C# Cairo.Context.SetSourceRGBA方法代码示例

		void OnDraw (object data)
		{
			Action<Cairo.Context> callback = (Action<Cairo.Context>) data;

			using (var context = new Cairo.Context (surface.Surface)) {
				context.Operator = Cairo.Operator.Source;
				context.SetSourceRGBA (0, 0, 0, 0);
				context.Paint ();
				context.Operator = Cairo.Operator.Over;

				context.Scale (Scale, Scale);
				callback (context);
			}
			runningSignal.Set ();
		}

        /// <summary>
        /// Draws the text.
        /// </summary>
        /// <param name="showCursor">Whether or not to show the mouse cursor in the drawing.</param>
        /// <param name="useTextLayer">Whether or not to use the TextLayer (as opposed to the Userlayer).</param>
        private void RedrawText(bool showCursor, bool useTextLayer)
        {
            Rectangle r = CurrentTextEngine.GetLayoutBounds();
            r.Inflate(10 + OutlineWidth, 10 + OutlineWidth);
            CurrentTextBounds = r;

            Rectangle cursorBounds = Rectangle.Zero;

            Cairo.ImageSurface surf;

            if (!useTextLayer)
            {
                //Draw text on the current UserLayer's surface as finalized text.
                surf = PintaCore.Workspace.ActiveDocument.CurrentUserLayer.Surface;
            }
            else
            {
                //Draw text on the current UserLayer's TextLayer's surface as re-editable text.
                surf = PintaCore.Workspace.ActiveDocument.CurrentUserLayer.TextLayer.Surface;

                ClearTextLayer();
            }

            using (var g = new Cairo.Context (surf)) {
                g.Save ();

                // Show selection if on text layer
                if (useTextLayer) {
                    // Selected Text
                    Cairo.Color c = new Cairo.Color (0.7, 0.8, 0.9, 0.5);
                    foreach (Rectangle rect in CurrentTextEngine.SelectionRectangles)
                        g.FillRectangle (rect.ToCairoRectangle (), c);
                }
                g.AppendPath (PintaCore.Workspace.ActiveDocument.Selection.SelectionPath);
                g.FillRule = Cairo.FillRule.EvenOdd;
                g.Clip ();

                g.MoveTo (new Cairo.PointD (CurrentTextEngine.Origin.X, CurrentTextEngine.Origin.Y));

                g.SetSourceRGBA (PintaCore.Palette.PrimaryColor);

                //Fill in background
                if (BackgroundFill) {
                    using (var g2 = new Cairo.Context (surf)) {
                        g2.FillRectangle(CurrentTextEngine.GetLayoutBounds().ToCairoRectangle(), PintaCore.Palette.SecondaryColor);
                    }
                }

                // Draw the text
                if (FillText)
                    Pango.CairoHelper.ShowLayout (g, CurrentTextEngine.Layout);

                if (FillText && StrokeText) {
                    g.SetSourceRGBA (PintaCore.Palette.SecondaryColor);
                    g.LineWidth = OutlineWidth;

                    Pango.CairoHelper.LayoutPath (g, CurrentTextEngine.Layout);
                    g.Stroke ();
                } else if (StrokeText) {
                    g.SetSourceRGBA (PintaCore.Palette.PrimaryColor);
                    g.LineWidth = OutlineWidth;

                    Pango.CairoHelper.LayoutPath (g, CurrentTextEngine.Layout);
                    g.Stroke ();
                }

                if (showCursor) {
                    var loc = CurrentTextEngine.GetCursorLocation ();

                    g.Antialias = Cairo.Antialias.None;
                    g.DrawLine (new Cairo.PointD (loc.X, loc.Y), new Cairo.PointD (loc.X, loc.Y + loc.Height), new Cairo.Color (0, 0, 0, 1), 1);

                    cursorBounds = Rectangle.Inflate (loc, 2, 10);
                }

                g.Restore ();

                if (useTextLayer && (is_editing || ctrlKey) && !CurrentTextEngine.IsEmpty())
                {
                    //Draw the text edit rectangle.

                    g.Save();

                    g.Translate(.5, .5);

                    using (Cairo.Path p = g.CreateRectanglePath(new Cairo.Rectangle(CurrentTextBounds.Left, CurrentTextBounds.Top,
                        CurrentTextBounds.Width, CurrentTextBounds.Height - FontSize)))
                    {
                        g.AppendPath(p);
                    }

                    g.LineWidth = 1;

                    g.SetSourceRGB (1, 1, 1);
                    g.StrokePreserve();
//.........这里部分代码省略.........