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Diffstat (limited to 'layout/base/ShapeUtils.h')
| -rw-r--r-- | layout/base/ShapeUtils.h | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/layout/base/ShapeUtils.h b/layout/base/ShapeUtils.h new file mode 100644 index 0000000000..972fa4efb3 --- /dev/null +++ b/layout/base/ShapeUtils.h @@ -0,0 +1,151 @@ +/* -*- 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 { +namespace gfx { +class Path; +class PathBuilder; +} // namespace gfx + +// 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 position based on |aRefBox|. + // @param aRefBox The reference box for the position. + // @return The point inside |aRefBox|. + static nsPoint ComputePosition(const StylePosition&, const nsRect&); + + // 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()/xywh()/rect(). + // 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/xywh/rect. + // @return The inset/xywh/rect rect in app units. + static nsRect ComputeInsetRect(const StyleRect<LengthPercentage>& aStyleRect, + const nsRect& aRefBox); + + // Compute the radii for a rectanglar shape, i.e. inset()/xywh()/rect(). + // @param aRefBox the reference box of the rect. + // @param aRect the rect we computed from Compute{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 ComputeRectRadii(const StyleBorderRadius&, const nsRect& aRefBox, + const nsRect& aRect, 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); + + // Compute a gfx::path from a circle. + // @param aRefBox the reference box of the circle. + // @param aCenter the center point of the circle. + // @return The gfx::Path of this circle. + static already_AddRefed<gfx::Path> BuildCirclePath(const StyleBasicShape&, + const nsRect& aRefBox, + const nsPoint& aCenter, + nscoord aAppUnitsPerPixel, + gfx::PathBuilder*); + + // Compute a gfx::path from an ellipse. + // @param aRefBox the reference box of the ellipse. + // @param aCenter the center point of the ellipse. + // @return The gfx::Path of this ellipse. + static already_AddRefed<gfx::Path> BuildEllipsePath(const StyleBasicShape&, + const nsRect& aRefBox, + const nsPoint& aCenter, + nscoord aAppUnitsPerPixel, + gfx::PathBuilder*); + + // Compute a gfx::path from a polygon. + // @param aRefBox the reference box of the polygon. + // @return The gfx::Path of this polygon. + static already_AddRefed<gfx::Path> BuildPolygonPath(const StyleBasicShape&, + const nsRect& aRefBox, + nscoord aAppUnitsPerPixel, + gfx::PathBuilder*); + + // Compute a gfx::path from a StyleBasicShape which is an inset. + // @param aRefBox the reference box of the inset. + // @return The gfx::Path of this inset. + static already_AddRefed<gfx::Path> BuildInsetPath(const StyleBasicShape&, + const nsRect& aRefBox, + nscoord aAppUnitsPerPixel, + gfx::PathBuilder*); + + // Compute a gfx::path from a rectanglar shape (i.e. inset()/xywh()/rect()) + // and the round radii. + // @param aRect the rect we computed from Compute{Inset}Rect(). + // @param aRadii the radii of the rect. It should be an array with length 8. + // If it's nullptr, we don't have the valid radii. + // @param aRefBox the reference box of the rect. + // @return The gfx::Path of this rect. + static already_AddRefed<gfx::Path> BuildRectPath(const nsRect& aRect, + const nscoord aRadii[8], + const nsRect& aRefBox, + nscoord aAppUnitsPerPixel, + gfx::PathBuilder*); +}; + +} // namespace mozilla + +#endif // mozilla_ShapeUtils_h |