From e5f383fbb5e3953d44b9767d3a73b32d2a32e480 Mon Sep 17 00:00:00 2001
From: Luke Campagnola <>
Date: Fri, 23 Nov 2012 16:01:25 -0500
Subject: [PATCH] Bugfixes and updates to functions.py:   - generalized
 makeARGB API: can now process arrays of arbitrary shape.   - affineSlice
 automatically converts vector arguments to array   - new function
 applyLookupTable taken from makeARGB   - isosurface function returns array
 Updated VideoSpeedTest example to follow new makeARGB API

LayoutWidget: row argument now accepts 'next' as value
ParameterTree bugfix: avoid infinite recursion when accessing non-existent attributes
ViewBox: avoid exit error caused when cleanup callback is invoked while python is shutting down
---
 examples/VideoSpeedTest.py       |  26 ++-
 examples/VideoTemplate.ui        |  10 +-
 examples/VideoTemplate_pyqt.py   |  14 +-
 examples/VideoTemplate_pyside.py |  14 +-
 functions.py                     | 367 ++++++++++++++++++-------------
 graphicsItems/GraphicsItem.py    |   8 +-
 graphicsItems/ViewBox/ViewBox.py |   4 +-
 parametertree/Parameter.py       |   7 +-
 widgets/LayoutWidget.py          |   7 +-
 9 files changed, 273 insertions(+), 184 deletions(-)

diff --git a/examples/VideoSpeedTest.py b/examples/VideoSpeedTest.py
index d51798bd..0a20e9cf 100644
--- a/examples/VideoSpeedTest.py
+++ b/examples/VideoSpeedTest.py
@@ -61,37 +61,41 @@ ui.alphaCheck.toggled.connect(updateLUT)
 def updateScale():
     global ui
     spins = [ui.minSpin1, ui.maxSpin1, ui.minSpin2, ui.maxSpin2, ui.minSpin3, ui.maxSpin3]
-    if ui.rgbCheck.isChecked():
+    if ui.rgbLevelsCheck.isChecked():
         for s in spins[2:]:
             s.setEnabled(True)
     else:
         for s in spins[2:]:
             s.setEnabled(False)
-ui.rgbCheck.toggled.connect(updateScale)
+ui.rgbLevelsCheck.toggled.connect(updateScale)
     
 cache = {}
 def mkData():
     global data, cache, ui
-    dtype = ui.dtypeCombo.currentText()
+    dtype = (ui.dtypeCombo.currentText(), ui.rgbCheck.isChecked())
     if dtype not in cache:
-        if dtype == 'uint8':
+        if dtype[0] == 'uint8':
             dt = np.uint8
             loc = 128
             scale = 64
             mx = 255
-        elif dtype == 'uint16':
+        elif dtype[0] == 'uint16':
             dt = np.uint16
             loc = 4096
             scale = 1024
             mx = 2**16
-        elif dtype == 'float':
+        elif dtype[0] == 'float':
             dt = np.float
             loc = 1.0
             scale = 0.1
         
-        data = np.random.normal(size=(20,512,512), loc=loc, scale=scale)
-        data = ndi.gaussian_filter(data, (0, 3, 3))
-        if dtype != 'float':
+        if ui.rgbCheck.isChecked():
+            data = np.random.normal(size=(20,512,512,3), loc=loc, scale=scale)
+            data = ndi.gaussian_filter(data, (0, 6, 6, 0))
+        else:
+            data = np.random.normal(size=(20,512,512), loc=loc, scale=scale)
+            data = ndi.gaussian_filter(data, (0, 6, 6))
+        if dtype[0] != 'float':
             data = np.clip(data, 0, mx)
         data = data.astype(dt)
         cache[dtype] = data
@@ -100,7 +104,7 @@ def mkData():
     updateLUT()
 mkData()
 ui.dtypeCombo.currentIndexChanged.connect(mkData)
-
+ui.rgbCheck.toggled.connect(mkData)
 
