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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
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