feat: animate the filler widgets

CHANGELOG

@@ -1,6 +1,6 @@
 21.3
 * add widget for displaying memory (RAM) status
-* randomly hide filler widgets
+* animate filler widgets
 
 21.2
 * add linking for systems with /usr/lib64 instead of /usr/lib

src/nativeMain/kotlin/de/atennert/lcarsde/statusbar/FillerAnimation.kt

@@ -0,0 +1,48 @@
+package de.atennert.lcarsde.statusbar
+
+import de.atennert.lcarsde.statusbar.widgets.StatusFillerWidget
+import kotlinx.coroutines.*
+import kotlin.random.Random
+
+/**
+ * Controls the update/animation lifecycle for all filler widgets.
+ */
+class FillerAnimation {
+
+    private val fillerWidgets = mutableListOf<StatusFillerWidget>()
+
+    private var updateJob: Job? = null
+
+    private val minimalSwitchDelay = 2_000L // ms
+    private val maximalSwitchDelay = 10_000L // ms
+
+    fun addFillerWidget(fillerWidget: StatusFillerWidget) {
+        fillerWidgets.add(fillerWidget)
+    }
+
+    fun clearWidgets() {
+        fillerWidgets.clear()
+    }
+
+    private fun animateFiller() {
+        val widget = fillerWidgets.randomOrNull() ?: return
+
+        widget.update()
+    }
+
+    fun startAnimation() {
+        fillerWidgets.forEach(StatusFillerWidget::start)
+        updateJob = GlobalScope.launch(Dispatchers.Unconfined) {
+            while (true) {
+                delay(Random.nextLong(minimalSwitchDelay, maximalSwitchDelay))
+                animateFiller()
+            }
+        }
+    }
+
+    fun stopAnimation() {
+        updateJob?.cancel()
+        updateJob = null
+        fillerWidgets.forEach(StatusFillerWidget::stop)
+    }
+}

src/nativeMain/kotlin/de/atennert/lcarsde/statusbar/StatusBar.kt

@@ -38,6 +38,7 @@ class StatusBar {
         private val widgetFactory = WidgetFactory(cssProvider)
 
         private var widgets = emptyList<StatusWidget>()
+        private val fillerAnimation = FillerAnimation()
 
         private var currentWidth = 40 // px
         private var initialized = false
@@ -70,6 +71,7 @@ class StatusBar {
             val (horizontalCells, leftOverPixels) = getCellsAndOverflow()
             if (initialized) {
                 stop()
+                fillerAnimation.clearWidgets()
 
                 for (i in 1..3) {
                     gtk_grid_remove_row(grid.reinterpret(), 0)
@@ -153,6 +155,7 @@ class StatusBar {
                     val configuration = WidgetConfiguration("", 0, 0, 2, 1)
                             .withAddedPx(addedPixelsPerFiller[col])
                     val filler = StatusFillerWidget(configuration, cssProvider)
+                    fillerAnimation.addFillerWidget(filler)
                     gtk_grid_attach(grid.reinterpret(), filler.widget, col * 2, row, 2, 1)
                 }
             }
@@ -171,9 +174,11 @@ class StatusBar {
 
         private fun start() {
             widgets.forEach(StatusWidget::start)
+            fillerAnimation.startAnimation()
         }
 
         fun stop() {
+            fillerAnimation.stopAnimation()
             widgets.forEach(StatusWidget::stop)
         }
     }

src/nativeMain/kotlin/de/atennert/lcarsde/statusbar/widgets/StatusFillerWidget.kt

@@ -1,33 +1,104 @@
 package de.atennert.lcarsde.statusbar.widgets
 
 import de.atennert.lcarsde.statusbar.configuration.WidgetConfiguration
-import de.atennert.lcarsde.statusbar.extensions.setStyling
-import kotlinx.cinterop.CPointer
-import kotlinx.cinterop.reinterpret
+import de.atennert.lcarsde.statusbar.extensions.gSignalConnect
+import kotlinx.cinterop.*
 import statusbar.*
+import kotlin.math.PI
 import kotlin.random.Random
 
 class StatusFillerWidget(widgetConfiguration: WidgetConfiguration, cssProvider: CPointer<GtkCssProvider>)
     : StatusWidget(widgetConfiguration, cssProvider, null) {
 
