From 2cc42ecc1220428d1c4fc19e9c85f89c1f5da4cf Mon Sep 17 00:00:00 2001
From: David Edmundson <kde@davidedmundson.co.uk>
Date: Sat, 23 Jun 2018 18:14:50 +0100
Subject: [PATCH] DRM cursor scaling

Summary:
We pass the buffer scale of the cursor through QImage::devicePixelRatio.

When copying the cursor with QPainter use Qt's in-built functionality to
handle resizing the cursor pixmap as necessary to match the screen.

As we're now resizing the cursor, the hotspot needs translating from
logical to device co-ordinates.

Test Plan: Used with associated patches

Reviewers: #kwin, graesslin

Reviewed By: #kwin, graesslin

Subscribers: graesslin, kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D13605
---
 plugins/platforms/drm/drm_output.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/plugins/platforms/drm/drm_output.cpp b/plugins/platforms/drm/drm_output.cpp
index de7d511283..ac2cfa194e 100644
--- a/plugins/platforms/drm/drm_output.cpp
+++ b/plugins/platforms/drm/drm_output.cpp
@@ -132,6 +132,8 @@ void DrmOutput::updateCursor()
     m_hasNewCursor = true;
     QImage *c = m_cursor[m_cursorIndex]->image();
     c->fill(Qt::transparent);
+    c->setDevicePixelRatio(m_scale);
+
     QPainter p;
     p.begin(c);
     if (m_orientation == Qt::InvertedLandscapeOrientation) {
@@ -158,6 +160,7 @@ void DrmOutput::moveCursor(const QPoint &globalPos)
         hotspotMatrix.rotate(180.0f, 0.0f, 0.0f, 1.0f);
         hotspotMatrix.translate(-cursorSize.width()/2.0, -cursorSize.height()/2.0);
     }
+    hotspotMatrix.scale(m_scale);
     matrix.scale(m_scale);
     matrix.translate(-m_globalPos.x(), -m_globalPos.y());
     const QPoint p = matrix.map(globalPos) - hotspotMatrix.map(m_backend->softwareCursorHotspot());