 ptr = 0
 lastTime = ptime.time()
@@ -113,7 +117,7 @@ def update():
         useLut = None
 
     if ui.scaleCheck.isChecked():
-        if ui.rgbCheck.isChecked():
+        if ui.rgbLevelsCheck.isChecked():
             useScale = [
                 [ui.minSpin1.value(), ui.maxSpin1.value()], 
                 [ui.minSpin2.value(), ui.maxSpin2.value()], 
diff --git a/examples/VideoTemplate.ui b/examples/VideoTemplate.ui
index 078e7ccf..3dddb928 100644
--- a/examples/VideoTemplate.ui
+++ b/examples/VideoTemplate.ui
@@ -25,7 +25,6 @@
           <verstretch>0</verstretch>
          </sizepolicy>
         </property>
-        <zorder>fpsLabel</zorder>
        </widget>
       </item>
       <item row="0" column="1">
@@ -84,7 +83,7 @@
      </widget>
     </item>
     <item row="3" column="1">
-     <widget class="QCheckBox" name="rgbCheck">
+     <widget class="QCheckBox" name="rgbLevelsCheck">
       <property name="text">
        <string>RGB</string>
       </property>
@@ -218,6 +217,13 @@
       </property>
      </widget>
     </item>
+    <item row="2" column="1">
+     <widget class="QCheckBox" name="rgbCheck">
+      <property name="text">
+       <string>RGB</string>
+      </property>
+     </widget>
+    </item>
    </layout>
   </widget>
  </widget>
diff --git a/examples/VideoTemplate_pyqt.py b/examples/VideoTemplate_pyqt.py
index 21e66635..c3430e2d 100644
--- a/examples/VideoTemplate_pyqt.py
+++ b/examples/VideoTemplate_pyqt.py
@@ -2,7 +2,7 @@
 
 # Form implementation generated from reading ui file './examples/VideoTemplate.ui'
 #
-# Created: Sun Sep  9 14:41:31 2012
+# Created: Sun Nov  4 18:24:20 2012
 #      by: PyQt4 UI code generator 4.9.1
 #
 # WARNING! All changes made in this file will be lost!
@@ -55,9 +55,9 @@ class Ui_MainWindow(object):
         self.scaleCheck = QtGui.QCheckBox(self.centralwidget)
         self.scaleCheck.setObjectName(_fromUtf8("scaleCheck"))
         self.gridLayout_2.addWidget(self.scaleCheck, 3, 0, 1, 1)
-        self.rgbCheck = QtGui.QCheckBox(self.centralwidget)
-        self.rgbCheck.setObjectName(_fromUtf8("rgbCheck"))
-        self.gridLayout_2.addWidget(self.rgbCheck, 3, 1, 1, 1)
+        self.rgbLevelsCheck = QtGui.QCheckBox(self.centralwidget)
+        self.rgbLevelsCheck.setObjectName(_fromUtf8("rgbLevelsCheck"))
+        self.gridLayout_2.addWidget(self.rgbLevelsCheck, 3, 1, 1, 1)
         self.horizontalLayout = QtGui.QHBoxLayout()
         self.horizontalLayout.setObjectName(_fromUtf8("horizontalLayout"))
         self.minSpin1 = SpinBox(self.centralwidget)
@@ -124,6 +124,9 @@ class Ui_MainWindow(object):
         self.fpsLabel.setAlignment(QtCore.Qt.AlignCenter)
         self.fpsLabel.setObjectName(_fromUtf8("fpsLabel"))
         self.gridLayout_2.addWidget(self.fpsLabel, 0, 0, 1, 4)
+        self.rgbCheck = QtGui.QCheckBox(self.centralwidget)
+        self.rgbCheck.setObjectName(_fromUtf8("rgbCheck"))
+        self.gridLayout_2.addWidget(self.rgbCheck, 2, 1, 1, 1)
         MainWindow.setCentralWidget(self.centralwidget)
 
