michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef MOZILLA_GFX_BASERECT_H_
michael@0: #define MOZILLA_GFX_BASERECT_H_
michael@0: 
michael@0: #include <algorithm>
michael@0: #include <cmath>
michael@0: 
michael@0: #include "mozilla/Assertions.h"
michael@0: #include "mozilla/FloatingPoint.h"
michael@0: #include "mozilla/TypeTraits.h"
michael@0: 
michael@0: namespace mozilla {
michael@0: namespace gfx {
michael@0: 
michael@0: /**
michael@0:  * Rectangles have two interpretations: a set of (zero-size) points,
michael@0:  * and a rectangular area of the plane. Most rectangle operations behave
michael@0:  * the same no matter what interpretation is being used, but some operations
michael@0:  * differ:
michael@0:  * -- Equality tests behave differently. When a rectangle represents an area,
michael@0:  * all zero-width and zero-height rectangles are equal to each other since they
michael@0:  * represent the empty area. But when a rectangle represents a set of
michael@0:  * mathematical points, zero-width and zero-height rectangles can be unequal.
michael@0:  * -- The union operation can behave differently. When rectangles represent
michael@0:  * areas, taking the union of a zero-width or zero-height rectangle with
michael@0:  * another rectangle can just ignore the empty rectangle. But when rectangles
michael@0:  * represent sets of mathematical points, we may need to extend the latter
michael@0:  * rectangle to include the points of a zero-width or zero-height rectangle.
michael@0:  *
michael@0:  * To ensure that these interpretations are explicitly disambiguated, we
michael@0:  * deny access to the == and != operators and require use of IsEqualEdges and
michael@0:  * IsEqualInterior instead. Similarly we provide separate Union and UnionEdges
michael@0:  * methods.
michael@0:  *
michael@0:  * Do not use this class directly. Subclass it, pass that subclass as the
michael@0:  * Sub parameter, and only use that subclass.
michael@0:  */
michael@0: template <class T, class Sub, class Point, class SizeT, class MarginT>
michael@0: struct BaseRect {
michael@0:   T x, y, width, height;
michael@0: 
michael@0:   // Constructors
michael@0:   BaseRect() : x(0), y(0), width(0), height(0) {}
michael@0:   BaseRect(const Point& aOrigin, const SizeT &aSize) :
michael@0:       x(aOrigin.x), y(aOrigin.y), width(aSize.width), height(aSize.height)
michael@0:   {
michael@0:   }
michael@0:   BaseRect(T aX, T aY, T aWidth, T aHeight) :
michael@0:       x(aX), y(aY), width(aWidth), height(aHeight)
michael@0:   {
michael@0:   }
michael@0: 
michael@0:   // Emptiness. An empty rect is one that has no area, i.e. its height or width
michael@0:   // is <= 0
michael@0:   bool IsEmpty() const { return height <= 0 || width <= 0; }
michael@0:   void SetEmpty() { width = height = 0; }
michael@0: 
michael@0:   // "Finite" means not inf and not NaN
michael@0:   bool IsFinite() const
michael@0:   {
michael@0:     typedef typename mozilla::Conditional<mozilla::IsSame<T, float>::value, float, double>::Type FloatType;
michael@0:     return (mozilla::IsFinite(FloatType(x)) &&
michael@0:             mozilla::IsFinite(FloatType(y)) &&
michael@0:             mozilla::IsFinite(FloatType(width)) &&
michael@0:             mozilla::IsFinite(FloatType(height)));
michael@0:   }
michael@0: 
michael@0:   // Returns true if this rectangle contains the interior of aRect. Always
michael@0:   // returns true if aRect is empty, and always returns false is aRect is
michael@0:   // nonempty but this rect is empty.
michael@0:   bool Contains(const Sub& aRect) const
michael@0:   {
michael@0:     return aRect.IsEmpty() ||
michael@0:            (x <= aRect.x && aRect.XMost() <= XMost() &&
michael@0:             y <= aRect.y && aRect.YMost() <= YMost());
michael@0:   }
michael@0:   // Returns true if this rectangle contains the rectangle (aX,aY,1,1).
