1 files changed, 153 insertions, 0 deletions

diff --git a/presentty/transition.py b/presentty/transition.py
new file mode 100644
index 0000000..9133629
--- /dev/null
+++ b/presentty/transition.py
@@ -0,0 +1,153 @@
+# Copyright (C) 2015 James E. Blair <corvus@gnu.org>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import urwid
+
+class Transition(urwid.Widget):
+    def __init__(self, duration=0.4):
+        super(Transition, self).__init__()
+        self.duration = 0.4
+        self.old = None
+        self.new = None
+        self.progress = 0.0
+
+    def getDuration(self):
+        return self.duration
+
+    def setTargets(self, old, new):
+        self.old = old
+        self.new = new
+        self.setProgress(0.0)
+
+    def setProgress(self, progress):
+        self.progress = progress
+        self._invalidate()
+
+class PanTransition(Transition):
+    def render(self, size, focus=False):
+        old = self.old.render((size[0], size[1]))
+        new = self.new.render((size[0], size[1]))
+        c = urwid.CanvasJoin([(old, None, False, size[0]),
+                              (new, None, False, size[0])])
+        #c = urwid.CanvasOverlay(new, old, 6, 0)
+        offset = int(size[0] * self.progress)
+        c.pad_trim_left_right(0-offset, 0-(size[0]-offset))
+        return c
+
+class DissolveTransition(Transition):
+    def __init__(self, *args, **kw):
+        super(DissolveTransition, self).__init__(*args, **kw)
+        self._oldbuf = None
+        self._newbuf = None
+        self._cache_size = None
+
+    def setTargets(self, old, new):
+        if old != self.old:
+            self._oldbuf = None
+            self._cache_size = None
+        if new != self.new:
+            self._newbuf = None
+            self._cache_size = None
+        super(DissolveTransition, self).setTargets(old, new)
+
+    def _to_buf(self, canvas):
+        buf = []
+        for line in canvas.content():
+            for (attr, cs, text) in line:
+                for char in unicode(text, 'utf8'):
+                    buf.append((attr, cs, char))
+        return buf
+
+    def render(self, size, focus=False):
+        if self._cache_size != size:
+            old = self.old.render((size[0], size[1]))
+            new = self.new.render((size[0], size[1]))
+            self._oldbuf = self._to_buf(old)
+            self._newbuf = self._to_buf(new)
+            self._cache_size = size
+        line_list = []
+        attr_list = []
+        line_text = ''
+        line_attrs = []
+        current_attr = [None, 0]
+        current_rgb = None
+        current_props = None
+        background = urwid.AttrSpec('light gray', 'black')
+        for i in range(len(self._oldbuf)):
+            oldattr, oldcs, oldchar = self._oldbuf[i]
+            newattr, newcs, newchar = self._newbuf[i]
+            oldrgb = oldattr.get_rgb_values()
+            newrgb = newattr.get_rgb_values()
+            if None in oldrgb:
+                oldrgb = background.get_rgb_values()
+            if None in newrgb:
+                newrgb = background.get_rgb_values()
+            if newchar == ' ':
+                char = oldchar
+                charattr = oldattr
+                newrgb = newrgb[3:]*2
+            elif oldchar == ' ':
+                char = newchar
+                charattr = newattr
+                oldrgb = oldrgb[3:]*2
+            elif self.progress >= 0.5:
+                char = newchar
+                charattr = newattr
+            else:
+                char = oldchar
+                charattr = oldattr
+            char = char.encode('utf8')
+            line_text += char
+            rgb = []
+            props = []
+            if charattr.bold:
+                props.append('bold')
+            if charattr.underline:
+                props.append('underline')
+            if charattr.standout:
+                props.append('standout')
+            if charattr.blink:
+                props.append('blink')
+            for x in range(len(oldrgb)):
+                rgb.append(int(((newrgb[x]-oldrgb[x])*self.progress)+oldrgb[x])>>4)
+            if current_rgb == rgb and current_props == props:
+                current_attr[1] += len(char)
+            else:
+                if current_attr[0]:
+                    line_attrs.append(tuple(current_attr))
+                fg = ', '.join(props + ['#%x%x%x' % tuple(rgb[:3])])
+                bg = '#%x%x%x' % tuple(rgb[3:])
+                attr = urwid.AttrSpec(fg, bg)
+                current_attr = [attr, len(char)]
+                current_rgb = rgb
+                current_props = props
+            if (i+1) % size[0] == 0:
+                line_attrs.append(tuple(current_attr))
+                current_attr = [None, 0]
+                current_rgb = None
+                line_list.append(line_text)
+                line_text = ''
+                attr_list.append(line_attrs)
+                line_attrs = []
+        canvas = urwid.TextCanvas(line_list, attr_list)
+        return canvas
+
+class CutTransition(Transition):
+    def __init__(self, *args, **kw):
+        super(CutTransition, self).__init__(*args, **kw)
+        self.duration = 0.0
+
+    def render(self, size, focus=False):
+        return self.new.render(size, focus)