[gnome-shell] levelBar: Factor out bar drawing

[Florian Müllner <fmuellner src gnome org>]

commit c90a4e48493072f02b87c2538b395b1549353b34
Author: Didier Roche <didrocks ubuntu com>
Date:   Thu Feb 8 19:04:42 2018 +0100

    levelBar: Factor out bar drawing
    
    Split drawing logic from Slider to BarLevel subclass.
    This changes part of the theme css from -slider- to -barlevel-.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=790280.

 data/theme/gnome-shell-sass/_common.scss |  12 +--
 js/js-resources.gresource.xml            |   1 +
 js/ui/barLevel.js                        | 131 +++++++++++++++++++++++++++++++
 js/ui/slider.js                          | 103 ++++--------------------
 4 files changed, 153 insertions(+), 94 deletions(-)
---
diff --git a/data/theme/gnome-shell-sass/_common.scss b/data/theme/gnome-shell-sass/_common.scss
index 594badc63..de107d7b7 100644
--- a/data/theme/gnome-shell-sass/_common.scss
+++ b/data/theme/gnome-shell-sass/_common.scss
@@ -128,12 +128,12 @@ StScrollBar {
 
 .slider {
   height: 1em;
-  -slider-height: 0.3em;
-  -slider-background-color: $insensitive_bg_color; //background of the trough
-  -slider-border-color: $borders_color; //trough border color
-  -slider-active-background-color: $selected_bg_color; //active trough fill
-  -slider-active-border-color: darken($selected_bg_color,10%); //active trough border
-  -slider-border-width: 1px;
+  -barlevel-height: 0.3em;
+  -barlevel-background-color: $insensitive_bg_color; //background of the trough
+  -barlevel-border-color: $borders_color; //trough border color
+  -barlevel-active-background-color: $selected_bg_color; //active trough fill
+  -barlevel-active-border-color: darken($selected_bg_color,10%); //active trough border
+  -barlevel-border-width: 1px;
   -slider-handle-radius: 6px;
 }
 
