summary | shortlog | log | commit | commitdiff | tree
raw | patch | inline | side by side (parent: 8887dc7)
raw | patch | inline | side by side (parent: 8887dc7)
author | johanengelen <johanengelen@users.sourceforge.net> | |
Mon, 7 Jul 2008 13:44:03 +0000 (13:44 +0000) | ||
committer | johanengelen <johanengelen@users.sourceforge.net> | |
Mon, 7 Jul 2008 13:44:03 +0000 (13:44 +0000) |
src/sp-shape.cpp | patch | blob | history | |
src/sp-shape.h | patch | blob | history |
diff --git a/src/sp-shape.cpp b/src/sp-shape.cpp
index 39c1f87a4d26ee280fdf8cac708a8976a6ed5060..e38dba48f140a4db506162fe47267d3ef32061b2 100644 (file)
--- a/src/sp-shape.cpp
+++ b/src/sp-shape.cpp
}
}
-
-/**
-* Works out whether a marker of a given type is required at a particular
-* point on a shape.
-*
-* \param shape Shape of interest.
-* \param m Marker type (e.g. SP_MARKER_LOC_START)
-* \param bp Path segment.
-* \return 1 if a marker is required here, otherwise 0.
-*/
-bool
-sp_shape_marker_required(SPShape const *shape, int const m, NArtBpath const *bp)
-{
- if (shape->marker[m] == NULL) {
- return false;
- }
-
- if (bp == SP_CURVE_BPATH(shape->curve))
- return m == SP_MARKER_LOC_START;
- else if (bp[1].code == NR_END)
- return m == SP_MARKER_LOC_END;
- else
- return m == SP_MARKER_LOC_MID;
-}
-
-static bool
-is_moveto(NRPathcode const c)
-{
- return c == NR_MOVETO || c == NR_MOVETO_OPEN;
-}
-
-/**
- * Helper function that advances a subpath's bpath to the first subpath
- * by checking for moveto segments.
- *
- * \pre The bpath[] containing bp begins with a moveto.
- */
-static NArtBpath const *
-first_seg_in_subpath(NArtBpath const *bp)
-{
- while (!is_moveto(bp->code)) {
- --bp;
- }
- return bp;
-}
-
-/**
- * Advances the bpath to the last segment in the subpath.
- */
-static NArtBpath const *
-last_seg_in_subpath(NArtBpath const *bp)
-{
- for(;;) {
- ++bp;
- switch (bp->code) {
- case NR_MOVETO:
- case NR_MOVETO_OPEN:
- case NR_END:
- --bp;
- return bp;
-
- default: continue;
- }
- }
-}
-
-
-/* A subpath begins with a moveto and ends immediately before the next moveto or NR_END.
- * (`moveto' here means either NR_MOVETO or NR_MOVETO_OPEN.) I'm assuming that non-empty
- * paths always begin with a moveto.
- *
- * The control points of the subpath are the control points of the path elements of the subpath.
- *
- * As usual, the control points of a moveto or NR_LINETO are {c(3)}, and
- * the control points of a NR_CURVETO are {c(1), c(2), c(3)}.
- * (It follows from the definition that NR_END isn't part of a subpath.)
- *
- * The initial control point is bpath[bi0].c(3).
- *
- * Reference: http://www.w3.org/TR/SVG11/painting.html#MarkerElement, the `orient' attribute.
- * Reference for behaviour of zero-length segments:
- * http://www.w3.org/TR/SVG11/implnote.html#PathElementImplementationNotes
- */
-
-static double const no_tangent = 128.0; /* arbitrarily-chosen value outside the range of atan2,
- * i.e. outside of [-pi, pi]. This value is incremented by
- * 1 and checked using > to be safe from floating-point
- * equality comparison madness.*/
-
-/**
- * Helper function to calculate the outgoing tangent of a path
- * ( atan2(other - p0) )
- * \pre The bpath[] containing bp0 begins with a moveto.
- */
-static double
-outgoing_tangent(NArtBpath const *bp0)
-{
- /* See notes in comment block above. */
-
- g_assert(bp0->code != NR_END);
- NR::Point const &p0 = bp0->c(3);
- NR::Point other;
- for (NArtBpath const *bp = bp0;;) {
- ++bp;
- switch (bp->code) {
- case NR_LINETO:
- other = bp->c(3);
- if (other != p0) {
- goto found;
- }
- break;
-
- case NR_CURVETO:
- for (unsigned ci = 1; ci <= 3; ++ci) {
- other = bp->c(ci);
- if (other != p0) {
- goto found;
- }
- }
- break;
-
- case NR_MOVETO_OPEN:
- case NR_END:
- case NR_MOVETO:
- bp = first_seg_in_subpath(bp0);
- if (bp == bp0) {
- /* Gone right around the subpath without finding any different point since the
- * initial moveto. */
- return no_tangent + 1;
- }
- if (bp->code != NR_MOVETO) {
- /* Open subpath. */
- return no_tangent + 1;
- }
- other = bp->c(3);
- if (other != p0) {
- goto found;
- }
- break;
- }
-
- if (bp == bp0) {
- /* Back where we started, so zero-length subpath. */
- return no_tangent + 1;
-
- /* Note: this test must come after we've looked at element bp, in case bp0 is a curve:
- * we must look at c(1) and c(2). (E.g. single-curve subpath.)
