[libcamera-devel] [PATCH v2 7/7] libcamera: camera_sensor: Retrieve sensor sizes

[Jacopo Mondi]

Retrieve the camera sensor pixel array sizes and the active pixel area
using the V4L2Subdevice selection API.

Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
---
 include/libcamera/geometry.h          |  1 +
 src/libcamera/camera_sensor.cpp       | 51 +++++++++++++++++++++++++++
 src/libcamera/geometry.cpp            | 24 +++++++++++++
 src/libcamera/include/camera_sensor.h |  4 +++
 4 files changed, 80 insertions(+)

diff --git a/include/libcamera/geometry.h b/include/libcamera/geometry.h
index 52f4d010de76..b91fcfa1dd17 100644
--- a/include/libcamera/geometry.h
+++ b/include/libcamera/geometry.h
@@ -42,6 +42,7 @@ struct Size {
 	unsigned int height;
 
 	const std::string toString() const;
+	bool contains(const Rectangle &rectangle) const;
 };
 
 bool operator==(const Size &lhs, const Size &rhs);
diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
index fc7fdcdcaf5b..b6ccaae0930b 100644
--- a/src/libcamera/camera_sensor.cpp
+++ b/src/libcamera/camera_sensor.cpp
@@ -128,6 +128,28 @@ int CameraSensor::init()
 	}
 	rotation_ = value;
 
+	/*
+	 * Retrieve and store the sensor pixel array size and active area
+	 * rectangle.
+	 */
+	Rectangle rect;
+	ret = subdev_->getSelection(0, V4L2_SEL_TGT_NATIVE_SIZE, &rect);
+	if (ret)
+		return ret;
+	pixelArray_.width = rect.w;
+	pixelArray_.height = rect.h;
+
+	ret = subdev_->getSelection(0, V4L2_SEL_TGT_CROP_BOUNDS, &rect);
+	if (ret)
+		return ret;
+
+	if (!pixelArray_.contains(rect)) {
+		LOG(CameraSensor, Error)
+			<< "Invalid camera sensor pixel array dimension";
+		return -EINVAL;
+	}
+	activeArea_ = rect;
+
 	/* Enumerate and cache media bus codes and sizes. */
 	const ImageFormats formats = subdev_->formats(0);
 	if (formats.isEmpty()) {
@@ -192,6 +214,35 @@ const Size &CameraSensor::resolution() const
 	return sizes_.back();
 }
 
+/**
+ * \fn CameraSensor::pixelArray()
+ * \brief Retrieve the camera sensor pixel array dimension
+ * \return The number of horizontal and vertical pixel units installed on the
+ * camera sensor
+ *
+ * The returned pixel array size is the number of pixels units physically
+ * installed on the sensor, including non-active ones, such as pixels used
+ * for calibration or testing.
+ */
+
+/**
+ * \fn CameraSensor::activeArea()
+ * \brief Retrieve the active pixels area
+ * \return A rectangle describing the active pixel area
+ *
+ * The returned rectangle is contained in the larger pixel array area,
+ * returned by the CameraSensor::pixelArray() operation.
+ *
+ * \todo This operation collides with CameraSensor::resolution() as they
+ * both reports the same information (bugs in the driver code apart).
+ * Also, for some sensors, the maximum available resolution might depend on
+ * the image size ratio (ie the maximumx resolution for images in 4:3 format
+ * is different from the maximum available resolution for 16:9 format). This
+ * has to be sorted out as well.
+ *
+ * \sa Size::contains()
+ */
+
 /**
  * \brief Retrieve the best sensor format for a desired output
  * \param[in] mbusCodes The list of acceptable media bus codes
diff --git a/src/libcamera/geometry.cpp b/src/libcamera/geometry.cpp
index 32b0faeadc63..9b60768a57a7 100644
--- a/src/libcamera/geometry.cpp
+++ b/src/libcamera/geometry.cpp
@@ -116,6 +116,30 @@ const std::string Size::toString() const
 	return std::to_string(width) + "x" + std::to_string(height);
 }
 
+/**
+ * \fn Size::contains()
+ * \param rectangle The rectangle to verify
+ * \return True if \a rectangle is contained in the area represented by this
+ * Size, false otherwise
+ *
+ * Return true if \a rectangle is completely contained in the area represented
+ * by the width and height of this Size, with its top left corner assumed to be
+ * at coordinates (0, 0). The rectangle 'x' and 'y' fields represent the
+ * horizontal and vertical positive displacement from the Size top left corner,
+ * from where the rectangle's horizontal and vertical sizes are calculated.
+ */
+bool Size::contains(const Rectangle &rectangle) const
+{
+	if (rectangle.x < 0 || rectangle.y < 0)
+		return false;
+
+	if (rectangle.x + rectangle.w > width ||
+	    rectangle.y + rectangle.h > height)
+		return false;
+
+	return true;
+}
+
 /**
  * \brief Compare sizes for equality
  * \return True if the two sizes are equal, false otherwise
diff --git a/src/libcamera/include/camera_sensor.h b/src/libcamera/include/camera_sensor.h
index 32d39127b275..abf5344cf9d8 100644
--- a/src/libcamera/include/camera_sensor.h
+++ b/src/libcamera/include/camera_sensor.h
@@ -38,6 +38,8 @@ public:
 	const std::vector<unsigned int> &mbusCodes() const { return mbusCodes_; }
 	const std::vector<Size> &sizes() const { return sizes_; }
 	const Size &resolution() const;
+	const Size pixelArray() const { return pixelArray_; }
+	const Rectangle activeArea() const { return activeArea_; }
 
 	V4L2SubdeviceFormat getFormat(const std::vector<unsigned int> &mbusCodes,
 				      const Size &size) const;
@@ -59,6 +61,8 @@ private:
 
 	CameraLocation location_;
 	unsigned int rotation_;
+	Size pixelArray_;
+	Rectangle activeArea_;
 };
 
 } /* namespace libcamera */
-- 
2.23.0