From 2f621920eaf084b29ce3ad15204b989e868df826 Mon Sep 17 00:00:00 2001 From: Jacopo Mondi Date: Tue, 24 Sep 2024 14:14:36 +0200 Subject: libcamera: geometry: Clarify Rectangle's top-left corner The libcamera::Rectangle class allows defining rectangles regardless of the orientation of the reference system where a rectangle is used in. This implies that, depending on the reference system in use, the rectangle's top-left corner, as defined by libcamera, doesn't correspond to the visual top-left position. ^ | | ------------------- | ^ | h | | | y| o---->------------- | w -------------------------------> (0,0) x (0,0) x ------------------------------> | w y| o---->------------- | | | h | v | | ------------------- | V Clarify that a Rectangle's top-left corner corresponds to the point with the smaller x and y coordinates and that the horizontal and vertical dimensions are obtained by positive increments along the corresponding axes. Signed-off-by: Jacopo Mondi Reviewed-by: Harvey Yang Reviewed-by: David Plowman --- src/libcamera/geometry.cpp | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/src/libcamera/geometry.cpp b/src/libcamera/geometry.cpp index 00015136..85a7f53a 100644 --- a/src/libcamera/geometry.cpp +++ b/src/libcamera/geometry.cpp @@ -594,6 +594,8 @@ std::ostream &operator<<(std::ostream &out, const SizeRange &sr) * * Rectangles are used to identify an area of an image. They are specified by * the coordinates of top-left corner and their horizontal and vertical size. + * By convention, the top-left corner is defined as the corner with the lowest + * x and y coordinates, regardless of the origin and direction of the axes. * * The measure unit of the rectangle coordinates and size, as well as the * reference point from which the Rectangle::x and Rectangle::y displacements @@ -611,6 +613,8 @@ std::ostream &operator<<(std::ostream &out, const SizeRange &sr) * \param[in] x The horizontal coordinate of the top-left corner * \param[in] y The vertical coordinate of the top-left corner * \param[in] size The size + * + * The rectangle's top-left corner is the point with the smaller x and y values. */ /** @@ -620,6 +624,8 @@ std::ostream &operator<<(std::ostream &out, const SizeRange &sr) * \param[in] y The vertical coordinate of the top-left corner * \param[in] width The width * \param[in] height The height + * + * The rectangle's top-left corner is the point with the smaller x and y values. */ /** @@ -632,11 +638,15 @@ std::ostream &operator<<(std::ostream &out, const SizeRange &sr) /** * \var Rectangle::x * \brief The horizontal coordinate of the rectangle's top-left corner + * + * The rectangle's top-left corner is the point with the smaller x and y values. */ /** * \var Rectangle::y * \brief The vertical coordinate of the rectangle's top-left corner + * + * The rectangle's top-left corner is the point with the smaller x and y values. */ /** @@ -685,6 +695,9 @@ Point Rectangle::center() const /** * \fn Point Rectangle::topLeft() const * \brief Retrieve the coordinates of the top left corner of this Rectangle + * + * The rectangle's top-left corner is the point with the smaller x and y values. + * * \return The Rectangle's top left corner */ -- cgit v1.2.1