Merge pull request #480 from trezor/tsusanka/numpad

NumPad to enter a number from arbitrary range easily

src/trezor/ui/num_pad.py

@@ -0,0 +1,47 @@
+from trezor import ui
+from trezor.ui import display
+from trezor.ui.button import BTN_CLICKED, Button
+
+ITEMS_PER_PAGE = 11
+
+
+def digit_area(i):
+    return ui.grid(i + 3)  # skip the first line
+
+
+class NumPad(ui.Widget):
+    def __init__(self, label: str, start: int, end: int):
+        """
+        Generates a numpad with numbers from `start` to `end` excluding.
+        """
+        self.label = label
+        self.start = start
+        self.end = end
+        self.page = 0
+
+        self._generate_buttons()
+
+    def render(self):
+        for btn in self.buttons:
+            btn.render()
+
+        # header label
+        display.text_center(ui.WIDTH // 2, 36, self.label, ui.BOLD, ui.GREY, ui.BG)
+
+    def touch(self, event, pos):
+        for btn in self.buttons:
+            if btn.touch(event, pos) == BTN_CLICKED:
+                if "+" in btn.content:
+                    self.page += 1
+                    self._generate_buttons()
+                else:
+                    return btn.content
+
+    def _generate_buttons(self):
+        display.clear()  # we need to clear old buttons
+        start = self.start + (ITEMS_PER_PAGE + 1) * self.page - self.page
+        end = min(self.end, (ITEMS_PER_PAGE + 1) * (self.page + 1) - self.page)
+        digits = list(range(start, end))
+        if len(digits) == ITEMS_PER_PAGE:
+            digits.append(str(end) + "+")
+        self.buttons = [Button(digit_area(i), str(d)) for i, d in enumerate(digits)]