         self.retranslateUi(MainWindow)
@@ -138,12 +141,13 @@ class Ui_MainWindow(object):
         self.dtypeCombo.setItemText(1, QtGui.QApplication.translate("MainWindow", "uint16", None, QtGui.QApplication.UnicodeUTF8))
         self.dtypeCombo.setItemText(2, QtGui.QApplication.translate("MainWindow", "float", None, QtGui.QApplication.UnicodeUTF8))
         self.scaleCheck.setText(QtGui.QApplication.translate("MainWindow", "Scale Data", None, QtGui.QApplication.UnicodeUTF8))
-        self.rgbCheck.setText(QtGui.QApplication.translate("MainWindow", "RGB", None, QtGui.QApplication.UnicodeUTF8))
+        self.rgbLevelsCheck.setText(QtGui.QApplication.translate("MainWindow", "RGB", None, QtGui.QApplication.UnicodeUTF8))
         self.label_2.setText(QtGui.QApplication.translate("MainWindow", "<--->", None, QtGui.QApplication.UnicodeUTF8))
         self.label_3.setText(QtGui.QApplication.translate("MainWindow", "<--->", None, QtGui.QApplication.UnicodeUTF8))
         self.label_4.setText(QtGui.QApplication.translate("MainWindow", "<--->", None, QtGui.QApplication.UnicodeUTF8))
         self.lutCheck.setText(QtGui.QApplication.translate("MainWindow", "Use Lookup  Table", None, QtGui.QApplication.UnicodeUTF8))
         self.alphaCheck.setText(QtGui.QApplication.translate("MainWindow", "alpha", None, QtGui.QApplication.UnicodeUTF8))
         self.fpsLabel.setText(QtGui.QApplication.translate("MainWindow", "FPS", None, QtGui.QApplication.UnicodeUTF8))
+        self.rgbCheck.setText(QtGui.QApplication.translate("MainWindow", "RGB", None, QtGui.QApplication.UnicodeUTF8))
 
 from pyqtgraph import SpinBox, GradientWidget, GraphicsView, RawImageWidget
diff --git a/examples/VideoTemplate_pyside.py b/examples/VideoTemplate_pyside.py
index 5cbce05c..d19e0f23 100644
--- a/examples/VideoTemplate_pyside.py
+++ b/examples/VideoTemplate_pyside.py
@@ -2,7 +2,7 @@
 
 # Form implementation generated from reading ui file './examples/VideoTemplate.ui'
 #
-# Created: Sun Sep  9 14:41:31 2012
+# Created: Sun Nov  4 18:24:21 2012
 #      by: pyside-uic 0.2.13 running on PySide 1.1.0
 #
 # WARNING! All changes made in this file will be lost!
@@ -50,9 +50,9 @@ class Ui_MainWindow(object):
         self.scaleCheck = QtGui.QCheckBox(self.centralwidget)
         self.scaleCheck.setObjectName("scaleCheck")
         self.gridLayout_2.addWidget(self.scaleCheck, 3, 0, 1, 1)
-        self.rgbCheck = QtGui.QCheckBox(self.centralwidget)
-        self.rgbCheck.setObjectName("rgbCheck")
-        self.gridLayout_2.addWidget(self.rgbCheck, 3, 1, 1, 1)
+        self.rgbLevelsCheck = QtGui.QCheckBox(self.centralwidget)
+        self.rgbLevelsCheck.setObjectName("rgbLevelsCheck")
+        self.gridLayout_2.addWidget(self.rgbLevelsCheck, 3, 1, 1, 1)
         self.horizontalLayout = QtGui.QHBoxLayout()
         self.horizontalLayout.setObjectName("horizontalLayout")
         self.minSpin1 = SpinBox(self.centralwidget)
@@ -119,6 +119,9 @@ class Ui_MainWindow(object):
         self.fpsLabel.setAlignment(QtCore.Qt.AlignCenter)
         self.fpsLabel.setObjectName("fpsLabel")
         self.gridLayout_2.addWidget(self.fpsLabel, 0, 0, 1, 4)
+        self.rgbCheck = QtGui.QCheckBox(self.centralwidget)
+        self.rgbCheck.setObjectName("rgbCheck")
+        self.gridLayout_2.addWidget(self.rgbCheck, 2, 1, 1, 1)
         MainWindow.setCentralWidget(self.centralwidget)
 
