adding path stroker component (first steps)
This commit is contained in:
David Turner
parent
318f3befc6
commit
b7e18efcd2
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@ -0,0 +1,144 @@
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#ifndef __FT_STROKER_H__
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#define __FT_STROKER_H__
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#include <ft2build.h>
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#include FT_OUTLINE_H
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FT_BEGIN_HEADER
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/**************************************************************
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*
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* @type: FT_Stroker
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*
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* @description:
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* opaque handler to a path stroker object
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*/
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typedef struct FT_StrokerRec_* FT_Stroker;
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/**************************************************************
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*
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* @enum: FT_Stroker_LineJoin
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*
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* @description:
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* these values determine how two joining lines are rendered
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* in a stroker.
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*
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* @values:
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* FT_STROKER_LINEJOIN_ROUND ::
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* used to render rounded line joins. circular arcs are used
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* to join two lines smoothly
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*
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* FT_STROKER_LINEJOIN_BEVEL ::
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* used to render beveled line joins; i.e. the two joining lines
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* are extended until they intersect
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*
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* FT_STROKER_LINEJOIN_MITER ::
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* same as beveled rendering, except that an additional line
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* break is added if the angle between the two joining lines
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* is too closed (this is useful to avoid unpleasant spikes
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* in beveled rendering).
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*/
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typedef enum
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{
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FT_STROKER_LINEJOIN_ROUND = 0,
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FT_STROKER_LINEJOIN_BEVEL,
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FT_STROKER_LINEJOIN_MITER
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} FT_Stroker_LineJoin;
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/**************************************************************
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*
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* @enum: FT_Stroker_LineCap
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*
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* @description:
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* these values determine how the end of opened sub-paths are
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* rendered in a stroke
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*
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* @values:
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* FT_STROKER_LINECAP_BUTT ::
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* the end of lines is rendered as a full stop on the last
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* point itself
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*
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* FT_STROKER_LINECAP_ROUND ::
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* the end of lines is rendered as a half-circle around the
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* last point
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*
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* FT_STROKER_LINEJOIN_MITER ::
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* the end of lines is rendered as a square around the
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* last point
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*/
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typedef enum
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{
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FT_STROKER_LINECAP_BUTT = 0,
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FT_STROKER_LINECAP_ROUND,
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FT_STROKER_LINECAP_SQUARE
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} FT_Stroker_LineCap;
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FT_EXPORT( FT_Error )
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FT_Stroker_New( FT_Memory memory,
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FT_Stroker *astroker );
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FT_EXPORT( void )
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FT_Stroker_Set( FT_Stroker stroker,
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FT_Fixed radius,
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FT_Stroker_LineCap line_cap,
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FT_Stroker_LineJoin line_join,
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FT_Fixed miter_limit );
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FT_EXPORT( FT_Error )
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FT_Stroker_BeginSubPath( FT_Stroker stroker,
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FT_Pos x,
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FT_Pos y,
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FT_Bool open );
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FT_EXPORT( FT_Error )
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FT_Stroker_EndSubPath( FT_Stroker stroker );
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FT_EXPORT( FT_Error )
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FT_Stroker_LineTo( FT_Stroker stroker,
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FT_Pos to_x,
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FT_Pos to_y );
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FT_EXPORT( FT_Error )
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FT_Stroker_ConicTo( FT_Stroker stroker,
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FT_Pos control_x,
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FT_Pos control_y,
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FT_Pos to_x,
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FT_Pos to_y );
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FT_EXPORT( FT_Error )
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FT_Stroker_CubicTo( FT_Stroker stroker,
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FT_Pos control1_x,
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FT_Pos control1_y,
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FT_Pos control2_x,
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FT_Pos control2_y,
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FT_Pos to_x,
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FT_Pos to_y );
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FT_EXPORT( FT_Error )
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FT_Stroker_GetCounts( FT_Stroker stroker,
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FT_UInt *anum_points,
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FT_UInt *anum_contours );
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FT_EXPORT( void )
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FT_Stroker_Export( FT_Stroker stroker,
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FT_Outliner* outline );
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FT_EXPORT( void )
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FT_Stroker_Done( FT_Stroker stroker );
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FT_EXPORT( FT_Error )
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FT_Stroker_ParseOutline( FT_Stroker stroker,
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FT_Outline* outline,
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FT_Bool opened );
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FT_END_HEADER
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#endif /* __FT_STROKER_H__ */
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@ -173,6 +173,27 @@ FT_BEGIN_HEADER
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FT_Fixed y );
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/*************************************************************************/
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/* */
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/* @function: */
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/* FT_Angle_Diff */
