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authorStefan Klug <stefan.klug@ideasonboard.com>2024-12-16 16:40:43 +0100
committerStefan Klug <stefan.klug@ideasonboard.com>2024-12-17 10:31:44 +0100
commitec097d63ef9064cc495d9126b54dc772e83137d7 (patch)
tree0a7f23e72f6468af617dafc06ff98b556a3385ee
parentdb9b6f8e2302842e0bb153f0c9600444a21ef670 (diff)
libcamera: geometry: Add Rectangle::transformedBetween()
Handling cropping and scaling within a complicated pipeline involves transformations of rectangles between different coordinate systems. For example the full input of the dewarper (0,0)/1920x1080 might correspond to the rectangle (0, 243)/2592x1458 in sensor coordinates (of a 2592x1944 sensor). Add a function that allows the transformation of a rectangle defined in one reference frame (dewarper) into the coordinates of a second reference frame (sensor). Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com> Reviewed-by: Paul Elder <paul.elder@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
-rw-r--r--include/libcamera/geometry.h3
-rw-r--r--src/libcamera/geometry.cpp49
-rw-r--r--test/geometry.cpp11
3 files changed, 63 insertions, 0 deletions
diff --git a/include/libcamera/geometry.h b/include/libcamera/geometry.h
index 9ca5865a..e5f0a843 100644
--- a/include/libcamera/geometry.h
+++ b/include/libcamera/geometry.h
@@ -299,6 +299,9 @@ public:
__nodiscard Rectangle scaledBy(const Size &numerator,
const Size &denominator) const;
__nodiscard Rectangle translatedBy(const Point &point) const;
+
+ Rectangle transformedBetween(const Rectangle &source,
+ const Rectangle &target) const;
};
bool operator==(const Rectangle &lhs, const Rectangle &rhs);
diff --git a/src/libcamera/geometry.cpp b/src/libcamera/geometry.cpp
index 90ccf8c1..81cc8cd5 100644
--- a/src/libcamera/geometry.cpp
+++ b/src/libcamera/geometry.cpp
@@ -838,6 +838,55 @@ Rectangle Rectangle::translatedBy(const Point &point) const
}
/**
+ * \brief Transform a Rectangle from one reference rectangle to another
+ * \param[in] source The \a source reference rectangle
+ * \param[in] destination The \a destination reference rectangle
+ *
+ * The \a source and \a destination parameters describe two rectangles defined
+ * in different reference systems. The Rectangle is translated from the source
+ * reference system into the destination reference system.
+ *
+ * The typical use case for this function is to translate a selection rectangle
+ * specified in a reference system, in example the sensor's pixel array, into
+ * the same rectangle re-scaled and translated into a different reference
+ * system, in example the output frame on which the selection rectangle is
+ * applied to.
+ *
+ * For example, consider a sensor with a resolution of 4040x2360 pixels and a
+ * assume a rectangle of (100, 100)/3840x2160 (sensorFrame) in sensor
+ * coordinates is mapped to a rectangle (0,0)/(1920,1080) (displayFrame) in
+ * display coordinates. This function can be used to transform an arbitrary
+ * rectangle from display coordinates to sensor coordinates or vice versa:
+ *
+ * \code{.cpp}
+ * Rectangle sensorReference(100, 100, 3840, 2160);
+ * Rectangle displayReference(0, 0, 1920, 1080);
+ *
+ * // Bottom right quarter in sensor coordinates
+ * Rectangle sensorRect(2020, 100, 1920, 1080);
+ * displayRect = sensorRect.transformedBetween(sensorReference, displayReference);
+ * // displayRect is now (960, 540)/960x540
+ *
+ * // Transformation back to sensor coordinates
+ * sensorRect = displayRect.transformedBetween(displayReference, sensorReference);
+ * \endcode
+ */
+Rectangle Rectangle::transformedBetween(const Rectangle &source,
+ const Rectangle &destination) const
+{
+ Rectangle r;
+ double sx = static_cast<double>(destination.width) / source.width;
+ double sy = static_cast<double>(destination.height) / source.height;
+
+ r.x = static_cast<int>((x - source.x) * sx) + destination.x;
+ r.y = static_cast<int>((y - source.y) * sy) + destination.y;
+ r.width = static_cast<int>(width * sx);
+ r.height = static_cast<int>(height * sy);
+
+ return r;
+}
+
+/**
* \brief Compare rectangles for equality
* \return True if the two rectangles are equal, false otherwise
*/
diff --git a/test/geometry.cpp b/test/geometry.cpp
index 5760fa3c..11df043b 100644
--- a/test/geometry.cpp
+++ b/test/geometry.cpp
@@ -495,6 +495,17 @@ protected:
return TestFail;
}
+ Rectangle f1 = Rectangle(100, 200, 3000, 2000);
+ Rectangle f2 = Rectangle(200, 300, 1500, 1000);
+ /* Bottom right quarter of the corresponding frames. */
+ Rectangle r1 = Rectangle(100 + 1500, 200 + 1000, 1500, 1000);
+ Rectangle r2 = Rectangle(200 + 750, 300 + 500, 750, 500);
+ if (r1.transformedBetween(f1, f2) != r2 ||
+ r2.transformedBetween(f2, f1) != r1) {
+ cout << "Rectangle::transformedBetween() test failed" << endl;
+ return TestFail;
+ }
+
return TestPass;
}
};