platforms/wayland: Round up fractional scale factors

Currently, fractional scale factors that are less than 1 will be floored
to 0, which is a protocol violation.

CCBUG: 432766

src/plugins/platforms/wayland/egl_wayland_backend.cpp

@@ -313,7 +313,7 @@ void EglWaylandBackend::presentOnSurface(EglWaylandOutput *output, const QRegion
     WaylandOutput *waylandOutput = output->m_waylandOutput;
 
     waylandOutput->surface()->setupFrameCallback();
-    waylandOutput->surface()->setScale(waylandOutput->scale());
+    waylandOutput->surface()->setScale(std::ceil(waylandOutput->scale()));
     Q_EMIT waylandOutput->outputChange(damage);
 
     if (supportsSwapBuffersWithDamage() && !output->m_damageHistory.isEmpty()) {

src/plugins/platforms/wayland/scene_qpainter_wayland_backend.cpp

@@ -18,6 +18,8 @@
 #include <KWayland/Client/shm_pool.h>
 #include <KWayland/Client/surface.h>
 
+#include <cmath>
+
 namespace KWin
 {
 namespace Wayland
@@ -86,7 +88,7 @@ void WaylandQPainterOutput::present(const QRegion &damage)
     auto s = m_waylandOutput->surface();
     s->attachBuffer(m_buffer);
     s->damage(damage);
-    s->setScale(m_waylandOutput->scale());
+    s->setScale(std::ceil(m_waylandOutput->scale()));
     s->commit();
 }
 

src/plugins/platforms/wayland/wayland_backend.cpp

@@ -114,7 +114,7 @@ void WaylandCursor::doInstallImage(wl_buffer *image, const QSize &size, qreal sc
 void WaylandCursor::drawSurface(wl_buffer *image, const QSize &size, qreal scale)
 {
     m_surface->attachBuffer(image);
-    m_surface->setScale(scale);
+    m_surface->setScale(std::ceil(scale));
     m_surface->damageBuffer(QRect(QPoint(0, 0), size));
     m_surface->commit(Surface::CommitFlag::None);
     m_backend->flush();

[Méven Car]

This broke build on FreeBsd :/

13:32:07  /usr/home/jenkins/workspace/Plasma/kwin/kf5-qt5 FreeBSDQt5.15/src/plugins/platforms/wayland/egl_wayland_backend.cpp:316:45: error: no member named 'ceil' in namespace 'std'
13:32:07      waylandOutput->surface()->setScale(std::ceil(waylandOutput->scale()));
13:32:07                                         ~~~~~^
13:32:07  /usr/home/jenkins/workspace/Plasma/kwin/kf5-qt5 FreeBSDQt5.15/src/plugins/platforms/wayland/egl_wayland_backend.cpp:376:63: warning: unused parameter 'renderedRegion' [-Wunused-parameter]
13:32:07  void EglWaylandBackend::endFrame(int screenId, const QRegion &renderedRegion, const QRegion &damagedRegion)
13:32:07                                                                ^
13:32:08  1 warning and 1 error generated.

https://build.kde.org/job/Plasma/job/kwin/job/kf5-qt5%20FreeBSDQt5.15/808/console

[Vlad Zahorodnii]

That's what CI is for, but it would be nice to have gitlab pipelines so we catch these issues during code review stage not after.

[Méven Car]

Totally agree, pre-merge builds are such a great quality garantee.