Re-add WebSnap class & included API in WebWindow for tab preview

5 files changed, 294 insertions, 0 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index eefabbc5..31966664 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -13,6 +13,8 @@ set(rekonq_KDEINIT_SRCS
     #----------------------------------------
     webwindow/webpage.cpp
     webwindow/webwindow.cpp
+    #----------------------------------------
+    websnap.cpp
 )
 
 
diff --git a/src/websnap.cpp b/src/websnap.cpp
new file mode 100644
index 00000000..6440136e
--- /dev/null
+++ b/src/websnap.cpp
@@ -0,0 +1,164 @@
+/* ============================================================
+*
+* This file is a part of the rekonq project
+*
+* Copyright (C) 2009-2012 by Andrea Diamantini <adjam7 at gmail dot com>
+* Copyright (C) 2010 by Matthieu Gicquel <matgic78 at gmail dot com>
+*
+*
+* This program is free software; you can redistribute it and/or
+* modify it under the terms of the GNU General Public License as
+* published by the Free Software Foundation; either version 2 of
+* the License or (at your option) version 3 or any later version
+* accepted by the membership of KDE e.V. (or its successor approved
+* by the membership of KDE e.V.), which shall act as a proxy
+* defined in Section 14 of version 3 of the license.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*
+* ============================================================ */
+
+
+// Self Includes
+#include "websnap.h"
+#include "websnap.moc"
+
+// KDE Includes
+#include <KStandardDirs>
+
+// Qt Includes
+#include <QSize>
+#include <QFile>
+
+#include <QCryptographicHash>
+
+#include <QPainter>
+#include <QAction>
+
+#include <QWebFrame>
+#include <QWebSettings>
+
+
+WebSnap::WebSnap(const QUrl& url, QObject *parent)
+    : QObject(parent)
+    , m_url(url)
+{
+    // this to not register websnap history
+    m_page.settings()->setAttribute(QWebSettings::PrivateBrowsingEnabled, true);
+
+    // this to not let this page open other windows
+    m_page.settings()->setAttribute(QWebSettings::PluginsEnabled, false);
+    m_page.settings()->setAttribute(QWebSettings::JavascriptEnabled, false);
+
+    connect(&m_page, SIGNAL(loadFinished(bool)), this, SLOT(saveResult(bool)));
+
+    QMetaObject::invokeMethod(this, "load", Qt::QueuedConnection);
+}
+
+
+WebSnap::~WebSnap()
+{
+    m_page.action(QWebPage::Stop)->trigger();
+    m_page.deleteLater();
+}
+
+
+void WebSnap::load()
+{
+    m_page.mainFrame()->load(m_url);
+}
+
+
+
+QPixmap WebSnap::render(const QWebPage &page, int w, int h)
+{
+    // create the page image
+    QPixmap pageImage = QPixmap(w, h);
+    pageImage.fill(Qt::transparent);
+
+    // render it
+    QPainter p(&pageImage);
+    page.mainFrame()->render(&p, QWebFrame::ContentsLayer);
+    p.end();
+
+    return pageImage;
+}
+
+
+// NOTE
+// to render page preview in a safe way, you CANNOT work with scrollbars!
+// In fact, disabling temporarily them DOES NOT work without reloading a page
+// that is something we CANNOT do.
+QPixmap WebSnap::renderPagePreview(const QWebPage &page, int w, int h)
+{
+    // store actual viewportsize
+    QSize oldSize = page.viewportSize();
+
+    // prepare page
+    // NOTE: I saw some sites with strange CMS and with absurd content size width (eg: 8584553)
+    // This usually leads setViewportSize to crash :(
+    // So, ensure renderWidth is no more than 2000.
+    int renderWidth = page.mainFrame()->contentsSize().width();
+    if (renderWidth > 2000)
+        renderWidth = 2000;
+    int renderHeight = renderWidth * ((0.0 + h) / w);
+
+    page.setViewportSize(QSize(renderWidth, renderHeight));
+
+    // consider scrollbars and render the page
+    bool verticalScrollBarActive = !page.mainFrame()->scrollBarGeometry(Qt::Vertical).isEmpty();
+    if (verticalScrollBarActive)
+        renderWidth -= 15;
+
+    bool horizontalScrollBarActive = !page.mainFrame()->scrollBarGeometry(Qt::Horizontal).isEmpty();
+    if (horizontalScrollBarActive)
+        renderHeight -= 15;
+
+    QPixmap pageImage = WebSnap::render(page, renderWidth, renderHeight);
+
+    // resize image
+    pageImage = pageImage.scaled(w, h, Qt::KeepAspectRatioByExpanding, Qt::SmoothTransformation);
+
+    // restore page state
+    page.setViewportSize(oldSize);
+
+    return pageImage;
+}
+
+
+QString WebSnap::imagePathFromUrl(const QUrl &url)
+{
+    QByteArray name = url.toEncoded(QUrl::RemoveScheme | QUrl::RemoveUserInfo | QUrl::StripTrailingSlash);
+
+    QByteArray hashedName = QCryptographicHash::hash(name, QCryptographicHash::Md5).toHex();
+
+    return KStandardDirs::locateLocal("cache", QString("thumbs/") + hashedName + ".png", true);
+}
+
+
+void WebSnap::saveResult(bool ok)
