Implement zooming in sprite editor window

QtGameMaker.pro

@@ -47,6 +47,7 @@ HEADERS += \
     src/editor/widgets/qlineeditwithmenu.h \
     src/editor/widgets/qscrollareawithmenu.h \
     src/editor/widgets/roomeditwidget.h \
+    src/editor/widgets/zoomablescrollarea.h \
     src/engine/gameengine.h \
     src/engine/glgamewindow.h \
     src/engine/vulkangamerenderer.h \
@@ -120,6 +121,7 @@ SOURCES += \
     src/editor/widgets/qlineeditwithmenu.cpp \
     src/editor/widgets/qscrollareawithmenu.cpp \
     src/editor/widgets/roomeditwidget.cpp \
+    src/editor/widgets/zoomablescrollarea.cpp \
     src/engine/gameengine.cpp \
     src/engine/glgamewindow.cpp \
     src/engine/vulkangamerenderer.cpp \

src/editor/dialogs/imageeditordialog.ui

@@ -698,7 +698,7 @@
       </layout>
      </item>
      <item>
-      <widget class="QScrollArea" name="scrollArea">
+      <widget class="ZoomableScrollArea" name="scrollArea">
        <property name="widgetResizable">
         <bool>true</bool>
        </property>
@@ -1136,6 +1136,12 @@
    <header>widgets/finecolorwidget.h</header>
    <container>1</container>
   </customwidget>
+  <customwidget>
+   <class>ZoomableScrollArea</class>
+   <extends>QScrollArea</extends>
+   <header>widgets/zoomablescrollarea.h</header>
+   <container>1</container>
+  </customwidget>
  </customwidgets>
  <resources>
   <include location="../resources_editor.qrc"/>

src/editor/widgets/drawingcanvaswidget.h

@@ -46,7 +46,7 @@ private:
 
     QPixmap *m_pixmap{};
 
-    float m_scale{4.f};
+    float m_scale{1.f};
 
     QColor m_leftButtonColor{Qt::white};
     QColor m_rightButtonColor{Qt::black};

src/editor/widgets/zoomablescrollarea.cpp

@@ -0,0 +1,29 @@
+#include "zoomablescrollarea.h"
+
+#include <QWheelEvent>
+
+#include "drawingcanvaswidget.h"
+
+void ZoomableScrollArea::wheelEvent(QWheelEvent *event)
+{
+    // Only zoom when Ctrl is held
+    if (!event->modifiers().testFlag(Qt::ControlModifier))
+    {
+        QScrollArea::wheelEvent(event);
+        return;
+    }
+
+    auto *w = qobject_cast<DrawingCanvasWidget*>(widget());
+    if (!w)
+        return;
+
+    auto scale = w->scale();
+    if (event->angleDelta().y() > 0)
+        scale *= 2;
+    else
+        scale /= 2;
+
+    w->setScale(scale);
+
+    event->accept();
+}

src/editor/widgets/zoomablescrollarea.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#include <QScrollArea>
+
+class ZoomableScrollArea : public QScrollArea
+{
+    Q_OBJECT
+
+public:
+    using QScrollArea::QScrollArea;
+
+protected:
+    void wheelEvent(QWheelEvent *event) override;
+};