windows: Add an ImageWin.

This adds an optional dependency on PIL.

poezio/windows/__init__.py

@@ -18,6 +18,7 @@ from poezio.windows.misc import VerticalSeparator
 from poezio.windows.muc import UserList, Topic
 from poezio.windows.roster_win import RosterWin, ContactInfoWin
 from poezio.windows.text_win import TextWin, XMLTextWin
+from poezio.windows.image import ImageWin
 
 __all__ = ['Win', 'FormWin', 'BookmarksWin', 'Dialog', 'GlobalInfoBar',
            'VerticalGlobalInfoBar', 'InfoWin', 'PrivateInfoWin', 'XMLInfoWin',
@@ -26,4 +27,4 @@ __all__ = ['Win', 'FormWin', 'BookmarksWin', 'Dialog', 'GlobalInfoBar',
            'BookmarksInfoWin', 'ConfirmStatusWin', 'HelpText', 'Input',
            'HistoryInput', 'MessageInput', 'CommandInput', 'ListWin',
            'ColumnHeaderWin', 'VerticalSeparator', 'UserList', 'Topic',
-           'RosterWin', 'ContactInfoWin', 'TextWin', 'XMLTextWin']
+           'RosterWin', 'ContactInfoWin', 'TextWin', 'XMLTextWin', 'ImageWin']

poezio/windows/image.py

@@ -0,0 +1,81 @@
+"""
+Defines a window which contains either an image or a border.
+"""
+
+import curses
+from io import BytesIO
+
+try:
+    from PIL import Image
+    HAS_PIL = True
+except ImportError:
+    HAS_PIL = False
+
+from poezio.windows.base_wins import Win
+from poezio.theming import to_curses_attr
+from poezio.xhtml import _parse_css_color
+
+class ImageWin(Win):
+    """
+    A window which contains either an image or a border.
+    """
+    def __init__(self):
+        self._image = None
+        Win.__init__(self)
+
+    def resize(self, height: int, width: int, y: int, x: int):
+        self._resize(height, width, y, x)
+        if self._image is None:
+            return
+        _display_avatar(width, height)
+
+    def refresh(self, data):
+        self._win.clear()
+        if data is None or not HAS_PIL:
+            self._image = None
+            self._display_border()
+        else:
+            image_file = BytesIO(data)
+            self._image = Image.open(image_file).convert('RGB')
+            self._display_avatar(self.width, self.height)
+        self._refresh()
+
+    def _display_border(self):
+        self._win.border(curses.ACS_VLINE, curses.ACS_VLINE,
+                         curses.ACS_HLINE, curses.ACS_HLINE,
+                         curses.ACS_ULCORNER, curses.ACS_URCORNER,
+                         curses.ACS_LLCORNER, curses.ACS_LRCORNER)
+
+    @staticmethod
+    def _compute_size(image_size, width: int, height: int):
+        height *= 2
+        src_width, src_height = image_size
+        ratio = src_width / src_height
+        new_width = height * ratio
+        new_height = width / ratio
+        if new_width > width:
+            height = int(new_height)
+        elif new_height > height:
+            width = int(new_width)
+        return width, height
+
+    def _display_avatar(self, width: int, height: int):
+        original_height = height
+        original_width = width
+        size = self._compute_size(self._image.size, width, height)
+        image2 = self._image.resize(size, resample=Image.BILINEAR)
+        data: bytes = image2.tobytes()
+        width, height = size
+        start_y = (original_height - height // 2) // 2
+        start_x = (original_width - width) // 2
+        for y in range(height // 2):
+            two_lines = data[(2 * y) * width * 3: (2 * y + 2) * width * 3]
+            line1 = two_lines[:width * 3]
+            line2 = two_lines[width * 3:]
+            self.move(start_y + y, start_x)
+            for x in range(width):
+                r, g, b = line1[x * 3: (x + 1) * 3]
+                top_color = _parse_css_color('#%02x%02x%02x' % (r, g, b))
+                r, g, b = line2[x * 3: (x + 1) * 3]
+                bot_color = _parse_css_color('#%02x%02x%02x' % (r, g, b))
+                self.addstr('▄', to_curses_attr((bot_color, top_color)))