         self.retranslateUi(MainWindow)
@@ -133,12 +136,13 @@ class Ui_MainWindow(object):
         self.dtypeCombo.setItemText(1, QtGui.QApplication.translate("MainWindow", "uint16", None, QtGui.QApplication.UnicodeUTF8))
         self.dtypeCombo.setItemText(2, QtGui.QApplication.translate("MainWindow", "float", None, QtGui.QApplication.UnicodeUTF8))
         self.scaleCheck.setText(QtGui.QApplication.translate("MainWindow", "Scale Data", None, QtGui.QApplication.UnicodeUTF8))
-        self.rgbCheck.setText(QtGui.QApplication.translate("MainWindow", "RGB", None, QtGui.QApplication.UnicodeUTF8))
+        self.rgbLevelsCheck.setText(QtGui.QApplication.translate("MainWindow", "RGB", None, QtGui.QApplication.UnicodeUTF8))
         self.label_2.setText(QtGui.QApplication.translate("MainWindow", "<--->", None, QtGui.QApplication.UnicodeUTF8))
         self.label_3.setText(QtGui.QApplication.translate("MainWindow", "<--->", None, QtGui.QApplication.UnicodeUTF8))
         self.label_4.setText(QtGui.QApplication.translate("MainWindow", "<--->", None, QtGui.QApplication.UnicodeUTF8))
         self.lutCheck.setText(QtGui.QApplication.translate("MainWindow", "Use Lookup  Table", None, QtGui.QApplication.UnicodeUTF8))
         self.alphaCheck.setText(QtGui.QApplication.translate("MainWindow", "alpha", None, QtGui.QApplication.UnicodeUTF8))
         self.fpsLabel.setText(QtGui.QApplication.translate("MainWindow", "FPS", None, QtGui.QApplication.UnicodeUTF8))
+        self.rgbCheck.setText(QtGui.QApplication.translate("MainWindow", "RGB", None, QtGui.QApplication.UnicodeUTF8))
 
 from pyqtgraph import SpinBox, GradientWidget, GraphicsView, RawImageWidget
diff --git a/functions.py b/functions.py
index 1342b527..4eafbbf3 100644
--- a/functions.py
+++ b/functions.py
@@ -434,8 +434,10 @@ def affineSlice(data, shape, origin, vectors, axes, order=1, returnCoords=False,
     
 
     ## make sure vectors are arrays
-    vectors = np.array(vectors)
-    origin = np.array(origin)
+    if not isinstance(vectors, np.ndarray):
+        vectors = np.array(vectors)
+    if not isinstance(origin, np.ndarray):
+        origin = np.array(origin)
     origin.shape = (len(axes),) + (1,)*len(shape)
     
     ## Build array of sample locations. 
@@ -580,171 +582,247 @@ def solveBilinearTransform(points1, points2):
     
     return matrix
     
+def rescaleData(data, scale, offset, dtype=None):
+    """Return data rescaled and optionally cast to a new dtype::
     
+        data => (data-offset) * scale
+        
+    Uses scipy.weave (if available) to improve performance.
+    """
+    global USE_WEAVE
+    if dtype is None:
+        dtype = data.dtype
     
