added checks to mitigate floating point crashes

src/messages/Image.cpp

@@ -46,8 +46,16 @@ namespace detail {
             this->items_.begin(), this->items_.end(), 0UL,
             [](auto init, auto &&frame) { return init + frame.duration; });
 
-        this->durationOffset_ = std::min<int>(
+        if (totalLength == 0)
-            int(getApp()->emotes->gifTimer.position() % totalLength), 60000);
+        {
+            this->durationOffset_ = 0;
+        }
+        else
+        {
+            this->durationOffset_ = std::min<int>(
+                int(getApp()->emotes->gifTimer.position() % totalLength),
+                60000);
+        }
         this->processOffset();
     }
 
@@ -72,6 +80,11 @@ namespace detail {
 
     void Frames::processOffset()
     {
+        if (this->items_.isEmpty())
+        {
+            return;
+        }
+
         while (true)
         {
             this->index_ %= this->items_.size();

src/providers/twitch/IrcMessageHandler.cpp

@@ -53,7 +53,10 @@ static float relativeSimilarity(const QString &str1, const QString &str2)
         }
     }
 
-    return z == 0 ? 0.f : float(z) / std::max(str1.size(), str2.size());
+    // ensure that no div by 0
+    return z == 0 ? 0.f
+                  : float(z) /
+                        std::max<int>(1, std::max(str1.size(), str2.size()));
 };
 
 float IrcMessageHandler::similarity(

src/providers/twitch/TwitchMessageBuilder.cpp

@@ -60,6 +60,7 @@ QColor getRandomColor(const QVariant &userId)
         colorSeed = std::rand();
     }
 
+    assert(twitchUsernameColors.size() != 0);
     const auto colorIndex = colorSeed % twitchUsernameColors.size();
     return twitchUsernameColors[colorIndex];
 }

src/widgets/BaseWidget.cpp

@@ -9,6 +9,7 @@
 #include <QIcon>
 #include <QLayout>
 #include <QtGlobal>
+#include <algorithm>
 
 namespace chatterino {
 
@@ -113,7 +114,8 @@ float BaseWidget::qtFontScale() const
 {
     if (auto window = dynamic_cast<BaseWindow *>(this->window()))
     {
-        return this->scale() / window->nativeScale_;
+        // ensure no div by 0
+        return this->scale() / std::max<float>(0.01f, window->nativeScale_);
     }
     else
     {

src/widgets/BaseWindow.cpp

@@ -104,12 +104,12 @@ QRect BaseWindow::getBounds()
 
 float BaseWindow::scale() const
 {
-    return this->overrideScale().value_or(this->scale_);
+    return std::max<float>(0.01f, this->overrideScale().value_or(this->scale_));
 }
 
 float BaseWindow::qtFontScale() const
 {
-    return this->scale() / this->nativeScale_;
+    return this->scale() / std::max<float>(0.01, this->nativeScale_);
 }
 
 void BaseWindow::init()

src/widgets/Label.cpp

@@ -93,10 +93,12 @@ void Label::paintEvent(QPaintEvent *)
 
     QFontMetrics metrics = getFonts()->getFontMetrics(
         this->getFontStyle(),
-        this->scale() * 96.f / this->logicalDpiX() * deviceDpi);
+        this->scale() * 96.f /
+            std::max<float>(0.01, this->logicalDpiX() * deviceDpi));
     painter.setFont(getFonts()->getFont(
         this->getFontStyle(),
-        this->scale() * 96.f / this->logicalDpiX() * deviceDpi));
+        this->scale() * 96.f /
+            std::max<float>(0.02, this->logicalDpiX() * deviceDpi)));
 
     int offset = this->getOffset();
 

src/widgets/Scrollbar.cpp

@@ -276,7 +276,8 @@ void Scrollbar::paintEvent(QPaintEvent *)
 
     int w = this->width();
     float y = 0;
-    float dY = float(this->height()) / float(snapshotLength);
+    float dY =
+        float(this->height()) / std::max<float>(1.0f, float(snapshotLength));
     int highlightHeight =
         int(std::ceil(std::max<float>(this->scale() * 2, dY)));
 
