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Implement Rect::IntersectLine

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This commit is contained in:
Dmitry Marakasov 2015-01-19 20:18:41 +03:00
parent 14f352dddd
commit ead93d1d69
3 changed files with 64 additions and 0 deletions
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8
SDL2pp/Rect.cc
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@ -197,6 +197,14 @@ Optional<Rect> Rect::GetIntersection(const Rect& rect) const {
);
}
bool Rect::IntersectLine(int& x1, int& y1, int& x2, int& y2) const {
return SDL_IntersectRectAndLine(this, &x1, &y1, &x2, &y2) == SDL_TRUE;
}
bool Rect::IntersectLine(Point& p1, Point& p2) const {
return SDL_IntersectRectAndLine(this, &p1.x, &p1.y, &p2.x, &p2.y) == SDL_TRUE;
}
Rect Rect::operator+(const Point& offset) const {
return Rect(x + offset.x, y + offset.y, w, h);
}

39
SDL2pp/Rect.hh
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@ -376,6 +376,45 @@ public:
////////////////////////////////////////////////////////////
Optional<Rect> GetIntersection(const Rect& rect) const;
////////////////////////////////////////////////////////////
/// \brief Calculate the intersection of a rectangle and line segment
///
/// \param[in,out] x1 Starting X-coordinate of the line
/// \param[in,out] y1 Starting Y-coordinate of the line
/// \param[in,out] x2 Ending X-coordinate of the line
/// \param[in,out] y2 Ending Y-coordinate of the line
///
/// \returns True if there is an intersection, false otherwise
///
/// This function is used to clip a line segment to a
/// rectangle. A line segment contained entirely within the
/// rectangle or that does not intersect will remain unchanged.
/// A line segment that crosses the rectangle at either or both
/// ends will be clipped to the boundary of the rectangle and
/// the new coordinates saved in x1, y1, x2, and/or y2 as
/// necessary.
///
////////////////////////////////////////////////////////////
bool IntersectLine(int& x1, int& y1, int& x2, int& y2) const;
////////////////////////////////////////////////////////////
/// \brief Calculate the intersection of a rectangle and line segment
///
/// \param[in,out] p1 Starting coordinates of the line
/// \param[in,out] p2 Ending coordinates of the line
///
/// \returns True if there is an intersection, false otherwise
///
/// This function is used to clip a line segment to a
/// rectangle. A line segment contained entirely within the
/// rectangle or that does not intersect will remain unchanged.
/// A line segment that crosses the rectangle at either or both
/// ends will be clipped to the boundary of the rectangle and
/// the new coordinates saved in p1 and/or p2 as necessary.
///
////////////////////////////////////////////////////////////
bool IntersectLine(Point& p1, Point& p2) const;
////////////////////////////////////////////////////////////
/// \brief Get rectangle moved by a given offset
///

17
tests/test_pointrect.cc
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@ -240,6 +240,23 @@ BEGIN_TEST()
EXPECT_TRUE(Rect(30, 40, 1, 1).Union(Rect(10, 20, 1, 1)) == Rect::FromCorners(10, 20, 30, 40));
}
{
// Rect/line intersections
Rect rect = Rect::FromCorners(10, 10, 20, 20);
Point p1(0, 0), p2(30, 30);
EXPECT_TRUE(rect.IntersectLine(p1, p2));
EXPECT_TRUE(p1 == Point(10, 10));
EXPECT_TRUE(p2 == Point(20, 20));
int x1 = 30, y1 = 0, x2 = 0, y2 = 30;
EXPECT_TRUE(rect.IntersectLine(x1, y1, x2, y2));
EXPECT_TRUE(x1 == 20);
EXPECT_TRUE(y1 == 10);
EXPECT_TRUE(x2 == 10);
EXPECT_TRUE(y2 == 20);
}
{
// Rect extend
EXPECT_TRUE(Rect(10, 20, 30, 40).GetExtension(0) == Rect(10, 20, 30, 40));