ladybird/Ladybird/Qt/TabBar.cpp
Timothy Flynn cbf1fd3e61 UI/Qt: Prevent division by zero in tab width calculation
On macOS, the first time TabBar::tabSizeHint is called, the count is
reportedly zero, and results in a floating point exception on x64.
2024-08-30 15:08:15 -04:00

130 lines
3.8 KiB
C++

/*
* Copyright (c) 2024, Tim Flynn <trflynn89@serenityos.org>
* Copyright (c) 2024, Jamie Mansfield <jmansfield@cadixdev.org>
* Copyright (c) 2024, Sam Atkins <sam@ladybird.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include "Tab.h"
#include <AK/StdLibExtras.h>
#include <AK/TypeCasts.h>
#include <Ladybird/Qt/TabBar.h>
#include <QContextMenuEvent>
#include <QEvent>
#include <QPushButton>
#include <QStylePainter>
namespace Ladybird {
TabBar::TabBar(QWidget* parent)
: QTabBar(parent)
{
}
QSize TabBar::tabSizeHint(int index) const
{
auto hint = QTabBar::tabSizeHint(index);
if (auto count = this->count(); count > 0) {
auto width = this->width() / count;
width = min(225, width);
width = max(128, width);
hint.setWidth(width);
}
return hint;
}
void TabBar::contextMenuEvent(QContextMenuEvent* event)
{
auto* tab_widget = verify_cast<QTabWidget>(this->parent());
auto* tab = verify_cast<Tab>(tab_widget->widget(tabAt(event->pos())));
if (tab)
tab->context_menu()->exec(event->globalPos());
}
TabWidget::TabWidget(QWidget* parent)
: QTabWidget(parent)
{
// This must be called first, otherwise several of the options below have no effect.
setTabBar(new TabBar(this));
setDocumentMode(true);
setElideMode(Qt::TextElideMode::ElideRight);
setMovable(true);
setTabsClosable(true);
setStyle(new TabStyle(this));
installEventFilter(parent);
}
void TabWidget::paintEvent(QPaintEvent*)
{
auto prepare_style_options = [](QTabBar* tab_bar, QSize widget_size) {
QStyleOptionTabBarBase style_options;
QStyleOptionTab tab_overlap;
tab_overlap.shape = tab_bar->shape();
auto overlap = tab_bar->style()->pixelMetric(QStyle::PM_TabBarBaseOverlap, &tab_overlap, tab_bar);
style_options.initFrom(tab_bar);
style_options.shape = tab_bar->shape();
style_options.documentMode = tab_bar->documentMode();
// NOTE: This assumes the tab bar is at the top of the tab widget.
style_options.rect = { 0, widget_size.height() - overlap, widget_size.width(), overlap };
return style_options;
};
QStylePainter painter { this, tabBar() };
if (auto* widget = cornerWidget(Qt::TopRightCorner)) {
// Manually paint the background for the area where the "new tab" button would have been
// if we hadn't relocated it in `TabStyle::subElementRect()`.
auto style_options = prepare_style_options(tabBar(), widget->size());
style_options.rect.translate(tabBar()->rect().width(), widget->y());
painter.drawPrimitive(QStyle::PE_FrameTabBarBase, style_options);
}
}
TabBarButton::TabBarButton(QIcon const& icon, QWidget* parent)
: QPushButton(icon, {}, parent)
{
resize({ 20, 20 });
setFlat(true);
}
bool TabBarButton::event(QEvent* event)
{
if (event->type() == QEvent::Enter)
setFlat(false);
if (event->type() == QEvent::Leave)
setFlat(true);
return QPushButton::event(event);
}
TabStyle::TabStyle(QObject* parent)
{
setParent(parent);
}
QRect TabStyle::subElementRect(QStyle::SubElement sub_element, QStyleOption const* option, QWidget const* widget) const
{
// Place our add-tab button (set as the top-right corner widget) directly after the last tab
if (sub_element == QStyle::SE_TabWidgetRightCorner) {
auto* tab_widget = verify_cast<TabWidget>(widget);
auto tab_bar_size = tab_widget->tabBar()->sizeHint();
auto new_tab_button_size = tab_bar_size.height();
return QRect {
qMin(tab_bar_size.width(), tab_widget->width() - new_tab_button_size),
0,
new_tab_button_size,
new_tab_button_size
};
}
return QProxyStyle::subElementRect(sub_element, option, widget);
}
}