Merge pull request #125 from naraesk/master

#51 Positioning relative to other slide

CHANGES.txt

@@ -4,12 +4,13 @@ Changes
 2.4 (unreleased)
 ----------------
 
+- #51: Positioning relative to other slide [naraesk]
+
 - Removed the code that uses pkg_util to access included templates. We don't
   support installing Hovercraft as a ZIP file anyway, so it only complicates
   things for no good reason.
 
 
-
 2.3 (2017-04-12)
 ----------------
 

README.rst

@@ -71,6 +71,8 @@ Other contributors (see CHANGES.txt for details):
 
 * Adam Johnson [adamchainz]
 
+* David Baum [naraesk]
+
 .. _impress.js: http://github.com/bartaz/impress.js
 .. _demo: http://regebro.github.com/hovercraft
 .. _readthedocs.org: https://hovercraft.readthedocs.io/

docs/examples/positions.rst

@@ -88,9 +88,10 @@ So here we rotated 90 degrees and zoomed out five times.
 :data-scale: 1
 :data-x: 4000
 :data-y: 2000
+:id: positions_last_slide
 
-Relative positions
-==================
+Relative positions to last slide
+================================
 
 One thing that *is* a problem is the absolute positioning. All the positions
 we used so far above are in relation to the start of the coordinate system.
@@ -105,6 +106,8 @@ relative coordinate to the last slide.
 
 :data-x: r1000
 
+----
+
 Like this
 =========
 
@@ -121,12 +124,23 @@ to use relative positioning.
 
 ----
 
+:data-y: positions_last_slide+1000
+
+Relative positions to any slide
+===============================
+
+You can reference any *previous* slide by its id and specify the position relative to it.
+This will work for all fields.
+However, you should not use ``r`` as a slide id since the positioning might not behave as you expect. 
+
+----
+
 :data-rotate: r15
 
 Automatic positioning
 =====================
 
-Every field will retain it's last value if you don't specify a new one.
+Every field will retain its last value if you don't specify a new one.
 In this case, we keep a r1000 value for data-x and introduce a new
 r15 value for data-rotate. This and the next slide will therefore
 move right 1000 pixels and rotate 15 degrees more for each slide.
@@ -135,6 +149,7 @@ It looks like it moves "up" because we are already rotated 90 degrees.
 
 ----
 
+:data-x: r1000
 :data-scale: 0.15
 
 **A warning!**

docs/introduction.rst

@@ -66,10 +66,15 @@ There are four ways to position slides:
  #. Absolute positioning: You simply add X and Y coordinates to a slide,
     in pixels. Doing only this will not be fun, but someone might need it.
 
- #. Relative positioning: By specifying x and/or y with with a starting r,
-    you specify the distance from the previous slide. By using this form of
-    positioning you can insert a slide, and the other slides will just move
-    to make space for the new slide.
+ #. Relative positioning to last slide: By specifying x and/or y with with
+    a starting r,you specify the distance from the previous slide. By using
+    this form of positioning you can insert a slide, and the other slides 
+    will just move to make space for the new slide.
+
+ #. Relative positiong to any slide: You can reference any *previous* slide
+    by its id and specify the position relative to it. This will work for
+    all positioning fields. However, you should not use ``r`` as a slide id
+    since the positioning might not behave as you expect. 
 
  #. Automatically: If you don’t specify any position the slide will have the
     same settings as the previous slide. With a relative positioning, this

hovercraft/position.py

@@ -110,11 +110,21 @@ def _update_position(pos1, pos2):
     for key in POSITION_ATTRIBS:
         val = pos2.get(key)
         if val is not None:
-            if val[0] == 'r':
-                # Relative movement
-                newval = pos1[key] + num(val[1:])
+            plus = val.find("+")
+            minus = val.find("-")
+            if plus > -1:
+                newval = num(val[plus+1:])
+                pos1[key + "-rel"] = val[0:plus]
+            elif minus > -1 and not val.startswith("r-"):
+                newval = num(val[minus:])
+                pos1[key + "-rel"] = val[0:minus]
             else:
-                newval = num(val)
+                if val[0] == 'r':
+                # Relative movement
+                    newval = pos1[key] + num(val[1:])
+                else:
+                    newval = num(val)
+                    pos1.pop(key+"-rel",  None)
             pos1[key] = newval
 
 
@@ -211,15 +221,26 @@ def update_positions(tree, positions):
 
     for step, pos in zip(tree.findall('step'), positions):
         for key in sorted(pos):
-            step.attrib[key] = str(pos[key])
+            value = pos.get(key)
+            if key.endswith("-rel"):
+                abs_key = key[:key.index("-rel")]
+                if value is not None:
+                    els = tree.findall(".//*[@id='" + value + "']")
+                    for el in els :
+                        pos[abs_key] = num(el.get(abs_key)) + pos.get(abs_key)
+                        print(num(el.get(abs_key)))
+                        print(pos.get(abs_key))
+                        step.attrib[abs_key] = str(pos.get(abs_key))
+            else: 
+                step.attrib[key] = str(pos[key])
 
         if 'hovercraft-path' in step.attrib:
             del step.attrib['hovercraft-path']
 
 
 def position_slides(tree):
     """Position the slides in the tree"""
-
+    
     positions = gather_positions(tree)
     positions = calculate_positions(positions)
     update_positions(tree, positions)

hovercraft/tests/test_data/positioning.rst

@@ -60,5 +60,18 @@ Move in Z and rotate. Path continues to be used.
 
 :data-x: 3000
 :data-y: 1000
+:id: firstID
 
 Explicit position
+
+
+----
+
+:id: secondID
+:data-x: firstID+1000
+:data-y: firstID-500
+
+----
+
+:data-x: secondID+800
+:data-y: 200

hovercraft/tests/test_position.py

@@ -63,6 +63,12 @@ def test_gathering(self):
             {'data-x': '3000', 'data-y': '1000', 'data-z': 'r0',
              'data-rotate-x': 'r0', 'data-rotate-y': 'r0',
              'data-rotate-z': 'r0', 'data-scale': 'r0', 'is_path': False},
+             {'data-x': 'firstID+1000', 'data-y': 'firstID-500', 'data-z': 'r0',
+             'data-rotate-x': 'r0', 'data-rotate-y': 'r0',
+             'data-rotate-z': 'r0', 'data-scale': 'r0', 'is_path': False},
+             {'data-x': 'secondID+800', 'data-y': '200', 'data-z': 'r0',
+             'data-rotate-x': 'r0', 'data-rotate-y': 'r0',
+             'data-rotate-z': 'r0', 'data-scale': 'r0', 'is_path': False}
         ])
 
 
@@ -390,6 +396,14 @@ def test_complete(self):
             {'data-x': '3000', 'data-y': '1000', 'data-z': '1000',
              'data-rotate-x': '180', 'data-rotate-y': '0',
              'data-rotate-z': '90.0', 'data-scale': '1'},
+            # Positioning relative to other slide by id
+            {'data-x': '4000', 'data-y': '500', 'data-z': '1000',
+             'data-rotate-x': '180', 'data-rotate-y': '0',
+             'data-rotate-z': '90.0', 'data-scale': '1'},
+            # Positioning x relative to other slide by id, Explicit y
+            {'data-x': '4800', 'data-y': '200', 'data-z': '1000',
+             'data-rotate-x': '180', 'data-rotate-y': '0',
+             'data-rotate-z': '90.0', 'data-scale': '1'},
         ])