nr-filter-composite.cpp

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * feComposite filter effect renderer
 *
 * Authors:
 *   Niko Kiirala <niko@kiirala.com>
 *
 * Copyright (C) 2007 authors
 *
 * Released under GNU GPL v2+, read the file 'COPYING' for more information.
 */
 
#include <cmath>
 
#include "display/cairo-templates.h"
#include "display/cairo-utils.h"
#include "display/nr-filter-composite.h"
#include "display/nr-filter-slot.h"
#include "display/nr-filter-units.h"
 
namespace Inkscape {
namespace Filters {
 
FilterComposite::FilterComposite()
    : op(COMPOSITE_DEFAULT)
    , k1(0)
    , k2(0)
    , k3(0)
    , k4(0)
    , _input2(Inkscape::Filters::NR_FILTER_SLOT_NOT_SET) {}
 
FilterComposite::~FilterComposite() = default;
 
struct ComposeArithmetic
{
    ComposeArithmetic(double k1, double k2, double k3, double k4)
        : _k1(round(k1 * 255))
        , _k2(round(k2 * 255*255))
        , _k3(round(k3 * 255*255))
        , _k4(round(k4 * 255*255*255)) {}
 
    guint32 operator()(guint32 in1, guint32 in2)
    {
        EXTRACT_ARGB32(in1, aa, ra, ga, ba)
        EXTRACT_ARGB32(in2, ab, rb, gb, bb)
 
        gint32 ao = _k1*aa*ab + _k2*aa + _k3*ab + _k4;
        gint32 ro = _k1*ra*rb + _k2*ra + _k3*rb + _k4;
        gint32 go = _k1*ga*gb + _k2*ga + _k3*gb + _k4;
        gint32 bo = _k1*ba*bb + _k2*ba + _k3*bb + _k4;
 
        ao = pxclamp(ao, 0, 255*255*255); // r, g and b are premultiplied, so should be clamped to the alpha channel
        ro = (pxclamp(ro, 0, ao) + (255*255/2)) / (255*255);
        go = (pxclamp(go, 0, ao) + (255*255/2)) / (255*255);
        bo = (pxclamp(bo, 0, ao) + (255*255/2)) / (255*255);
        ao = (ao + (255*255/2)) / (255*255);
 
        ASSEMBLE_ARGB32(pxout, ao, ro, go, bo)
        return pxout;
    }
 
private:
    gint32 _k1, _k2, _k3, _k4;
};
 
void FilterComposite::render_cairo(FilterSlot &slot) const
{
    cairo_surface_t *input1 = slot.getcairo(_input);
    cairo_surface_t *input2 = slot.getcairo(_input2);
 
    // We may need to transform input surface to correct color interpolation space. The input surface
    // might be used as input to another primitive but it is likely that all the primitives in a given
    // filter use the same color interpolation space so we don't copy the input before converting.
    set_cairo_surface_ci(input1, color_interpolation);
    set_cairo_surface_ci(input2, color_interpolation);
 
    cairo_surface_t *out = ink_cairo_surface_create_output(input1, input2);
    set_cairo_surface_ci(out, color_interpolation);
 
    Geom::Rect vp = filter_primitive_area( slot.get_units() );
    slot.set_primitive_area(_output, vp); // Needed for tiling
 
    if (op == COMPOSITE_ARITHMETIC) {
        ink_cairo_surface_blend(input1, input2, out, ComposeArithmetic(k1, k2, k3, k4));
    } else {
        ink_cairo_surface_blit(input2, out);
        cairo_t *ct = cairo_create(out);
        cairo_set_source_surface(ct, input1, 0, 0);
        switch(op) {
        case COMPOSITE_IN:
            cairo_set_operator(ct, CAIRO_OPERATOR_IN);
            break;
        case COMPOSITE_OUT:
            cairo_set_operator(ct, CAIRO_OPERATOR_OUT);
            break;
        case COMPOSITE_ATOP:
            cairo_set_operator(ct, CAIRO_OPERATOR_ATOP);
            break;
        case COMPOSITE_XOR:
            cairo_set_operator(ct, CAIRO_OPERATOR_XOR);
            break;
        case COMPOSITE_LIGHTER:
            cairo_set_operator(ct, CAIRO_OPERATOR_ADD);
            break;
        case COMPOSITE_OVER:
        case COMPOSITE_DEFAULT:
        default:
            // OVER is the default operator
            break;
        }
        cairo_paint(ct);
        cairo_destroy(ct);
    }
 
    slot.set(_output, out);
    cairo_surface_destroy(out);
}
 
bool FilterComposite::can_handle_affine(Geom::Affine const &) const
{
    return true;
}
 
void FilterComposite::set_input(int input)
{
    _input = input;
}
 
void FilterComposite::set_input(int input, int slot)
{
    if (input == 0) _input = slot;
    if (input == 1) _input2 = slot;
}
 
void FilterComposite::set_operator(FeCompositeOperator op_)
{
    if (op_ == COMPOSITE_DEFAULT) {
        op = COMPOSITE_OVER;
    } else if (op_ != COMPOSITE_ENDOPERATOR) {
        op = op_;
    }
}
 
void FilterComposite::set_arithmetic(double k1_, double k2_, double k3_, double k4_)
{
    if (!std::isfinite(k1) || !std::isfinite(k2) || !std::isfinite(k3) || !std::isfinite(k4)) {
        g_warning("Non-finite parameter for feComposite arithmetic operator");
        return;
    }
    k1 = k1_;
    k2 = k2_;
    k3 = k3_;
    k4 = k4_;
}
 
double FilterComposite::complexity(Geom::Affine const &) const
{
    return 1.1;
}
 
} // namespace Filters
} // namespace Inkscape
 
/*
  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:fileencoding=utf-8:textwidth=99 :