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gecko-dev/gfx/2d/BaseRect.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* 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_GFX_BASERECT_H_
#define MOZILLA_GFX_BASERECT_H_
#include <algorithm>
#include <cmath>
#include <ostream>
#include "mozilla/Assertions.h"
#include "mozilla/FloatingPoint.h"
#include "mozilla/TypeTraits.h"
#include "Types.h"
namespace mozilla {
namespace gfx {
/**
* Rectangles have two interpretations: a set of (zero-size) points,
* and a rectangular area of the plane. Most rectangle operations behave
* the same no matter what interpretation is being used, but some operations
* differ:
* -- Equality tests behave differently. When a rectangle represents an area,
* all zero-width and zero-height rectangles are equal to each other since they
* represent the empty area. But when a rectangle represents a set of
* mathematical points, zero-width and zero-height rectangles can be unequal.
* -- The union operation can behave differently. When rectangles represent
* areas, taking the union of a zero-width or zero-height rectangle with
* another rectangle can just ignore the empty rectangle. But when rectangles
* represent sets of mathematical points, we may need to extend the latter
* rectangle to include the points of a zero-width or zero-height rectangle.
*
* To ensure that these interpretations are explicitly disambiguated, we
* deny access to the == and != operators and require use of IsEqualEdges and
* IsEqualInterior instead. Similarly we provide separate Union and UnionEdges
* methods.
*
* Do not use this class directly. Subclass it, pass that subclass as the
* Sub parameter, and only use that subclass.
*/
template <class T, class Sub, class Point, class SizeT, class MarginT>
struct BaseRect {
T x, y, width, height;
// Constructors
BaseRect() : x(0), y(0), width(0), height(0) {}
BaseRect(const Point& aOrigin, const SizeT &aSize) :
x(aOrigin.x), y(aOrigin.y), width(aSize.width), height(aSize.height)
{
}
BaseRect(T aX, T aY, T aWidth, T aHeight) :
x(aX), y(aY), width(aWidth), height(aHeight)
{
}
// Emptiness. An empty rect is one that has no area, i.e. its height or width
// is <= 0
bool IsEmpty() const { return height <= 0 || width <= 0; }
void SetEmpty() { width = height = 0; }
// "Finite" means not inf and not NaN
bool IsFinite() const
{
typedef typename mozilla::Conditional<mozilla::IsSame<T, float>::value, float, double>::Type FloatType;
return (mozilla::IsFinite(FloatType(x)) &&
mozilla::IsFinite(FloatType(y)) &&
mozilla::IsFinite(FloatType(width)) &&
mozilla::IsFinite(FloatType(height)));
}
// Returns true if this rectangle contains the interior of aRect. Always
// returns true if aRect is empty, and always returns false is aRect is
// nonempty but this rect is empty.
bool Contains(const Sub& aRect) const
{
return aRect.IsEmpty() ||
(x <= aRect.x && aRect.XMost() <= XMost() &&
y <= aRect.y && aRect.YMost() <= YMost());
}
// Returns true if this rectangle contains the point. Points are considered
// in the rectangle if they are on the left or top edge, but outside if they
// are on the right or bottom edge.
bool Contains(T aX, T aY) const
{
return x <= aX && aX < XMost() &&
y <= aY && aY < YMost();
}
// Returns true if this rectangle contains the point. Points are considered
// in the rectangle if they are on the left or top edge, but outside if they
// are on the right or bottom edge.
bool Contains(const Point& aPoint) const { return Contains(aPoint.x, aPoint.y); }
// Intersection. Returns TRUE if the receiver's area has non-empty
// intersection with aRect's area, and FALSE otherwise.
// Always returns false if aRect is empty or 'this' is empty.
bool Intersects(const Sub& aRect) const
{
return !IsEmpty() && !aRect.IsEmpty() &&
x < aRect.XMost() && aRect.x < XMost() &&
y < aRect.YMost() && aRect.y < YMost();
}
// Returns the rectangle containing the intersection of the points
// (including edges) of *this and aRect. If there are no points in that
// intersection, returns an empty rectangle with x/y set to the std::max of the x/y
// of *this and aRect.
