Allow specifying scene geometry

The main motivation behind this change is to decouple the scene a bit
further from Screens, which is also obsolete.

src/scene.cpp

@@ -71,7 +71,6 @@
 #include "deleted.h"
 #include "effects.h"
 #include "renderloop.h"
-#include "screens.h"
 #include "shadow.h"
 #include "wayland_server.h"
 #include "composite.h"
@@ -100,15 +99,19 @@ void Scene::initialize()
 
     connect(workspace(), &Workspace::deletedRemoved, this, &Scene::removeToplevel);
 
-    connect(workspace(), &Workspace::geometryChanged, this, &Scene::addRepaintFull);
     connect(workspace(), &Workspace::currentActivityChanged, this, &Scene::addRepaintFull);
     connect(workspace(), &Workspace::currentDesktopChanged, this, &Scene::addRepaintFull);
     connect(workspace(), &Workspace::stackingOrderChanged, this, &Scene::addRepaintFull);
+
+    setGeometry(workspace()->geometry());
+    connect(workspace(), &Workspace::geometryChanged, this, [this]() {
+        setGeometry(workspace()->geometry());
+    });
 }
 
 void Scene::addRepaintFull()
 {
-    addRepaint(workspace()->geometry());
+    addRepaint(geometry());
 }
 
 void Scene::addRepaint(int x, int y, int width, int height)
@@ -138,6 +141,19 @@ void Scene::addRepaint(const QRegion &region)
     }
 }
 
+QRect Scene::geometry() const
+{
+    return m_geometry;
+}
+
+void Scene::setGeometry(const QRect &rect)
+{
+    if (m_geometry != rect) {
+        m_geometry = rect;
+        addRepaintFull();
+    }
+}
+
 QRegion Scene::repaints(AbstractOutput *output) const
 {
     return m_repaints.value(output, infiniteRegion());
@@ -196,8 +212,7 @@ void Scene::paintScreen(const QRegion &damage, const QRegion &repaint,
                         QRegion *updateRegion, QRegion *validRegion, RenderLoop *renderLoop,
                         const QMatrix4x4 &projection)
 {
-    const QSize &screenSize = screens()->size();
-    const QRegion displayRegion(0, 0, screenSize.width(), screenSize.height());
+    const QRegion displayRegion(geometry());
 
     const std::chrono::milliseconds presentTime =
             std::chrono::duration_cast<std::chrono::milliseconds>(renderLoop->nextPresentationTimestamp());
@@ -309,7 +324,7 @@ void Scene::paintGenericScreen(int orig_mask, const ScreenPaintData &)
         phase2.append({w, infiniteRegion(), data.clip, data.mask,});
     }
 
-    damaged_region = QRegion(QRect {{}, screens()->size()});
+    damaged_region = geometry();
     if (m_paintScreenCount == 1) {
         aboutToStartPainting(painted_screen, damaged_region);
 
@@ -407,8 +422,7 @@ void Scene::paintSimpleScreen(int orig_mask, const QRegion &region)
     const QRegion repaintClip = repaint_region - dirtyArea;
     dirtyArea |= repaint_region;
 
-    const QSize &screenSize = screens()->size();
-    const QRegion displayRegion(0, 0, screenSize.width(), screenSize.height());
+    const QRegion displayRegion(geometry());
     bool fullRepaint(dirtyArea == displayRegion); // spare some expensive region operations
     if (!fullRepaint) {
         extendPaintRegion(dirtyArea, opaqueFullscreen);
@@ -535,7 +549,7 @@ void Scene::clearStackingOrder()
 void Scene::paintWindow(Window* w, int mask, const QRegion &_region)
 {
     // no painting outside visible screen (and no transformations)
-    const QRegion region = _region & QRect({0, 0}, screens()->size());
+    const QRegion region = _region & geometry();
     if (region.isEmpty())  // completely clipped
         return;
 

src/scene.h

@@ -62,6 +62,9 @@ public:
     void addRepaint(int x, int y, int width, int height);
     void addRepaintFull();
 