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/* */
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/* @description: */
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/* Returns the difference between two angles. The result is always */
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/* constrained to the ]-PI..PI] interval */
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/* */
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/* @input: */
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/* angle1 :: first angle */
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/* angle2 :: second angle */
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/* */
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/* @return: */
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/* contrainted value of 'value2-value1' */
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/* */
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FT_EXPORT_DEF( FT_Angle )
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FT_Angle_Dif( FT_Angle angle1,
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FT_Angle angle2 );
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/*************************************************************************/
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/* */
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/* @function: */
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@ -0,0 +1,290 @@
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#include <ft2build.h>
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#include FT_STROKER_H
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#include FT_TRIGONOMETRY_H
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/***************************************************************************/
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/***************************************************************************/
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/***** *****/
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/***** STROKE BORDERS *****/
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/***** *****/
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/***************************************************************************/
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/***************************************************************************/
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typedef enum
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{
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FT_STROKE_TAG_ON = 1, /* on-curve point */
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FT_STROKE_TAG_CUBIC = 2, /* cubic off-point */
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FT_STROKE_TAG_BEGIN = 4, /* sub-path start */
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FT_STROKE_TAG_END = 8 /* sub-path end */
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} FT_StrokeTags;
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typedef struct FT_StrokeBorderRec_
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{
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FT_UInt num_points;
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FT_UInt max_points;
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FT_Vector* points;
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FT_Byte* tags;
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FT_Bool movable;
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FT_Int start; /* index of current sub-path start point */
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FT_Memory memory;
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} FT_StrokeBorderRec, *FT_StrokeBorder;
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static FT_Error
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ft_stroke_border_grow( FT_StrokeBorder border,
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FT_UInt new_points )
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{
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FT_UInt old_max = border->max_points;
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FT_UInt new_max = border->num_points + new_points;
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FT_Error error = 0;
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if ( new_max > old_max )
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{
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FT_UInt cur_max = old_max;
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FT_Memory memory =
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while ( cur_max < new_max )
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cur_max += (cur_max >> 1) + 16;
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if ( FT_RENEW_ARRAY( border->points, old_max, cur_max ) ||
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FT_RENEW_ARRAY( border->tags, old_max, cur_max ) )
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goto Exit;
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border->max_points = cur_max;
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}
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Exit:
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return error;
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}
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static void
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ft_stroke_border_close( FT_StrokeBorder border )
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{
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FT_ASSERT( border->start >= 0 );
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border->tags[ border->start ] |= FT_STROKE_TAG_BEGIN;
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border->tags[ border->num_points-1 ] |= FT_STROKE_TAG_END;
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border->start = -1;
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}
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static FT_Error
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ft_stroke_border_lineto( FT_StrokeBorder border,
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FT_Vector* to )
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{
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FT_Error error;
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FT_ASSERT( border->start >= 0 );
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error = ft_stroker_border_grow( border, 1 );
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if (!error)
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{
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FT_Vector* vec = border->points + border->num_points;
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FT_Byte* tag = border->tags + border->num_points;
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vec[0] = *to;
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tag[0] = FT_STROKE_TAG_ON;
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border->num_points += 1;
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}
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return error;
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}
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static FT_Error
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ft_stroke_border_conicto( FT_StrokeBorder border,
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FT_Vector* control,
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FT_Vector* to )
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{
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FT_Error error;
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FT_ASSERT( border->start >= 0 );
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error = ft_stroker_border_grow( border, 2 );
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if (!error)
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{
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FT_Vector* vec = border->points + border->num_points;
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FT_Byte* tag = border->tags + border->num_points;
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vec[0] = *control;
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vec[1] = *to;
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tag[0] = 0;
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tag[1] = FT_STROKE_TAG_ON;
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border->num_points += 2;
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}
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return error;
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}
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static FT_Error
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ft_stroke_border_cubicto( FT_StrokeBorder border,
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FT_Vector* control1,
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FT_Vector* control2,
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FT_Vector* to )
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{
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FT_Error error;
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FT_ASSERT( border->start >= 0 );
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error = ft_stroker_border_grow( border, 3 );
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if (!error)
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{
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FT_Vector* vec = border->points + border->num_points;
