1 files changed, 126 insertions, 0 deletions
diff --git a/src/display/nr-filter-merge.cpp b/src/display/nr-filter-merge.cpp
new file mode 100644
index 0000000..9ebfe40
--- /dev/null
+++ b/src/display/nr-filter-merge.cpp
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * feMerge 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 <vector>
+#include "display/cairo-utils.h"
+#include "display/nr-filter-merge.h"
+#include "display/nr-filter-slot.h"
+#include "display/nr-filter-utils.h"
+
+namespace Inkscape {
+namespace Filters {
+
+FilterMerge::FilterMerge() :
+    _input_image(1, NR_FILTER_SLOT_NOT_SET)
+{}
+
+FilterPrimitive * FilterMerge::create() {
+    return new FilterMerge();
+}
+
+FilterMerge::~FilterMerge()
+= default;
+
+void FilterMerge::render_cairo(FilterSlot &slot)
+{
+    if (_input_image.empty()) return;
+
+    SPColorInterpolation ci_fp  = SP_CSS_COLOR_INTERPOLATION_AUTO;
+    if( _style ) {
+        ci_fp = (SPColorInterpolation)_style->color_interpolation_filters.computed;
+    }
+
+    Geom::Rect vp = filter_primitive_area( slot.get_units() );
+    slot.set_primitive_area(_output, vp); // Needed for tiling
+
+    // output is RGBA if at least one input is RGBA
+    bool rgba32 = false;
+    cairo_surface_t *out = nullptr;
+    for (int & i : _input_image) {
+        cairo_surface_t *in = slot.getcairo(i);
+        if (cairo_surface_get_content(in) == CAIRO_CONTENT_COLOR_ALPHA) {
+            out = ink_cairo_surface_create_identical(in);
+            set_cairo_surface_ci( out, ci_fp );
+            rgba32 = true;
+            break;
+        }
+    }
+
+    if (!rgba32) {
+        out = ink_cairo_surface_create_identical(slot.getcairo(_input_image[0]));
+    }
+    cairo_t *out_ct = cairo_create(out);
+
+    for (int & i : _input_image) {
+        cairo_surface_t *in = slot.getcairo(i);
+
+        set_cairo_surface_ci( in, ci_fp );
+        cairo_set_source_surface(out_ct, in, 0, 0);
+        cairo_paint(out_ct);
+    }
+
+    cairo_destroy(out_ct);
+    slot.set(_output, out);
+    cairo_surface_destroy(out);
+}
+
+bool FilterMerge::can_handle_affine(Geom::Affine const &)
+{
+    // Merge is a per-pixel primitive and is immutable under transformations
+    return true;
+}
+
+double FilterMerge::complexity(Geom::Affine const &)
+{
+    return 1.02;
+}
+
+bool FilterMerge::uses_background()
+{
+    for (int input : _input_image) {
+        if (input == NR_FILTER_BACKGROUNDIMAGE || input == NR_FILTER_BACKGROUNDALPHA) {
+            return true;
+        }
+    }
+    return false;
+}
+
+void FilterMerge::set_input(int slot) {
+    _input_image[0] = slot;
+}
+
+void FilterMerge::set_input(int input, int slot) {
+    if (input < 0) return;
+
+    if (static_cast<int>(_input_image.size()) > input) {
+        _input_image[input] = slot;
+    } else {
+        for (int i = static_cast<int>(_input_image.size()) ; i < input ; i++) {
+            _input_image.push_back(NR_FILTER_SLOT_NOT_SET);
+        }
+        _input_image.push_back(slot);
+    }
+}
+
+} /* 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 :