MOZ_MUST_USE Sub Intersect(const Sub& aRect) const
{
Sub result;
result.x = std::max<T>(x, aRect.x);
result.y = std::max<T>(y, aRect.y);
result.width = std::min<T>(x - result.x + width, aRect.x - result.x + aRect.width);
result.height = std::min<T>(y - result.y + height, aRect.y - result.y + aRect.height);
if (result.width < 0 || result.height < 0) {
result.SizeTo(0, 0);
}
return result;
}
// Sets *this to be the rectangle containing the intersection of the points
// (including edges) of *this and aRect. If there are no points in that
// intersection, sets *this to be an empty rectangle with x/y set to the std::max
// of the x/y of *this and aRect.
//
// 'this' can be the same object as either aRect1 or aRect2
bool IntersectRect(const Sub& aRect1, const Sub& aRect2)
{
*static_cast<Sub*>(this) = aRect1.Intersect(aRect2);
return !IsEmpty();
}
// Returns the smallest rectangle that contains both the area of both
// this and aRect2.
// Thus, empty input rectangles are ignored.
// If both rectangles are empty, returns this.
// WARNING! This is not safe against overflow, prefer using SafeUnion instead
// when dealing with int-based rects.
MOZ_MUST_USE Sub Union(const Sub& aRect) const
{
if (IsEmpty()) {
return aRect;
} else if (aRect.IsEmpty()) {
return *static_cast<const Sub*>(this);
} else {
return UnionEdges(aRect);
}
}
// Returns the smallest rectangle that contains both the points (including
// edges) of both aRect1 and aRect2.
// Thus, empty input rectangles are allowed to affect the result.
// WARNING! This is not safe against overflow, prefer using SafeUnionEdges
// instead when dealing with int-based rects.
MOZ_MUST_USE Sub UnionEdges(const Sub& aRect) const
{
Sub result;
result.x = std::min(x, aRect.x);
result.y = std::min(y, aRect.y);
result.width = std::max(XMost(), aRect.XMost()) - result.x;
result.height = std::max(YMost(), aRect.YMost()) - result.y;
return result;
}
// Computes the smallest rectangle that contains both the area of both
// aRect1 and aRect2, and fills 'this' with the result.
// Thus, empty input rectangles are ignored.
// If both rectangles are empty, sets 'this' to aRect2.
//
// 'this' can be the same object as either aRect1 or aRect2
void UnionRect(const Sub& aRect1, const Sub& aRect2)
{
*static_cast<Sub*>(this) = aRect1.Union(aRect2);
}
// Computes the smallest rectangle that contains both the points (including
// edges) of both aRect1 and aRect2.
// Thus, empty input rectangles are allowed to affect the result.
//
// 'this' can be the same object as either aRect1 or aRect2
void UnionRectEdges(const Sub& aRect1, const Sub& aRect2)
{
*static_cast<Sub*>(this) = aRect1.UnionEdges(aRect2);
}
// Expands the rect to include the point
void ExpandToEnclose(const Point& aPoint)
{
if (aPoint.x < x) {
width = XMost() - aPoint.x;
x = aPoint.x;
} else if (aPoint.x > XMost()) {
width = aPoint.x - x;
}
if (aPoint.y < y) {
height = YMost() - aPoint.y;
y = aPoint.y;
} else if (aPoint.y > YMost()) {
height = aPoint.y - y;
}
}
void SetRect(T aX, T aY, T aWidth, T aHeight)
{
x = aX; y = aY; width = aWidth; height = aHeight;
}
void SetRect(const Point& aPt, const SizeT& aSize)
{
SetRect(aPt.x, aPt.y, aSize.width, aSize.height);
}
void MoveTo(T aX, T aY) { x = aX; y = aY; }
void MoveTo(const Point& aPoint) { x = aPoint.x; y = aPoint.y; }
void MoveBy(T aDx, T aDy) { x += aDx; y += aDy; }
void MoveBy(const Point& aPoint) { x += aPoint.x; y += aPoint.y; }
void SizeTo(T aWidth, T aHeight) { width = aWidth; height = aHeight; }
void SizeTo(const SizeT& aSize) { width = aSize.width; height = aSize.height; }
void Inflate(T aD) { Inflate(aD, aD); }
void Inflate(T aDx, T aDy)
{
x -= aDx;
y -= aDy;
width += 2 * aDx;
height += 2 * aDy;
}
void Inflate(const MarginT& aMargin)
{
x -= aMargin.left;
y -= aMargin.top;
width += aMargin.LeftRight();
height += aMargin.TopBottom();
}
void Inflate(const SizeT& aSize) { Inflate(aSize.width, aSize.height); }
void Deflate(T aD) { Deflate(aD, aD); }
void Deflate(T aDx, T aDy)
{
x += aDx;
y += aDy;
width = std::max(T(0), width - 2 * aDx);
height = std::max(T(0), height - 2 * aDy);
}
void Deflate(const MarginT& aMargin)
{
x += aMargin.left;
y += aMargin.top;
width = std::max(T(0), width - aMargin.LeftRight());
height = std::max(T(0), height - aMargin.TopBottom());
}
void Deflate(const SizeT& aSize) { Deflate(aSize.width, aSize.height); }
// Return true if the rectangles contain the same set of points, including
// points on the edges.
