1 files changed, 90 insertions, 0 deletions
diff --git a/src/Ryujinx/Ui/Applet/GtkHostUiTheme.cs b/src/Ryujinx/Ui/Applet/GtkHostUiTheme.cs
new file mode 100644
index 00000000..f25da47c
--- /dev/null
+++ b/src/Ryujinx/Ui/Applet/GtkHostUiTheme.cs
@@ -0,0 +1,90 @@
+using Gtk;
+using Ryujinx.HLE.Ui;
+using System.Diagnostics;
+
+namespace Ryujinx.Ui.Applet
+{
+    internal class GtkHostUiTheme : IHostUiTheme
+    {
+        private const int RenderSurfaceWidth  = 32;
+        private const int RenderSurfaceHeight = 32;
+
+        public string FontFamily { get; private set; }
+
+        public ThemeColor DefaultBackgroundColor { get; }
+        public ThemeColor DefaultForegroundColor { get; }
+        public ThemeColor DefaultBorderColor { get; }
+        public ThemeColor SelectionBackgroundColor { get; }
+        public ThemeColor SelectionForegroundColor { get; }
+
+        public GtkHostUiTheme(Window parent)
+        {
+            Entry entry = new Entry();
+            entry.SetStateFlags(StateFlags.Selected, true);
+
+            // Get the font and some colors directly from GTK.
+            FontFamily = entry.PangoContext.FontDescription.Family;
+
+            // Get foreground colors from the style context.
+
+            var defaultForegroundColor = entry.StyleContext.GetColor(StateFlags.Normal);
+            var selectedForegroundColor = entry.StyleContext.GetColor(StateFlags.Selected);
+
+            DefaultForegroundColor   = new ThemeColor((float) defaultForegroundColor.Alpha, (float) defaultForegroundColor.Red, (float) defaultForegroundColor.Green, (float) defaultForegroundColor.Blue);
+            SelectionForegroundColor = new ThemeColor((float)selectedForegroundColor.Alpha, (float)selectedForegroundColor.Red, (float)selectedForegroundColor.Green, (float)selectedForegroundColor.Blue);
+
+            ListBoxRow row = new ListBoxRow();
+            row.SetStateFlags(StateFlags.Selected, true);
+
+            // Request the main thread to render some UI elements to an image to get an approximation for the color.
+            // NOTE (caian): This will only take the color of the top-left corner of the background, which may be incorrect
+            // if someone provides a custom style with a gradient or image.
+
+            using (var surface = new Cairo.ImageSurface(Cairo.Format.Argb32, RenderSurfaceWidth, RenderSurfaceHeight))
+            using (var context = new Cairo.Context(surface))
+            {
+                context.SetSourceRGBA(1, 1, 1, 1);
+                context.Rectangle(0, 0, RenderSurfaceWidth, RenderSurfaceHeight);
+                context.Fill();
+
+                // The background color must be from the main Window because entry uses a different color.
+                parent.StyleContext.RenderBackground(context, 0, 0, RenderSurfaceWidth, RenderSurfaceHeight);
+
+                DefaultBackgroundColor = ToThemeColor(surface.Data);
+
+                context.SetSourceRGBA(1, 1, 1, 1);
+                context.Rectangle(0, 0, RenderSurfaceWidth, RenderSurfaceHeight);
+                context.Fill();
+
+                // Use the background color of the list box row when selected as the text box frame color because they are the
+                // same in the default theme.
+                row.StyleContext.RenderBackground(context, 0, 0, RenderSurfaceWidth, RenderSurfaceHeight);
+
+                DefaultBorderColor = ToThemeColor(surface.Data);
+            }
+
+            // Use the border color as the text selection color.
+            SelectionBackgroundColor = DefaultBorderColor;
+        }
+
+        private ThemeColor ToThemeColor(byte[] data)
+        {
+            Debug.Assert(data.Length == 4 * RenderSurfaceWidth * RenderSurfaceHeight);
+
+            // Take the center-bottom pixel of the surface.
+            int position = 4 * (RenderSurfaceWidth * (RenderSurfaceHeight - 1) + RenderSurfaceWidth / 2);
+
+            if (position + 4 > data.Length)
+            {
+                return new ThemeColor(1, 0, 0, 0);
+            }
+
+            float a = data[position + 3] / 255.0f;
+            float r = data[position + 2] / 255.0f;
+            float g = data[position + 1] / 255.0f;
+            float b = data[position + 0] / 255.0f;
+
+            return new ThemeColor(a, r, g, b);
+        }
+    }
+}
+\ No newline at end of file