @Input: - * [TODO] + * internal_params :: + * Internal parameters and properties required by the rasterizer. + * See `SDF_Params' for the actual parameters. + * + * shape :: + * A complete shape which is used to generate SDF. + * + * spread :: + * Maximum distances to be allowed inthe output bitmap. + * + * @Return + * bitmap :: + * The output bitmap which will contain the SDF information. + * + * FT_Error :: + * FreeType error, 0 means success. * - * @Return: - * [TODO] */ static FT_Error sdf_generate( const SDF_Params internal_params, @@ -2565,10 +2670,23 @@ * safely. * * @Input: - * [TODO] + * internal_params :: + * Internal parameters and properties required by the rasterizer. + * See `SDF_Params' for the actual parameters. + * + * shape :: + * A complete shape which is used to generate SDF. + * + * spread :: + * Maximum distances to be allowed inthe output bitmap. + * + * @Return + * bitmap :: + * The output bitmap which will contain the SDF information. + * + * FT_Error :: + * FreeType error, 0 means success. * - * @Return: - * [TODO] */ static FT_Error sdf_generate_bounding_box( const SDF_Params internal_params, @@ -2763,10 +2881,23 @@ * original edges, it will only contain lines. * * @Input: - * [TODO] + * internal_params :: + * Internal parameters and properties required by the rasterizer. + * See `SDF_Params' for the actual parameters. + * + * shape :: + * A complete shape which is used to generate SDF. + * + * spread :: + * Maximum distances to be allowed inthe output bitmap. + * + * @Return + * bitmap :: + * The output bitmap which will contain the SDF information. + * + * FT_Error :: + * FreeType error, 0 means success. * - * @Return: - * [TODO] */ static FT_Error sdf_generate_subdivision( const SDF_Params internal_params, @@ -2800,10 +2931,23 @@ * the pixels inside the coarse grid. * * @Input: - * [TODO] + * internal_params :: + * Internal parameters and properties required by the rasterizer. + * See `SDF_Params' for the actual parameters. + * + * shape :: + * A complete shape which is used to generate SDF. + * + * spread :: + * Maximum distances to be allowed inthe output bitmap. + * + * @Return + * bitmap :: + * The output bitmap which will contain the SDF information. + * + * FT_Error :: + * FreeType error, 0 means success. * - * @Return: - * [TODO] */ static FT_Error sdf_generate_coarse_grid( const SDF_Params internal_params, |