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Fix note list rendering at fractional display scaling #769

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Fix note list rendering at fractional display scaling #769

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d1e60e0
Fix note list rendering at fractional scaling
Shriram-Vasudevan May 11, 2026
404e7cf
Format DPI buffer initializers
Shriram-Vasudevan May 12, 2026
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3 changes: 3 additions & 0 deletions src/main.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -8,9 +8,12 @@
#include "singleinstance.h"
#include <QApplication>
#include <QFontDatabase>
#include <QGuiApplication>

int main(int argc, char *argv[])
{
QGuiApplication::setHighDpiScaleFactorRoundingPolicy(Qt::HighDpiScaleFactorRoundingPolicy::PassThrough);

QApplication app(argc, argv);
// Set application information
QApplication::setApplicationName("Notes");
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6 changes: 3 additions & 3 deletions src/notelistdelegate.cpp
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Expand Up @@ -294,11 +294,11 @@ QTimeLine::State NoteListDelegate::animationState()
void NoteListDelegate::paintBackground(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
auto bufferSize = bufferSizeHint(option, index);
QPixmap buffer{ bufferSize };
QPixmap buffer = utils::makeDevicePixelRatioPixmap(bufferSize, m_view);

@nuttyartist nuttyartist May 15, 2026

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Once this buffer is DPR-aware, the drawPixmap(..., buffer, QRect{...}) calls lower in paintBackground() still need to convert their source rects before drawing. One compact way is to add this near the draw section and route those calls through it:

auto drawBuffer = [&buffer, painter](const QRect &targetRect, const QRect &sourceRect) {
    painter->drawPixmap(targetRect, buffer, utils::devicePixelRatioPixmapSourceRect(sourceRect, buffer));
};

Then replace each painter->drawPixmap(..., buffer, QRect{...}) in this function with drawBuffer(..., QRect{...}). The same pattern applies to the animated label buffer in paintLabels().

buffer.fill(Qt::transparent);
QPainter bufferPainter{ &buffer };
bufferPainter.setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform);
QRect bufferRect = buffer.rect();
QRect bufferRect{ QPoint{ }, bufferSize };
auto isPinned = index.data(NoteListModel::NoteIsPinned).toBool();
auto const *model = static_cast<NoteListModel *>(m_view->model());
if (model->hasPinnedNote() && model->isFirstPinnedNote(index) && static_cast<NoteListView *>(m_view)->isPinnedNotesCollapsed()) {
Expand Down Expand Up @@ -419,7 +419,7 @@ void NoteListDelegate::paintLabels(QPainter *painter, const QStyleOptionViewItem
{
if (m_animatedIndexes.contains(index)) {
auto bufferSize = bufferSizeHint(option, index);
QPixmap buffer{ bufferSize };
QPixmap buffer = utils::makeDevicePixelRatioPixmap(bufferSize, m_view);
buffer.fill(Qt::transparent);
QPainter bufferPainter{ &buffer };
bufferPainter.setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform);
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6 changes: 3 additions & 3 deletions src/notelistdelegateeditor.cpp
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Expand Up @@ -135,11 +135,11 @@ NoteListDelegateEditor::~NoteListDelegateEditor()
void NoteListDelegateEditor::paintBackground(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
auto bufferSize = rect().size();
QPixmap buffer{ bufferSize };
QPixmap buffer = utils::makeDevicePixelRatioPixmap(bufferSize, this);

@nuttyartist nuttyartist May 15, 2026

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Same coordinate-space issue here: the buffer is now DPR-aware, but the later source rect passed to drawPixmap() is still logical. The final draw should convert that source rect first, for example:

auto rowHeight = rect().height();
const QRect sourceRect{ 0, bufferSize.height() - rowHeight, rect().width(), rowHeight };
painter->drawPixmap(rect(), buffer, utils::devicePixelRatioPixmapSourceRect(sourceRect, buffer));

buffer.fill(Qt::transparent);
QPainter bufferPainter{ &buffer };
bufferPainter.setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform);
QRect bufferRect = buffer.rect();
QRect bufferRect{ QPoint{ }, bufferSize };
auto const *noteListModel = static_cast<NoteListModel *>(m_view->model());
if (noteListModel->hasPinnedNote() && (noteListModel->isFirstPinnedNote(index) || noteListModel->isFirstUnpinnedNote(index))) {
int fifthYOffset = 0;
Expand Down Expand Up @@ -375,7 +375,7 @@ bool NoteListDelegateEditor::underMouseC() const

QPixmap NoteListDelegateEditor::renderToPixmap()
{
QPixmap result{ rect().size() };
QPixmap result = utils::makeDevicePixelRatioPixmap(rect().size(), this);
result.fill(Qt::yellow);
QPainter painter(&result);
painter.setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform);
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34 changes: 32 additions & 2 deletions src/utils.h
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Original file line number Diff line number Diff line change
@@ -1,8 +1,13 @@
#pragma once

#include <QGuiApplication>
#include <cmath>
#include <QString>
#include <QDateTime>
#include <QPixmap>

@nuttyartist nuttyartist May 15, 2026

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This helper will also need QRect for converting logical source rects to pixmap/device-pixel source rects.

Suggested change
#include <QPixmap>
#include <QPixmap>
#include <QRect>

#include <QScreen>
#include <QString>
#include <QWidget>
#include <QWindow>

namespace utils {

Expand Down Expand Up @@ -44,4 +49,29 @@ inline QString parseDateTime(const QDateTime &dateTime)
return dateTime.date().toString("M/d/yy");
}

} // namespace utils
inline qreal devicePixelRatioForWidget(const QWidget *widget)
{
if (widget != nullptr) {
if (auto *topLevelWindow = widget->window(); (topLevelWindow != nullptr) && (topLevelWindow->windowHandle() != nullptr)) {
return topLevelWindow->windowHandle()->devicePixelRatio();
}

return widget->devicePixelRatioF();
}

if (auto *screen = QGuiApplication::primaryScreen(); screen != nullptr) {
return screen->devicePixelRatio();
}

return qreal(1);
}

inline QPixmap makeDevicePixelRatioPixmap(const QSize &logicalSize, const QWidget *widget)
{
const qreal scale = devicePixelRatioForWidget(widget);
QPixmap pixmap(logicalSize * scale);
pixmap.setDevicePixelRatio(scale);
return pixmap;
}
Comment on lines +69 to +75

@nuttyartist nuttyartist May 15, 2026

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Could we pair the DPR pixmap allocator with a small source-rect conversion helper? Painting into the pixmap stays in logical coordinates, but QPainter::drawPixmap(..., sourceRect) reads sourceRect in pixmap/device pixels.

Suggested change
inline QPixmap makeDevicePixelRatioPixmap(const QSize &logicalSize, const QWidget *widget)
{
const qreal scale = devicePixelRatioForWidget(widget);
QPixmap pixmap(logicalSize * scale);
pixmap.setDevicePixelRatio(scale);
return pixmap;
}
inline QPixmap makeDevicePixelRatioPixmap(const QSize &logicalSize, const QWidget *widget)
{
const qreal scale = devicePixelRatioForWidget(widget);
QPixmap pixmap(logicalSize * scale);
pixmap.setDevicePixelRatio(scale);
return pixmap;
}
inline QRect devicePixelRatioPixmapSourceRect(const QRect &logicalRect, const QPixmap &pixmap)
{
const qreal scale = pixmap.devicePixelRatio();
const QRectF scaledRect(logicalRect.x() * scale, logicalRect.y() * scale, logicalRect.width() * scale, logicalRect.height() * scale);
return scaledRect.toAlignedRect();
}


} // namespace utils