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FT_Byte* tag = border->tags + border->num_points;
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vec[0] = *control1;
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vec[1] = *control2;
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vec[2] = *to;
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tag[0] = FT_STROKE_TAG_CUBIC;
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tag[1] = FT_STROKE_TAG_CUBIC;
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tag[2] = FT_STROKE_TAG_ON;
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border->num_points += 3;
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}
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return error;
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}
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static FT_Error
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ft_stroke_border_moveto( FT_StrokeBorder border,
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FT_Vector* to )
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{
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FT_Error error;
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/* close current open path if any ? */
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if ( border->start >= 0 )
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ft_stroke_border_close( border );
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border->start = border->num_points;
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return ft_stroke_border_lineto( border, to );
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}
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static void
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ft_stroke_border_init( FT_StrokeBorder border,
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FT_Memory memory )
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{
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border->memory = memory;
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border->points = NULL;
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border->tags = NULL;
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border->num_points = 0;
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border->max_points = 0;
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border->start = -1;
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}
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static void
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ft_stroke_border_reset( FT_StrokeBorder border )
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{
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border->num_points = 0;
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border->start = -1;
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}
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static void
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ft_stroke_border_done( FT_StrokeBorder border )
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{
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memory = border->memory;
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FT_FREE( border->points );
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FT_FREE( border->tags );
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border->num_points = 0;
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border->max_points = 0;
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border->start = -1;
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}
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/***************************************************************************/
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/***************************************************************************/
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/***** *****/
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/***** STROKER *****/
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/***** *****/
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/***************************************************************************/
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/***************************************************************************/
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#define FT_SIDE_TO_ROTATE(s) (FT_PI2 - (s)*FT_PI)
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typedef struct FT_StrokerRec_
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{
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FT_Angle angle_in;
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FT_Angle angle_out;
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FT_Vector center;
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FT_Bool first_point;
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FT_Bool subpath_open;
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FT_Angle subpath_angle;
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FT_Vector subpath_start;
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FT_Stroker_LineCap line_cap;
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FT_Stroker_LineJoin line_join;
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FT_Fixed miter_limit;
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FT_Fixed radius;
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FT_StrokeBorderRec borders[2];
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FT_Memory memory;
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} FT_StrokerRec;
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FT_EXPORT_DEF( FT_Error )
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FT_Stroker_New( FT_Memory memory,
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FT_Stroker *astroker )
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{
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FT_Error error;
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FT_Stroker stroker;
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if ( !FT_NEW( stroker ) )
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{
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stroker->memory = memory;
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ft_stroke_border_init( &stroker->borders[0], memory );
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ft_stroke_border_init( &stroker->borders[1], memory );
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}
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*astroker = stroker;
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return error;
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}
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FT_EXPORT_DEF( void )
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FT_Stroker_Set( FT_Stroker stroker,
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FT_Fixed radius,
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FT_Stroker_LineCap line_cap,
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FT_Stroker_LineJoin line_join,
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FT_Fixed miter_limit )
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{
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stroker->radius = radius;
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stroker->line_cap = line_cap;
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stroker->line_join = line_join;
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stroker->miter_limit = miter_limit;
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ft_stroke_border_reset( &stroker->borders[0] );
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ft_stroke_border_reset( &stroker->borders[1] );
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}
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FT_EXPORT( void )
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FT_Stroker_Done( FT_Stroker stroker )
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{
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if ( stroker )
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{
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FT_Memory memory = stroker->memory;
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ft_stroke_border_done( &stroker->borders[0] );
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ft_stroke_border_done( &stroker->borders[1] );
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stroker->memory = NULL;
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FT_FREE( stroker );
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}
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}
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@ -451,4 +451,21 @@
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}
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/* documentation is in fttrigon.h */
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FT_EXPORT_DEF( FT_Angle )
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FT_Angle_Dif( FT_Angle angle1,
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FT_Angle angle2 )
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{
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FT_Angle delta = angle2 - angle1;
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delta %= FT_ANGLE_2PI;
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if ( delta > FT_ANGLE_PI )
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delta -= FT_ANGLE_2PI;
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return delta;
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}
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/* END */
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