- */
- }
- }
-
-found:
- return atan2( other - p0 );
-}
-
-/**
- * Helper function to calculate the incoming tangent of a path
- * ( atan2(p0 - other) )
- *
- * \pre The bpath[] containing bp0 begins with a moveto.
- */
-static double
-incoming_tangent(NArtBpath const *bp0)
-{
- /* See notes in comment block before outgoing_tangent. */
-
- g_assert(bp0->code != NR_END);
- NR::Point const &p0 = bp0->c(3);
- NR::Point other;
- for (NArtBpath const *bp = bp0;;) {
- switch (bp->code) {
- case NR_LINETO:
- other = bp->c(3);
- if (other != p0) {
- goto found;
- }
- --bp;
- break;
-
- case NR_CURVETO:
- for (unsigned ci = 3; ci != 0; --ci) {
- other = bp->c(ci);
- if (other != p0) {
- goto found;
- }
- }
- --bp;
- break;
-
- case NR_MOVETO:
- case NR_MOVETO_OPEN:
- other = bp->c(3);
- if (other != p0) {
- goto found;
- }
- if (bp->code != NR_MOVETO) {
- /* Open subpath. */
- return no_tangent + 1;
- }
- bp = last_seg_in_subpath(bp0);
- break;
-
- default: /* includes NR_END */
- g_error("Found invalid path code %u in middle of path.", bp->code);
- return no_tangent + 1;
- }
-
- if (bp == bp0) {
- /* Back where we started from: zero-length subpath. */
- return no_tangent + 1;
- }
- }
-
-found:
- return atan2( p0 - other );
-}
-
-
-/**
- * Calculate the transform required to get a marker's path object in the
- * right place for particular path segment on a shape. You should
- * call sp_shape_marker_required first to see if a marker is required
- * at this point.
- *
- * \see sp_shape_marker_required.
- *
- * \param shape Shape which the marker is for.
- * \param m Marker type (e.g. SP_MARKER_LOC_START)
- * \param bp Path segment which the arrow is for.
- * \return Transform matrix.
- */
-NR::Matrix
-sp_shape_marker_get_transform(SPShape const *shape, NArtBpath const *bp)
-{
- g_return_val_if_fail(( is_moveto(SP_CURVE_BPATH(shape->curve)[0].code)
- && ( 0 < shape->curve->get_length() )
- && ( SP_CURVE_BPATH(shape->curve)[shape->curve->get_length()].code == NR_END ) ),
- NR::Matrix(NR::translate(bp->c(3))));
- double const angle1 = incoming_tangent(bp);
- double const angle2 = outgoing_tangent(bp);
-
- double ret_angle;
- if (angle1 > no_tangent) {
- /* First vertex of an open subpath. */
- ret_angle = ( angle2 > no_tangent
- ? 0.
- : angle2 );
- } else if (angle2 > no_tangent) {
- /* Last vertex of an open subpath. */
- ret_angle = angle1;
- } else {
- ret_angle = .5 * (angle1 + angle2);
-
- if ( fabs( angle2 - angle1 ) > M_PI ) {
- /* ret_angle is in the middle of the larger of the two sectors between angle1 and
- * angle2, so flip it by 180degrees to force it to the middle of the smaller sector.
- *
- * (Imagine a circle with rays drawn at angle1 and angle2 from the centre of the
- * circle. Those two rays divide the circle into two sectors.)
- */
- ret_angle += M_PI;
- }
- }
-
- return NR::Matrix(NR::rotate(ret_angle)) * NR::translate(bp->c(3));
-}
-
/**
* Calculate the transform required to get a marker's path object in the
* right place for particular path segment on a shape.
* element and the slope of the curve at the given vertex. (Note: if there is a discontinuity at a vertex, the slope
* is the average of the slopes of the two segments of the curve that join at the given vertex. If a slope cannot be
* determined, the slope is assumed to be zero.)
+ *
+ * Reference: http://www.w3.org/TR/SVG11/painting.html#MarkerElement, the `orient' attribute.
+ * Reference for behaviour of zero-length segments:
+ * http://www.w3.org/TR/SVG11/implnote.html#PathElementImplementationNotes
*/
Geom::Matrix
sp_shape_marker_get_transform(Geom::Curve const & c1, Geom::Curve const & c2)
diff --git a/src/sp-shape.h b/src/sp-shape.h
index aa78fcc33c1d3a6137aa9c7de28bd2516d38a6f5..4b1ded23649394f2066412c1d4be334d62b72817 100644 (file)
--- a/src/sp-shape.h
+++ b/src/sp-shape.h
void sp_shape_set_marker (SPObject *object, unsigned int key, const gchar *value);
int sp_shape_has_markers (SPShape const *shape);
int sp_shape_number_of_markers (SPShape* Shape, int type);
-NR::Matrix sp_shape_marker_get_transform(SPShape const *shape, NArtBpath const *bp);
-bool sp_shape_marker_required(SPShape const *shape, int const m, NArtBpath const *bp);
Geom::Matrix sp_shape_marker_get_transform(Geom::Curve const & c1, Geom::Curve const & c2);
Geom::Matrix sp_shape_marker_get_transform_at_start(Geom::Curve const & c);