[gnome-games/wip/exalm/gamepad-drawing: 1/2] ui: Simplify GamepadView drawing

[Alexander Mikhaylenko <alexm src gnome org>]

commit 56e3f93074e464b42a8541ead6da4021c5d2c023
Author: Alexander Mikhaylenko <exalm7659 gmail com>
Date:   Thu Sep 13 15:56:11 2018 +0500

    ui: Simplify GamepadView drawing
    
    Use groups instead of creating additional contexts.
    
    Also, use double.min() instead of an 'if' statement.

 src/ui/gamepad-view.vala | 55 +++++++++++++++++-------------------------------
 1 file changed, 19 insertions(+), 36 deletions(-)
---
diff --git a/src/ui/gamepad-view.vala b/src/ui/gamepad-view.vala
index 88cfb187..702816e2 100644
--- a/src/ui/gamepad-view.vala
+++ b/src/ui/gamepad-view.vala
@@ -44,62 +44,45 @@ private class Games.GamepadView : Gtk.DrawingArea {
                double x, y, scale;
                calculate_image_dimensions (out x, out y, out scale);
 
-               var color_context = create_similar_context (context, x, y, scale);
-               color_gamepad (context, color_context);
-               var highlight_context = create_similar_context (context, x, y, scale);
-               highlight_gamepad (context, highlight_context);
+               context.translate (x, y);
+               context.scale (scale, scale);
+
+               color_gamepad (context);
+               highlight_gamepad (context);
 
                return false;
        }
 
-       private void color_gamepad (Cairo.Context gamepad_context, Cairo.Context color_context) {
-               var color_surface = color_context.get_target ();
-
-               handle.render_cairo (color_context);
+       private void color_gamepad (Cairo.Context context) {
+               context.push_group ();
+               handle.render_cairo (context);
+               var group = context.pop_group ();
 
                Gdk.RGBA color;
                get_style_context ().lookup_color ("theme_fg_color", out color);
-               gamepad_context.set_source_rgba (color.red, color.green, color.blue, color.alpha);
-               gamepad_context.mask_surface (color_surface, 0, 0);
+               context.set_source_rgba (color.red, color.green, color.blue, color.alpha);
+               context.mask (group);
        }
 
-       private void highlight_gamepad (Cairo.Context gamepad_context, Cairo.Context highlight_context) {
-               var highlight_surface = highlight_context.get_target ();
-
+       private void highlight_gamepad (Cairo.Context context) {
+               context.push_group ();
                for (var i = 0; i < configuration.input_paths.length; ++i)
                        if (input_highlights[i])
-                               handle.render_cairo_sub (highlight_context, "#" + 
configuration.input_paths[i].path);
+                               handle.render_cairo_sub (context, "#" + configuration.input_paths[i].path);
+               var group = context.pop_group ();
 
                Gdk.RGBA color;
                get_style_context ().lookup_color ("theme_selected_bg_color", out color);
-               gamepad_context.set_source_rgba (color.red, color.green, color.blue, color.alpha);
-               gamepad_context.mask_surface (highlight_surface, 0, 0);
-       }
-
-       private Cairo.Context create_similar_context (Cairo.Context context, double x, double y, double 
scale) {
-               var w = get_allocated_width ();
-               var h = get_allocated_height ();
-               var surface = context.get_target ();
-               var similar_surface = new Cairo.Surface.similar (surface, Cairo.Content.COLOR_ALPHA, w, h);
-               var similar_context = new Cairo.Context (similar_surface);
-               similar_context.translate (x, y);
-               similar_context.scale (scale, scale);
-
-               return similar_context;
+               context.set_source_rgba (color.red, color.green, color.blue, color.alpha);
+               context.mask (group);
        }
 
        private void calculate_image_dimensions (out double x, out double y, out double scale) {
                double w = get_allocated_width ();
                double h = get_allocated_height ();
-               double allocation_ratio = w / h;
-               double image_ratio = (double) handle.width / handle.height;
 
-               if (allocation_ratio > image_ratio) {
-                       scale = h / handle.height;
-               }
-               else {
-                       scale = w / handle.width;
-               }
+               scale = double.min (h / handle.height, w / handle.width);
+
                x = (w - handle.width * scale) / 2;
                y = (h - handle.height * scale) / 2;
        }