improve support for mirroring output transforms

CCBUG: 447792

src/backends/drm/drm_egl_cursor_layer.cpp

@@ -24,15 +24,16 @@ static TextureTransforms drmToTextureRotation(DrmPipeline *pipeline)
     if (angle < 0) {
         angle += 360;
     }
+    TextureTransforms flip = (pipeline->renderOrientation() & DrmPlane::Transformation::ReflectX) ? TextureTransform::MirrorX : TextureTransforms();
     switch (angle % 360) {
     case 0:
-        return TextureTransforms();
+        return TextureTransforms() | flip;
     case 90:
-        return TextureTransform::Rotate90;
+        return TextureTransforms(TextureTransform::Rotate90) | flip;
     case 180:
-        return TextureTransform::Rotate180;
+        return TextureTransforms(TextureTransform::Rotate180) | flip;
     case 270:
-        return TextureTransform::Rotate270;
+        return TextureTransforms(TextureTransform::Rotate270) | flip;
     default:
         Q_UNREACHABLE();
     }

src/backends/drm/drm_egl_layer.cpp

@@ -31,15 +31,16 @@ static TextureTransforms drmToTextureRotation(DrmPipeline *pipeline)
     if (angle < 0) {
         angle += 360;
     }
+    TextureTransforms flip = (pipeline->renderOrientation() & DrmPlane::Transformation::ReflectX) ? TextureTransform::MirrorX : TextureTransforms();
     switch (angle % 360) {
     case 0:
-        return TextureTransforms();
+        return TextureTransforms() | flip;
     case 90:
-        return TextureTransform::Rotate90;
+        return TextureTransforms(TextureTransform::Rotate90) | flip;
     case 180:
-        return TextureTransform::Rotate180;
+        return TextureTransforms(TextureTransform::Rotate180) | flip;
     case 270:
-        return TextureTransform::Rotate270;
+        return TextureTransforms(TextureTransform::Rotate270) | flip;
     default:
         Q_UNREACHABLE();
     }

src/backends/drm/drm_egl_layer_surface.cpp

@@ -84,6 +84,9 @@ std::optional<OutputLayerBeginFrameInfo> EglGbmLayerSurface::startRendering(cons
         return std::nullopt;
     }
 
+    if (slot->framebuffer()->colorAttachment()->contentTransforms() != transformation) {
+        m_surface->damageJournal.clear();
+    }
     slot->framebuffer()->colorAttachment()->setContentTransform(transformation);
     m_surface->currentSlot = slot;
 

src/backends/drm/drm_output.cpp

@@ -204,21 +204,23 @@ DrmPlane::Transformations outputToPlaneTransform(OutputTransform transform)
 {
     using PlaneTrans = DrmPlane::Transformation;
 
-    // TODO: Do we want to support reflections (flips)?
-
     switch (transform.kind()) {
     case OutputTransform::Normal:
-    case OutputTransform::Flipped:
         return PlaneTrans::Rotate0;
+    case OutputTransform::Flipped:
+        return PlaneTrans::ReflectX | PlaneTrans::Rotate0;
     case OutputTransform::Rotated90:
-    case OutputTransform::Flipped90:
         return PlaneTrans::Rotate90;
+    case OutputTransform::Flipped90:
+        return PlaneTrans::ReflectX | PlaneTrans::Rotate90;
     case OutputTransform::Rotated180:
-    case OutputTransform::Flipped180:
         return PlaneTrans::Rotate180;
+    case OutputTransform::Flipped180:
+        return PlaneTrans::ReflectX | PlaneTrans::Rotate180;
     case OutputTransform::Rotated270:
-    case OutputTransform::Flipped270:
         return PlaneTrans::Rotate270;
+    case OutputTransform::Flipped270:
+        return PlaneTrans::ReflectX | PlaneTrans::Rotate270;
     default:
         Q_UNREACHABLE();
     }

src/outputconfigurationstore.cpp

@@ -559,6 +559,14 @@ void OutputConfigurationStore::load()
                 state.transform = state.manualTransform = OutputTransform::Kind::Rotated180;
             } else if (str == "Rotated270") {
                 state.transform = state.manualTransform = OutputTransform::Kind::Rotated270;
+            } else if (str == "Flipped") {
+                state.transform = state.manualTransform = OutputTransform::Kind::Flipped;
+            } else if (str == "Flipped90") {
+                state.transform = state.manualTransform = OutputTransform::Kind::Flipped90;
+            } else if (str == "Flipped180") {
+                state.transform = state.manualTransform = OutputTransform::Kind::Flipped180;
+            } else if (str == "Flipped270") {
+                state.transform = state.manualTransform = OutputTransform::Kind::Flipped270;
             }
         }
         if (const auto it = data.find("overscan"); it != data.end()) {
@@ -744,6 +752,14 @@ void OutputConfigurationStore::save()
             o["transform"] = "Rotated180";
         } else if (output.manualTransform == OutputTransform::Kind::Rotated270) {
             o["transform"] = "Rotated270";
+        } else if (output.manualTransform == OutputTransform::Kind::Flipped) {
+            o["transform"] = "Flipped";
+        } else if (output.manualTransform == OutputTransform::Kind::Flipped90) {
+            o["transform"] = "Flipped90";
+        } else if (output.manualTransform == OutputTransform::Kind::Flipped180) {
+            o["transform"] = "Flipped180";
+        } else if (output.manualTransform == OutputTransform::Kind::Flipped270) {
+            o["transform"] = "Flipped270";
         }
         if (output.overscan) {
             o["overscan"] = int(*output.overscan);

src/plugins/screentransform/screentransform.cpp

@@ -68,7 +68,7 @@ void ScreenTransformEffect::addScreen(EffectScreen *screen)
 {
     connect(screen, &EffectScreen::changed, this, [this, screen] {
         auto &state = m_states[screen];
-        if (screen->transform() == state.m_oldTransform) {
+        if (transformAngle(screen->transform(), state.m_oldTransform) == 0) {
             effects->makeOpenGLContextCurrent();
             m_states.remove(screen);
             return;