PangoGtkGui.cs

gistfile1.txt

using Gtk;
using System;
using Cairo;

namespace Nereid
{
    public class Program
    {
        public static void Main (string [] args)
        {
            Gtk.Application.Init ();
            new GuiClient ();
            Gtk.Application.Run ();
        }
    }


    public class GuiClient : Window
    {
        // Major Layout Components
        private VBox primary_vbox;
        private Widget track_info_container;

        public GuiClient () : base ("bug")
        {
            Show ();
        }

        protected override void OnShown ()
        {
            BuildPrimaryLayout ();

            base.OnShown ();
        }


        private void BuildPrimaryLayout ()
        {
            primary_vbox = new VBox ();

            var track_info_display = new ClassicTrackInfoDisplay ();
            track_info_display.Show ();
            track_info_container = new EditorBox (track_info_display);
            track_info_container.Show ();

            primary_vbox.PackStart (track_info_container, false, false, 0);
            primary_vbox.Show ();
            Add (primary_vbox);


            track_info_display.Start ();
        }

        public class EditorBox : EventBox
        {
            public EditorBox (Widget child)
            {
                Child = child;
                VisibleWindow = false;
            }
        }

    }

    internal static class CairoHelper
    {
        public static string ColorGetHex (Cairo.Color color, bool withAlpha)
        {
            if (withAlpha) {
                return String.Format("#{0:x2}{1:x2}{2:x2}{3:x2}", (byte)(color.R * 255), (byte)(color.G * 255),
                    (byte)(color.B * 255), (byte)(color.A * 255));
            } else {
                return String.Format("#{0:x2}{1:x2}{2:x2}", (byte)(color.R * 255), (byte)(color.G * 255),
                    (byte)(color.B * 255));
            }
        }
    }

    public class SomeInfo {
        public string DisplayArtistName {
            get;
            set;
        }

        public string DisplayAlbumTitle {
            get;
            set;
        }

        public string DisplayTrackTitle {
            get;
            set;
        }
    }

    public class ClassicTrackInfoDisplay : Widget
    {
        public ClassicTrackInfoDisplay ()
        {
			#if GTK3
            HasWindow = false;
			#else
			WidgetFlags |= WidgetFlags.NoWindow;
			#endif
        }

        public void Start ()
        {
            var incoming_track = new SomeInfo {
                DisplayArtistName = "theArtist",
                DisplayAlbumTitle = "theAlbum",
                DisplayTrackTitle = "theTitle"
            };

            QueueDraw ();
            current_track = incoming_track;
        }

        private Cairo.Color text_color;
        private Cairo.Color text_light_color;

        private SomeInfo current_track;

        protected override bool 
		#if GTK3
		OnDrawn (Cairo.Context cr) {
		#else
		OnExposeEvent(Gdk.EventExpose evnt) {
			Cairo.Context cr = Gdk.CairoHelper.Create (evnt.Window);
		#endif
            bool idle = current_track == null;
            if (!Visible || !IsMapped || idle) {
                return true;
            }

            RenderTrackInfo (cr, current_track);

            return true;
        }

        protected virtual string GetFirstLineText (SomeInfo track)
        {
            var result = String.Format ("<b>{0}</b>", GLib.Markup.EscapeText (track.DisplayTrackTitle));
            //return String.Format ("<span color=\"{0}\">{1}</span>",
            //    CairoHelper.ColorGetHex (text_color, false),
            //    result);
            return result;
        }

        protected virtual string GetSecondLineText (SomeInfo track)
        {
            string markup = GetByFrom (track.DisplayArtistName, track.DisplayAlbumTitle);

            return String.Format ("<span color=\"{0}\">{1}</span>",
                CairoHelper.ColorGetHex (text_color, false),
                markup);
        }

        private string MarkupFormat (string fmt, params string [] args)
        {
            string [] new_args = new string [args.Length + 2];
            new_args[0] = String.Format ("<span color=\"{0}\" size=\"small\">",
                CairoHelper.ColorGetHex (text_light_color, false));
            new_args[1] = "</span>";

            for (int i = 0; i < args.Length; i++) {
                new_args[i + 2] = GLib.Markup.EscapeText (args[i]);
            }

            return String.Format (fmt, new_args);
        }

        private string GetByFrom (string display_artist, string display_album)
        {
            return MarkupFormat ("{0}by{1} {2} {0}from{1} {3}", display_artist, display_album);
        }

        private Pango.Layout first_line_layout;
        private Pango.Layout second_line_layout;

		#if GTK3
        protected override void OnGetPreferredHeight (out int minimum_height, out int natural_height)
        {
            minimum_height = ComputeWidgetHeight ();
            natural_height = minimum_height;
        }

        protected override void OnGetPreferredWidth (out int minimum_width, out int natural_width)
        {
            minimum_width = ComputeWidgetHeight () * 20;
            natural_width = minimum_width;
        }
		#else
		protected override void OnSizeRequested (ref Requisition requisition)
		{
			requisition.Height = ComputeWidgetHeight ();
			requisition.Width = ComputeWidgetHeight () * 20;
		}
		#endif

        private int ComputeWidgetHeight ()
        {
            int width, height;
            Pango.Layout layout = new Pango.Layout (PangoContext);
            layout.SetText ("W");
            layout.GetPixelSize (out width, out height);
            layout.Dispose ();
            return 2 * height;
        }

        protected void RenderTrackInfo (Context cr, SomeInfo track)
        {
            double offset = Allocation.Height + 10;
            double y = 0;
            double x = offset;
            double width = Allocation.Width - offset;
            int unused, fl_height, sl_height;
            int pango_width = (int)(width * Pango.Scale.PangoScale);

            if (first_line_layout == null) {
                first_line_layout = Pango.CairoHelper.CreateLayout (cr);
            }

            if (second_line_layout == null) {
                second_line_layout = Pango.CairoHelper.CreateLayout (cr);
            }

            // Set up the text layouts
            first_line_layout.Width = pango_width;
            second_line_layout.Width = pango_width;

            // Compute the layout coordinates
            //first_line_layout.SetMarkup (GetFirstLineText (track));
            first_line_layout.SetMarkup (GetFirstLineText (track) + "__" + GetSecondLineText (track) + "___________");
            first_line_layout.GetPixelSize (out unused, out fl_height);
            second_line_layout.SetMarkup (GetSecondLineText (track));
            second_line_layout.GetPixelSize (out unused, out sl_height);

            y = (Allocation.Height - (fl_height + sl_height)) / 2;

            cr.MoveTo (x, y);
			#if GTK3
            cr.SetSourceColor (text_color);
			#else
			cr.Color = text_color;
			#endif
            Pango.CairoHelper.ShowLayout (cr, first_line_layout);

            cr.MoveTo (x, y + fl_height);
            Pango.CairoHelper.ShowLayout (cr, second_line_layout);
        }
    }

}