Add fee slider class with network callback.

gui/qt/fee_slider.py

@@ -0,0 +1,43 @@
+from electrum.i18n import _
+
+import PyQt4
+from PyQt4.QtGui import *
+from PyQt4.QtCore import *
+import PyQt4.QtCore as QtCore
+
+class FeeSlider(QSlider):
+
+    def __init__(self, window, config, callback):
+        QSlider.__init__(self, Qt.Horizontal)
+        self.config = config
+        self.fee_step = self.config.max_fee_rate() / 10
+        self.window = window
+        self.callback = callback
+        self.setToolTip('')
+        self.update()
+        self.valueChanged.connect(self.moved)
+
+    def moved(self, pos):
+        from electrum.util import fee_levels
+        dyn = self.config.is_dynfee()
+        fee_rate = self.config.dynfee(pos) if dyn else pos * self.fee_step
+        rate_str = self.window.format_amount(fee_rate) + ' ' + self.window.base_unit() + '/kB'
+        if dyn:
+            tooltip = fee_levels[pos] + '\n' + rate_str
+        else:
+            tooltip = rate_str
+            if self.config.has_fee_estimates():
+                i = self.config.reverse_dynfee(fee_rate)
+                tooltip += '\n' + (_('low fee') if i < 0 else 'Within %d blocks'%i)
+        QToolTip.showText(QCursor.pos(), tooltip, self)
+        self.callback(dyn, pos, fee_rate)
+
+    def update(self):
+        if self.config.is_dynfee():
+            self.setRange(0, 4)
+            self.setValue(self.config.get('fee_level', 2))
+        else:
+            self.setRange(1, 10)
+            fee_rate = self.config.fee_per_kb()
+            pos = min(fee_rate / self.fee_step, 10)
+            self.setValue(pos)