[libcamera-devel] [PATCH v3 2/5] ipa: ipu3: af: Use geometry classes to perform grid centering

[Kieran Bingham]

Use our geometry classes for Rectangle, Size and Point to identify
the region of interest for the autofocus, and center it on the BDS output.

This will facilitate custom ROI being passed in through controls at a later
time.

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
---
 src/ipa/ipu3/algorithms/af.cpp | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/src/ipa/ipu3/algorithms/af.cpp b/src/ipa/ipu3/algorithms/af.cpp
index 634d0f2e3176..4476857fa772 100644
--- a/src/ipa/ipu3/algorithms/af.cpp
+++ b/src/ipa/ipu3/algorithms/af.cpp
@@ -141,16 +141,23 @@ int Af::configure(IPAContext &context, const IPAConfigInfo &configInfo)
 	grid.block_height_log2 = kAfMinGridBlockHeight;
 	grid.height_per_slice = kAfDefaultHeightPerSlice;
 
-	/* x_start and y start are default to BDS center */
-	grid.x_start = (configInfo.bdsOutputSize.width / 2) -
-		       (((grid.width << grid.block_width_log2) / 2));
-	grid.y_start = (configInfo.bdsOutputSize.height / 2) -
-		       (((grid.height << grid.block_height_log2) / 2));
+	/* Position the AF grid in the center of the BDS output. */
+	Rectangle bds(configInfo.bdsOutputSize);
+	Size gridSize(grid.width << grid.block_width_log2,
+		      grid.height << grid.block_height_log2);
+
+	/*
+	 * \todo - Support request metadata
+	 * - Set the ROI based on any input controls in the request
+	 * - Return the AF ROI as metadata in the Request
+	 */
+	Rectangle roi = gridSize.centeredTo(bds.center());
+	Point start = roi.topLeft();
 
 	/* x_start and y_start should be even */
-	grid.x_start = (grid.x_start / 2) * 2;
-	grid.y_start = (grid.y_start / 2) * 2;
-	grid.y_start = grid.y_start | IPU3_UAPI_GRID_Y_START_EN;
+	grid.x_start = utils::alignDown(start.x, 2);
+	grid.y_start = utils::alignDown(start.y, 2);
+	grid.y_start |= IPU3_UAPI_GRID_Y_START_EN;
 
 	/* Initial max focus step */
 	maxStep_ = kMaxFocusSteps;
-- 
2.32.0