michael@0:   bool Contains(T aX, T aY) const
michael@0:   {
michael@0:     return x <= aX && aX + 1 <= XMost() &&
michael@0:            y <= aY && aY + 1 <= YMost();
michael@0:   }
michael@0:   // Returns true if this rectangle contains the rectangle (aPoint.x,aPoint.y,1,1).
michael@0:   bool Contains(const Point& aPoint) const { return Contains(aPoint.x, aPoint.y); }
michael@0: 
michael@0:   // Intersection. Returns TRUE if the receiver's area has non-empty
michael@0:   // intersection with aRect's area, and FALSE otherwise.
michael@0:   // Always returns false if aRect is empty or 'this' is empty.
michael@0:   bool Intersects(const Sub& aRect) const
michael@0:   {
michael@0:     return x < aRect.XMost() && aRect.x < XMost() &&
michael@0:            y < aRect.YMost() && aRect.y < YMost();
michael@0:   }
michael@0:   // Returns the rectangle containing the intersection of the points
michael@0:   // (including edges) of *this and aRect. If there are no points in that
michael@0:   // intersection, returns an empty rectangle with x/y set to the std::max of the x/y
michael@0:   // of *this and aRect.
michael@0:   Sub Intersect(const Sub& aRect) const
michael@0:   {
michael@0:     Sub result;
michael@0:     result.x = std::max<T>(x, aRect.x);
michael@0:     result.y = std::max<T>(y, aRect.y);
michael@0:     result.width = std::min<T>(XMost(), aRect.XMost()) - result.x;
michael@0:     result.height = std::min<T>(YMost(), aRect.YMost()) - result.y;
michael@0:     if (result.width < 0 || result.height < 0) {
michael@0:       result.SizeTo(0, 0);
michael@0:     }
michael@0:     return result;
michael@0:   }
michael@0:   // Sets *this to be the rectangle containing the intersection of the points
michael@0:   // (including edges) of *this and aRect. If there are no points in that
michael@0:   // intersection, sets *this to be an empty rectangle with x/y set to the std::max
michael@0:   // of the x/y of *this and aRect.
michael@0:   //
michael@0:   // 'this' can be the same object as either aRect1 or aRect2
michael@0:   bool IntersectRect(const Sub& aRect1, const Sub& aRect2)
michael@0:   {
michael@0:     *static_cast<Sub*>(this) = aRect1.Intersect(aRect2);
michael@0:     return !IsEmpty();
michael@0:   }
michael@0: 
michael@0:   // Returns the smallest rectangle that contains both the area of both
michael@0:   // this and aRect2.
michael@0:   // Thus, empty input rectangles are ignored.
michael@0:   // If both rectangles are empty, returns this.
michael@0:   Sub Union(const Sub& aRect) const
michael@0:   {
michael@0:     if (IsEmpty()) {
michael@0:       return aRect;
michael@0:     } else if (aRect.IsEmpty()) {
michael@0:       return *static_cast<const Sub*>(this);
michael@0:     } else {
michael@0:       return UnionEdges(aRect);
michael@0:     }
michael@0:   }
michael@0:   // Returns the smallest rectangle that contains both the points (including
michael@0:   // edges) of both aRect1 and aRect2.
michael@0:   // Thus, empty input rectangles are allowed to affect the result.
michael@0:   Sub UnionEdges(const Sub& aRect) const
michael@0:   {
michael@0:     Sub result;
michael@0:     result.x = std::min(x, aRect.x);
michael@0:     result.y = std::min(y, aRect.y);
michael@0:     result.width = std::max(XMost(), aRect.XMost()) - result.x;
michael@0:     result.height = std::max(YMost(), aRect.YMost()) - result.y;
michael@0:     return result;
michael@0:   }
michael@0:   // Computes the smallest rectangle that contains both the area of both
michael@0:   // aRect1 and aRect2, and fills 'this' with the result.
michael@0:   // Thus, empty input rectangles are ignored.
michael@0:   // If both rectangles are empty, sets 'this' to aRect2.
