Initial commit

src/svg_pattern.cpp

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+/*
+ * This program source code file is part of KICAD, a free EDA CAD application.
+ *
+ * Copyright (C) 2021 Jan Sebastian Götte <kicad@jaseg.de>
+ * Copyright (C) 2021 KiCad Developers, see AUTHORS.txt for contributors.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, you may find one here:
+ * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+ * or you may search the http://www.gnu.org website for the version 2 license,
+ * or you may write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ */
+
+#include <assert.h>
+#include "svg_import_util.h"
+#include "svg_pattern.h"
+#include "svg_import_defs.h"
+#include "svg_geom.h"
+#include "svg_doc.h"
+
+using namespace std;
+
+svg_plugin::Pattern::Pattern(const pugi::xml_node &node, SVGDocument &doc) : _node(node), doc(&doc) {
+    /* Read pattern attributes from SVG node */
+    cerr << "creating pattern for node with id \"" << node.attribute("id").value() << "\"" << endl;
+    x = usvg_double_attr(node, "x");
+    y = usvg_double_attr(node, "y");
+    w = usvg_double_attr(node, "width");
+    h = usvg_double_attr(node, "height");
+    patternTransform = node.attribute("patternTransform").value();
+
+    string vb_s(node.attribute("viewBox").value());
+    has_vb = !vb_s.empty();
+    if (has_vb) {
+        istringstream vb_stream(vb_s);
+        vb_stream >> vb_x >> vb_y >> vb_w >> vb_h;
+    }
+
+    patternUnits = map_str_to_units(node.attribute("patternUnits").value(), SVG_ObjectBoundingBox);
+    patternContentUnits = map_str_to_units(node.attribute("patternContentUnits").value(), SVG_UserSpaceOnUse);
+}
+
+/* Tile pattern into gerber. Note that this function may be called several times in case the pattern is
+ * referenced from multiple places, so we must not clobber any of the object's state. */
+void svg_plugin::Pattern::tile (ClipperLib::Paths &clip) {
+    assert(doc);
+    cairo_t *cr = doc->cairo();
+    assert(cr);
+
+    cairo_save(cr);
+    /* Transform x, y, w, h from pattern coordinate space into parent coordinates by applying the inverse
+     * patternTransform. This is necessary so we iterate over the correct bounds when tiling below */
+    cairo_matrix_t mat;
+    load_cairo_matrix_from_svg(patternTransform, mat);
+    if (cairo_matrix_invert(&mat) != CAIRO_STATUS_SUCCESS) {
+        cerr << "Cannot invert patternTransform matrix on pattern \"" << _node.attribute("id").value() << "\"." << endl;
+        cairo_restore(cr);
+    }
+    double inst_x = x, inst_y = y, inst_w = w, inst_h = h;
+    cairo_user_to_device(cr, &inst_x, &inst_y);
+    cairo_user_to_device_distance(cr, &inst_w, &inst_h);
+    cairo_restore(cr);
+
+    ClipperLib::IntRect clip_bounds = get_paths_bounds(clip);
+    double bx = clip_bounds.left / clipper_scale;
+    double by = clip_bounds.top / clipper_scale;
+    double bw = (clip_bounds.right - clip_bounds.left) / clipper_scale;
+    double bh = (clip_bounds.bottom - clip_bounds.top) / clipper_scale;
+
+    if (patternUnits == SVG_ObjectBoundingBox) {
+        inst_x *= bw;
+        inst_y *= bh;
+        inst_w *= bw;
+        inst_h *= bh;
+    }
+
+    /* Switch to pattern coordinates */
+    cairo_save(cr);
+    cairo_translate(cr, bx, by);
+    apply_cairo_transform_from_svg(cr, patternTransform);
+
+    /* Iterate over all pattern tiles in pattern coordinates */
+    for (double inst_off_x = fmod(inst_x, inst_w) - inst_w;
+            inst_off_x < bw + inst_w;
+            inst_off_x += inst_w) {
+
+        for (double inst_off_y = fmod(inst_y, inst_h) - inst_h;
+                inst_off_y < bh + inst_h;
+                inst_off_y += inst_h) {
+
+            cairo_save(cr);
+            /* Change into this individual tile's coordinate system */
+            cairo_translate(cr, inst_off_x, inst_off_y);
+            if (has_vb) {
+                cairo_translate(cr, vb_x, vb_y);
+                cairo_scale(cr, inst_w / vb_w, inst_h / vb_h);
+            } else if (patternContentUnits == SVG_ObjectBoundingBox) {
+                cairo_scale(cr, bw, bh);
+            }
+
+            /* Export the pattern tile's content like a group */
+            doc->export_svg_group(_node, clip);
+            cairo_restore(cr);
+        }
+    }
+    cairo_restore(cr);
+}
+