diff --git a/src/pdf_preview_widget.cpp b/src/pdf_preview_widget.cpp
index acbebdd..27a6ab7 100644
--- a/src/pdf_preview_widget.cpp
+++ b/src/pdf_preview_widget.cpp
@@ -3,21 +3,22 @@
 
 PDFPreviewWidget::PDFPreviewWidget(QWidget* parent) : QWidget(parent) {
   pPage = NULL;
-}
-
-void PDFPreviewWidget::setImage(QImage image) {
-  previewImage = image;
-  update();
+  currentPixmapSize = QSize(0,0);
 }
 
 void PDFPreviewWidget::regenImage(void) {
   double dpi;
   double dpi2;
-  QSize targetSize  = this->size();
+  QSize targetSize;
+
+  if(currentPixmapSize == QSize(0,0))
+    currentPixmapSize = this->size();
+
+  targetSize = currentPixmapSize;
   QSizeF oriSize    = pPage->pageSizeF();
   double oriDpi     = 72;
-  dpi   = targetSize.height() / (float)oriSize.height()*72;
-  dpi2  = targetSize.width()  / (float)oriSize.width()*72;
+  dpi   = targetSize.height() / (float)oriSize.height()*oriDpi;
+  dpi2  = targetSize.width()  / (float)oriSize.width()*oriDpi;
   dpi   = dpi<dpi2?dpi:dpi2;
   previewImage = pPage->renderToImage(dpi, dpi);
 }
@@ -28,8 +29,20 @@ void PDFPreviewWidget::previewUpdate(Poppler::Page* pp) {
   update();
 }
 
-void PDFPreviewWidget::resizeEvent(QResizeEvent* event) {
-  if(pPage != NULL) regenImage();
+void PDFPreviewWidget::wheelEvent(QWheelEvent* event) {
+  if(pPage != NULL) {
+    if(event->delta() > 0)
+      currentPixmapSize += QSize(30, 30);
+    else if(event->delta() < 0)
+      currentPixmapSize -= QSize(30, 30);
+
+    if(currentPixmapSize.width() < 150 || currentPixmapSize.height() < 150) {
+      currentPixmapSize = QSize(150, 150);
+    }
+
+    regenImage();
+    update();
+  }
 }
 
 void PDFPreviewWidget::paintEvent(QPaintEvent* event) {
@@ -37,7 +50,8 @@ void PDFPreviewWidget::paintEvent(QPaintEvent* event) {
 
     QPainter painter(this);
     QPixmap pixmap = QPixmap::fromImage(previewImage);
-    pixmap = pixmap.scaled(size(), Qt::KeepAspectRatio);
+    pixmap = pixmap.scaled(currentPixmapSize, Qt::KeepAspectRatio);
+    currentPixmapSize = pixmap.size();
     painter.drawPixmap(QRect((size().width() - pixmap.width()) / 2,
                       (size().height() - pixmap.height()) / 2,
                       pixmap.width(), pixmap.height()), pixmap);
diff --git a/src/pdf_preview_widget.h b/src/pdf_preview_widget.h
index db5c258..c2b211f 100644
--- a/src/pdf_preview_widget.h
+++ b/src/pdf_preview_widget.h
@@ -4,7 +4,8 @@
 
 class QImage;
 class QSize;
-class QResizeEvent;
+class QPoint;
+class QWheelEvent;
 class QPaintEvent;
 class QMouseEvent;
 
@@ -14,12 +15,11 @@ public:
   explicit PDFPreviewWidget(QWidget* parent = 0);
 
 public slots:
-  void setImage(QImage image);
   void regenImage(void);
   void previewUpdate(Poppler::Page*);
 
 protected:
-  void resizeEvent(QResizeEvent* event);
+  void wheelEvent(QWheelEvent* event);
   void paintEvent(QPaintEvent* event);
 
 private:
@@ -27,6 +27,7 @@ private:
   Poppler::Page* pPage;
  
   QSize currentPixmapSize;
+  QPoint currentPixmapPos;
 
 signals:
   void updatePreview(QImage);