// 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-linear-gradient.h"

#include "attributes.h"
#include "style.h"
#include "xml/repr.h"

/*
 * Linear Gradient
 */
SPLinearGradient::SPLinearGradient() : SPGradient() {
    this->x1.unset(SVGLength::PERCENT, 0.0, 0.0);
    this->y1.unset(SVGLength::PERCENT, 0.0, 0.0);
    this->x2.unset(SVGLength::PERCENT, 1.0, 1.0);
    this->y2.unset(SVGLength::PERCENT, 0.0, 0.0);
}

SPLinearGradient::~SPLinearGradient() = default;

void SPLinearGradient::build(SPDocument *document, Inkscape::XML::Node *repr) {
    SPGradient::build(document, repr);

    this->readAttr( "x1" );
    this->readAttr( "y1" );
    this->readAttr( "x2" );
    this->readAttr( "y2" );
}

/**
 * Callback: set attribute.
 */
void SPLinearGradient::set(SPAttributeEnum key, const gchar* value) {
    switch (key) {
        case SP_ATTR_X1:
            this->x1.readOrUnset(value, SVGLength::PERCENT, 0.0, 0.0);
            this->requestModified(SP_OBJECT_MODIFIED_FLAG);
            break;

        case SP_ATTR_Y1:
            this->y1.readOrUnset(value, SVGLength::PERCENT, 0.0, 0.0);
            this->requestModified(SP_OBJECT_MODIFIED_FLAG);
            break;

        case SP_ATTR_X2:
            this->x2.readOrUnset(value, SVGLength::PERCENT, 1.0, 1.0);
            this->requestModified(SP_OBJECT_MODIFIED_FLAG);
            break;

        case SP_ATTR_Y2:
            this->y2.readOrUnset(value, SVGLength::PERCENT, 0.0, 0.0);
            this->requestModified(SP_OBJECT_MODIFIED_FLAG);
            break;

        default:
            SPGradient::set(key, value);
            break;
    }
}

void
SPLinearGradient::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->x1.update(em, ex, w);
            this->y1.update(em, ex, h);
            this->x2.update(em, ex, w);
            this->y2.update(em, ex, h);
        }
    }
}

/**
 * Callback: write attributes to associated repr.
 */
Inkscape::XML::Node* SPLinearGradient::write(Inkscape::XML::Document *xml_doc, Inkscape::XML::Node *repr, guint flags) {
    if ((flags & SP_OBJECT_WRITE_BUILD) && !repr) {
        repr = xml_doc->createElement("svg:linearGradient");
    }

    if ((flags & SP_OBJECT_WRITE_ALL) || this->x1._set) {
        sp_repr_set_svg_double(repr, "x1", this->x1.computed);
    }

    if ((flags & SP_OBJECT_WRITE_ALL) || this->y1._set) {
        sp_repr_set_svg_double(repr, "y1", this->y1.computed);
    }

    if ((flags & SP_OBJECT_WRITE_ALL) || this->x2._set) {
        sp_repr_set_svg_double(repr, "x2", this->x2.computed);
    }

    if ((flags & SP_OBJECT_WRITE_ALL) || this->y2._set) {
        sp_repr_set_svg_double(repr, "y2", this->y2.computed);
    }

    SPGradient::write(xml_doc, repr, flags);

    return repr;
}

cairo_pattern_t* SPLinearGradient::pattern_new(cairo_t * /*ct*/, Geom::OptRect const &bbox, double opacity) {
    this->ensureVector();

    cairo_pattern_t *cp = cairo_pattern_create_linear(
        this->x1.computed, this->y1.computed,
        this->x2.computed, this->y2.computed);

    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 :
