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// SPDX-License-Identifier: GPL-2.0-or-later
/**
* @file
* Utility functions for previewing icon representation.
*/
/* Authors:
* Jon A. Cruz
* Bob Jamison
* Other dudes from The Inkscape Organization
* Abhishek Sharma
* Anshudhar Kumar Singh <anshudhar2001@gmail.com>
*
* Copyright (C) 2004 Bob Jamison
* Copyright (C) 2005,2010 Jon A. Cruz
* Copyright (C) 2021 Anshudhar Kumar Singh
*
* Released under GNU GPL v2+, read the file 'COPYING' for more information.
*/
#ifndef INKSCAPE_UTIL_PREVIEW_H
#define INKSCAPE_UTIL_PREVIEW_H
#include <cstdint>
#include <cairomm/surface.h>
#include "display/drawing.h"
#include "async/channel.h"
class SPDocument;
class SPItem;
namespace Inkscape {
namespace UI {
namespace Preview {
/**
* Launch a background task to render a drawing to a surface.
*
* If the area to render is invalid, nothing is returned and no action is taken.
* Otherwise, first the drawing is snapshotted, then an async task is launched to render the drawing to a surface.
* Upon completion, the drawing is unsnapshotted on the calling thread and the result passed to onfinished().
* If the return object is destroyed before this happens, then the drawing will instead be destroyed on an unspecified
* thread while still in the snapshotted state.
*
* Contracts: (This isn't Rust, so we need a comment instead, and great trust in the caller.)
*
* - The caller must ensure onfinished() remains valid to call during the lifetime of the return object.
* (This is the same as for sigc::slots and connections.)
*
* - The caller must not call drawing->unsnapshot(), or any other method that bypasses snapshotting.
* However, it is ok to modify or destroy drawing in any other way, because the background task has shared
* ownership of the drawing (=> Sync), and snapshotting prevents modification of the data being read by the
* background task (=> Send/const).
*/
Cairo::RefPtr<Cairo::ImageSurface>
render_preview(SPDocument *doc, std::shared_ptr<Inkscape::Drawing> drawing, uint32_t bg_color, Inkscape::DrawingItem *item,
unsigned width_in, unsigned height_in, Geom::Rect const &dboxIn);
} // namespace Preview
} // namespace UI
} // namespace Inkscape
#endif // INKSCAPE_UTIL_PREVIEW_H
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