@@ -356,8 +357,10 @@ void Scrollbar::mouseMoveEvent(QMouseEvent *event)
     {
         int delta = event->pos().y() - this->lastMousePosition_.y();
 
-        setDesiredValue(this->desiredValue_ +
+        setDesiredValue(
-                        qreal(delta) / this->trackHeight_ * this->maximum_);
+            this->desiredValue_ +
+            qreal(delta) /
+                std::max<qreal>(0.02, this->trackHeight_ * this->maximum_));
     }
 
     this->lastMousePosition_ = event->pos();
@@ -442,13 +445,11 @@ void Scrollbar::updateScroll()
     this->trackHeight_ = this->height() - this->buttonHeight_ -
                          this->buttonHeight_ - MIN_THUMB_HEIGHT - 1;
 
+    auto div = std::max<qreal>(0.01, this->maximum_ * this->trackHeight_);
+
     this->thumbRect_ =
-        QRect(0,
+        QRect(0, int(this->currentValue_ / div) + 1 + this->buttonHeight_,
-              int(this->currentValue_ / this->maximum_ * this->trackHeight_) +
+              this->width(), int(this->largeChange_ / div) + MIN_THUMB_HEIGHT);
-                  1 + this->buttonHeight_,
-              this->width(),
-              int(this->largeChange_ / this->maximum_ * this->trackHeight_) +
-                  MIN_THUMB_HEIGHT);
 
     this->update();
 }

src/widgets/dialogs/ColorPickerDialog.cpp

@@ -210,6 +210,7 @@ void ColorPickerDialog::initRecentColors(LayoutCreator<QWidget> &creator)
         this->ui_.recent.colors.push_back(new ColorButton(*it, this));
         auto *button = this->ui_.recent.colors[ind];
 
+        static_assert(RECENT_COLORS_PER_ROW != 0);
         const int rowInd = (ind / RECENT_COLORS_PER_ROW) + 1;
         const int columnInd = ind % RECENT_COLORS_PER_ROW;
 

src/widgets/helper/ChannelView.cpp

@@ -319,7 +319,9 @@ void ChannelView::scaleChangedEvent(float scale)
     {
         auto factor = this->qtFontScale();
 #ifdef Q_OS_MACOS
-        factor = scale * 80.f / this->logicalDpiX() * this->devicePixelRatioF();
+        factor = scale * 80.f /
+                 std::max<float>(
+                     0.01, this->logicalDpiX() * this->devicePixelRatioF());
 #endif
         this->goToBottom_->getLabel().setFont(
             getFonts()->getFont(FontStyle::UiMedium, factor));
@@ -426,8 +428,9 @@ void ChannelView::updateScrollbar(
 
         if (h < 0)  // break condition
         {
-            this->scrollBar_->setLargeChange((messages.size() - i) +
+            this->scrollBar_->setLargeChange(
-                                             qreal(h) / message->getHeight());
+                (messages.size() - i) +
+                qreal(h) / std::max<int>(1, message->getHeight()));
 
             showScrollbar = true;
             break;
@@ -964,8 +967,8 @@ void ChannelView::wheelEvent(QWheelEvent *event)
         if (delta > 0)
         {
             qreal scrollFactor = fmod(desired, 1);
-            qreal currentScrollLeft =
+            qreal currentScrollLeft = std::max<qreal>(
-                int(scrollFactor * snapshot[i]->getHeight());
+                0.01, int(scrollFactor * snapshot[i]->getHeight()));
 
             for (; i >= 0; i--)
             {
@@ -997,8 +1000,8 @@ void ChannelView::wheelEvent(QWheelEvent *event)
         {
             delta = -delta;
             qreal scrollFactor = 1 - fmod(desired, 1);
-            qreal currentScrollLeft =
+            qreal currentScrollLeft = std::max<qreal>(
-                int(scrollFactor * snapshot[i]->getHeight());
+                0.01, int(scrollFactor * snapshot[i]->getHeight()));
 
             for (; i < snapshotLength; i++)
             {

src/widgets/helper/NotebookTab.cpp

@@ -282,12 +282,11 @@ void NotebookTab::paintEvent(QPaintEvent *)
     QPainter painter(this);
     float scale = this->scale();
 
