[gnome-games/wip/exalm/gameapd: 7/10] gamepad-view: Support analog sticks

[Alexander Mikhaylenko <alexm src gnome org>]

commit 9d24dba6afc22957670276ff78bf933711e47ae4
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Wed Mar 4 20:10:45 2020 +0500

    gamepad-view: Support analog sticks
    
    Currently we show analog sticks by highlighting either horizontal or
    vertical part of the image. Allow showing the position precisely
    instead.

 src/ui/gamepad-view-configuration.vala |  9 +++++++++
 src/ui/gamepad-view.vala               | 37 +++++++++++++++++++++++++++++++---
 2 files changed, 43 insertions(+), 3 deletions(-)
---
diff --git a/src/ui/gamepad-view-configuration.vala b/src/ui/gamepad-view-configuration.vala
index 8f3fdb52..cd65e24f 100644
--- a/src/ui/gamepad-view-configuration.vala
+++ b/src/ui/gamepad-view-configuration.vala
@@ -30,9 +30,17 @@ namespace Games {
                string path;
        }
 
+       private struct GamepadAnalogPath {
+               GamepadInput input_x;
+               GamepadInput input_y;
+               double offset_radius;
+               string path;
+       }
+
        private struct GamepadViewConfiguration {
                string svg_path;
                GamepadButtonPath[] button_paths;
+               GamepadAnalogPath[] analog_paths;
                string[] background_paths;
 
                public static GamepadViewConfiguration get_default () {
@@ -40,6 +48,7 @@ namespace Games {
 
                        conf.svg_path = "/org/gnome/Games/gamepads/standard-gamepad.svg";
                        conf.button_paths = STANDARD_GAMEPAD_BUTTON_PATHS;
+                       conf.analog_paths = {};
                        conf.background_paths = {};
 
                        return conf;
diff --git a/src/ui/gamepad-view.vala b/src/ui/gamepad-view.vala
index d986d764..8bbd886a 100644
--- a/src/ui/gamepad-view.vala
+++ b/src/ui/gamepad-view.vala
@@ -3,6 +3,8 @@
 private class Games.GamepadView : Gtk.DrawingArea {
        private struct InputState {
                bool highlight;
+               double offset_x;
+               double offset_y;
        }
 
        private Rsvg.Handle handle;
@@ -44,6 +46,13 @@ private class Games.GamepadView : Gtk.DrawingArea {
                                input_state[path.path] = {};
                        }
 
+                       foreach (var path in configuration.analog_paths) {
+                               if (path.path in input_state)
+                                       continue;
+
+                               input_state[path.path] = {};
+                       }
+
                        reset ();
                }
        }
@@ -72,6 +81,8 @@ private class Games.GamepadView : Gtk.DrawingArea {
        public void reset () {
                input_state.foreach ((path, state) => {
                        state.highlight = false;
+                       state.offset_x = 0;
+                       state.offset_y = 0;
                });
 
                queue_draw ();
@@ -92,6 +103,24 @@ private class Games.GamepadView : Gtk.DrawingArea {
                return false;
        }
 
+       public bool set_analog (GamepadInput input, double value) {
+               foreach (var path in configuration.analog_paths) {
+                       if (input != path.input_x && input != path.input_y)
+                               continue;
+
+                       if (input == path.input_x)
+                               input_state[path.path].offset_x = value * path.offset_radius;
+                       else
+                               input_state[path.path].offset_y = value * path.offset_radius;
+
+                       queue_draw ();
+
+                       return true;
+               }
+
+               return false;
+       }
+
        public override bool draw (Cairo.Context context) {
                double x, y, scale;
                calculate_image_dimensions (out x, out y, out scale);
@@ -103,7 +132,7 @@ private class Games.GamepadView : Gtk.DrawingArea {
                        Gdk.RGBA color;
                        get_style_context ().lookup_color ("theme_fg_color", out color);
 
-                       draw_path (context, path, color);
+                       draw_path (context, path, color, 0, 0);
                }
 
                input_state.for_each ((path, state) => {
@@ -112,15 +141,17 @@ private class Games.GamepadView : Gtk.DrawingArea {
                        Gdk.RGBA color;
                        get_style_context ().lookup_color (color_name, out color);
 
-                       draw_path (context, path, color);
+                       draw_path (context, path, color, state.offset_x, state.offset_y);
                });
 
                return false;
        }
 
-       private void draw_path (Cairo.Context context, string path, Gdk.RGBA color) {
+       private void draw_path (Cairo.Context context, string path, Gdk.RGBA color, double offset_x, double 
offset_y) {
                context.push_group ();
 
+               context.translate (offset_x, offset_y);
+
                handle.render_cairo_sub (context, @"#$path");
                var group = context.pop_group ();