add new canvas Image item, with somewhat optimized API for asynchronous, threaded rendering directly into an image buffer suitable for use by cairo as a source surface (currently untested)

1 files changed, 80 insertions, 0 deletions

diff --git a/libs/canvas/image.cc b/libs/canvas/image.cc
new file mode 100644
index 0000000000..0c7ce6eb28
--- /dev/null
+++ b/libs/canvas/image.cc
@@ -0,0 +1,80 @@
+#include "canvas/image.h"
+
+#include "gtkmm2ext/gui_thread.h"
+
+#include "pbd/xml++.h"
+
+using namespace ArdourCanvas;
+
+Image::Image (Group* group, Cairo::Format fmt, int width, int height)
+	: Item (group)
+	, _format (fmt)
+	, _width (width)
+	, _height (height)
+	, _need_render (false)
+{
+	DataReady.connect (data_connections, MISSING_INVALIDATOR, boost::bind (&Image::accept_data, this), gui_context());
+}
+
+void 
+Image::render (Rect const& area, Cairo::RefPtr<Cairo::Context> context) const
+{
+	if (_current) {
+		_surface = Cairo::ImageSurface::create (_current->data.get(),
+							_current->format,
+							_current->width,
+							_current->height,
+							_current->stride);
+	}
+
+	_current.reset ();
+
+	context->set_source (_surface, 0, 0);
+	context->rectangle (area.x0, area.y0, area.width(), area.height());
+	context->fill ();
+}
+
+void
+Image::compute_bounding_box () const
+{
+	_bounding_box = boost::optional<Rect> (Rect (0, 0, _width, _height));
+	_bounding_box_dirty = false;
+}
+
+boost::shared_ptr<Image::Data>
+Image::get_image ()
+{
+	int stride = Cairo::ImageSurface::format_stride_for_width (_format, _width);
+	boost::shared_ptr<Data> d (new Data (boost::shared_array<uint8_t> (new uint8_t[stride*_height]), _width, _height, stride, _format));
+
+	return d;
+}
+
+void
+Image::put_image (boost::shared_ptr<Data> d)
+{
+	_pending = d;
+	DataReady (); /* EMIT SIGNAL */
+}
+
+void
+Image::accept_data () 
+{
+	/* must be executed in gui thread */
+	_current = _pending;
+	_pending.reset ();
+	_need_render = true;
+}	     
+
+XMLNode *
+Image::get_state () const
+{
+	/* XXX */
+	return new XMLNode ("Image");
+}
+
+void
+Image::set_state (XMLNode const * /*node*/)
+{
+	/* XXX */
+}