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/*
* Helper functions to use cairo with inkscape
*
* Copyright (C) 2007 bulia byak
* Copyright (C) 2008 Johan Engelen
*
* Released under GNU GPL
*
*/
#include <cairo.h>
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <libnr/nr-pixblock.h>
#include <libnr/nr-convert2geom.h>
#include "../style.h"
#include "nr-arena.h"
#include "sp-canvas.h"
#include <2geom/pathvector.h>
#include <2geom/bezier-curve.h>
#include <2geom/hvlinesegment.h>
#include <2geom/matrix.h>
#include <2geom/point.h>
#include <2geom/path.h>
#include <2geom/transforms.h>
#include <2geom/sbasis-to-bezier.h>
/** Creates a cairo context to render to the given pixblock on the given area */
cairo_t *
nr_create_cairo_context_for_data (NRRectL *area, NRRectL *buf_area, unsigned char *px, unsigned int rowstride)
{
if (!nr_rect_l_test_intersect_ptr(buf_area, area))
return NULL;
NRRectL clip;
nr_rect_l_intersect (&clip, buf_area, area);
unsigned char *dpx = px + (clip.y0 - buf_area->y0) * rowstride + 4 * (clip.x0 - buf_area->x0);
int width = area->x1 - area->x0;
int height = area->y1 - area->y0;
// even though cairo cannot draw in nonpremul mode, select ARGB32 for R8G8B8A8N as the closest; later eliminate R8G8B8A8N everywhere
cairo_surface_t* cst = cairo_image_surface_create_for_data
(dpx,
CAIRO_FORMAT_ARGB32,
width,
height,
rowstride);
cairo_t *ct = cairo_create (cst);
return ct;
}
/** Creates a cairo context to render to the given SPCanvasBuf on the given area */
cairo_t *
nr_create_cairo_context_canvasbuf (NRRectL */*area*/, SPCanvasBuf *b)
{
return nr_create_cairo_context_for_data (&(b->rect), &(b->rect), b->buf, b->buf_rowstride);
}
/** Creates a cairo context to render to the given NRPixBlock on the given area */
cairo_t *
nr_create_cairo_context (NRRectL *area, NRPixBlock *pb)
{
return nr_create_cairo_context_for_data (area, &(pb->area), NR_PIXBLOCK_PX (pb), pb->rs);
}
/*
* Can be called recursively.
* If optimize_stroke == false, the view Rect is not used.
*/
static void
feed_curve_to_cairo(cairo_t *cr, Geom::Curve const &c, Geom::Matrix const & trans, Geom::Rect view, bool optimize_stroke)
{
if( dynamic_cast<Geom::LineSegment const*>(&c) ||
dynamic_cast<Geom::HLineSegment const*>(&c) ||
dynamic_cast<Geom::VLineSegment const*>(&c) )
{
Geom::Point end_tr = c.finalPoint() * trans;
if (!optimize_stroke) {
cairo_line_to(cr, end_tr[0], end_tr[1]);
} else {
Geom::Rect swept(c.initialPoint()*trans, end_tr);
if (swept.intersects(view)) {
cairo_line_to(cr, end_tr[0], end_tr[1]);
} else {
cairo_move_to(cr, end_tr[0], end_tr[1]);
}
}
}
else if(Geom::QuadraticBezier const *quadratic_bezier = dynamic_cast<Geom::QuadraticBezier const*>(&c)) {
std::vector<Geom::Point> points = quadratic_bezier->points();
points[0] *= trans;
points[1] *= trans;
points[2] *= trans;
Geom::Point b1 = points[0] + (2./3) * (points[1] - points[0]);
Geom::Point b2 = b1 + (1./3) * (points[2] - points[0]);
if (!optimize_stroke) {
cairo_curve_to(cr, b1[0], b1[1], b2[0], b2[1], points[2][0], points[2][1]);
} else {
Geom::Rect swept(points[0], points[2]);
swept.expandTo(points[1]);
if (swept.intersects(view)) {
cairo_curve_to(cr, b1[0], b1[1], b2[0], b2[1], points[2][0], points[2][1]);
} else {
cairo_move_to(cr, points[2][0], points[2][1]);
}
}
}
else if(Geom::CubicBezier const *cubic_bezier = dynamic_cast<Geom::CubicBezier const*>(&c)) {
std::vector<Geom::Point> points = cubic_bezier->points();
//points[0] *= trans; // don't do this one here for fun: it is only needed for optimized strokes
points[1] *= trans;
points[2] *= trans;
points[3] *= trans;
if (!optimize_stroke) {
cairo_curve_to(cr, points[1][0], points[1][1], points[2][0], points[2][1], points[3][0], points[3][1]);
} else {
points[0] *= trans; // didn't transform this point yet
Geom::Rect swept(points[0], points[3]);
swept.expandTo(points[1]);
swept.expandTo(points[2]);
if (swept.intersects(view)) {
cairo_curve_to(cr, points[1][0], points[1][1], points[2][0], points[2][1], points[3][0], points[3][1]);
} else {
cairo_move_to(cr, points[3][0], points[3][1]);
}
}
}
// else if(Geom::SVGEllipticalArc const *svg_elliptical_arc = dynamic_cast<Geom::SVGEllipticalArc *>(c)) {
// //TODO: get at the innards and spit them out to cairo
