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authorLaurent Pinchart <laurent.pinchart@ideasonboard.com>2022-08-07 20:39:19 +0300
committerLaurent Pinchart <laurent.pinchart@ideasonboard.com>2022-08-09 02:31:12 +0300
commit293e23e21cea5c1eb46df3938ac8b107e43b0c2b (patch)
tree64feef166ad98e3bc424b61bfa2647666c065d64
parent96a5c699700492750183c925339a69da7e2c2326 (diff)
cam: kms_sink: Scale the frame buffer to full screen if supported
The KMS sink currently displays the frame buffer on the top-left corner of the screen, resulting in either a black area on the bottom and right sides (if the frame buffer is smaller than the display resolution) of in a restricted field of view (if the frame buffer is larger than the display resolution). Improve this by scaling the frame buffer to full screen if supported, and aligning the crop rectangle to the frame buffer center if the field of view needs to be restricted. The implementation test for possible composition options, from best to worst. The tests are performed when the camera is started, as testing atomic commits requires access to frame buffer objects, which are not available at configure time. Changing this would require either a large refactoring of the cam application to provide frame buffers earlier, or extending the KMS API to support testing commits with dummy buffer objects. Both are candidates for later development. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Eric Curtin <ecurtin@redhat.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com> Tested-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
-rw-r--r--src/cam/kms_sink.cpp109
-rw-r--r--src/cam/kms_sink.h8
2 files changed, 109 insertions, 8 deletions
diff --git a/src/cam/kms_sink.cpp b/src/cam/kms_sink.cpp
index 16435ede..17e2fa69 100644
--- a/src/cam/kms_sink.cpp
+++ b/src/cam/kms_sink.cpp
@@ -284,6 +284,94 @@ int KMSSink::stop()
return FrameSink::stop();
}
+bool KMSSink::testModeSet(DRM::FrameBuffer *drmBuffer,
+ const libcamera::Rectangle &src,
+ const libcamera::Rectangle &dst)
+{
+ DRM::AtomicRequest drmRequest{ &dev_ };
+
+ drmRequest.addProperty(connector_, "CRTC_ID", crtc_->id());
+
+ drmRequest.addProperty(crtc_, "ACTIVE", 1);
+ drmRequest.addProperty(crtc_, "MODE_ID", mode_->toBlob(&dev_));
+
+ drmRequest.addProperty(plane_, "CRTC_ID", crtc_->id());
+ drmRequest.addProperty(plane_, "FB_ID", drmBuffer->id());
+ drmRequest.addProperty(plane_, "SRC_X", src.x << 16);
+ drmRequest.addProperty(plane_, "SRC_Y", src.y << 16);
+ drmRequest.addProperty(plane_, "SRC_W", src.width << 16);
+ drmRequest.addProperty(plane_, "SRC_H", src.height << 16);
+ drmRequest.addProperty(plane_, "CRTC_X", dst.x);
+ drmRequest.addProperty(plane_, "CRTC_Y", dst.y);
+ drmRequest.addProperty(plane_, "CRTC_W", dst.width);
+ drmRequest.addProperty(plane_, "CRTC_H", dst.height);
+
+ return !drmRequest.commit(DRM::AtomicRequest::FlagAllowModeset |
+ DRM::AtomicRequest::FlagTestOnly);
+}
+
+bool KMSSink::setupComposition(DRM::FrameBuffer *drmBuffer)
+{
+ /*
+ * Test composition options, from most to least desirable, to select the
+ * best one.
+ */
+ const libcamera::Rectangle framebuffer{ size_ };
+ const libcamera::Rectangle display{ 0, 0, mode_->hdisplay, mode_->vdisplay };
+
+ /* 1. Scale the frame buffer to full screen, preserving aspect ratio. */
+ libcamera::Rectangle src = framebuffer;
+ libcamera::Rectangle dst = display.size().boundedToAspectRatio(framebuffer.size())
+ .centeredTo(display.center());
+
+ if (testModeSet(drmBuffer, src, dst)) {
+ std::cout << "KMS: full-screen scaled output, square pixels"
+ << std::endl;
+ src_ = src;
+ dst_ = dst;
+ return true;
+ }
+
+ /*
+ * 2. Scale the frame buffer to full screen, without preserving aspect
+ * ratio.