diff --git a/js/js-resources.gresource.xml b/js/js-resources.gresource.xml
index cc1da4461..3c0feab60 100644
--- a/js/js-resources.gresource.xml
+++ b/js/js-resources.gresource.xml
@@ -43,6 +43,7 @@
     <file>ui/audioDeviceSelection.js</file>
     <file>ui/backgroundMenu.js</file>
     <file>ui/background.js</file>
+    <file>ui/barLevel.js</file>
     <file>ui/boxpointer.js</file>
     <file>ui/calendar.js</file>
     <file>ui/checkBox.js</file>
diff --git a/js/ui/barLevel.js b/js/ui/barLevel.js
new file mode 100644
index 000000000..c018ef31b
--- /dev/null
+++ b/js/ui/barLevel.js
@@ -0,0 +1,131 @@
+/* -*- mode: js2; js2-basic-offset: 4; indent-tabs-mode: nil -*- */
+
+const Atk = imports.gi.Atk;
+const Cairo = imports.cairo;
+const Clutter = imports.gi.Clutter;
+const Lang = imports.lang;
+const St = imports.gi.St;
+const Signals = imports.signals;
+
+var BarLevel = new Lang.Class({
+    Name: "BarLevel",
+
+    _init(value, params) {
+        if (isNaN(value))
+            // Avoid spreading NaNs around
+            throw TypeError('The bar level value must be a number');
+        this._value = Math.max(Math.min(value, 1), 0);
+        this._barLevelWidth = 0;
+
+        if (params == undefined)
+            params = {}
+
+        this.actor = new St.DrawingArea({ styleClass: params['styleClass'] || 'barlevel',
+                                          can_focus: params['canFocus'] || false,
+                                          reactive: params['reactive'] || false,
+                                          accessible_role: params['accessibleRole'] || Atk.Role.LEVEL_BAR });
+        this.actor.connect('repaint', this._barLevelRepaint.bind(this));
+        this.actor.connect('allocation-changed', (actor, box) => {
+            this._barLevelWidth = box.get_width();
+        });
+
+        this._customAccessible = St.GenericAccessible.new_for_actor(this.actor);
+        this.actor.set_accessible(this._customAccessible);
+
+        this._customAccessible.connect('get-current-value', this._getCurrentValue.bind(this));
+        this._customAccessible.connect('get-minimum-value', this._getMinimumValue.bind(this));
+        this._customAccessible.connect('get-maximum-value', this._getMaximumValue.bind(this));
+        this._customAccessible.connect('set-current-value', this._setCurrentValue.bind(this));
+
+        this.connect('value-changed', this._valueChanged.bind(this));
+    },
+
+    setValue(value) {
+        if (isNaN(value))
+            throw TypeError('The bar level value must be a number');
+
+        this._value = Math.max(Math.min(value, 1), 0);
+        this.actor.queue_repaint();
+    },
+
+    _barLevelRepaint(area) {
+        let cr = area.get_context();
+        let themeNode = area.get_theme_node();
+        let [width, height] = area.get_surface_size();
+
+        let barLevelHeight = themeNode.get_length('-barlevel-height');
+        let barLevelBorderRadius = Math.min(width, barLevelHeight) / 2;
+        let fgColor = themeNode.get_foreground_color();
+
+        let barLevelColor = themeNode.get_color('-barlevel-background-color');
+        let barLevelActiveColor = themeNode.get_color('-barlevel-active-background-color');
+
+        let barLevelBorderWidth = themeNode.get_length('-barlevel-border-width');
+        let barLevelBorderColor = themeNode.get_color('-barlevel-border-color');
+        let barLevelActiveBorderColor = themeNode.get_color('-barlevel-active-border-color');
+
+        const TAU = Math.PI * 2;
+
+        let endX = barLevelBorderRadius + (width - 2 * barLevelBorderRadius) * this._value;
+
+        /* background bar */
+        cr.arc(width - barLevelBorderRadius - barLevelBorderWidth, height / 2, barLevelBorderRadius, TAU * 3 
/ 4, TAU * 1 / 4);
+        cr.lineTo(endX, (height + barLevelHeight) / 2);
+        cr.lineTo(endX, (height - barLevelHeight) / 2);
+        cr.lineTo(width - barLevelBorderRadius - barLevelBorderWidth, (height - barLevelHeight) / 2);
+        Clutter.cairo_set_source_color(cr, barLevelColor);
+        cr.fillPreserve();
+        Clutter.cairo_set_source_color(cr, barLevelBorderColor);
+        cr.setLineWidth(barLevelBorderWidth);
+        cr.stroke();
+
+        /* normal progress bar */
+        cr.arc(barLevelBorderRadius + barLevelBorderWidth, height / 2, barLevelBorderRadius, TAU * 1 / 4, 
TAU * 3 / 4);
+        cr.lineTo(endX, (height - barLevelHeight) / 2);
+        cr.lineTo(endX, (height + barLevelHeight) / 2);
+        cr.lineTo(barLevelBorderRadius + barLevelBorderWidth, (height + barLevelHeight) / 2);
+        Clutter.cairo_set_source_color(cr, barLevelActiveColor);
+        cr.fillPreserve();
+        Clutter.cairo_set_source_color(cr, barLevelActiveBorderColor);
+        cr.setLineWidth(barLevelBorderWidth);
+        cr.stroke();
+
+        /* end progress bar arc */
+        Clutter.cairo_set_source_color(cr, barLevelActiveColor);
+        cr.arc(endX, height / 2, barLevelBorderRadius, TAU * 3 / 4, TAU * 1 / 4);
+        cr.lineTo(Math.floor(endX), (height + barLevelHeight) / 2);
+        cr.lineTo(Math.floor(endX), (height - barLevelHeight) / 2);
+        cr.lineTo(endX, (height - barLevelHeight) / 2);
+        cr.fillPreserve();
+        cr.setLineWidth(barLevelBorderWidth);
+        cr.stroke();
+
+        cr.$dispose();
+    },
+
+    _getCurrentValue(actor) {
+        return this._value;
+    },
+
+    _getMinimumValue(actor) {
+        return 0;
+    },
+
+    _getMaximumValue(actor) {
+        return 1;
+    },
+
+    _setCurrentValue(actor, value) {
+        this._value = value;
+    },
+
+    _valueChanged(barLevel, value, property) {
+        this._customAccessible.notify("accessible-value");
+    },
+
+    get value() {
+        return this._value;
+    }
+});
+
+Signals.addSignalMethods(BarLevel.prototype);
diff --git a/js/ui/slider.js b/js/ui/slider.js
index 9853929eb..c1e2ea6a6 100644
--- a/js/ui/slider.js
+++ b/js/ui/slider.js
@@ -7,55 +7,38 @@ const Lang = imports.lang;
 const St = imports.gi.St;
 const Signals = imports.signals;
 
+const BarLevel = imports.ui.barLevel;
+
 var SLIDER_SCROLL_STEP = 0.02; /* Slider scrolling step in % */
 
 var Slider = new Lang.Class({
     Name: "Slider",
+    Extends: BarLevel.BarLevel,
 
     _init(value) {
-        if (isNaN(value))
-            // Avoid spreading NaNs around
-            throw TypeError('The slider value must be a number');
-        this._value = Math.max(Math.min(value, 1), 0);
-        this._sliderWidth = 0;
-
-        this.actor = new St.DrawingArea({ style_class: 'slider',
-                                          can_focus: true,
-                                          reactive: true,
-                                          accessible_role: Atk.Role.SLIDER });
-        this.actor.connect('repaint', this._sliderRepaint.bind(this));
+        let params = {
+            styleClass: 'slider',
+            canFocus: true,
+            reactive: true,
+            accessibleRole: Atk.Role.SLIDER,
+        }
+        this.parent(value, params)
+
         this.actor.connect('button-press-event', this._startDragging.bind(this));
         this.actor.connect('touch-event', this._touchDragging.bind(this));
         this.actor.connect('scroll-event', this._onScrollEvent.bind(this));
         this.actor.connect('key-press-event', this.onKeyPressEvent.bind(this));
-        this.actor.connect('allocation-changed', (actor, box) => {
-            this._sliderWidth = box.get_width();
-        });
 
         this._releaseId = this._motionId = 0;
         this._dragging = false;
 
