From 3d43f8ad93fc97026b1de41b5117f4c8a6e6be40 Mon Sep 17 00:00:00 2001
From: David Edmundson <kde@davidedmundson.co.uk>
Date: Fri, 30 Oct 2020 20:47:41 +0000
Subject: [PATCH] Drop QGraphicsView classes in PaintData

QGraphicsRotation and Scale are QObject wrappers. It's not useful in
data structures where we're creating mulitple of these every frame. It's
large enough to appear in hotspot as taking over 1% of a regular frame.

We don't even use the QGraphicsRotation mapping inside scene for a
reason, so it's not giving us much.

It's technically an API break in libkwineffects. Pragamatically no-one
would use these. We also lose QGraphicsScale's origin, but we never
exposed this in PaintData's public header.
---
 libkwineffects/kwineffects.cpp         | 61 ++++++++++++++++----------
 libkwineffects/kwineffects.h           |  3 +-
 plugins/scenes/opengl/scene_opengl.cpp |  6 ++-
 3 files changed, 42 insertions(+), 28 deletions(-)

diff --git a/libkwineffects/kwineffects.cpp b/libkwineffects/kwineffects.cpp
index d03122a10d..7232143bab 100644
--- a/libkwineffects/kwineffects.cpp
+++ b/libkwineffects/kwineffects.cpp
@@ -21,8 +21,6 @@
 #include <QFontMetrics>
 #include <QPainter>
 #include <QPixmap>
-#include <QGraphicsRotation>
-#include <QGraphicsScale>
 #include <QtMath>
 
 #include <ksharedconfig.h>
@@ -56,9 +54,17 @@ void WindowPrePaintData::setTransformed()
 
 class PaintDataPrivate {
 public:
-    QGraphicsScale scale;
+    PaintDataPrivate()
+        :  scale(1., 1., 1.)
+        , rotationAxis(0, 0, 1.)
+        , rotationAngle(0.)
+    {}
+    QVector3D scale;
     QVector3D translation;
-    QGraphicsRotation rotation;
+
+    QVector3D rotationAxis;
+    QVector3D rotationOrigin;
+    qreal rotationAngle;
 };
 
 PaintData::PaintData()
@@ -73,48 +79,45 @@ PaintData::~PaintData()
 
 qreal PaintData::xScale() const
 {
-    return d->scale.xScale();
+    return d->scale.x();
 }
 
 qreal PaintData::yScale() const
 {
-    return d->scale.yScale();
+    return d->scale.y();
 }
 
 qreal PaintData::zScale() const
 {
-    return d->scale.zScale();
+    return d->scale.z();
 }
 
 void PaintData::setScale(const QVector2D &scale)
 {
-    d->scale.setXScale(scale.x());
-    d->scale.setYScale(scale.y());
+    d->scale.setX(scale.x());
+    d->scale.setY(scale.y());
 }
 
 void PaintData::setScale(const QVector3D &scale)
 {
-    d->scale.setXScale(scale.x());
-    d->scale.setYScale(scale.y());
-    d->scale.setZScale(scale.z());
+    d->scale = scale;
 }
-
 void PaintData::setXScale(qreal scale)
 {
-    d->scale.setXScale(scale);
+    d->scale.setX(scale);
 }
 
 void PaintData::setYScale(qreal scale)
 {
-    d->scale.setYScale(scale);
+    d->scale.setY(scale);
 }
 
 void PaintData::setZScale(qreal scale)
 {
-    d->scale.setZScale(scale);
+    d->scale.setZ(scale);
 }
 
-const QGraphicsScale &PaintData::scale() const
+const QVector3D &PaintData::scale() const
 {
     return d->scale;
 }
@@ -166,37 +169,47 @@ const QVector3D &PaintData::translation() const
 
 qreal PaintData::rotationAngle() const
 {
-    return d->rotation.angle();
+    return d->rotationAngle;
 }
 
 QVector3D PaintData::rotationAxis() const
 {
-    return d->rotation.axis();
+    return d->rotationAxis;
 }
 
 QVector3D PaintData::rotationOrigin() const
 {
-    return d->rotation.origin();
+    return d->rotationOrigin;
 }
 
 void PaintData::setRotationAngle(qreal angle)
 {
-    d->rotation.setAngle(angle);
+    d->rotationAngle = angle;
 }
 
 void PaintData::setRotationAxis(Qt::Axis axis)
 {
-    d->rotation.setAxis(axis);
+    switch (axis) {
+    case Qt::XAxis:
+        setRotationAxis(QVector3D(1, 0, 0));
+        break;
+    case Qt::YAxis:
+        setRotationAxis(QVector3D(0, 1, 0));
+        break;
+    case Qt::ZAxis:
+        setRotationAxis(QVector3D(0, 0, 1));
+        break;
+    }
 }
 
 void PaintData::setRotationAxis(const QVector3D &axis)
 {
-    d->rotation.setAxis(axis);
+    d->rotationAxis = axis;
 }
 
 void PaintData::setRotationOrigin(const QVector3D &origin)
 {
-    d->rotation.setOrigin(origin);
+    d->rotationOrigin = origin;
 }
 
 class WindowPaintDataPrivate {
diff --git a/libkwineffects/kwineffects.h b/libkwineffects/kwineffects.h
index 8c8a65572e..8cecb10bd9 100644
--- a/libkwineffects/kwineffects.h
+++ b/libkwineffects/kwineffects.h
@@ -43,7 +43,6 @@
 
 class KConfigGroup;
 class QFont;
-class QGraphicsScale;
 class QKeyEvent;
 class QMatrix4x4;
 class QAction;
@@ -2663,7 +2662,7 @@ public:
      * @since 4.10
      */
     void setScale(const QVector3D &scale);
-    const QGraphicsScale &scale() const;
+    const QVector3D &scale() const;
     const QVector3D &translation() const;
     /**
      * @returns the translation in X direction.
diff --git a/plugins/scenes/opengl/scene_opengl.cpp b/plugins/scenes/opengl/scene_opengl.cpp
index 73b5dabb17..170773fd61 100644
--- a/plugins/scenes/opengl/scene_opengl.cpp
+++ b/plugins/scenes/opengl/scene_opengl.cpp
@@ -729,7 +729,8 @@ QMatrix4x4 SceneOpenGL::transformation(int mask, const ScreenPaintData &data) co
         return matrix;
 
     matrix.translate(data.translation());
-    data.scale().applyTo(&matrix);
+    const QVector3D scale = data.scale();
+    matrix.scale(scale.x(), scale.y(), scale.z());
 
     if (data.rotationAngle() == 0.0)
         return matrix;
@@ -1126,7 +1127,8 @@ QMatrix4x4 OpenGLWindow::transformation(int mask, const WindowPaintData &data) c
         return matrix;
 
     matrix.translate(data.translation());
-    data.scale().applyTo(&matrix);
+    const QVector3D scale = data.scale();
+    matrix.scale(scale.x(), scale.y(), scale.z());
 
     if (data.rotationAngle() == 0.0)
         return matrix;