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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_ShapeUtils_h
+#define mozilla_ShapeUtils_h
+
+#include "nsCoord.h"
+#include "nsSize.h"
+#include "nsStyleConsts.h"
+#include "nsTArray.h"
+
+struct nsPoint;
+struct nsRect;
+
+namespace mozilla {
+// ShapeUtils is a namespace class containing utility functions related to
+// processing basic shapes in the CSS Shapes Module.
+// https://drafts.csswg.org/css-shapes/#basic-shape-functions
+//
+struct ShapeUtils final {
+ // Compute the length of a keyword <shape-radius>, i.e. closest-side or
+ // farthest-side, for a circle or an ellipse on a single dimension. The
+ // caller needs to call for both dimensions and combine the result.
+ // https://drafts.csswg.org/css-shapes/#typedef-shape-radius.
+ // @return The length of the radius in app units.
+ static nscoord ComputeShapeRadius(const StyleShapeRadius& aType,
+ const nscoord aCenter,
+ const nscoord aPosMin,
+ const nscoord aPosMax);
+
+ // Compute the center of a circle or an ellipse.
+ // @param aRefBox The reference box of the basic shape.
+ // @return The point of the center.
+ static nsPoint ComputeCircleOrEllipseCenter(const StyleBasicShape&,
+ const nsRect& aRefBox);
+
+ // Compute the radius for a circle.
+ // @param aCenter the center of the circle.
+ // @param aRefBox the reference box of the circle.
+ // @return The length of the radius in app units.
+ static nscoord ComputeCircleRadius(const StyleBasicShape&,
+ const nsPoint& aCenter,
+ const nsRect& aRefBox);
+
+ // Compute the radii for an ellipse.
+ // @param aCenter the center of the ellipse.
+ // @param aRefBox the reference box of the ellipse.
+ // @return The radii of the ellipse in app units. The width and height
+ // represent the x-axis and y-axis radii of the ellipse.
+ static nsSize ComputeEllipseRadii(const StyleBasicShape&,
+ const nsPoint& aCenter,
+ const nsRect& aRefBox);
+
+ // Compute the rect for an inset. If the inset amount is larger than
+ // aRefBox itself, this will return a rect the same shape as the inverse
+ // rect that would be created by insetting aRefBox by the inset amount.
+ // This process is *not* what is called for by the current spec at
+ // https://drafts.csswg.org/css-shapes-1/#supported-basic-shapes.
+ // The spec currently treats empty shapes, including overly-inset rects, as
+ // defining 'empty float areas' that don't affect layout. However, it is
+ // practically useful to treat empty shapes as having edges for purposes of
+ // affecting layout, and there is growing momentum for the approach we
+ // are taking here.
+ // @param aRefBox the reference box of the inset.
+ // @return The inset rect in app units.
+ static nsRect ComputeInsetRect(const StyleBasicShape&, const nsRect& aRefBox);
+
+ // Compute the radii for an inset.
+ // @param aRefBox the reference box of the inset.
+ // @param aInsetRect the inset rect in app units.
+ // @param aRadii the returned radii in app units.
+ // @return true if any of the radii is nonzero; false otherwise.
+ static bool ComputeInsetRadii(const StyleBasicShape&, const nsRect& aRefBox,
+ const nsRect& aInsetRect, nscoord aRadii[8]);
+
+ // Compute the vertices for a polygon.
+ // @param aRefBox the reference box of the polygon.
+ // @return The vertices in app units; the coordinate space is the same
+ // as aRefBox.
+ static nsTArray<nsPoint> ComputePolygonVertices(const StyleBasicShape&,
+ const nsRect& aRefBox);
+};
+
+} // namespace mozilla
+
+#endif // mozilla_ShapeUtils_h