Restore viewport dimensions after rendering screenshots

Fixes #388.

spec/driver_rendering_spec.rb

@@ -43,7 +43,7 @@ describe Capybara::Webkit::Driver, "rendering an image" do
     end
 
     it "height should be at least 10px" do
-      @image[:height].should >= 10
+      @image[:height].should be >= 10
     end
   end
 
@@ -55,7 +55,12 @@ describe Capybara::Webkit::Driver, "rendering an image" do
     end
 
     it "height should match the height given" do
-      @image[:height].should > 10
+      @image[:height].should == 400
+    end
+
+    it "should reset window dimensions to their default value" do
+      driver.evaluate_script('window.innerWidth').should == 1680
+      driver.evaluate_script('window.innerHeight').should == 1050
     end
   end
 
@@ -63,11 +68,26 @@ describe Capybara::Webkit::Driver, "rendering an image" do
     before { render(:width => 50, :height => 10) }
 
     it "width should be greater than the width given" do
-      @image[:width].should > 50
+      @image[:width].should be > 50
     end
 
     it "height should be greater than the height given" do
-      @image[:height].should > 10
+      @image[:height].should be > 10
+    end
+
+    it "should restore viewport dimensions after rendering" do
+      driver.evaluate_script('window.innerWidth').should == 1680
+      driver.evaluate_script('window.innerHeight').should == 1050
+    end
+  end
+
+  context "with a custom viewport size" do
+    before { driver.resize_window(800, 600) }
+
+    it "should restore viewport dimensions after rendering" do
+      render({})
+      driver.evaluate_script('window.innerWidth').should == 800
+      driver.evaluate_script('window.innerHeight').should == 600
     end
   end
 end

src/Render.cpp

@@ -11,9 +11,8 @@ void Render::start() {
   int height = arguments()[2].toInt();
 
   QSize size(width, height);
-  page()->setViewportSize(size);
 
-  bool result = page()->render( imagePath );
+  bool result = page()->render( imagePath, size );
 
   emitFinished(result);
 }

src/WebPage.cpp

@@ -193,12 +193,13 @@ QString WebPage::failureString() {
     return message + m_errorPageMessage;
 }
 
-bool WebPage::render(const QString &fileName) {
+bool WebPage::render(const QString &fileName, const QSize &minimumSize) {
   QFileInfo fileInfo(fileName);
   QDir dir;
   dir.mkpath(fileInfo.absolutePath());
 
   QSize viewportSize = this->viewportSize();
+  this->setViewportSize(minimumSize);
   QSize pageSize = this->mainFrame()->contentsSize();
   if (pageSize.isEmpty()) {
     return false;

src/WebPage.h

@@ -20,7 +20,7 @@ class WebPage : public QWebPage {
     void setPromptText(QString action);
     int getLastStatus();
     void setCustomNetworkAccessManager();
-    bool render(const QString &fileName);
+    bool render(const QString &fileName, const QSize &minimumSize);
     virtual bool extension (Extension extension, const ExtensionOption *option=0, ExtensionReturn *output=0);
     void setSkipImageLoading(bool skip);
     QVariantList consoleMessages();