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// SPDX-License-Identifier: GPL-2.0-or-later
/** @file
* TODO: insert short description here
*//*
* Authors: see git history
*
* Copyright (C) 2018 Authors
* Released under GNU GPL v2+, read the file 'COPYING' for more information.
*/
#include <cairo.h>
#include "sp-radial-gradient.h"
#include "attributes.h"
#include "style.h"
#include "xml/repr.h"
#include <2geom/transforms.h>
/*
* Radial Gradient
*/
SPRadialGradient::SPRadialGradient() : SPGradient() {
this->cx.unset(SVGLength::PERCENT, 0.5, 0.5);
this->cy.unset(SVGLength::PERCENT, 0.5, 0.5);
this->r.unset(SVGLength::PERCENT, 0.5, 0.5);
this->fx.unset(SVGLength::PERCENT, 0.5, 0.5);
this->fy.unset(SVGLength::PERCENT, 0.5, 0.5);
this->fr.unset(SVGLength::PERCENT, 0.5, 0.5);
}
SPRadialGradient::~SPRadialGradient() = default;
/**
* Set radial gradient attributes from associated repr.
*/
void SPRadialGradient::build(SPDocument *document, Inkscape::XML::Node *repr) {
SPGradient::build(document, repr);
this->readAttr(SPAttr::CX);
this->readAttr(SPAttr::CY);
this->readAttr(SPAttr::R);
this->readAttr(SPAttr::FX);
this->readAttr(SPAttr::FY);
this->readAttr(SPAttr::FR);
}
/**
* Set radial gradient attribute.
*/
void SPRadialGradient::set(SPAttr key, gchar const *value) {
switch (key) {
case SPAttr::CX:
if (!this->cx.read(value)) {
this->cx.unset(SVGLength::PERCENT, 0.5, 0.5);
}
if (!this->fx._set) {
this->fx.value = this->cx.value;
this->fx.computed = this->cx.computed;
}
this->requestModified(SP_OBJECT_MODIFIED_FLAG);
break;
case SPAttr::CY:
if (!this->cy.read(value)) {
this->cy.unset(SVGLength::PERCENT, 0.5, 0.5);
}
if (!this->fy._set) {
this->fy.value = this->cy.value;
this->fy.computed = this->cy.computed;
}
this->requestModified(SP_OBJECT_MODIFIED_FLAG);
break;
case SPAttr::R:
if (!this->r.read(value)) {
this->r.unset(SVGLength::PERCENT, 0.5, 0.5);
}
this->requestModified(SP_OBJECT_MODIFIED_FLAG);
break;
case SPAttr::FX:
if (!this->fx.read(value)) {
this->fx.unset(this->cx.unit, this->cx.value, this->cx.computed);
}
this->requestModified(SP_OBJECT_MODIFIED_FLAG);
break;
case SPAttr::FY:
if (!this->fy.read(value)) {
this->fy.unset(this->cy.unit, this->cy.value, this->cy.computed);
}
this->requestModified(SP_OBJECT_MODIFIED_FLAG);
break;
case SPAttr::FR:
if (!this->fr.read(value)) {
this->fr.unset(SVGLength::PERCENT, 0.0, 0.0);
}
this->requestModified(SP_OBJECT_MODIFIED_FLAG);
break;
default:
SPGradient::set(key, value);
break;
}
}
void
SPRadialGradient::update(SPCtx *ctx, guint flags)
{
// To do: Verify flags.
if (flags & (SP_OBJECT_MODIFIED_FLAG | SP_OBJECT_STYLE_MODIFIED_FLAG | SP_OBJECT_VIEWPORT_MODIFIED_FLAG)) {
SPItemCtx const *ictx = reinterpret_cast<SPItemCtx const *>(ctx);
if (getUnits() == SP_GRADIENT_UNITS_USERSPACEONUSE) {
double w = ictx->viewport.width();
double h = ictx->viewport.height();
double d = sqrt ((w*w + h*h)/2.0);
double const em = style->font_size.computed;
double const ex = 0.5 * em; // fixme: get x height from pango or libnrtype.
this->cx.update(em, ex, w);
this->cy.update(em, ex, h);
this->r.update(em, ex, d);
this->fx.update(em, ex, w);
this->fy.update(em, ex, h);
this->fr.update(em, ex, d);
}
}
}
/**
* Write radial gradient attributes to associated repr.