// Use when we care about the exact x/y/width/height values being
// equal (i.e. we care about differences in empty rectangles).
bool IsEqualEdges(const Sub& aRect) const
{
return x == aRect.x && y == aRect.y &&
width == aRect.width && height == aRect.height;
}
// Return true if the rectangles contain the same area of the plane.
// Use when we do not care about differences in empty rectangles.
bool IsEqualInterior(const Sub& aRect) const
{
return IsEqualEdges(aRect) || (IsEmpty() && aRect.IsEmpty());
}
friend Sub operator+(Sub aSub, const Point& aPoint)
{
aSub += aPoint;
return aSub;
}
friend Sub operator-(Sub aSub, const Point& aPoint)
{
aSub -= aPoint;
return aSub;
}
friend Sub operator+(Sub aSub, const SizeT& aSize)
{
aSub += aSize;
return aSub;
}
friend Sub operator-(Sub aSub, const SizeT& aSize)
{
aSub -= aSize;
return aSub;
}
Sub& operator+=(const Point& aPoint)
{
MoveBy(aPoint);
return *static_cast<Sub*>(this);
}
Sub& operator-=(const Point& aPoint)
{
MoveBy(-aPoint);
return *static_cast<Sub*>(this);
}
Sub& operator+=(const SizeT& aSize)
{
width += aSize.width;
height += aSize.height;
return *static_cast<Sub*>(this);
}
Sub& operator-=(const SizeT& aSize)
{
width -= aSize.width;
height -= aSize.height;
return *static_cast<Sub*>(this);
}
// Find difference as a Margin
MarginT operator-(const Sub& aRect) const
{
return MarginT(aRect.y - y,
XMost() - aRect.XMost(),
YMost() - aRect.YMost(),
aRect.x - x);
}
// Helpers for accessing the vertices
Point TopLeft() const { return Point(x, y); }
Point TopRight() const { return Point(XMost(), y); }
Point BottomLeft() const { return Point(x, YMost()); }
Point BottomRight() const { return Point(XMost(), YMost()); }
Point AtCorner(int aCorner) const {
switch (aCorner) {
case RectCorner::TopLeft: return TopLeft();
case RectCorner::TopRight: return TopRight();
case RectCorner::BottomRight: return BottomRight();
case RectCorner::BottomLeft: return BottomLeft();
}
MOZ_CRASH("GFX: Incomplete switch");
}
Point CCWCorner(mozilla::Side side) const {
switch (side) {
case NS_SIDE_TOP: return TopLeft();
case NS_SIDE_RIGHT: return TopRight();
case NS_SIDE_BOTTOM: return BottomRight();
case NS_SIDE_LEFT: return BottomLeft();
}
MOZ_CRASH("GFX: Incomplete switch");
}
Point CWCorner(mozilla::Side side) const {
switch (side) {
case NS_SIDE_TOP: return TopRight();
case NS_SIDE_RIGHT: return BottomRight();
case NS_SIDE_BOTTOM: return BottomLeft();
case NS_SIDE_LEFT: return TopLeft();
}
MOZ_CRASH("GFX: Incomplete switch");
}
Point Center() const { return Point(x, y) + Point(width, height)/2; }
SizeT Size() const { return SizeT(width, height); }
T Area() const { return width * height; }
// Helper methods for computing the extents
T X() const { return x; }
T Y() const { return y; }
T Width() const { return width; }
T Height() const { return height; }
T XMost() const { return x + width; }
T YMost() const { return y + height; }
// Get the coordinate of the edge on the given side.
