A new design for the busy spinner

src/calibre/gui2/progress_indicator/__init__.py

@@ -1,17 +1,119 @@
 #!/usr/bin/env python2
-# vim:fileencoding=UTF-8:ts=4:sw=4:sta:et:sts=4:ai
-from __future__ import with_statement
+# vim:fileencoding=utf-8
+# License: GPLv3 Copyright: 2015, Kovid Goyal <kovid at kovidgoyal.net>
 
-__license__   = 'GPL v3'
-__copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
-__docformat__ = 'restructuredtext en'
+from __future__ import (unicode_literals, division, absolute_import,
+                        print_function)
 
+import math
+from PyQt5.Qt import (
+    Qt, QWidget, QSizePolicy, QSize, QRect, QConicalGradient, QPen, QBrush,
+    QPainter, QTimer
+)
 
-from calibre.constants import plugins
-pi, pi_error = plugins['progress_indicator']
+def draw_snake_spinner(painter, rect, angle, light, dark):
+    painter.setRenderHint(QPainter.Antialiasing)
 
-if pi_error:
-    raise RuntimeError('Failed to load the Progress Indicator plugin: '+\
-            pi_error)
+    if rect.width() > rect.height():
+        delta = (rect.width() - rect.height()) // 2
+        rect = rect.adjusted(delta, 0, -delta, 0)
+    elif rect.height() > rect.width():
+        delta = (rect.height() - rect.width()) // 2
+        rect = rect.adjusted(0, delta, 0, -delta)
+    disc_width = max(4, rect.width() // 10)
 
-ProgressIndicator = pi.QProgressIndicator
+    drawing_rect = QRect(rect.x() + disc_width, rect.y() + disc_width, rect.width() - 2 * disc_width, rect.height() - 2 *disc_width)
+    try:
+        angle_for_width = math.degrees(math.atan2(1.3 * disc_width, drawing_rect.width()))
+    except ZeroDivisionError:
+        angle_for_width = 5
+
+    gradient = QConicalGradient(drawing_rect.center(), angle - angle_for_width)
+    gradient.setColorAt(1, light)
+    gradient.setColorAt(0, dark)
+
+    painter.setPen(QPen(light, disc_width))
+    painter.drawArc(drawing_rect, 0, 360 * 16)
+    pen = QPen(QBrush(gradient), disc_width)
+    pen.setCapStyle(Qt.RoundCap)
+    painter.setPen(pen)
+    painter.drawArc(drawing_rect, angle * 16, (360 - 2 * angle_for_width) * 16)
+
+class ProgressSpinner(QWidget):
+
+    def __init__(self, parent=None, size=64, interval=10):
+        QWidget.__init__(self, parent)
+        self.setSizePolicy(QSizePolicy(
+            QSizePolicy.GrowFlag | QSizePolicy.ShrinkFlag, QSizePolicy.GrowFlag | QSizePolicy.ShrinkFlag))
+        self._size_hint = QSize(size, size)
+        self.timer = t = QTimer(self)
+        t.setInterval(interval)
+        self.timer.timeout.connect(self.tick)
+        self.loading_angle = 0
+        pal = self.palette()
+        self.dark = pal.color(pal.Text)
+        self.light = pal.color(pal.Window)
+
+    @property
+    def animation_interval(self):
+        return self.timer.interval()
+
+    @animation_interval.setter
+    def animation_interval(self, val):
+        self.timer.setInterval(val)
+
+    def heightForWidth(self, w):
+        return w
+
+    def set_colors(self, dark, light):
+        self.dark, self.light = dark, light
+        self.update()
+
+    def start(self):
+        self.loading_angle = 0
+        self.timer.start()
+        self.update()
+    startAnimation = start
+
+    def stop(self):
+        self.timer.stop()
+        self.loading_angle = 0
+        self.update()
+    stopAnimation = stop
+
+    @property
+    def is_animated(self):
+        return self.timer.isActive()
+
+    @is_animated.setter
+    def is_animated(self, val):
+        (self.start if val else self.stop)()
+
+    def isAnimated(self):
+        return self.is_animated
+
+    def sizeHint(self):
+        return self._size_hint
+
+    def setSizeHint(self, val):
+        self._size_hint = val
+        self.update()
+    setDisplaySize = setSizeHint
+
+    def tick(self):
+        self.loading_angle -= 2
+        self.loading_angle %= 360
+        self.update()
+
+    def paintEvent(self, ev):
+        draw_snake_spinner(QPainter(self), self.rect(), self.loading_angle, self.light, self.dark)
+
+ProgressIndicator = ProgressSpinner
+if __name__ == '__main__':
+    from calibre.gui2 import Application
+    app = Application([])
+    w = ProgressSpinner()
+    w.show()
+    w.start()
+    app.exec_()
+    del app