#9130 Text in main work area isn't rendered with high resolution

Add pixel_ratio to graphics params to use it for displays with high resolution.
It holds the ratio between physical pixels and device-independent pixels of the graphics.

src/graphics/GraphicsLoader.cpp

@@ -191,6 +191,15 @@ public:
 	/// The connection of the signal StatusChanged 	
 	boost::signals::connection sc_;
 
+	double displayPixelRatio() const
+	{
+		return params_.pixel_ratio;
+	}
+	void setDisplayPixelRatio(double scale)
+	{
+		params_.pixel_ratio = scale;
+	}
+
 private:
 	///
 	void statusChanged();
@@ -326,6 +335,18 @@ ImageStatus Loader::status() const
 }
 
 
+double Loader::displayPixelRatio() const
+{
+	return pimpl_->displayPixelRatio();
+}
+
+
+void Loader::setDisplayPixelRatio(double scale)
+{
+	pimpl_->setDisplayPixelRatio(scale);
+}
+
+
 boost::signals::connection Loader::connect(slot_type const & slot) const
 {
 	return pimpl_->signal_.connect(slot);
@@ -433,6 +454,16 @@ void Loader::Impl::createPixmap()
 
 	image_.reset(cached_item_->image()->clone());
 
+	if (params_.pixel_ratio == 1.0) {
+		string filename = cached_item_->filename().absFileName();
+		size_t idx = filename.find_last_of('.');
+		if (idx != string::npos && idx > 3) {
+			if (filename.substr(idx - 3, 3) == "@2x") {
+				params_.pixel_ratio = 2.0;
+			}
+		}
+	}
+
 	bool const success = image_->setPixmap(params_);
 
 	if (success) {

src/graphics/GraphicsLoader.h

@@ -101,6 +101,9 @@ public:
 	 */
 	Image const * image() const;
 
+	double displayPixelRatio() const;
+	void setDisplayPixelRatio(double scale);
+
 private:
 	/// Use the Pimpl idiom to hide the internals.
 	class Impl;

src/graphics/GraphicsParams.cpp

@@ -25,6 +25,7 @@ namespace graphics {
 Params::Params()
 	: display(true),
 	  scale(100),
+	  pixel_ratio(1.0),
 	  angle(0)
 {}
 
@@ -35,6 +36,7 @@ bool operator==(Params const & a, Params const & b)
 		a.display == b.display &&
 		a.bb == b.bb &&
 		a.scale == b.scale &&
+		a.pixel_ratio == b.pixel_ratio &&
 		a.angle == b.angle);
 }
 

src/graphics/GraphicsParams.h

@@ -55,6 +55,7 @@ public:
 
 	bool display;
 	unsigned int scale;
+	double pixel_ratio;
 
 	/// The image filename.
 	support::FileName filename;