Commit 2de1b5630d7717f5fc5401a7ca3aa756d3c204fd
2020-08-17T16:36:30
[sdf] Add functions to decompose `FT_Outline`. * src/sdf/ftsdf.c (sdf_move_to, sdf_line_to, sdf_conic_to, sdf_cubic_to): New auxiliary decomposition functions. (sdf_compose_funcs): New structure. (sdf_outline_decompose): New function.
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diff --git a/ChangeLog b/ChangeLog
index ba583ad..6c3c986 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,14 @@
2020-08-17 Anuj Verma <anujv@iitbhilai.ac.in>
+ [sdf] Add functions to decompose `FT_Outline`.
+
+ * src/sdf/ftsdf.c (sdf_move_to, sdf_line_to, sdf_conic_to,
+ sdf_cubic_to): New auxiliary decomposition functions.
+ (sdf_compose_funcs): New structure.
+ (sdf_outline_decompose): New function.
+
+2020-08-17 Anuj Verma <anujv@iitbhilai.ac.in>
+
[sdf] Structs, enums, macros, and functions for 'sdf' rasterizer.
* src/sdf/ftsdf.c (FT_DEBUG_INNER, FT_ASSIGNP_INNER)
diff --git a/src/sdf/ftsdf.c b/src/sdf/ftsdf.c
index be7c2b4..4967ed4 100644
--- a/src/sdf/ftsdf.c
+++ b/src/sdf/ftsdf.c
@@ -643,4 +643,203 @@
SDF_FREE( *shape );
}
+
+ /**************************************************************************
+ *
+ * shape decomposition functions
+ *
+ */
+
+ /* This function is called when starting a new contour at `to`, */
+ /* which gets added to the shape's list. */
+ static FT_Error
+ sdf_move_to( const FT_26D6_Vec* to,
+ void* user )
+ {
+ SDF_Shape* shape = ( SDF_Shape* )user;
+ SDF_Contour* contour = NULL;
+
+ FT_Error error = FT_Err_Ok;
+ FT_Memory memory = shape->memory;
+
+
+ if ( !to || !user )
+ {
+ error = FT_THROW( Invalid_Argument );
+ goto Exit;
+ }
+
+ FT_CALL( sdf_contour_new( memory, &contour ) );
+
+ contour->last_pos = *to;
+ contour->next = shape->contours;
+ shape->contours = contour;
+
+ Exit:
+ return error;
+ }
+
+
+ /* This function is called when there is a line in the */
+ /* contour. The line starts at the previous edge point and */
+ /* stops at `to`. */
+ static FT_Error
+ sdf_line_to( const FT_26D6_Vec* to,
+ void* user )
+ {
+ SDF_Shape* shape = ( SDF_Shape* )user;
+ SDF_Edge* edge = NULL;
+ SDF_Contour* contour = NULL;
+
+ FT_Error error = FT_Err_Ok;
+ FT_Memory memory = shape->memory;
+
+
+ if ( !to || !user )
+ {
+ error = FT_THROW( Invalid_Argument );
+ goto Exit;
+ }
+
+ contour = shape->contours;
+
+ if ( contour->last_pos.x == to->x &&
+ contour->last_pos.y == to->y )
+ goto Exit;
+
+ FT_CALL( sdf_edge_new( memory, &edge ) );
+
+ edge->edge_type = SDF_EDGE_LINE;
+ edge->start_pos = contour->last_pos;
+ edge->end_pos = *to;
+
+ edge->next = contour->edges;
+ contour->edges = edge;
+ contour->last_pos = *to;
+
+ Exit:
+ return error;
+ }
+
+
+ /* This function is called when there is a conic Bezier curve */
+ /* in the contour. The curve starts at the previous edge point */
+ /* and stops at `to`, with control point `control_1`. */
+ static FT_Error
+ sdf_conic_to( const FT_26D6_Vec* control_1,
+ const FT_26D6_Vec* to,
+ void* user )
+ {
+ SDF_Shape* shape = ( SDF_Shape* )user;
+ SDF_Edge* edge = NULL;
+ SDF_Contour* contour = NULL;
+
+ FT_Error error = FT_Err_Ok;
+ FT_Memory memory = shape->memory;
+
+
+ if ( !control_1 || !to || !user )
+ {
+ error = FT_THROW( Invalid_Argument );
+ goto Exit;
+ }
+
+ contour = shape->contours;
+
+ FT_CALL( sdf_edge_new( memory, &edge ) );
+
+ edge->edge_type = SDF_EDGE_CONIC;
+ edge->start_pos = contour->last_pos;
+ edge->control_a = *control_1;
+ edge->end_pos = *to;
+
+ edge->next = contour->edges;
+ contour->edges = edge;
+ contour->last_pos = *to;
+
+ Exit:
+ return error;
+ }
+
+
+ /* This function is called when there is a cubic Bezier curve */
+ /* in the contour. The curve starts at the previous edge point */
+ /* and stops at `to`, with two control points `control_1` and */
+ /* `control_2`. */
+ static FT_Error
+ sdf_cubic_to( const FT_26D6_Vec* control_1,
+ const FT_26D6_Vec* control_2,
+ const FT_26D6_Vec* to,
+ void* user )
+ {
+ SDF_Shape* shape = ( SDF_Shape* )user;
+ SDF_Edge* edge = NULL;
+ SDF_Contour* contour = NULL;
+
+ FT_Error error = FT_Err_Ok;
+ FT_Memory memory = shape->memory;
+
+
+ if ( !control_2 || !control_1 || !to || !user )
+ {
+ error = FT_THROW( Invalid_Argument );
+ goto Exit;
+ }
+
+ contour = shape->contours;
+
+ FT_CALL( sdf_edge_new( memory, &edge ) );
+
+ edge->edge_type = SDF_EDGE_CUBIC;
+ edge->start_pos = contour->last_pos;
+ edge->control_a = *control_1;
+ edge->control_b = *control_2;
+ edge->end_pos = *to;
+
+ edge->next = contour->edges;
+ contour->edges = edge;
+ contour->last_pos = *to;
+
+ Exit:
+ return error;
+ }
+
+
+ /* Construct the structure to hold all four outline */
+ /* decomposition functions. */
+ FT_DEFINE_OUTLINE_FUNCS(
+ sdf_decompose_funcs,
+
+ (FT_Outline_MoveTo_Func) sdf_move_to, /* move_to */
+ (FT_Outline_LineTo_Func) sdf_line_to, /* line_to */
+ (FT_Outline_ConicTo_Func)sdf_conic_to, /* conic_to */
+ (FT_Outline_CubicTo_Func)sdf_cubic_to, /* cubic_to */
+
+ 0, /* shift */
+ 0 /* delta */
+ )
+
+
+ /* Decompose `outline` and put it into the `shape` structure. */
+ static FT_Error
+ sdf_outline_decompose( FT_Outline* outline,
+ SDF_Shape* shape )
+ {
+ FT_Error error = FT_Err_Ok;
+
+
+ if ( !outline || !shape )
+ {
+ error = FT_THROW( Invalid_Argument );
+ goto Exit;
+ }
+
+ error = FT_Outline_Decompose( outline,
+ &sdf_decompose_funcs,
+ (void*)shape );
+
+ Exit:
+ return error;
+ }
+
/* END */