michael@0:   //
michael@0:   // 'this' can be the same object as either aRect1 or aRect2
michael@0:   void UnionRect(const Sub& aRect1, const Sub& aRect2)
michael@0:   {
michael@0:     *static_cast<Sub*>(this) = aRect1.Union(aRect2);
michael@0:   }
michael@0: 
michael@0:   // Computes the smallest rectangle that contains both the points (including
michael@0:   // edges) of both aRect1 and aRect2.
michael@0:   // Thus, empty input rectangles are allowed to affect the result.
michael@0:   //
michael@0:   // 'this' can be the same object as either aRect1 or aRect2
michael@0:   void UnionRectEdges(const Sub& aRect1, const Sub& aRect2)
michael@0:   {
michael@0:     *static_cast<Sub*>(this) = aRect1.UnionEdges(aRect2);
michael@0:   }
michael@0: 
michael@0:   void SetRect(T aX, T aY, T aWidth, T aHeight)
michael@0:   {
michael@0:     x = aX; y = aY; width = aWidth; height = aHeight;
michael@0:   }
michael@0:   void SetRect(const Point& aPt, const SizeT& aSize)
michael@0:   {
michael@0:     SetRect(aPt.x, aPt.y, aSize.width, aSize.height);
michael@0:   }
michael@0:   void MoveTo(T aX, T aY) { x = aX; y = aY; }
michael@0:   void MoveTo(const Point& aPoint) { x = aPoint.x; y = aPoint.y; }
michael@0:   void MoveBy(T aDx, T aDy) { x += aDx; y += aDy; }
michael@0:   void MoveBy(const Point& aPoint) { x += aPoint.x; y += aPoint.y; }
michael@0:   void SizeTo(T aWidth, T aHeight) { width = aWidth; height = aHeight; }
michael@0:   void SizeTo(const SizeT& aSize) { width = aSize.width; height = aSize.height; }
michael@0: 
michael@0:   void Inflate(T aD) { Inflate(aD, aD); }
michael@0:   void Inflate(T aDx, T aDy)
michael@0:   {
michael@0:     x -= aDx;
michael@0:     y -= aDy;
michael@0:     width += 2 * aDx;
michael@0:     height += 2 * aDy;
michael@0:   }
michael@0:   void Inflate(const MarginT& aMargin)
michael@0:   {
michael@0:     x -= aMargin.left;
michael@0:     y -= aMargin.top;
michael@0:     width += aMargin.LeftRight();
michael@0:     height += aMargin.TopBottom();
michael@0:   }
michael@0:   void Inflate(const SizeT& aSize) { Inflate(aSize.width, aSize.height); }
michael@0: 
michael@0:   void Deflate(T aD) { Deflate(aD, aD); }
michael@0:   void Deflate(T aDx, T aDy)
michael@0:   {
michael@0:     x += aDx;
michael@0:     y += aDy;
michael@0:     width = std::max(T(0), width - 2 * aDx);
michael@0:     height = std::max(T(0), height - 2 * aDy);
michael@0:   }
michael@0:   void Deflate(const MarginT& aMargin)
michael@0:   {
michael@0:     x += aMargin.left;
michael@0:     y += aMargin.top;
michael@0:     width = std::max(T(0), width - aMargin.LeftRight());
michael@0:     height = std::max(T(0), height - aMargin.TopBottom());
michael@0:   }
michael@0:   void Deflate(const SizeT& aSize) { Deflate(aSize.width, aSize.height); }
michael@0: 
michael@0:   // Return true if the rectangles contain the same set of points, including
michael@0:   // points on the edges.
michael@0:   // Use when we care about the exact x/y/width/height values being
michael@0:   // equal (i.e. we care about differences in empty rectangles).
michael@0:   bool IsEqualEdges(const Sub& aRect) const
michael@0:   {
michael@0:     return x == aRect.x && y == aRect.y &&
michael@0:            width == aRect.width && height == aRect.height;
michael@0:   }
michael@0:   // Return true if the rectangles contain the same area of the plane.
michael@0:   // Use when we do not care about differences in empty rectangles.
