Better render dialog resizing. Fixes #386.

qt/lc_renderdialog.cpp

@@ -11,6 +11,32 @@
 #define LC_POVRAY_MEMORY_MAPPED_FILE 1
 #endif
 
+void lcRenderPreviewWidget::resizeEvent(QResizeEvent* Event)
+{
+	mScaledImage = QImage();
+
+	QWidget::resizeEvent(Event);
+}
+
+void lcRenderPreviewWidget::paintEvent(QPaintEvent* PaintEvent)
+{
+	Q_UNUSED(PaintEvent);
+
+	QPainter Painter(this);
+
+	if (!mImage.isNull())
+	{
+		QSize Size = size();
+
+		if (mScaledImage.isNull())
+			mScaledImage = mImage.scaled(Size, Qt::KeepAspectRatio, Qt::SmoothTransformation);
+
+		Painter.drawImage((Size.width() - mScaledImage.width()) / 2, (Size.height() - mScaledImage.height()) / 2, mScaledImage);
+	}
+	else
+		Painter.fillRect(rect(), Qt::white);
+}
+
 lcRenderDialog::lcRenderDialog(QWidget* Parent)
 	: QDialog(Parent),
 	ui(new Ui::lcRenderDialog)
@@ -30,7 +56,7 @@ lcRenderDialog::lcRenderDialog(QWidget* Parent)
 
 	QImage Image(LC_POVRAY_PREVIEW_WIDTH, LC_POVRAY_PREVIEW_HEIGHT, QImage::Format_RGB32);
 	Image.fill(QColor(255, 255, 255));
-	ui->preview->setPixmap(QPixmap::fromImage(Image));
+	ui->preview->SetImage(Image);
 
 	connect(&mUpdateTimer, SIGNAL(timeout()), this, SLOT(Update()));
 	mUpdateTimer.start(500);
@@ -173,6 +199,10 @@ void lcRenderDialog::on_RenderButton_clicked()
 #endif
 	mProcess->start(POVRayPath, Arguments);
 
+	mImage = QImage(ui->WidthEdit->text().toInt(), ui->HeightEdit->text().toInt(), QImage::Format_ARGB32);
+	mImage.fill(QColor(255, 255, 255));
+	ui->preview->SetImage(mImage);
+
 	if (mProcess->waitForStarted())
 	{
 		ui->RenderButton->setText(tr("Cancel"));
@@ -255,9 +285,6 @@ void lcRenderDialog::Update()
 	int Height = Header->Height;
 	int PixelsWritten = Header->PixelsWritten;
 
-	if (!Header->PixelsRead)
-		mImage = QImage(Width, Height, QImage::Format_ARGB32);
-
 	quint8* Pixels = (quint8*)(Header + 1);
 
 	for (int y = 0; y < Height; y++)
@@ -274,7 +301,7 @@ void lcRenderDialog::Update()
 	ui->RenderProgress->setMaximum(mImage.width() * mImage.height());
 	ui->RenderProgress->setValue(int(Header->PixelsRead));
 
-	ui->preview->setPixmap(QPixmap::fromImage(mImage.scaled(LC_POVRAY_PREVIEW_WIDTH, LC_POVRAY_PREVIEW_HEIGHT, Qt::KeepAspectRatio, Qt::SmoothTransformation)));
+	ui->preview->SetImage(mImage);
 #endif
 }
 
@@ -296,7 +323,7 @@ void lcRenderDialog::ShowResult()
 		return;
 	}
 
-	ui->preview->setPixmap(QPixmap::fromImage(mImage.scaled(LC_POVRAY_PREVIEW_WIDTH, LC_POVRAY_PREVIEW_HEIGHT, Qt::KeepAspectRatio, Qt::SmoothTransformation)));
+	ui->preview->SetImage(mImage);
 
 	QString FileName = ui->OutputEdit->text();
 

qt/lc_renderdialog.h

@@ -6,6 +6,31 @@ namespace Ui {
 class lcRenderDialog;
 }
 
+class lcRenderPreviewWidget : public QWidget
+{
+	Q_OBJECT
+
+public:
+	lcRenderPreviewWidget(QWidget* Parent)
+		: QWidget(Parent)
+	{
+	}
+
+	void SetImage(QImage Image)
+	{
+		mImage = Image;
+		mScaledImage = QImage();
+		update();
+	}
+
+protected:
+	virtual void resizeEvent(QResizeEvent* Event) override;
+	virtual void paintEvent(QPaintEvent* PaintEvent) override;
+
+	QImage mImage;
+	QImage mScaledImage;
+};
+
 class lcRenderDialog : public QDialog
 {
 	Q_OBJECT

qt/lc_renderdialog.ui

@@ -18,6 +18,12 @@
     <layout class="QVBoxLayout" name="topLayout">
      <item>
       <widget class="QGroupBox" name="groupBox">
+       <property name="sizePolicy">
+        <sizepolicy hsizetype="Preferred" vsizetype="Fixed">
+         <horstretch>0</horstretch>
+         <verstretch>0</verstretch>
+        </sizepolicy>
+       </property>
        <property name="title">
         <string>Settings</string>
        </property>
@@ -113,17 +119,21 @@
        </item>
       </layout>
      </item>
+     <item>
+      <widget class="lcRenderPreviewWidget" name="preview" native="true"/>
+     </item>
     </layout>
    </item>
-   <item>
-    <widget class="QLabel" name="preview">
-     <property name="text">
-      <string/>
-     </property>
-    </widget>
-   </item>
   </layout>
  </widget>
+ <customwidgets>
+  <customwidget>
+   <class>lcRenderPreviewWidget</class>
+   <extends>QWidget</extends>
+   <header>lc_renderdialog.h</header>
+   <container>1</container>
+  </customwidget>
+ </customwidgets>
  <tabstops>
   <tabstop>QualityComboBox</tabstop>
   <tabstop>OutputEdit</tabstop>