kwin/plugins/scenes/qpainter/scene_qpainter.h
Vlad Zahorodnii 9f2cb0ae1b Provide expected presentation time to effects
Effects are given the interval between two consecutive frames. The main
flaw of this approach is that if the Compositor transitions from the idle
state to "active" state, i.e. when there is something to repaint,
effects may see a very large interval between the last painted frame and
the current. In order to address this issue, the Scene invalidates the
timer that is used to measure time between consecutive frames before the
Compositor is about to become idle.

While this works perfectly fine with Xinerama-style rendering, with per
screen rendering, determining whether the compositor is about to idle is
rather a tedious task mostly because a single output can't be used for
the test.

Furthermore, since the Compositor schedules pointless repaints just to
ensure that it's idle, it might take several attempts to figure out
whether the scene timer must be invalidated if you use (true) per screen
rendering.

Ideally, all effects should use a timeline helper that is aware of the
underlying render loop and its timings. However, this option is off the
table because it will involve a lot of work to implement it.

Alternative and much simpler option is to pass the expected presentation
time to effects rather than time between consecutive frames. This means
that effects are responsible for determining how much animation timelines
have to be advanced. Typically, an effect would have to store the
presentation timestamp provided in either prePaint{Screen,Window} and
use it in the subsequent prePaint{Screen,Window} call to estimate the
amount of time passed between the next and the last frames.

Unfortunately, this is an API incompatible change. However, it shouldn't
take a lot of work to port third-party binary effects, which don't use the
AnimationEffect class, to the new API. On the bright side, we no longer
need to be concerned about the Compositor getting idle.

We do still try to determine whether the Compositor is about to idle,
primarily, because the OpenGL render backend swaps buffers on present,
but that will change with the ongoing compositing timing rework.
2020-12-10 07:14:42 +00:00

196 lines
5 KiB
C++

/*
KWin - the KDE window manager
This file is part of the KDE project.
SPDX-FileCopyrightText: 2013 Martin Gräßlin <mgraesslin@kde.org>
SPDX-License-Identifier: GPL-2.0-or-later
*/
#ifndef KWIN_SCENE_QPAINTER_H
#define KWIN_SCENE_QPAINTER_H
#include "scene.h"
#include <platformsupport/scenes/qpainter/backend.h>
#include "shadow.h"
#include "decorations/decorationrenderer.h"
namespace KWin {
class KWIN_EXPORT SceneQPainter : public Scene
{
Q_OBJECT
public:
~SceneQPainter() override;
bool usesOverlayWindow() const override;
OverlayWindow* overlayWindow() const override;
void paint(int screenId, const QRegion &damage, const QList<Toplevel *> &windows,
std::chrono::milliseconds presentTime) override;
void paintGenericScreen(int mask, const ScreenPaintData &data) override;
CompositingType compositingType() const override;
bool initFailed() const override;
EffectFrame *createEffectFrame(EffectFrameImpl *frame) override;
Shadow *createShadow(Toplevel *toplevel) override;
Decoration::Renderer *createDecorationRenderer(Decoration::DecoratedClientImpl *impl) override;
void screenGeometryChanged(const QSize &size) override;
bool animationsSupported() const override {
return false;
}
QPainter *scenePainter() const override;
QImage *qpainterRenderBuffer(int screenId) const override;
QPainterBackend *backend() const {
return m_backend.data();
}
static SceneQPainter *createScene(QObject *parent);
protected:
void paintBackground(const QRegion &region) override;
Scene::Window *createWindow(Toplevel *toplevel) override;
void paintCursor(const QRegion &region) override;
void paintEffectQuickView(EffectQuickView *w) override;
private:
explicit SceneQPainter(QPainterBackend *backend, QObject *parent = nullptr);
QScopedPointer<QPainterBackend> m_backend;
QScopedPointer<QPainter> m_painter;
class Window;
};
class QPainterWindowPixmap : public WindowPixmap
{
public:
explicit QPainterWindowPixmap(Scene::Window *window);
~QPainterWindowPixmap() override;
void create() override;
void update() override;
bool isValid() const override;
const QImage &image();
protected:
WindowPixmap *createChild(KWaylandServer::SubSurfaceInterface *subSurface) override;
private:
explicit QPainterWindowPixmap(KWaylandServer::SubSurfaceInterface *subSurface, WindowPixmap *parent);
QImage m_image;
};
class SceneQPainter::Window : public Scene::Window
{
Q_OBJECT
public:
Window(SceneQPainter *scene, Toplevel *c);
~Window() override;
void performPaint(int mask, const QRegion &region, const WindowPaintData &data) override;
protected:
WindowPixmap *createWindowPixmap() override;
private:
void renderWindowPixmap(QPainter *painter, QPainterWindowPixmap *windowPixmap);
void renderShadow(QPainter *painter);
void renderWindowDecorations(QPainter *painter);
SceneQPainter *m_scene;
};
class QPainterEffectFrame : public Scene::EffectFrame
{
public:
QPainterEffectFrame(EffectFrameImpl *frame, SceneQPainter *scene);
~QPainterEffectFrame() override;
void crossFadeIcon() override {}
void crossFadeText() override {}
void free() override {}
void freeIconFrame() override {}
void freeTextFrame() override {}
void freeSelection() override {}
void render(const QRegion &region, double opacity, double frameOpacity) override;
private:
SceneQPainter *m_scene;
};
class SceneQPainterShadow : public Shadow
{
public:
SceneQPainterShadow(Toplevel* toplevel);
~SceneQPainterShadow() override;
QImage &shadowTexture() {
return m_texture;
}
protected:
void buildQuads() override;
bool prepareBackend() override;
private:
QImage m_texture;
};
class SceneQPainterDecorationRenderer : public Decoration::Renderer
{
Q_OBJECT
public:
enum class DecorationPart : int {
Left,
Top,
Right,
Bottom,
Count
};
explicit SceneQPainterDecorationRenderer(Decoration::DecoratedClientImpl *client);
~SceneQPainterDecorationRenderer() override;
void render() override;
void reparent(Deleted *deleted) override;
QImage image(DecorationPart part) const;
private:
void resizeImages();
QImage m_images[int(DecorationPart::Count)];
};
class KWIN_EXPORT QPainterFactory : public SceneFactory
{
Q_OBJECT
Q_INTERFACES(KWin::SceneFactory)
Q_PLUGIN_METADATA(IID "org.kde.kwin.Scene" FILE "qpainter.json")
public:
explicit QPainterFactory(QObject *parent = nullptr);
~QPainterFactory() override;
Scene *create(QObject *parent = nullptr) const override;
};
inline
bool SceneQPainter::usesOverlayWindow() const
{
return false;
}
inline
OverlayWindow* SceneQPainter::overlayWindow() const
{
return nullptr;
}
inline
QPainter* SceneQPainter::scenePainter() const
{
return m_painter.data();
}
inline
const QImage &QPainterWindowPixmap::image()
{
return m_image;
}
} // KWin
#endif // KWIN_SCENEQPAINTER_H