michael@0:   bool IsEqualInterior(const Sub& aRect) const
michael@0:   {
michael@0:     return IsEqualEdges(aRect) || (IsEmpty() && aRect.IsEmpty());
michael@0:   }
michael@0: 
michael@0:   Sub operator+(const Point& aPoint) const
michael@0:   {
michael@0:     return Sub(x + aPoint.x, y + aPoint.y, width, height);
michael@0:   }
michael@0:   Sub operator-(const Point& aPoint) const
michael@0:   {
michael@0:     return Sub(x - aPoint.x, y - aPoint.y, width, height);
michael@0:   }
michael@0:   Sub& operator+=(const Point& aPoint)
michael@0:   {
michael@0:     MoveBy(aPoint);
michael@0:     return *static_cast<Sub*>(this);
michael@0:   }
michael@0:   Sub& operator-=(const Point& aPoint)
michael@0:   {
michael@0:     MoveBy(-aPoint);
michael@0:     return *static_cast<Sub*>(this);
michael@0:   }
michael@0: 
michael@0:   // Find difference as a Margin
michael@0:   MarginT operator-(const Sub& aRect) const
michael@0:   {
michael@0:     return MarginT(aRect.y - y,
michael@0:                    XMost() - aRect.XMost(),
michael@0:                    YMost() - aRect.YMost(),
michael@0:                    aRect.x - x);
michael@0:   }
michael@0: 
michael@0:   // Helpers for accessing the vertices
michael@0:   Point TopLeft() const { return Point(x, y); }
michael@0:   Point TopRight() const { return Point(XMost(), y); }
michael@0:   Point BottomLeft() const { return Point(x, YMost()); }
michael@0:   Point BottomRight() const { return Point(XMost(), YMost()); }
michael@0:   Point Center() const { return Point(x, y) + Point(width, height)/2; }
michael@0:   SizeT Size() const { return SizeT(width, height); }
michael@0: 
michael@0:   // Helper methods for computing the extents
michael@0:   T X() const { return x; }
michael@0:   T Y() const { return y; }
michael@0:   T Width() const { return width; }
michael@0:   T Height() const { return height; }
michael@0:   T XMost() const { return x + width; }
michael@0:   T YMost() const { return y + height; }
michael@0: 
michael@0:   // Moves one edge of the rect without moving the opposite edge.
michael@0:   void SetLeftEdge(T aX) {
michael@0:     MOZ_ASSERT(aX <= XMost());
michael@0:     width = XMost() - aX;
michael@0:     x = aX;
michael@0:   }
michael@0:   void SetRightEdge(T aXMost) { 
michael@0:     MOZ_ASSERT(aXMost >= x);
michael@0:     width = aXMost - x; 
michael@0:   }
michael@0:   void SetTopEdge(T aY) {
michael@0:     MOZ_ASSERT(aY <= YMost());
michael@0:     height = YMost() - aY;
michael@0:     y = aY;
michael@0:   }
michael@0:   void SetBottomEdge(T aYMost) { 
michael@0:     MOZ_ASSERT(aYMost >= y);
michael@0:     height = aYMost - y; 
michael@0:   }
michael@0: 
michael@0:   // Round the rectangle edges to integer coordinates, such that the rounded
michael@0:   // rectangle has the same set of pixel centers as the original rectangle.
michael@0:   // Edges at offset 0.5 round up.
michael@0:   // Suitable for most places where integral device coordinates
michael@0:   // are needed, but note that any translation should be applied first to
michael@0:   // avoid pixel rounding errors.
michael@0:   // Note that this is *not* rounding to nearest integer if the values are negative.
michael@0:   // They are always rounding as floor(n + 0.5).
michael@0:   // See https://bugzilla.mozilla.org/show_bug.cgi?id=410748#c14
michael@0:   // If you need similar method which is using NS_round(), you should create
michael@0:   // new |RoundAwayFromZero()| method.
michael@0:   void Round()
michael@0:   {
michael@0:     T x0 = static_cast<T>(floor(T(X()) + 0.5));
michael@0:     T y0 = static_cast<T>(floor(T(Y()) + 0.5));
michael@0:     T x1 = static_cast<T>(floor(T(XMost()) + 0.5));
michael@0:     T y1 = static_cast<T>(floor(T(YMost()) + 0.5));
michael@0: 
michael@0:     x = x0;
michael@0:     y = y0;
michael@0: 
michael@0:     width = x1 - x0;
michael@0:     height = y1 - y0;
michael@0:   }
michael@0: 
michael@0:   // Snap the rectangle edges to integer coordinates, such that the
michael@0:   // original rectangle contains the resulting rectangle.