*/
Inkscape::XML::Node* SPRadialGradient::write(Inkscape::XML::Document *xml_doc, Inkscape::XML::Node *repr, guint flags) {
if ((flags & SP_OBJECT_WRITE_BUILD) && !repr) {
repr = xml_doc->createElement("svg:radialGradient");
}
if ((flags & SP_OBJECT_WRITE_ALL) || this->cx._set) {
repr->setAttributeSvgDouble("cx", this->cx.computed);
}
if ((flags & SP_OBJECT_WRITE_ALL) || this->cy._set) {
repr->setAttributeSvgDouble("cy", this->cy.computed);
}
if ((flags & SP_OBJECT_WRITE_ALL) || this->r._set) {
repr->setAttributeSvgDouble("r", this->r.computed);
}
if ((flags & SP_OBJECT_WRITE_ALL) || this->fx._set) {
repr->setAttributeSvgDouble("fx", this->fx.computed);
}
if ((flags & SP_OBJECT_WRITE_ALL) || this->fy._set) {
repr->setAttributeSvgDouble("fy", this->fy.computed);
}
if ((flags & SP_OBJECT_WRITE_ALL) || this->fr._set) {
repr->setAttributeSvgDouble("fr", this->fr.computed);
}
SPGradient::write(xml_doc, repr, flags);
return repr;
}
cairo_pattern_t* SPRadialGradient::pattern_new(cairo_t *ct, Geom::OptRect const &bbox, double opacity) {
this->ensureVector();
Geom::Point focus(this->fx.computed, this->fy.computed);
Geom::Point center(this->cx.computed, this->cy.computed);
double radius = this->r.computed;
double focusr = this->fr.computed;
double scale = 1.0;
double tolerance = cairo_get_tolerance(ct);
// NOTE: SVG2 will allow the use of a focus circle which can
// have its center outside the first circle.
// code below suggested by Cairo devs to overcome tolerance problems
// more: https://bugs.freedesktop.org/show_bug.cgi?id=40918
// Corrected for
// https://bugs.launchpad.net/inkscape/+bug/970355
Geom::Affine gs2user = this->gradientTransform;
if (this->getUnits() == SP_GRADIENT_UNITS_OBJECTBOUNDINGBOX && bbox) {
Geom::Affine bbox2user(bbox->width(), 0, 0, bbox->height(), bbox->left(), bbox->top());
gs2user *= bbox2user;
}
// we need to use vectors with the same direction to represent the transformed
// radius and the focus-center delta, because gs2user might contain non-uniform scaling
Geom::Point d(focus - center);
Geom::Point d_user(d.length(), 0);
Geom::Point r_user(radius, 0);
Geom::Point fr_user(focusr, 0);
d_user *= gs2user.withoutTranslation();
r_user *= gs2user.withoutTranslation();
fr_user *= gs2user.withoutTranslation();
double dx = d_user.x(), dy = d_user.y();
cairo_user_to_device_distance(ct, &dx, &dy);
// compute the tolerance distance in user space
// create a vector with the same direction as the transformed d,
// with the length equal to tolerance
double dl = hypot(dx, dy);
double tx = tolerance * dx / dl, ty = tolerance * dy / dl;
cairo_device_to_user_distance(ct, &tx, &ty);
double tolerance_user = hypot(tx, ty);
if (d_user.length() + tolerance_user > r_user.length()) {
scale = r_user.length() / d_user.length();
// nudge the focus slightly inside
scale *= 1.0 - 2.0 * tolerance / dl;
}
cairo_pattern_t *cp = cairo_pattern_create_radial(
scale * d.x() + center.x(), scale * d.y() + center.y(), focusr,
center.x(), center.y(), radius);
sp_gradient_pattern_common_setup(cp, this, bbox, opacity);
return cp;
}
/*
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 :
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