summaryrefslogtreecommitdiffstats
path: root/src/ui/widget/canvas/pixelstreamer.h
diff options
context:
space:
mode:
Diffstat (limited to 'src/ui/widget/canvas/pixelstreamer.h')
-rw-r--r--src/ui/widget/canvas/pixelstreamer.h75
1 files changed, 75 insertions, 0 deletions
diff --git a/src/ui/widget/canvas/pixelstreamer.h b/src/ui/widget/canvas/pixelstreamer.h
new file mode 100644
index 0000000..bcd3684
--- /dev/null
+++ b/src/ui/widget/canvas/pixelstreamer.h
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * A class hierarchy implementing various ways of streaming pixel buffers to the GPU.
+ * Copyright (C) 2022 PBS <pbs3141@gmail.com>
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#ifndef INKSCAPE_UI_WIDGET_CANVAS_PIXELSTREAMER_H
+#define INKSCAPE_UI_WIDGET_CANVAS_PIXELSTREAMER_H
+
+#include <memory>
+#include <2geom/int-point.h>
+#include <cairomm/refptr.h>
+#include <cairomm/surface.h>
+
+namespace Inkscape {
+namespace UI {
+namespace Widget {
+
+// A class for turning Cairo image surfaces into OpenGL textures.
+class PixelStreamer
+{
+public:
+ virtual ~PixelStreamer() = default;
+
+ // Method for streaming pixels to the GPU.
+ enum class Method
+ {
+ Auto, // Use the best option available at runtime.
+ Persistent, // Persistent buffer mapping. (Best, requires OpenGL 4.4.)
+ Asynchronous, // Ordinary buffer mapping. (Almost as good, requires OpenGL 3.0.)
+ Synchronous // Synchronous texture uploads. (Worst but still tolerable, requires OpenGL 1.1.)
+ };
+
+ // Create a PixelStreamer using a choice of method specified at runtime, falling back if unsupported.
+ static std::unique_ptr<PixelStreamer> create_supported(Method method);
+
+ // Return the method in use.
+ virtual Method get_method() const = 0;
+
+ /**
+ * Request a drawing surface of the given dimensions. If nogl is true, no GL commands will be issued,
+ * but the request may fail. An effort is made to keep such failures to a minimum.
+ *
+ * The surface must be returned to the PixelStreamer by calling finish(), in order to deallocate
+ * GL resourecs.
+ */
+ virtual Cairo::RefPtr<Cairo::ImageSurface> request(Geom::IntPoint const &dimensions, bool nogl = false) = 0;
+
+ /**
+ * Give back a drawing surface produced by request(), uploading the contents to the currently bound texture.
+ * The texture must be at least as big as the surface.
+ *
+ * If junk is true, then the surface will be junked instead, meaning nothing will be done with the contents,
+ * and its GL resources will simply be deallocated.
+ */
+ virtual void finish(Cairo::RefPtr<Cairo::ImageSurface> surface, bool junk = false) = 0;
+};
+
+} // namespace Widget
+} // namespace UI
+} // namespace Inkscape
+
+#endif // INKSCAPE_UI_WIDGET_CANVAS_PIXELSTREAMER_H
+
+/*
+ Local Variables:
+ mode:c++
+ c-file-style:"stroustrup"
+ c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+ indent-tabs-mode:nil
+ fill-column:99
+ End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :