1 files changed, 41 insertions, 7 deletions

diff --git a/examples/widgets/pdfviewer/sequentialpagewidget.cpp b/examples/widgets/pdfviewer/sequentialpagewidget.cpp
index 5de4f2e..e7dd087 100644
--- a/examples/widgets/pdfviewer/sequentialpagewidget.cpp
+++ b/examples/widgets/pdfviewer/sequentialpagewidget.cpp
@@ -14,25 +14,45 @@ SequentialPageWidget::SequentialPageWidget(QWidget *parent)
     , m_background(Qt::darkGray)
     , m_pageSpacing(3)
     , m_zoom(1.)
-    , m_top(0.)
     , m_screenResolution(QGuiApplication::primaryScreen()->logicalDotsPerInch() / 72.0)
 {
 }
 
 SequentialPageWidget::~SequentialPageWidget()
 {
-
 }
 
 void SequentialPageWidget::setDocument(QPdfDocument *doc)
 {
     m_doc = doc;
+    invalidate();
 }
 
 void SequentialPageWidget::setZoom(qreal factor)
 {
     m_zoom = factor;
+    invalidate();
+}
+
+QSizeF SequentialPageWidget::pageSize(int page)
+{
+    return m_doc->pageSize(page) * m_screenResolution * m_zoom;
+}
+
+void SequentialPageWidget::invalidate()
+{
     m_pageCache.clear();
+    QSizeF totalSize(0, m_pageSpacing);
+    for (int page = 0; page < m_doc->pageCount(); ++page) {
+        QSizeF size = pageSize(page);
+        qDebug() << "page" << page << "size" << size;
+        totalSize.setHeight(totalSize.height() + size.height());
+        if (size.width() > totalSize.width())
+            totalSize.setWidth(size.width());
+    }
+    m_totalSize = totalSize.toSize();
+    setMinimumSize(m_totalSize);
+    qCDebug(lcExample) << "total size" << m_totalSize;
     update();
 }
 
@@ -45,19 +65,33 @@ void SequentialPageWidget::paintEvent(QPaintEvent * event)
     }
 
     painter.fillRect(event->rect(), m_background);
-    qCDebug(lcExample) << event->rect() << m_doc->pageCount();
 
-    int page = 0; // qFloor(m_top);
-    int y = 0; // TODO event->rect().top();
+    // Find the first page that needs to be rendered
+    int page = 0;
+    int y = 0;
+    while (page < m_doc->pageCount()) {
+        QSizeF size = pageSize(page);
+        int height = size.toSize().height();
+        if (y + height >= event->rect().top())
+            break;
+        y += height;
+        ++page;
+    }
+    y += m_pageSpacing;
+    int startPage = page;
+
+    // Actually render pages
     while (y < event->rect().bottom() && page < m_doc->pageCount()) {
-        QSizeF size = m_doc->pageSize(page) * m_screenResolution * m_zoom;
         if (!m_pageCache.contains(page)) {
+            QSizeF size = pageSize(page);
             qCDebug(lcExample) << "rendering page" << page << "to size" << size;
             m_pageCache.insert(page, QPixmap::fromImage(m_doc->render(page, size)));
         }
         const QPixmap &pm = m_pageCache[page];
-        painter.drawPixmap(0, y, pm);
+        painter.drawPixmap((width() - pm.width()) / 2, y, pm);
         y += pm.height() + m_pageSpacing;
         ++page;
     }
+
+    emit showingPageRange(startPage, page - 1);
 }