From fb1a6ecd8d0303426f85625327f58bff3ece02bc Mon Sep 17 00:00:00 2001
From: Vlad Zahorodnii <vlad.zahorodnii@kde.org>
Date: Tue, 3 Jan 2023 12:59:17 +0200
Subject: [PATCH] backends/drm: Fix buffer centering with active hardware
 transform

Prior to beb6cca65d9036eb47cd9209250c75ad0eeca8c8, the drm backend used
to specify QRect(0, 0, modeSize.width(), modeSize.height()) CRTC rect,
so we didn't have to care about buffer transforms, but now that we
compute the CRTC rect from the buffer size, we have to take the buffer
transform into account.

It fixes squashed output contents when the output is rotated 90 or 270
degrees and it uses hardware transforms.
---
 src/backends/drm/drm_pipeline.cpp | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/backends/drm/drm_pipeline.cpp b/src/backends/drm/drm_pipeline.cpp
index 62e5eae94d..a069abcfd7 100644
--- a/src/backends/drm/drm_pipeline.cpp
+++ b/src/backends/drm/drm_pipeline.cpp
@@ -207,6 +207,15 @@ DrmPipeline::Error DrmPipeline::commitPipelinesAtomic(const QVector<DrmPipeline
     }
 }
 
+static QSize orientateSize(const QSize &size, DrmPlane::Transformations transforms)
+{
+    if (transforms & (DrmPlane::Transformation::Rotate90 | DrmPlane::Transformation::Rotate270)) {
+        return size.transposed();
+    } else {
+        return size;
+    }
+}
+
 static QRect centerBuffer(const QSize &bufferSize, const QSize &modeSize)
 {
     const double widthScale = bufferSize.width() / double(modeSize.width());
@@ -231,7 +240,7 @@ void DrmPipeline::prepareAtomicPresentation()
     m_pending.crtc->setPending(DrmCrtc::PropertyIndex::VrrEnabled, m_pending.syncMode == RenderLoopPrivate::SyncMode::Adaptive || m_pending.syncMode == RenderLoopPrivate::SyncMode::AdaptiveAsync);
     m_pending.crtc->setPending(DrmCrtc::PropertyIndex::Gamma_LUT, m_pending.gamma ? m_pending.gamma->blobId() : 0);
     const auto fb = m_pending.layer->currentBuffer().get();
-    m_pending.crtc->primaryPlane()->set(QPoint(0, 0), fb->buffer()->size(), centerBuffer(fb->buffer()->size(), m_pending.mode->size()));
+    m_pending.crtc->primaryPlane()->set(QPoint(0, 0), fb->buffer()->size(), centerBuffer(orientateSize(fb->buffer()->size(), m_pending.bufferOrientation), m_pending.mode->size()));
     m_pending.crtc->primaryPlane()->setBuffer(fb);
 
     if (m_pending.crtc->cursorPlane()) {