// }
else {
//this case handles sbasis as well as all other curve types
Geom::Path sbasis_path = Geom::cubicbezierpath_from_sbasis(c.toSBasis(), 0.1);
//recurse to convert the new path resulting from the sbasis to svgd
for(Geom::Path::iterator iter = sbasis_path.begin(); iter != sbasis_path.end(); ++iter) {
feed_curve_to_cairo(cr, *iter, trans, view, optimize_stroke);
}
}
}
/** Feeds path-creating calls to the cairo context translating them from the Path */
static void
feed_path_to_cairo (cairo_t *ct, Geom::Path const &path)
{
if (path.empty())
return;
cairo_move_to(ct, path.initialPoint()[0], path.initialPoint()[1] );
for(Geom::Path::const_iterator cit = path.begin(); cit != path.end_open(); ++cit) {
feed_curve_to_cairo(ct, *cit, Geom::identity(), Geom::Rect(), false); // optimize_stroke is false, so the view rect is not used
}
if (path.closed()) {
cairo_line_to(ct, path.initialPoint()[0], path.initialPoint()[1]);
// cairo_close_path(ct);
/* I think we should use cairo_close_path(ct) here but it doesn't work. (the closing line is not rendered completely)
According to cairo documentation:
The behavior of cairo_close_path() is distinct from simply calling cairo_line_to() with the equivalent coordinate
in the case of stroking. When a closed sub-path is stroked, there are no caps on the ends of the sub-path. Instead,
there is a line join connecting the final and initial segments of the sub-path.
*/
}
}
/** Feeds path-creating calls to the cairo context translating them from the Path, with the given transform and shift */
static void
feed_path_to_cairo (cairo_t *ct, Geom::Path const &path, Geom::Matrix trans, NR::Maybe<NR::Rect> area, bool optimize_stroke, double stroke_width)
{
if (!area || area->isEmpty())
return;
if (path.empty())
return;
// Transform all coordinates to coords within "area"
Geom::Point shift = to_2geom(area->min());
NR::Rect view = *area;
view.growBy (stroke_width);
view = view * from_2geom(Geom::Translate(-shift));
// Pass transformation to feed_curve, so that we don't need to create a whole new path.
Geom::Matrix transshift(trans * Geom::Translate(-shift));
Geom::Point initial = path.initialPoint() * transshift;
cairo_move_to(ct, initial[0], initial[1] );
for(Geom::Path::const_iterator cit = path.begin(); cit != path.end_open(); ++cit) {
feed_curve_to_cairo(ct, *cit, transshift, to_2geom(view), optimize_stroke);
}
if (path.closed()) {
cairo_line_to(ct, initial[0], initial[1]);
/* It seems we cannot use cairo_close_path(ct) here; maybe because some parts of the path have been clipped and not drawn (maybe the before last segment was outside view area)
However, according to cairo documentation:
The behavior of cairo_close_path() is distinct from simply calling cairo_line_to() with the equivalent coordinate
in the case of stroking. When a closed sub-path is stroked, there are no caps on the ends of the sub-path. Instead,
there is a line join connecting the final and initial segments of the sub-path.
*/
}
}
/** Feeds path-creating calls to the cairo context translating them from the PathVector, with the given transform and shift
* One must have done cairo_new_path(ct); before calling this function. */
void
feed_pathvector_to_cairo (cairo_t *ct, Geom::PathVector const &pathv, Geom::Matrix trans, NR::Maybe<NR::Rect> area, bool optimize_stroke, double stroke_width)
{
if (!area || area->isEmpty())
return;
if (pathv.empty())
return;
for(Geom::PathVector::const_iterator it = pathv.begin(); it != pathv.end(); ++it) {
feed_path_to_cairo(ct, *it, trans, area, optimize_stroke, stroke_width);
}
}
/** Feeds path-creating calls to the cairo context translating them from the PathVector
* One must have done cairo_new_path(ct); before calling this function. */
void
feed_pathvector_to_cairo (cairo_t *ct, Geom::PathVector const &pathv)
{
if (pathv.empty())
return;
for(Geom::PathVector::const_iterator it = pathv.begin(); it != pathv.end(); ++it) {
feed_path_to_cairo(ct, *it);
}
}
/*
Local Variables:
mode:c++
c-file-style:"stroustrup"
c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
indent-tabs-mode:nil
fill-column:99
End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :
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