T Edge(mozilla::Side aSide) const
{
switch (aSide) {
case NS_SIDE_TOP: return Y();
case NS_SIDE_RIGHT: return XMost();
case NS_SIDE_BOTTOM: return YMost();
case NS_SIDE_LEFT: return X();
}
MOZ_CRASH("GFX: Incomplete switch");
}
// Moves one edge of the rect without moving the opposite edge.
void SetLeftEdge(T aX) {
MOZ_ASSERT(aX <= XMost());
width = XMost() - aX;
x = aX;
}
void SetRightEdge(T aXMost) {
MOZ_ASSERT(aXMost >= x);
width = aXMost - x;
}
void SetTopEdge(T aY) {
MOZ_ASSERT(aY <= YMost());
height = YMost() - aY;
y = aY;
}
void SetBottomEdge(T aYMost) {
MOZ_ASSERT(aYMost >= y);
height = aYMost - y;
}
// Round the rectangle edges to integer coordinates, such that the rounded
// rectangle has the same set of pixel centers as the original rectangle.
// Edges at offset 0.5 round up.
// Suitable for most places where integral device coordinates
// are needed, but note that any translation should be applied first to
// avoid pixel rounding errors.
// Note that this is *not* rounding to nearest integer if the values are negative.
// They are always rounding as floor(n + 0.5).
// See https://bugzilla.mozilla.org/show_bug.cgi?id=410748#c14
// If you need similar method which is using NS_round(), you should create
// new |RoundAwayFromZero()| method.
void Round()
{
T x0 = static_cast<T>(floor(T(X()) + 0.5));
T y0 = static_cast<T>(floor(T(Y()) + 0.5));
T x1 = static_cast<T>(floor(T(XMost()) + 0.5));
T y1 = static_cast<T>(floor(T(YMost()) + 0.5));
x = x0;
y = y0;
width = x1 - x0;
height = y1 - y0;
}
// Snap the rectangle edges to integer coordinates, such that the
// original rectangle contains the resulting rectangle.
void RoundIn()
{
T x0 = static_cast<T>(ceil(T(X())));
T y0 = static_cast<T>(ceil(T(Y())));
T x1 = static_cast<T>(floor(T(XMost())));
T y1 = static_cast<T>(floor(T(YMost())));
x = x0;
y = y0;
width = x1 - x0;
height = y1 - y0;
}
// Snap the rectangle edges to integer coordinates, such that the
// resulting rectangle contains the original rectangle.
void RoundOut()
{
T x0 = static_cast<T>(floor(T(X())));
T y0 = static_cast<T>(floor(T(Y())));
T x1 = static_cast<T>(ceil(T(XMost())));
T y1 = static_cast<T>(ceil(T(YMost())));
x = x0;
y = y0;
width = x1 - x0;
height = y1 - y0;
}
// Scale 'this' by aScale without doing any rounding.
void Scale(T aScale) { Scale(aScale, aScale); }
// Scale 'this' by aXScale and aYScale, without doing any rounding.
void Scale(T aXScale, T aYScale)
{
T right = XMost() * aXScale;
T bottom = YMost() * aYScale;
x = x * aXScale;
y = y * aYScale;
width = right - x;
height = bottom - y;
}
// Scale 'this' by aScale, converting coordinates to integers so that the result is
// the smallest integer-coordinate rectangle containing the unrounded result.
// Note: this can turn an empty rectangle into a non-empty rectangle
void ScaleRoundOut(double aScale) { ScaleRoundOut(aScale, aScale); }
// Scale 'this' by aXScale and aYScale, converting coordinates to integers so
// that the result is the smallest integer-coordinate rectangle containing the
// unrounded result.
// Note: this can turn an empty rectangle into a non-empty rectangle
void ScaleRoundOut(double aXScale, double aYScale)
{
T right = static_cast<T>(ceil(double(XMost()) * aXScale));
T bottom = static_cast<T>(ceil(double(YMost()) * aYScale));
x = static_cast<T>(floor(double(x) * aXScale));
y = static_cast<T>(floor(double(y) * aYScale));
width = right - x;
height = bottom - y;
}
// Scale 'this' by aScale, converting coordinates to integers so that the result is
// the largest integer-coordinate rectangle contained by the unrounded result.
void ScaleRoundIn(double aScale) { ScaleRoundIn(aScale, aScale); }
// Scale 'this' by aXScale and aYScale, converting coordinates to integers so
// that the result is the largest integer-coordinate rectangle contained by the
// unrounded result.
void ScaleRoundIn(double aXScale, double aYScale)
{
T right = static_cast<T>(floor(double(XMost()) * aXScale));
T bottom = static_cast<T>(floor(double(YMost()) * aYScale));
x = static_cast<T>(ceil(double(x) * aXScale));
y = static_cast<T>(ceil(double(y) * aYScale));
width = std::max<T>(0, right - x);
height = std::max<T>(0, bottom - y);
}
// Scale 'this' by 1/aScale, converting coordinates to integers so that the result is
// the smallest integer-coordinate rectangle containing the unrounded result.