-        this._customAccessible = St.GenericAccessible.new_for_actor(this.actor);
-        this.actor.set_accessible(this._customAccessible);
-
-        this._customAccessible.connect('get-current-value', this._getCurrentValue.bind(this));
-        this._customAccessible.connect('get-minimum-value', this._getMinimumValue.bind(this));
-        this._customAccessible.connect('get-maximum-value', this._getMaximumValue.bind(this));
         this._customAccessible.connect('get-minimum-increment', this._getMinimumIncrement.bind(this));
-        this._customAccessible.connect('set-current-value', this._setCurrentValue.bind(this));
-
-        this.connect('value-changed', this._valueChanged.bind(this));
     },
 
-    setValue(value) {
-        if (isNaN(value))
-            throw TypeError('The slider value must be a number');
-
-        this._value = Math.max(Math.min(value, 1), 0);
-        this.actor.queue_repaint();
-    },
+    _barLevelRepaint(area) {
+        this.parent(area);
 
-    _sliderRepaint(area) {
+        // Add handle
         let cr = area.get_context();
         let themeNode = area.get_theme_node();
         let [width, height] = area.get_surface_size();
@@ -66,41 +49,9 @@ var Slider = new Lang.Class({
         let [hasHandleColor, handleBorderColor] =
             themeNode.lookup_color('-slider-handle-border-color', false);
 
-        let sliderHeight = themeNode.get_length('-slider-height');
-
-        let sliderBorderWidth = themeNode.get_length('-slider-border-width');
-        let sliderBorderRadius = Math.min(width, sliderHeight) / 2;
-
-        let sliderBorderColor = themeNode.get_color('-slider-border-color');
-        let sliderColor = themeNode.get_color('-slider-background-color');
-
-        let sliderActiveBorderColor = themeNode.get_color('-slider-active-border-color');
-        let sliderActiveColor = themeNode.get_color('-slider-active-background-color');
-
         const TAU = Math.PI * 2;
 
         let handleX = handleRadius + (width - 2 * handleRadius) * this._value;
-
-        cr.arc(sliderBorderRadius + sliderBorderWidth, height / 2, sliderBorderRadius, TAU * 1/4, TAU * 3/4);
-        cr.lineTo(handleX, (height - sliderHeight) / 2);
-        cr.lineTo(handleX, (height + sliderHeight) / 2);
-        cr.lineTo(sliderBorderRadius + sliderBorderWidth, (height + sliderHeight) / 2);
-        Clutter.cairo_set_source_color(cr, sliderActiveColor);
-        cr.fillPreserve();
-        Clutter.cairo_set_source_color(cr, sliderActiveBorderColor);
-        cr.setLineWidth(sliderBorderWidth);
-        cr.stroke();
-
-        cr.arc(width - sliderBorderRadius - sliderBorderWidth, height / 2, sliderBorderRadius, TAU * 3/4, 
TAU * 1/4);
-        cr.lineTo(handleX, (height + sliderHeight) / 2);
-        cr.lineTo(handleX, (height - sliderHeight) / 2);
-        cr.lineTo(width - sliderBorderRadius - sliderBorderWidth, (height - sliderHeight) / 2);
-        Clutter.cairo_set_source_color(cr, sliderColor);
-        cr.fillPreserve();
-        Clutter.cairo_set_source_color(cr, sliderBorderColor);
-        cr.setLineWidth(sliderBorderWidth);
-        cr.stroke();
-
         let handleY = height / 2;
 
         let color = themeNode.get_foreground_color();
@@ -246,7 +197,7 @@ var Slider = new Lang.Class({
         relX = absX - sliderX;
         relY = absY - sliderY;
 
-        let width = this._sliderWidth;
+        let width = this._barLevelWidth;
         let handleRadius = this.actor.get_theme_node().get_length('-slider-handle-radius');
 
         let newvalue;
@@ -261,33 +212,9 @@ var Slider = new Lang.Class({
         this.emit('value-changed', this._value);
     },
 
-    _getCurrentValue(actor) {
-        return this._value;
-    },
-
-    _getMinimumValue(actor) {
-        return 0;
-    },
-
-    _getMaximumValue(actor) {
-        return 1;
-    },
-
     _getMinimumIncrement(actor) {
         return 0.1;
     },
-
-    _setCurrentValue(actor, value) {
-        this._value = value;
-    },
-
-    _valueChanged(slider, value, property) {
-        this._customAccessible.notify ("accessible-value");
-    },
-
-    get value() {
-        return this._value;
-    }
 });
 
 Signals.addSignalMethods(Slider.prototype);