nr-filter-tile.cpp

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * feTile filter primitive renderer
 *
 * Authors:
 *   Felipe Corrêa da Silva Sanches <juca@members.fsf.org>
 *
 * Copyright (C) 2007 authors
 *
 * Released under GNU GPL v2+, read the file 'COPYING' for more information.
 */
 
#include <glib.h>
 
#include "display/cairo-utils.h"
#include "display/nr-filter-tile.h"
#include "display/nr-filter-slot.h"
#include "display/nr-filter-units.h"
 
namespace Inkscape {
namespace Filters {
 
FilterTile::FilterTile() = default;
 
FilterTile::~FilterTile() = default;
 
void FilterTile::render_cairo(FilterSlot &slot) const
{
    // This input source contains only the "rendering" tile.
    cairo_surface_t *in = slot.getcairo(_input);
 
    // For debugging
    // static int i = 0;
    // ++i;
    // std::stringstream filename;
    // filename << "dump." << i << ".png";
    // cairo_surface_write_to_png( in, filename.str().c_str() );
 
    // This is the feTile source area as determined by the input primitive area (see SVG spec).
    Geom::Rect tile_area = slot.get_primitive_area(_input);
 
    if (tile_area.width() == 0.0 || tile_area.height() == 0.0) {
 
        slot.set(_output, in);
        std::cerr << "FileTile::render_cairo: tile has zero width or height" << std::endl;
 
    } else {
 
        cairo_surface_t *out = ink_cairo_surface_create_identical(in);
        // color_interpolation_filters for out same as in.
        copy_cairo_surface_ci(in, out);
        cairo_t *ct = cairo_create(out);
 
        // The rectangle of the "rendering" tile.
        Geom::Rect sa = slot.get_slot_area();
 
        Geom::Affine trans = slot.get_units().get_matrix_user2pb();
 
        // Create feTile tile ----------------
 
        // Get tile area in pixbuf units (tile transformed).
        Geom::Rect tt = tile_area * trans;
        
        // Shift between "rendering" tile and feTile tile
        Geom::Point shift = sa.min() - tt.min(); 
 
        // Create feTile tile surface
        cairo_surface_t *tile = cairo_surface_create_similar(in, cairo_surface_get_content(in),
                                                             tt.width(), tt.height());
        cairo_t *ct_tile = cairo_create(tile);
        cairo_set_source_surface(ct_tile, in, shift[Geom::X], shift[Geom::Y]);
        cairo_paint(ct_tile);
 
        // Paint tiles ------------------
        
        // For debugging
        // std::stringstream filename;
        // filename << "tile." << i << ".png";
        // cairo_surface_write_to_png( tile, filename.str().c_str() );
        
        // Determine number of feTile rows and columns
        Geom::Rect pr = filter_primitive_area(slot.get_units());
        int tile_cols = std::ceil(pr.width()  / tile_area.width());
        int tile_rows = std::ceil(pr.height() / tile_area.height());
 
        // Do tiling (TO DO: restrict to slot area.)
        for (int col = 0; col < tile_cols; ++col) {
            for (int row = 0; row < tile_rows; ++row) {
                Geom::Point offset(col * tile_area.width(), row * tile_area.height());
                offset *= trans;
                offset[Geom::X] -= trans[4];
                offset[Geom::Y] -= trans[5];
        
                cairo_set_source_surface(ct, tile, offset[Geom::X], offset[Geom::Y]);
                cairo_paint(ct);
            }
        }
        slot.set(_output, out);
 
        // Clean up
        cairo_destroy(ct);
        cairo_surface_destroy(out);
        cairo_destroy(ct_tile);
        cairo_surface_destroy(tile);
    }
}
 
void FilterTile::area_enlarge(Geom::IntRect &area, Geom::Affine const &trans) const
{
    // Set to very large rectangle so we get tile source. It will be clipped later.
 
    // Note, setting to infinite using Geom::IntRect::infinite() causes overflow/underflow problems.
    Geom::IntCoord max = std::numeric_limits<Geom::IntCoord>::max() / 4;
    area = Geom::IntRect(-max, -max, max, max);
}
 
double FilterTile::complexity(Geom::Affine const &) const
{
    return 1.0;
}
 
} // 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 :