Allow scaling of images

3 files changed, 57 insertions, 3 deletions

diff --git a/example/demo.rst b/example/demo.rst
index c105e7d..e202bc2 100644
--- a/example/demo.rst
+++ b/example/demo.rst
@@ -154,3 +154,15 @@ Images
 .. image:: gg.jpg
 
 "Golden Gate Bridge" by Kevin Cole (CC-BY: https://flic.kr/p/7L2Rdu)
+
+Scaling Images
+==============
+.. container:: handout
+
+   You can also give the image directive a scale parameter to scale the image.
+   the image will be centered within the slide.
+
+.. image:: gg.jpg
+   :scale: 75
+
+"Golden Gate Bridge" by Kevin Cole (CC-BY: https://flic.kr/p/7L2Rdu)
diff --git a/presentty/image.py b/presentty/image.py
index 9aabee8..d82face 100644
--- a/presentty/image.py
+++ b/presentty/image.py
@@ -32,13 +32,17 @@ def nearest_color(x):
     return 'f'
 
 class ANSIImage(urwid.Widget):
-    def __init__(self, uri, hinter=None):
+    def __init__(self, uri, hinter=None, scale=1, background=None):
         super(ANSIImage, self).__init__()
         self.uri = uri
         image = self._loadImage()
         self.htmlparser = HTMLParser.HTMLParser()
         self.ratio = float(image.size[0])/float(image.size[1])
         self.hinter = hinter
+        if scale > 1:
+            scale = 1
+        self.scale = scale
+        self.background = background or 'black'
 
     def _loadImage(self):
         image = PIL.Image.open(self.uri)
@@ -81,7 +85,18 @@ class ANSIImage(urwid.Widget):
     def render(self, size, focus=False):
         spanre = self.SPAN_RE
         htmlparser = self.htmlparser
-        width, height = self.pack(size, focus)
+
+        # Calculate image size and any bounding box
+        total_width, total_height = self.pack(size, focus)
+        width, height = self.pack([s * self.scale for s in size], focus)
+        width = int(width)
+        height = int(height)
+        top_pad = (total_height - height) // 2
+        bottom_pad = total_height - height - top_pad
+        left_pad = (total_width - width) // 2
+        right_pad = total_width - width - left_pad
+        padding_attr = urwid.AttrSpec(self.background, self.background)
+
         jp2a = subprocess.Popen(['jp2a', '--colors', '--fill',
                                  '--width=%s' % width,
                                  '--height=%s' % height,
@@ -104,10 +119,23 @@ class ANSIImage(urwid.Widget):
         current_fg = None
         current_bg = None
         current_props = None
+
+        # Top pad
+        for padding in range(0, top_pad):
+            line_list.append(' ' * total_width)
+            attr_list.append([(padding_attr, 1)] * total_width)
+
         for line in data.split('<br/>'):
             if not line:
                 continue
+
+            # Left pad
+            line_text += ' ' * left_pad
+            for fake_attr in range(0, left_pad):
+                line_attrs.append((padding_attr, 1))
+
             for span in line.split('</span>'):
+
                 if not span:
                     continue
                 m = spanre.match(span)
@@ -141,10 +169,22 @@ class ANSIImage(urwid.Widget):
             current_attr = [None, 0]
             current_fg = None
             current_bg = None
+
+            # Right pad
+            line_text += ' ' * right_pad
+            for fake_attr in range(0, right_pad):
+                line_attrs.append((padding_attr, 1))
+
             line_list.append(line_text)
             line_text = ''
             attr_list.append(line_attrs)
             line_attrs = []
+
+        # Bottom pad
+        for padding in range(0, bottom_pad):
+            line_list.append(' ' * total_width)
+            attr_list.append([(padding_attr, 1)] * total_width)
+
         canvas = urwid.TextCanvas(line_list, attr_list)
         return canvas
 
diff --git a/presentty/rst.py b/presentty/rst.py
index 8368a6a..3c55f1e 100644
--- a/presentty/rst.py
+++ b/presentty/rst.py
@@ -306,8 +306,10 @@ class UrwidTranslator(docutils.nodes.GenericNodeVisitor):
         if not PIL:
             return
         uri = node['uri']
+        scale = float(node.get('scale', 100))/100.0
         fn = os.path.join(self.basedir, uri)
-        w = image.ANSIImage(fn, self.hinter)
+        w = image.ANSIImage(fn, self.hinter, scale=scale,
+                background=self.palette['_default'].background)
         self._append(node, w, 'pack')
 
     def visit_ansi(self, node):