+    private var ref: StableRef<StatusFillerWidget>? = null
+
+    private var lastColor = "123"
+
     init {
-        val text = "${Random.nextInt(10000)}".padStart(4, '0')
-        widget = gtk_label_new(text)!!
+        widget = gtk_drawing_area_new()!!
         gtk_widget_set_size_request(widget, widthPx, heightPx)
-        gtk_label_set_xalign(widget.reinterpret(), 1f)
-        gtk_label_set_yalign(widget.reinterpret(), 1f)
+    }
+
+    override fun start() {
+        ref = StableRef.create(this)
+
+        gSignalConnect(widget, "draw",
+            staticCFunction { _: CPointer<GtkWidget>, c: CPointer<cairo_t>, p: COpaquePointer -> draw(c, p) },
+            ref!!.asCPointer())
 
-        val colorIdx = Random.nextInt(colors.size)
-        val color = colors[colorIdx]
+        super.start()
 
-        widget.setStyling(cssProvider, "button--$color", "button--long")
+        update()
+    }
+
+    override fun stop() {
+        super.stop()
+
+        ref!!.dispose()
     }
 
     override fun update() {
-        // Nothing to do
+        gtk_widget_queue_draw(widget)
     }
 
     companion object {
         private val colors = arrayOf("c9c", "99c", "f96", "000")
+
+        private fun draw(context: CPointer<cairo_t>, ref: COpaquePointer) {
+            val widget = ref.asStableRef<StatusFillerWidget>().get()
+
+            val availableColors = colors.filterNot { it == widget.lastColor }
+            val colorIdx = Random.nextInt(availableColors.size)
+            val newColor = availableColors[colorIdx]
+            val text = "${Random.nextInt(10000)}".padStart(4, '0')
+            widget.lastColor = newColor
+
+            cairo_set_source_rgb(context, convertColor(newColor[0]), convertColor(newColor[1]), convertColor(newColor[2]))
+            createBorderPath(context, widget)
+            cairo_fill(context)
+
+            drawText(context, widget, text)
+        }
+
+        private fun convertColor(char: Char): Double {
+            return when(char) {
+                'f' -> 1.0
+                'c' -> 0.8
+                '9' -> 0.6
+                '6' -> 0.4
+                else -> 0.0
+            }
+        }
+
+        private fun createBorderPath(context: CPointer<cairo_t>, widget: StatusFillerWidget) {
+            cairo_arc(context, 20.0, 20.0, 20.0, 1.0 * PI, 1.5 * PI)
+            cairo_line_to(context, widget.widthPx - 20.0, 0.0)
+            cairo_arc(context, widget.widthPx - 20.0, 20.0, 20.0, 1.5 * PI, 2.0 * PI)
+            cairo_line_to(context, widget.widthPx.toDouble(), widget.heightPx - 20.0)
+            cairo_arc(context, widget.widthPx - 20.0, widget.heightPx - 20.0, 20.0, 0.0 * PI, 0.5 * PI)
+            cairo_line_to(context, 20.0, widget.heightPx.toDouble())
+            cairo_arc(context, 20.0, widget.heightPx - 20.0, 20.0, 0.5 * PI, 1.0 * PI)
+            cairo_close_path(context)
+        }
+
+        private fun drawText(context: CPointer<cairo_t>, widget: StatusFillerWidget, text: String) {
+            cairo_set_source_rgb(context, 0.0, 0.0, 0.0)
+            val layout = pango_cairo_create_layout(context)!!
+
+            val fontDescription = pango_font_description_from_string("Ubuntu Condensed, 12")
+            pango_layout_set_font_description(layout, fontDescription)
+            pango_layout_set_text(layout, text, text.length)
+
+            val layoutSize = IntArray(2)
+            pango_layout_get_size(layout, layoutSize.refTo(0), layoutSize.refTo(1))
+            cairo_move_to(context,
+                widget.widthPx - (layoutSize[0].toFloat() / 1024.0) - 16,
+                widget.heightPx - (layoutSize[1].toFloat() / 1024.0)
+            )
+
+            pango_cairo_show_layout(context, layout)
+            pango_font_description_free(fontDescription)
+            g_object_unref(layout)
+        }
     }
 }