+    QRect geometry() const;
+    void setGeometry(const QRect &rect);
+
     /**
      * Returns the repaints region for output with the specified @a output.
      */
@@ -261,6 +264,7 @@ private:
     std::chrono::milliseconds m_expectedPresentTimestamp = std::chrono::milliseconds::zero();
     QHash< Toplevel*, Window* > m_windows;
     QMap<AbstractOutput *, QRegion> m_repaints;
+    QRect m_geometry;
     // how many times finalPaintScreen() has been called
     int m_paintScreenCount = 0;
 };

src/scenes/opengl/lanczosfilter.cpp

@@ -12,7 +12,6 @@
 #include "x11client.h"
 #include "deleted.h"
 #include "effects.h"
-#include "screens.h"
 #include "unmanaged.h"
 #include "options.h"
 #include "utils.h"
@@ -98,7 +97,7 @@ void LanczosFilter::init()
 
 void LanczosFilter::updateOffscreenSurfaces()
 {
-    const QSize &s = screens()->size();
+    const QSize &s = m_scene->geometry().size();
     int w = s.width();
     int h = s.height();
 

src/scenes/opengl/scene_opengl.cpp

@@ -28,7 +28,6 @@
 #include "main.h"
 #include "overlaywindow.h"
 #include "renderloop.h"
-#include "screens.h"
 #include "cursor.h"
 #include "decorations/decoratedclient.h"
 #include "shadowitem.h"
@@ -255,7 +254,7 @@ void SceneOpenGL::paint(AbstractOutput *output, const QRegion &damage, const QLi
         geo = output->geometry();
         scaling = output->scale();
     } else {
-        geo = screens()->geometry();
+        geo = geometry();
         scaling = 1;
     }
 
@@ -320,8 +319,7 @@ void SceneOpenGL::paint(AbstractOutput *output, const QRegion &damage, const QLi
             paintCursor(valid);
 
             if (!GLPlatform::instance()->isGLES() && !output) {
-                const QSize &screenSize = screens()->size();
-                const QRegion displayRegion(0, 0, screenSize.width(), screenSize.height());
+                const QRegion displayRegion(geometry());
 
                 // copy dirty parts from front to backbuffer
                 if (!m_backend->supportsBufferAge() &&
@@ -395,11 +393,11 @@ void SceneOpenGL::extendPaintRegion(QRegion &region, bool opaqueFullscreen)
     if (m_backend->supportsBufferAge())
         return;
 
-    const QSize &screenSize = screens()->size();
     if (options->glPreferBufferSwap() == Options::ExtendDamage) { // only Extend "large" repaints
-        const QRegion displayRegion(0, 0, screenSize.width(), screenSize.height());
+        const QRegion displayRegion(geometry());
         uint damagedPixels = 0;
-        const uint fullRepaintLimit = (opaqueFullscreen?0.49f:0.748f)*screenSize.width()*screenSize.height();
+        const QSize &sceneSize = geometry().size();
+        const uint fullRepaintLimit = (opaqueFullscreen?0.49f:0.748f)*sceneSize.width()*sceneSize.height();
         // 16:9 is 75% of 4:3 and 2.55:1 is 49.01% of 5:4
         // (5:4 is the most square format and 2.55:1 is Cinemascope55 - the widest ever shot
         // movie aspect - two times ;-) It's a Fox format, though, so maybe we want to restrict
@@ -414,7 +412,7 @@ void SceneOpenGL::extendPaintRegion(QRegion &region, bool opaqueFullscreen)
             }
         }
     } else if (options->glPreferBufferSwap() == Options::PaintFullScreen) { // forced full rePaint
-        region = QRegion(0, 0, screenSize.width(), screenSize.height());
+        region = QRegion(geometry());
     }
 }
 
@@ -422,7 +420,7 @@ void SceneOpenGL::paintDesktop(int desktop, int mask, const QRegion &region, Scr
 {
     const QRect r = region.boundingRect();
     glEnable(GL_SCISSOR_TEST);
-    glScissor(r.x(), screens()->size().height() - r.y() - r.height(), r.width(), r.height());
+    glScissor(r.x(), geometry().size().height() - r.y() - r.height(), r.width(), r.height());
     KWin::Scene::paintDesktop(desktop, mask, region, data);
     glDisable(GL_SCISSOR_TEST);
 }