Add a generic Output::transformation method

Makes it possible to map any space into the output's coordinates system

abstract_wayland_output.cpp

@@ -19,6 +19,7 @@
 // KF5
 #include <KLocalizedString>
 
+#include <QMatrix4x4>
 #include <cmath>
 
 namespace KWin
@@ -310,4 +311,46 @@ AbstractWaylandOutput::Transform AbstractWaylandOutput::transform() const
     return static_cast<Transform>(m_waylandOutputDevice->transform());
 }
 
+// TODO: Do we need to handle the flipped cases differently?
+int transformToRotation(AbstractWaylandOutput::Transform transform)
+{
+    switch (transform) {
+    case AbstractWaylandOutput::Transform::Normal:
+    case AbstractWaylandOutput::Transform::Flipped:
+        return 0;
+    case AbstractWaylandOutput::Transform::Rotated90:
+    case AbstractWaylandOutput::Transform::Flipped90:
+        return 90;
+    case AbstractWaylandOutput::Transform::Rotated180:
+    case AbstractWaylandOutput::Transform::Flipped180:
+        return 180;
+    case AbstractWaylandOutput::Transform::Rotated270:
+    case AbstractWaylandOutput::Transform::Flipped270:
+        return 270;
+    }
+    Q_UNREACHABLE();
+    return 0;
+}
+
+int AbstractWaylandOutput::rotation() const
+{
+    return transformToRotation(transform());
+}
+
+QMatrix4x4 AbstractWaylandOutput::transformation() const
+{
+    const QSize outputSize = modeSize();
+    const QSize logicalSize = pixelSize();
+
+    QMatrix4x4 matrix;
+    matrix.translate(outputSize.width()/2, outputSize.height()/2);
+    matrix.rotate(rotation(), 0, 0, 1);
+    matrix.translate(-logicalSize.width()/2, -logicalSize.height()/2);
+    matrix.scale(scale());
+
+    const QPoint topLeft = -globalPos();
+    matrix.translate(-topLeft.x(), -topLeft.y());
+    return matrix;
+}
+
 }

abstract_wayland_output.h

@@ -112,6 +112,18 @@ public:
 
     QString description() const;
 
+    /**
+     * The current rotation of the output
+     *
+     * @return rotation in degrees
+     */
+    int rotation() const;
+
+    /**
+     * Returns a matrix that can translate into the display's coordinates system
+     */
+    QMatrix4x4 transformation() const;
+
 Q_SIGNALS:
     void modeChanged();
     void geometryChanged();

plugins/platforms/drm/drm_output.cpp

@@ -129,31 +129,10 @@ bool DrmOutput::showCursor()
     return ret;
 }
 
-// TODO: Do we need to handle the flipped cases differently?
-int transformToRotation(DrmOutput::Transform transform)
-{
-    switch (transform) {
-    case DrmOutput::Transform::Normal:
-    case DrmOutput::Transform::Flipped:
-        return 0;
-    case DrmOutput::Transform::Rotated90:
-    case DrmOutput::Transform::Flipped90:
-        return 90;
-    case DrmOutput::Transform::Rotated180:
-    case DrmOutput::Transform::Flipped180:
-        return 180;
-    case DrmOutput::Transform::Rotated270:
-    case DrmOutput::Transform::Flipped270:
-        return 270;
-    }
-    Q_UNREACHABLE();
-    return 0;
-}
-
 QMatrix4x4 DrmOutput::matrixDisplay(const QSize &s) const
 {
     QMatrix4x4 matrix;
-    const int angle = transformToRotation(transform());
+    const int angle = rotation();
     if (angle) {
         const QSize center = s / 2;
 
@@ -680,11 +659,6 @@ bool DrmOutput::hardwareTransforms() const
     return m_primaryPlane->transformation() == outputToPlaneTransform(transform());
 }
 
-int DrmOutput::rotation() const
-{
-    return transformToRotation(transform());
-}
-
 void DrmOutput::updateTransform(Transform transform)
 {
     const auto planeTransform = outputToPlaneTransform(transform);

plugins/platforms/drm/drm_output.h

@@ -92,13 +92,6 @@ public:
      */
     bool hardwareTransforms() const;
 
-    /**
-     * The current rotation of the output
-     *
-     * @return rotation in degree
-     */
-    int rotation() const;
-
 private:
     friend class DrmBackend;
     friend class DrmCrtc;   // TODO: For use of setModeLegacy. Remove later when we allow multiple connectors per crtc