trezor.utils: rework split_words, use it in CipherKeyValue and Sign/Verify Message layouts

src/apps/common/signverify.py

@@ -1,5 +1,7 @@
 from ubinascii import hexlify
 from trezor.crypto.hashlib import sha256
+from trezor import ui
+from trezor.ui.text import TEXT_MARGIN_LEFT
 from trezor.utils import chunks, split_words
 from apps.common.hash_writer import HashWriter
 from apps.wallet.sign_tx.signing import write_varint
@@ -17,7 +19,7 @@ def message_digest(coin, message):
 def split_message(message):
     try:
         m = bytes(message).decode()
-        lines = split_words(m, 18)
+        lines = split_words(m, ui.WIDTH - 2 * TEXT_MARGIN_LEFT, metric=lambda x: ui.display.text_width(x, ui.NORMAL))
     except UnicodeError:
         m = hexlify(message)
         lines = chunks(m, 16)

src/apps/wallet/cipher_key_value.py

@@ -4,7 +4,8 @@ from trezor.crypto.aes import AES_CBC_Decrypt, AES_CBC_Encrypt
 from trezor.crypto.hashlib import sha512
 from trezor.messages.CipheredKeyValue import CipheredKeyValue
 from trezor.messages.FailureType import DataError
-from trezor.ui.text import Text
+from trezor.ui.text import Text, TEXT_MARGIN_LEFT
+from trezor.utils import split_words
 from apps.common import seed
 from apps.common.confirm import require_confirm
 
@@ -21,7 +22,8 @@ async def cipher_key_value(ctx, msg):
             title = 'Encrypt value'
         else:
             title = 'Decrypt value'
-        await require_confirm(ctx, Text(title, ui.ICON_DEFAULT, msg.key))
+        lines = split_words(msg.key, ui.WIDTH - 2 * TEXT_MARGIN_LEFT, metric=lambda x: ui.display.text_width(x, ui.NORMAL))
+        await require_confirm(ctx, Text(title, ui.ICON_DEFAULT, *lines))
 
     node = await seed.derive_node(ctx, msg.address_n)
     value = compute_cipher_key_value(msg, node.private_key())

src/apps/wallet/sign_message.py

@@ -34,5 +34,5 @@ async def sign_message(ctx, msg):
 
 async def confirm_sign_message(ctx, message):
     message = split_message(message)
-    content = Text('Sign message', ui.ICON_CONFIRM, ui.MONO, *message)
+    content = Text('Sign message', ui.ICON_CONFIRM, *message)
     await require_confirm(ctx, content)

src/trezor/utils.py

@@ -29,19 +29,16 @@ def chunks(items, size):
 
 
 def split_words(sentence, width, metric=len):
-    line = ''
+    line = []
-    for c in sentence:
+    for w in sentence.split(' '):
-        line += c
+        if not w:
-        if metric(line) >= width:
+            continue
-            c = line[-1]
+        if metric(' '.join(line + [w])) >= width:
-            if c == ' ':
+            yield ' '.join(line)
-                yield line
+            line = [w]
-                line = ''
+        else:
-            else:
+            line.append(w)
-                yield line[:-1] + '-'
+    yield ' '.join(line)
-                line = c
-    if line != '':
-        yield line
 
 
 def format_amount(amount, decimals):