+{
+    if (ok)
+    {
+        QPixmap image = renderPagePreview(m_page, defaultWidth, defaultHeight);
+        QString path = imagePathFromUrl(m_url);
+        QFile::remove(path);
+        image.save(path);
+    }
+
+    emit snapDone(ok);
+
+    this->deleteLater();
+}
+
+
+bool WebSnap::existsImage(const QUrl &u)
+{
+    return QFile::exists(imagePathFromUrl(u));
+}
diff --git a/src/websnap.h b/src/websnap.h
new file mode 100644
index 00000000..9d3c214d
--- /dev/null
+++ b/src/websnap.h
@@ -0,0 +1,118 @@
+/* ============================================================
+*
+* This file is a part of the rekonq project
+*
+* Copyright (C) 2009-2012 by Andrea Diamantini <adjam7 at gmail dot com>
+* Copyright (C) 2010 by Matthieu Gicquel <matgic78 at gmail dot com>
+*
+*
+* This program is free software; you can redistribute it and/or
+* modify it under the terms of the GNU General Public License as
+* published by the Free Software Foundation; either version 2 of
+* the License or (at your option) version 3 or any later version
+* accepted by the membership of KDE e.V. (or its successor approved
+* by the membership of KDE e.V.), which shall act as a proxy
+* defined in Section 14 of version 3 of the license.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*
+* ============================================================ */
+
+
+#ifndef WEB_SNAP_H
+#define WEB_SNAP_H
+
+
+// Qt Includes
+#include <QObject>
+#include <QWebPage>
+#include <QUrl>
+
+// Forward Declarations
+class QPixmap;
+
+/**
+ * This class is used in many classes of rekonq to produce an image
+ * based on the site corresponding to the url passed as argument.
+ * It also cached the images to not retrieve them every time :)
+ *
+ * Heavily based on Graphics-Dojo WebSnap example (thanks!)
+ *
+ * We use this in the following rekonq classes:
+ *
+ * - TabBar class:          to show a tab preview                (given a page, you show AND save an image)
+ * - PreviewSelector class: to save new favorite selection       (given a page, you show AND save an image)
+ *
+ * - NewTabPage class:      to show the favorites page "preview" (given an url, you show AND save an image)
+ *
+ */
+
+class WebSnap : public QObject
+{
+    Q_OBJECT
+
+public:
+    /**
+     * Creates a WebSnap object. It will load the url in one WebPage
+     * and snap an image from it.
+     *
+     * @param url the url to load
+     * @param parent the object parent
+     */
+    explicit WebSnap(const QUrl &url, QObject *parent = 0);
+
+    ~WebSnap();
+
+    /**
+     * Snaps a pixmap of size w * h from a page
+     *
+     * @param page the page to snap
+     * @param w the image width
+     * @param h the image height
+     *
+     * @return the pixmap snapped from the page
+     */
+    static QPixmap renderPagePreview(const QWebPage &page, int w = defaultWidth, int h = defaultHeight);
+
+    /**
+     * Guess the local path where the image for the url provided
+     * should be
+     *
+     * @param url the url to guess snap path
+     *
+     * @return the local path of the url snap
+     */
+    static QString imagePathFromUrl(const QUrl &url);
+
+    /**
+     * Determines if a snap exists for that url
+     *
+     */
+    static bool existsImage(const QUrl &url);
+
+
+private Q_SLOTS:
+    void saveResult(bool ok = true);
+    void load();
+
+Q_SIGNALS:
+    void snapDone(bool ok);
+
+private:
+    // Constants
+    static const int defaultWidth = 200;
+    static const int defaultHeight = 150;
+    QWebPage m_page;
+    QUrl m_url;
+
+    //render a preview: common part of renderPagePreview() and renderTabPreview()
+    static QPixmap render(const QWebPage &page, int w, int h);
+};
+
+#endif // WEB_SNAP_H
diff --git a/src/webwindow/webwindow.cpp b/src/webwindow/webwindow.cpp
index 631c9a2c..6d0d4d72 100644
--- a/src/webwindow/webwindow.cpp
+++ b/src/webwindow/webwindow.cpp
@@ -22,6 +22,7 @@
 #include "webwindow.moc"
 
 #include "webpage.h"
+#include "websnap.h"
 
 #include <QUrl>
 #include <QLineEdit>
@@ -148,3 +149,9 @@ QIcon WebWindow::icon() const
 {
     return _view->icon();
 }
+
+
+QPixmap WebWindow::tabPreview(int width, int height)
+{
+    return WebSnap::renderPagePreview(*page(), width, height);
+}
diff --git a/src/webwindow/webwindow.h b/src/webwindow/webwindow.h
index 7d72ed34..189f111f 100644
--- a/src/webwindow/webwindow.h
+++ b/src/webwindow/webwindow.h
@@ -29,6 +29,7 @@ class WebPage;
 
 class QWebView;
 class QLineEdit;
+class QPixmap;
 class QUrl;
 
 
@@ -47,6 +48,8 @@ public:
     QUrl url() const;
     QString title() const;
     QIcon icon() const;
+    
+    QPixmap tabPreview(int width, int height);
 
 private Q_SLOTS:
     void checkLoadUrl();