libcamera: geometry: Add helper functions to the Size class

Pipeline handlers commonly have to calculate the minimum or maximum of
multiple sizes, or align a size's width and height. Add helper functions
to the Size class to perform those tasks.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

include/libcamera/geometry.h

@@ -8,6 +8,7 @@
 #ifndef __LIBCAMERA_GEOMETRY_H__
 #define __LIBCAMERA_GEOMETRY_H__
 
+#include <algorithm>
 #include <string>
 
 namespace libcamera {
@@ -43,6 +44,38 @@ struct Size {
 
 	bool isNull() const { return !width && !height; }
 	const std::string toString() const;
+
+	Size alignedDownTo(unsigned int hAlignment, unsigned int vAlignment) const
+	{
+		return {
+			width / hAlignment * hAlignment,
+			height / vAlignment * vAlignment
+		};
+	}
+
+	Size alignedUpTo(unsigned int hAlignment, unsigned int vAlignment) const
+	{
+		return {
+			(width + hAlignment - 1) / hAlignment * hAlignment,
+			(height + vAlignment - 1) / vAlignment * vAlignment
+		};
+	}
+
+	Size boundedTo(const Size &bound) const
+	{
+		return {
+			std::min(width, bound.width),
+			std::min(height, bound.height)
+		};
+	}
+
+	Size expandedTo(const Size &expand) const
+	{
+		return {
+			std::max(width, expand.width),
+			std::max(height, expand.height)
+		};
+	}
 };
 
 bool operator==(const Size &lhs, const Size &rhs);

src/libcamera/geometry.cpp

@@ -122,6 +122,42 @@ const std::string Size::toString() const
 	return std::to_string(width) + "x" + std::to_string(height);
 }
 
+/**
+ * \fn Size::alignedDownTo(unsigned int hAlignment, unsigned int vAlignment)
+ * \brief Align the size down horizontally and vertically
+ * \param[in] hAlignment Horizontal alignment
+ * \param[in] vAlignment Vertical alignment
+ * \return A Size whose width and height are equal to the width and height of
+ * this size rounded down to the nearest multiple of \a hAlignment and
+ * \a vAlignment respectively
+ */
+
+/**
+ * \fn Size::alignedUpTo(unsigned int hAlignment, unsigned int vAlignment)
+ * \brief Align the size up horizontally and vertically
+ * \param[in] hAlignment Horizontal alignment
+ * \param[in] vAlignment Vertical alignment
+ * \return A Size whose width and height are equal to the width and height of
+ * this size rounded up to the nearest multiple of \a hAlignment and
+ * \a vAlignment respectively
+ */
+
+/**
+ * \fn Size::boundedTo(const Size &bound)
+ * \brief Bound the size to \a bound
+ * \param[in] bound The maximum size
+ * \return A Size whose width and height are the minimum of the width and
+ * height of this size and the \a bound size
+ */
+
+/**
+ * \fn Size::expandedTo(const Size &expand)
+ * \brief Expand the size to \a expand
+ * \param[in] expand The minimum size
+ * \return A Size whose width and height are the maximum of the width and
+ * height of this size and the \a expand size
+ */
+
 /**
  * \brief Compare sizes for equality
  * \return True if the two sizes are equal, false otherwise

test/geometry.cpp

@@ -46,6 +46,35 @@ protected:
 			return TestFail;
 		}
 
+		/* Test alignedDownTo(), alignedUpTo(), boundedTo() and expandedTo() */
+		if (Size(0, 0).alignedDownTo(16, 8) != Size(0, 0) ||
+		    Size(1, 1).alignedDownTo(16, 8) != Size(0, 0) ||
+		    Size(16, 8).alignedDownTo(16, 8) != Size(16, 8)) {
+			cout << "Size::alignedDownTo() test failed" << endl;
+			return TestFail;
+		}
+
+		if (Size(0, 0).alignedUpTo(16, 8) != Size(0, 0) ||
+		    Size(1, 1).alignedUpTo(16, 8) != Size(16, 8) ||
+		    Size(16, 8).alignedUpTo(16, 8) != Size(16, 8)) {
+			cout << "Size::alignedUpTo() test failed" << endl;
+			return TestFail;
+		}
+
+		if (Size(0, 0).boundedTo({ 100, 100 }) != Size(0, 0) ||
+		    Size(200, 50).boundedTo({ 100, 100 }) != Size(100, 50) ||
+		    Size(50, 200).boundedTo({ 100, 100 }) != Size(50, 100)) {
+			cout << "Size::boundedTo() test failed" << endl;
+			return TestFail;
+		}
+
+		if (Size(0, 0).expandedTo({ 100, 100 }) != Size(100, 100) ||
+		    Size(200, 50).expandedTo({ 100, 100 }) != Size(200, 100) ||
+		    Size(50, 200).expandedTo({ 100, 100 }) != Size(100, 200)) {
+			cout << "Size::expandedTo() test failed" << endl;
+			return TestFail;
+		}
+
 		/* Test Size equality and inequality. */
 		if (!compare(Size(100, 100), Size(100, 100), &operator==, "==", true))
 			return TestFail;