1 files changed, 169 insertions, 0 deletions
diff --git a/src/display/nr-filter-units.h b/src/display/nr-filter-units.h
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+++ b/src/display/nr-filter-units.h
@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#ifndef SEEN_NR_FILTER_UNITS_H
+#define SEEN_NR_FILTER_UNITS_H
+
+/*
+ * Utilities for handling coordinate system transformations in filters
+ *
+ * Author:
+ *   Niko Kiirala <niko@kiirala.com>
+ *
+ * Copyright (C) 2007 Niko Kiirala
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include "object/sp-filter-units.h"
+#include <2geom/affine.h>
+#include <2geom/rect.h>
+
+namespace Inkscape {
+namespace Filters {
+
+/* Notes:
+ * - "filter units" is a coordinate system where the filter region is contained
+ *   between (0,0) and (1,1). Do not confuse this with the filterUnits property
+ * - "primitive units" is the coordinate system in which all lengths and distances
+ *   in the filter definition should be interpreted. They are affected by the value
+ *   of the primitiveUnits attribute
+ * - "pb" is the coordinate system in which filter rendering happens.
+ *   It might be aligned with user or screen coordinates depending on
+ *   the filter primitives used in the filter.
+ * - "display" are world coordinates of the canvas - pixel grid coordinates
+ *   of the drawing area translated so that (0,0) corresponds to the document origin
+ */
+class FilterUnits {
+public:
+    FilterUnits();
+    FilterUnits(SPFilterUnits const filterUnits, SPFilterUnits const primitiveUnits);
+
+    /**
+     * Sets the current transformation matrix, i.e. transformation matrix
+     * from object's user coordinates to screen coordinates
+     */
+    void set_ctm(Geom::Affine const &ctm);
+
+    /**
+     * Sets the resolution, the filter should be rendered with.
+     */
+    void set_resolution(double const x_res, double const y_res);
+
+    /**
+     * Sets the item bounding box in user coordinates
+     */
+    void set_item_bbox(Geom::OptRect const &bbox);
+
+    /**
+     * Sets the filter effects area in user coordinates
+     */
+    void set_filter_area(Geom::OptRect const &area);
+
+    /**
+     * Sets, if x and y axis in pixblock coordinates should be paraller
+     * to x and y of user coordinates.
+     */
+    void set_paraller(bool const paraller);
+
+    /**
+     * Sets, if filter resolution is automatic.
+     * NOTE: even if resolution is automatic, it must be set with
+     * set_resolution. This only tells, if the set value is automatic.
+     */
+    void set_automatic_resolution(bool const automatic);
+
+    /**
+     * Gets the item bounding box in user coordinates
+     */
+    Geom::OptRect get_item_bbox() const { return item_bbox; };
+
+    /**
+     * Gets the filter effects area in user coordinates
+     */
+    Geom::OptRect get_filter_area() const { return filter_area; };
+
+    /**
+     * Gets Filter Units (userSpaceOnUse or objectBoundingBox)
+     */
+    SPFilterUnits get_filter_units() const { return filterUnits; };
+
+    /**
+     * Gets Primitive Units (userSpaceOnUse or objectBoundingBox)
+     */
+    SPFilterUnits get_primitive_units() const { return primitiveUnits; };
+
+    /**
+     * Gets the user coordinates to pixblock coordinates transformation matrix.
+     */
+    Geom::Affine get_matrix_user2pb() const;
+
+    /**
+     * Gets the filterUnits to pixblock coordinates transformation matrix.
+     */
+    Geom::Affine get_matrix_filterunits2pb() const;
+
+    /**
+     * Gets the primitiveUnits to pixblock coordinates transformation matrix.
+     */
+    Geom::Affine get_matrix_primitiveunits2pb() const;
+
+    /**
+     * Gets the display coordinates to pixblock coordinates transformation
+     * matrix.
+     */
+    Geom::Affine get_matrix_display2pb() const;
+
+    /**
+     * Gets the pixblock coordinates to display coordinates transformation
+     * matrix
+     */
+    Geom::Affine get_matrix_pb2display() const;
+
+    /**
+     * Gets the user coordinates to filterUnits transformation matrix.
+     */
+    Geom::Affine get_matrix_user2filterunits() const;
+
+    /**
+     * Gets the user coordinates to primitiveUnits transformation matrix.
+     */
+    Geom::Affine get_matrix_user2primitiveunits() const;
+
+    /**
+     * Returns the filter area in pixblock coordinates.
+     * NOTE: use only in filters, that define TRAIT_PARALLER in
+     * get_input_traits. The filter effects area may not be representable
+     * by simple rectangle otherwise. */
+    Geom::IntRect get_pixblock_filterarea_paraller() const;
+
+    FilterUnits& operator=(FilterUnits const &other);
+
+private:
+    Geom::Affine get_matrix_units2pb(SPFilterUnits units) const;
+    Geom::Affine get_matrix_user2units(SPFilterUnits units) const;
+
+    SPFilterUnits filterUnits, primitiveUnits;
+    double resolution_x, resolution_y;
+    bool paraller_axis;
+    bool automatic_resolution;
+    Geom::Affine ctm;
+    Geom::OptRect item_bbox;
+    Geom::OptRect filter_area;
+
+};
+
+
+} /* namespace Filters */
+} /* namespace Inkscape */
+
+
+#endif /* __NR_FILTER_UNITS_H__ */
+/*
+  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 :