michael@0:   void RoundIn()
michael@0:   {
michael@0:     T x0 = static_cast<T>(ceil(T(X())));
michael@0:     T y0 = static_cast<T>(ceil(T(Y())));
michael@0:     T x1 = static_cast<T>(floor(T(XMost())));
michael@0:     T y1 = static_cast<T>(floor(T(YMost())));
michael@0: 
michael@0:     x = x0;
michael@0:     y = y0;
michael@0: 
michael@0:     width = x1 - x0;
michael@0:     height = y1 - y0;
michael@0:   }
michael@0: 
michael@0:   // Snap the rectangle edges to integer coordinates, such that the
michael@0:   // resulting rectangle contains the original rectangle.
michael@0:   void RoundOut()
michael@0:   {
michael@0:     T x0 = static_cast<T>(floor(T(X())));
michael@0:     T y0 = static_cast<T>(floor(T(Y())));
michael@0:     T x1 = static_cast<T>(ceil(T(XMost())));
michael@0:     T y1 = static_cast<T>(ceil(T(YMost())));
michael@0: 
michael@0:     x = x0;
michael@0:     y = y0;
michael@0: 
michael@0:     width = x1 - x0;
michael@0:     height = y1 - y0;
michael@0:   }
michael@0: 
michael@0:   // Scale 'this' by aScale without doing any rounding.
michael@0:   void Scale(T aScale) { Scale(aScale, aScale); }
michael@0:   // Scale 'this' by aXScale and aYScale, without doing any rounding.
michael@0:   void Scale(T aXScale, T aYScale)
michael@0:   {
michael@0:     T right = XMost() * aXScale;
michael@0:     T bottom = YMost() * aYScale;
michael@0:     x = x * aXScale;
michael@0:     y = y * aYScale;
michael@0:     width = right - x;
michael@0:     height = bottom - y;
michael@0:   }
michael@0:   // Scale 'this' by aScale, converting coordinates to integers so that the result is
michael@0:   // the smallest integer-coordinate rectangle containing the unrounded result.
michael@0:   // Note: this can turn an empty rectangle into a non-empty rectangle
michael@0:   void ScaleRoundOut(double aScale) { ScaleRoundOut(aScale, aScale); }
michael@0:   // Scale 'this' by aXScale and aYScale, converting coordinates to integers so
michael@0:   // that the result is the smallest integer-coordinate rectangle containing the
michael@0:   // unrounded result.
michael@0:   // Note: this can turn an empty rectangle into a non-empty rectangle
michael@0:   void ScaleRoundOut(double aXScale, double aYScale)
michael@0:   {
michael@0:     T right = static_cast<T>(ceil(double(XMost()) * aXScale));
michael@0:     T bottom = static_cast<T>(ceil(double(YMost()) * aYScale));
michael@0:     x = static_cast<T>(floor(double(x) * aXScale));
michael@0:     y = static_cast<T>(floor(double(y) * aYScale));
michael@0:     width = right - x;
michael@0:     height = bottom - y;
michael@0:   }
michael@0:   // Scale 'this' by aScale, converting coordinates to integers so that the result is
michael@0:   // the largest integer-coordinate rectangle contained by the unrounded result.
michael@0:   void ScaleRoundIn(double aScale) { ScaleRoundIn(aScale, aScale); }
michael@0:   // Scale 'this' by aXScale and aYScale, converting coordinates to integers so
michael@0:   // that the result is the largest integer-coordinate rectangle contained by the
michael@0:   // unrounded result.
michael@0:   void ScaleRoundIn(double aXScale, double aYScale)
michael@0:   {
michael@0:     T right = static_cast<T>(floor(double(XMost()) * aXScale));
michael@0:     T bottom = static_cast<T>(floor(double(YMost()) * aYScale));
michael@0:     x = static_cast<T>(ceil(double(x) * aXScale));
michael@0:     y = static_cast<T>(ceil(double(y) * aYScale));
michael@0:     width = std::max<T>(0, right - x);
michael@0:     height = std::max<T>(0, bottom - y);
michael@0:   }
michael@0:   // Scale 'this' by 1/aScale, converting coordinates to integers so that the result is
michael@0:   // the smallest integer-coordinate rectangle containing the unrounded result.
michael@0:   // Note: this can turn an empty rectangle into a non-empty rectangle
michael@0:   void ScaleInverseRoundOut(double aScale) { ScaleInverseRoundOut(aScale, aScale); }
michael@0:   // Scale 'this' by 1/aXScale and 1/aYScale, converting coordinates to integers so
michael@0:   // that the result is the smallest integer-coordinate rectangle containing the
michael@0:   // unrounded result.
michael@0:   // Note: this can turn an empty rectangle into a non-empty rectangle
michael@0:   void ScaleInverseRoundOut(double aXScale, double aYScale)
michael@0:   {
michael@0:     T right = static_cast<T>(ceil(double(XMost()) / aXScale));
michael@0:     T bottom = static_cast<T>(ceil(double(YMost()) / aYScale));
michael@0:     x = static_cast<T>(floor(double(x) / aXScale));
michael@0:     y = static_cast<T>(floor(double(y) / aYScale));
michael@0:     width = right - x;
michael@0:     height = bottom - y;
michael@0:   }
michael@0:   // Scale 'this' by 1/aScale, converting coordinates to integers so that the result is
michael@0:   // the largest integer-coordinate rectangle contained by the unrounded result.
michael@0:   void ScaleInverseRoundIn(double aScale) { ScaleInverseRoundIn(aScale, aScale); }
michael@0:   // Scale 'this' by 1/aXScale and 1/aYScale, converting coordinates to integers so
michael@0:   // that the result is the largest integer-coordinate rectangle contained by the
michael@0:   // unrounded result.
michael@0:   void ScaleInverseRoundIn(double aXScale, double aYScale)
michael@0:   {
michael@0:     T right = static_cast<T>(floor(double(XMost()) / aXScale));
michael@0:     T bottom = static_cast<T>(floor(double(YMost()) / aYScale));
michael@0:     x = static_cast<T>(ceil(double(x) / aXScale));
michael@0:     y = static_cast<T>(ceil(double(y) / aYScale));
michael@0:     width = std::max<T>(0, right - x);
michael@0:     height = std::max<T>(0, bottom - y);
michael@0:   }
michael@0: 
michael@0:   /**
michael@0:    * Clamp aPoint to this rectangle. It is allowed to end up on any
michael@0:    * edge of the rectangle.
michael@0:    */
michael@0:   Point ClampPoint(const Point& aPoint) const
michael@0:   {
michael@0:     return Point(std::max(x, std::min(XMost(), aPoint.x)),
michael@0:                  std::max(y, std::min(YMost(), aPoint.y)));
michael@0:   }
michael@0: 
michael@0:   /**
michael@0:    * Clamp this rectangle to be inside aRect. The function returns a copy of
michael@0:    * this rect after it is forced inside the bounds of aRect. It will attempt to
michael@0:    * retain the size but will shrink the dimensions that don't fit.
michael@0:    */
michael@0:   Sub ForceInside(const Sub& aRect) const
michael@0:   {
michael@0:     Sub rect(std::max(aRect.x, x),
michael@0:              std::max(aRect.y, y),
michael@0:              std::min(aRect.width, width),
michael@0:              std::min(aRect.height, height));
michael@0:     rect.x = std::min(rect.XMost(), aRect.XMost()) - rect.width;
michael@0:     rect.y = std::min(rect.YMost(), aRect.YMost()) - rect.height;
michael@0:     return rect;
michael@0:   }
michael@0: 
michael@0: private:
michael@0:   // Do not use the default operator== or operator!= !
michael@0:   // Use IsEqualEdges or IsEqualInterior explicitly.
michael@0:   bool operator==(const Sub& aRect) const { return false; }
michael@0:   bool operator!=(const Sub& aRect) const { return false; }
michael@0: };
michael@0: 
michael@0: }
michael@0: }
michael@0: 
michael@0: #endif /* MOZILLA_GFX_BASERECT_H_ */