1 files changed, 114 insertions, 0 deletions
diff --git a/src/display/nr-filter-offset.cpp b/src/display/nr-filter-offset.cpp
new file mode 100644
index 0000000..2f73389
--- /dev/null
+++ b/src/display/nr-filter-offset.cpp
@@ -0,0 +1,114 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * feOffset filter primitive renderer
+ *
+ * Authors:
+ *   Niko Kiirala <niko@kiirala.com>
+ *
+ * Copyright (C) 2007 authors
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include "display/cairo-utils.h"
+#include "display/nr-filter-offset.h"
+#include "display/nr-filter-slot.h"
+#include "display/nr-filter-units.h"
+
+namespace Inkscape {
+namespace Filters {
+
+using Geom::X;
+using Geom::Y;
+
+FilterOffset::FilterOffset() :
+    dx(0), dy(0)
+{}
+
+FilterPrimitive * FilterOffset::create() {
+    return new FilterOffset();
+}
+
+FilterOffset::~FilterOffset()
+= default;
+
+void FilterOffset::render_cairo(FilterSlot &slot)
+{
+    cairo_surface_t *in = slot.getcairo(_input);
+    cairo_surface_t *out = ink_cairo_surface_create_identical(in);
+    // color_interpolation_filters for out same as in. See spec (DisplacementMap).
+    copy_cairo_surface_ci(in, out);
+    cairo_t *ct = cairo_create(out);
+
+    Geom::Rect vp = filter_primitive_area( slot.get_units() );
+    slot.set_primitive_area(_output, vp); // Needed for tiling
+
+    Geom::Affine p2pb = slot.get_units().get_matrix_primitiveunits2pb();
+    double x = dx * p2pb.expansionX();
+    double y = dy * p2pb.expansionY();
+
+    cairo_set_source_surface(ct, in, x, y);
+    cairo_paint(ct);
+    cairo_destroy(ct);
+
+    slot.set(_output, out);
+    cairo_surface_destroy(out);
+}
+
+bool FilterOffset::can_handle_affine(Geom::Affine const &)
+{
+    return true;
+}
+
+void FilterOffset::set_dx(double amount) {
+    dx = amount;
+}
+
+void FilterOffset::set_dy(double amount) {
+    dy = amount;
+}
+
+void FilterOffset::area_enlarge(Geom::IntRect &area, Geom::Affine const &trans)
+{
+    Geom::Point offset(dx, dy);
+    offset *= trans;
+    offset[X] -= trans[4];
+    offset[Y] -= trans[5];
+    double x0, y0, x1, y1;
+    x0 = area.left();
+    y0 = area.top();
+    x1 = area.right();
+    y1 = area.bottom();
+
+    if (offset[X] > 0) {
+        x0 -= ceil(offset[X]);
+    } else {
+        x1 -= floor(offset[X]);
+    }
+
+    if (offset[Y] > 0) {
+        y0 -= ceil(offset[Y]);
+    } else {
+        y1 -= floor(offset[Y]);
+    }
+    area = Geom::IntRect(x0, y0, x1, y1);
+}
+
+double FilterOffset::complexity(Geom::Affine const &)
+{
+    return 1.02;
+}
+
+} /* 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 :