+ */
+ src = framebuffer;
+ dst = display;
+
+ if (testModeSet(drmBuffer, src, dst)) {
+ std::cout << "KMS: full-screen scaled output, non-square pixels"
+ << std::endl;
+ src_ = src;
+ dst_ = dst;
+ return true;
+ }
+
+ /* 3. Center the frame buffer on the display. */
+ src = display.size().centeredTo(framebuffer.center()).boundedTo(framebuffer);
+ dst = framebuffer.size().centeredTo(display.center()).boundedTo(display);
+
+ if (testModeSet(drmBuffer, src, dst)) {
+ std::cout << "KMS: centered output" << std::endl;
+ src_ = src;
+ dst_ = dst;
+ return true;
+ }
+
+ /* 4. Align the frame buffer on the top-left of the display. */
+ src = framebuffer.boundedTo(display);
+ dst = display.boundedTo(framebuffer);
+
+ if (testModeSet(drmBuffer, src, dst)) {
+ std::cout << "KMS: top-left aligned output" << std::endl;
+ src_ = src;
+ dst_ = dst;
+ return true;
+ }
+
+ return false;
+}
+
bool KMSSink::processRequest(libcamera::Request *camRequest)
{
/*
@@ -307,20 +395,25 @@ bool KMSSink::processRequest(libcamera::Request *camRequest)
if (!active_ && !queued_) {
/* Enable the display pipeline on the first frame. */
+ if (!setupComposition(drmBuffer)) {
+ std::cerr << "Failed to setup composition" << std::endl;
+ return true;
+ }
+
drmRequest->addProperty(connector_, "CRTC_ID", crtc_->id());
drmRequest->addProperty(crtc_, "ACTIVE", 1);
drmRequest->addProperty(crtc_, "MODE_ID", mode_->toBlob(&dev_));
drmRequest->addProperty(plane_, "CRTC_ID", crtc_->id());
- drmRequest->addProperty(plane_, "SRC_X", 0 << 16);
- drmRequest->addProperty(plane_, "SRC_Y", 0 << 16);
- drmRequest->addProperty(plane_, "SRC_W", size_.width << 16);
- drmRequest->addProperty(plane_, "SRC_H", size_.height << 16);
- drmRequest->addProperty(plane_, "CRTC_X", 0);
- drmRequest->addProperty(plane_, "CRTC_Y", 0);
- drmRequest->addProperty(plane_, "CRTC_W", size_.width);
- drmRequest->addProperty(plane_, "CRTC_H", size_.height);
+ drmRequest->addProperty(plane_, "SRC_X", src_.x << 16);
+ drmRequest->addProperty(plane_, "SRC_Y", src_.y << 16);
+ drmRequest->addProperty(plane_, "SRC_W", src_.width << 16);
+ drmRequest->addProperty(plane_, "SRC_H", src_.height << 16);
+ drmRequest->addProperty(plane_, "CRTC_X", dst_.x);
+ drmRequest->addProperty(plane_, "CRTC_Y", dst_.y);
+ drmRequest->addProperty(plane_, "CRTC_W", dst_.width);
+ drmRequest->addProperty(plane_, "CRTC_H", dst_.height);
flags |= DRM::AtomicRequest::FlagAllowModeset;
}
diff --git a/src/cam/kms_sink.h b/src/cam/kms_sink.h
index 8f5f0866..76c4e611 100644
--- a/src/cam/kms_sink.h
+++ b/src/cam/kms_sink.h
@@ -50,6 +50,11 @@ private:
int selectPipeline(const libcamera::PixelFormat &format);
int configurePipeline(const libcamera::PixelFormat &format);
+ bool testModeSet(DRM::FrameBuffer *drmBuffer,
+ const libcamera::Rectangle &src,
+ const libcamera::Rectangle &dst);
+ bool setupComposition(DRM::FrameBuffer *drmBuffer);
+
void requestComplete(DRM::AtomicRequest *request);
DRM::Device dev_;
@@ -63,6 +68,9 @@ private:
libcamera::Size size_;
unsigned int stride_;
+ libcamera::Rectangle src_;
+ libcamera::Rectangle dst_;
+
std::map<libcamera::FrameBuffer *, std::unique_ptr<DRM::FrameBuffer>> buffers_;
std::mutex lock_;