-    painter.setFont(getApp()->fonts->getFont(
+    auto div = std::max<float>(0.01f, this->logicalDpiX() * deviceDpi(this));
-        FontStyle::UiTabs,
+    painter.setFont(
-        scale * 96.f / this->logicalDpiX() * deviceDpi(this)));
+        getApp()->fonts->getFont(FontStyle::UiTabs, scale * 96.f / div));
-    QFontMetrics metrics = app->fonts->getFontMetrics(
+    QFontMetrics metrics =
-        FontStyle::UiTabs,
+        app->fonts->getFontMetrics(FontStyle::UiTabs, scale * 96.f / div);
-        scale * 96.f / this->logicalDpiX() * deviceDpi(this));
 
     int height = int(scale * NOTEBOOK_TAB_HEIGHT);
 

src/widgets/settingspages/AboutPage.cpp

@@ -32,8 +32,11 @@ AboutPage::AboutPage()
 
         auto logo = layout.emplace<QLabel>().assign(&this->logo_);
         logo->setPixmap(pixmap);
-        logo->setFixedSize(PIXMAP_WIDTH,
+        if (pixmap.width() != 0)
-                           PIXMAP_WIDTH * pixmap.height() / pixmap.width());
+        {
+            logo->setFixedSize(PIXMAP_WIDTH,
+                               PIXMAP_WIDTH * pixmap.height() / pixmap.width());
+        }
         logo->setScaledContents(true);
 
         // this does nothing

src/widgets/splits/SplitContainer.cpp

@@ -962,8 +962,10 @@ void SplitContainer::Node::insertNextToThis(Split *_split, Direction _direction)
 {
     auto &siblings = this->parent_->children_;
 
-    qreal width = this->parent_->geometry_.width() / siblings.size();
+    qreal width = this->parent_->geometry_.width() /
-    qreal height = this->parent_->geometry_.height() / siblings.size();
+                  std::max<qreal>(0.0001, siblings.size());
+    qreal height = this->parent_->geometry_.height() /
+                   std::max<qreal>(0.0001, siblings.size());
 
     if (siblings.size() == 1)
     {
@@ -1117,16 +1119,20 @@ void SplitContainer::Node::layout(bool addSpacing, float _scale,
             // vars
             qreal minSize = qreal(48 * _scale);
 
-            qreal totalFlex = this->getChildrensTotalFlex(isVertical);
+            qreal totalFlex = std::max<qreal>(
+                0.0001, this->getChildrensTotalFlex(isVertical));
             qreal totalSize = std::accumulate(
                 this->children_.begin(), this->children_.end(), qreal(0),
                 [=](int val, std::unique_ptr<Node> &node) {
-                    return val + std::max<qreal>(this->getSize(isVertical) /
+                    return val + std::max<qreal>(
-                                                     totalFlex *
+                                     this->getSize(isVertical) /
-                                                     node->getFlex(isVertical),
+                                         std::max<qreal>(0.0001, totalFlex) *
-                                                 minSize);
+                                         node->getFlex(isVertical),
+                                     minSize);
                 });
 
+            totalSize = std::max<qreal>(0.0001, totalSize);
+
             qreal sizeMultiplier = this->getSize(isVertical) / totalSize;
             QRectF childRect = this->geometry_;
 
@@ -1242,7 +1248,7 @@ void SplitContainer::Node::layout(bool addSpacing, float _scale,
             }
         }
         break;
-    };
+    }
 }
 
 SplitContainer::Node::Type SplitContainer::Node::toContainerType(Direction _dir)