ardour/libs/canvas/image.cc

/*
    Copyright (C) 2013 Paul Davis

    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) any later version.

    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, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "canvas/image.h"

#include "gtkmm2ext/gui_thread.h"

using namespace ArdourCanvas;

Image::Image (Canvas* canvas, Cairo::Format fmt, int width, int height)
	: Item (canvas)
	, _format (fmt)
	, _width (width)
	, _height (height)
	, _need_render (false)
{
	DataReady.connect (data_connections, MISSING_INVALIDATOR, boost::bind (&Image::accept_data, this), gui_context());
}

Image::Image (Item* parent, Cairo::Format fmt, int width, int height)
	: Item (parent)
	, _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 (_need_render && _pending) {
		_surface = Cairo::ImageSurface::create (_pending->data,
							_pending->format,
							_pending->width,
							_pending->height,
							_pending->stride);
		_current = _pending;
	}
	
	Rect self = item_to_window (Rect (0, 0, _width, _height));
	boost::optional<Rect> draw = self.intersection (area);

	if (_surface && draw) {
		context->set_source (_surface, self.x0, self.y0);
		context->rectangle (draw->x0, draw->y0, draw->width(), draw->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 (bool allocate_data)
{
	/* can be called by any thread */

	int stride = Cairo::ImageSurface::format_stride_for_width (_format, _width);
	if (allocate_data)  {
		boost::shared_ptr<Data> d (new Data (new uint8_t[stride*_height], _width, _height, stride, _format));
		return d;
	} else {
		boost::shared_ptr<Data> d (new Data (NULL, _width, _height, stride, _format));
		return d;
	}
}

void
Image::put_image (boost::shared_ptr<Data> d)
{
	/* can be called by any thread */

	_pending = d;
	DataReady (); /* EMIT SIGNAL */
}

void
Image::accept_data ()
{
	/* must be executed in gui thread */

	begin_change ();
	_need_render = true;
	end_change (); // notify canvas that we need redrawing
}