image/svg+xml WORLD (0, 0) world VIEWPORT CANVAS x: pixels or frames (frames = pixels * Editor::frames_per_unit) y: pixels "units" == pixels in Ardour Carl's handy cut-out-and-keep guide to the Ardour canvas master_group time_line_group trackview_group Editor::canvas_timebars_vsize Clicks are delivered in pixels relative to the viewport.Since the viewport is always at (0,0) in world coordinates,trackview_group->w2i() will convert a click to a trackview coordinate.Editor::event_frame() will do this and also convert x pixels to frames.y scrolling moves the trackview_group. WORLD (0, 0) world VIEWPORT CANVAS master_group time_line_group trackview_group WORLD (0, 0) world VIEWPORT CANVAS master_group time_line_group trackview_group x scrolling: move master group