// Note: this can turn an empty rectangle into a non-empty rectangle
void ScaleInverseRoundOut(double aScale) { ScaleInverseRoundOut(aScale, aScale); }
// Scale 'this' by 1/aXScale and 1/aYScale, converting coordinates to integers so
// that the result is the smallest integer-coordinate rectangle containing the
// unrounded result.
// Note: this can turn an empty rectangle into a non-empty rectangle
void ScaleInverseRoundOut(double aXScale, double aYScale)
{
T right = static_cast<T>(ceil(double(XMost()) / aXScale));
T bottom = static_cast<T>(ceil(double(YMost()) / aYScale));
x = static_cast<T>(floor(double(x) / aXScale));
y = static_cast<T>(floor(double(y) / aYScale));
width = right - x;
height = bottom - y;
}
// Scale 'this' by 1/aScale, converting coordinates to integers so that the result is
// the largest integer-coordinate rectangle contained by the unrounded result.
void ScaleInverseRoundIn(double aScale) { ScaleInverseRoundIn(aScale, aScale); }
// Scale 'this' by 1/aXScale and 1/aYScale, converting coordinates to integers so
// that the result is the largest integer-coordinate rectangle contained by the
// unrounded result.
void ScaleInverseRoundIn(double aXScale, double aYScale)
{
T right = static_cast<T>(floor(double(XMost()) / aXScale));
T bottom = static_cast<T>(floor(double(YMost()) / aYScale));
x = static_cast<T>(ceil(double(x) / aXScale));
y = static_cast<T>(ceil(double(y) / aYScale));
width = std::max<T>(0, right - x);
height = std::max<T>(0, bottom - y);
}
/**
* Clamp aPoint to this rectangle. It is allowed to end up on any
* edge of the rectangle.
*/
MOZ_MUST_USE Point ClampPoint(const Point& aPoint) const
{
return Point(std::max(x, std::min(XMost(), aPoint.x)),
std::max(y, std::min(YMost(), aPoint.y)));
}
/**
* Translate this rectangle to be inside aRect. If it doesn't fit inside
* aRect then the dimensions that don't fit will be shrunk so that they
* do fit. The resulting rect is returned.
*/
MOZ_MUST_USE Sub MoveInsideAndClamp(const Sub& aRect) const
{
Sub rect(std::max(aRect.x, x),
std::max(aRect.y, y),
std::min(aRect.width, width),
std::min(aRect.height, height));
rect.x = std::min(rect.XMost(), aRect.XMost()) - rect.width;
rect.y = std::min(rect.YMost(), aRect.YMost()) - rect.height;
return rect;
}
// Returns the largest rectangle that can be represented with 32-bit
// signed integers, centered around a point at 0,0. As BaseRect's represent
// the dimensions as a top-left point with a width and height, the width
// and height will be the largest positive 32-bit value. The top-left
// position coordinate is divided by two to center the rectangle around a
// point at 0,0.
static Sub MaxIntRect()
{
return Sub(
static_cast<T>(-std::numeric_limits<int32_t>::max() * 0.5),
static_cast<T>(-std::numeric_limits<int32_t>::max() * 0.5),
static_cast<T>(std::numeric_limits<int32_t>::max()),
static_cast<T>(std::numeric_limits<int32_t>::max())
);
};
friend std::ostream& operator<<(std::ostream& stream,
const BaseRect<T, Sub, Point, SizeT, MarginT>& aRect) {
return stream << '(' << aRect.x << ',' << aRect.y << ','
<< aRect.width << ',' << aRect.height << ')';
}
private:
// Do not use the default operator== or operator!= !
// Use IsEqualEdges or IsEqualInterior explicitly.
bool operator==(const Sub& aRect) const { return false; }
bool operator!=(const Sub& aRect) const { return false; }
};
} // namespace gfx
} // namespace mozilla
#endif /* MOZILLA_GFX_BASERECT_H_ */
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