libcamera: camera_sensor: Add parameter to limit returned sensor size

The getFormat function takes the aspect ratio and the area of the
requested size into account when choosing the best sensor size. In case
the sensor is connected to an rkisp1 the maximum supported frame size of
the ISP is another constraining factor for the selection of the best
format. Add a maxSize parameter to support such a constraint.

Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>

src/libcamera/sensor/camera_sensor_legacy.cpp

@@ -74,7 +74,8 @@ public:
 	Size resolution() const override;
 
 	V4L2SubdeviceFormat getFormat(const std::vector<unsigned int> &mbusCodes,
-				      const Size &size) const override;
+				      const Size &size,
+				      const Size maxSize) const override;
 	int setFormat(V4L2SubdeviceFormat *format,
 		      Transform transform = Transform::Identity) override;
 	int tryFormat(V4L2SubdeviceFormat *format) const override;
@@ -699,7 +700,7 @@ Size CameraSensorLegacy::resolution() const
 
 V4L2SubdeviceFormat
 CameraSensorLegacy::getFormat(const std::vector<unsigned int> &mbusCodes,
-			      const Size &size) const
+			      const Size &size, Size maxSize) const
 {
 	unsigned int desiredArea = size.width * size.height;
 	unsigned int bestArea = UINT_MAX;
@@ -716,6 +717,10 @@ CameraSensorLegacy::getFormat(const std::vector<unsigned int> &mbusCodes,
 		for (const SizeRange &range : formats->second) {
 			const Size &sz = range.max;
 
+			if (!maxSize.isNull() &&
+			    (sz.width > maxSize.width || sz.height > maxSize.height))
+				continue;
+
 			if (sz.width < size.width || sz.height < size.height)
 				continue;