+    try:
+        if not USE_WEAVE:
+            raise Exception('Weave is disabled; falling back to slower version.')
+        
+        newData = np.empty((data.size,), dtype=dtype)
+        flat = np.ascontiguousarray(data).reshape(data.size)
+        size = data.size
+        
+        code = """
+        double sc = (double)scale;
+        double off = (double)offset;
+        for( int i=0; i<size; i++ ) {
+            newData[i] = ((double)flat[i] - off) * sc;
+        }
+        """
+        scipy.weave.inline(code, ['flat', 'newData', 'size', 'offset', 'scale'], compiler='gcc')
+        data = newData.reshape(data.shape)
+    except:
+        if USE_WEAVE:
+            debug.printExc("Error; disabling weave.")
+            USE_WEAVE = False
+        
+        #p = np.poly1d([scale, -offset*scale])
+        #data = p(data).astype(dtype)
+        d2 = data-offset
+        d2 *= scale
+        data = d2.astype(dtype)
+    return data
+    
+def applyLookupTable(data, lut):
+    """
+    Uses values in *data* as indexes to select values from *lut*.
+    The returned data has shape data.shape + lut.shape[1:]
+    
+    Uses scipy.weave to improve performance if it is available.
+    Note: color gradient lookup tables can be generated using GradientWidget.
+    """
+    global USE_WEAVE
+    
+    if data.dtype.kind not in ('i', 'u'):
+        data = data.astype(int)
+    
+    ## using np.take appears to be faster than even the scipy.weave method and takes care of clipping as well.
+    return np.take(lut, data, axis=0, mode='clip')  
+    
+    ### old methods: 
+    #data = np.clip(data, 0, lut.shape[0]-1)
+    
+    #try:
+        #if not USE_WEAVE:
+            #raise Exception('Weave is disabled; falling back to slower version.')
+        
+        ### number of values to copy for each LUT lookup
+        #if lut.ndim == 1:
+            #ncol = 1
+        #else:
+            #ncol = sum(lut.shape[1:])
+        
+        ### output array
+        #newData = np.empty((data.size, ncol), dtype=lut.dtype)
+        
+        ### flattened input arrays
+        #flatData = data.flatten()
+        #flatLut = lut.reshape((lut.shape[0], ncol))
+        
+        #dataSize = data.size
+        
+        ### strides for accessing each item 
+        #newStride = newData.strides[0] / newData.dtype.itemsize
+        #lutStride = flatLut.strides[0] / flatLut.dtype.itemsize
+        #dataStride = flatData.strides[0] / flatData.dtype.itemsize
+        
+        ### strides for accessing individual values within a single LUT lookup
+        #newColStride = newData.strides[1] / newData.dtype.itemsize
+        #lutColStride = flatLut.strides[1] / flatLut.dtype.itemsize
+        
+        #code = """
+        
+        #for( int i=0; i<dataSize; i++ ) {
+            #for( int j=0; j<ncol; j++ ) {
+                #newData[i*newStride + j*newColStride] = flatLut[flatData[i*dataStride]*lutStride + j*lutColStride];
+            #}
+        #}
+        #"""
+        #scipy.weave.inline(code, ['flatData', 'flatLut', 'newData', 'dataSize', 'ncol', 'newStride', 'lutStride', 'dataStride', 'newColStride', 'lutColStride'])
+        #newData = newData.reshape(data.shape + lut.shape[1:])
+        ##if np.any(newData != lut[data]):
+            ##print "mismatch!"
+            
+        #data = newData
+    #except:
+        #if USE_WEAVE:
+            #debug.printExc("Error; disabling weave.")
+            #USE_WEAVE = False
+        #data = lut[data]
+        
+    #return data
+
+
 def makeRGBA(*args, **kwds):
     """Equivalent to makeARGB(..., useRGBA=True)"""
     kwds['useRGBA'] = True
     return makeARGB(*args, **kwds)
 
-def makeARGB(data, lut=None, levels=None, useRGBA=False): 
+def makeARGB(data, lut=None, levels=None, scale=None, useRGBA=False): 
     """ 
-    Convert a 2D or 3D array into an ARGB array suitable for building QImages
-    Will optionally do scaling and/or table lookups to determine final colors.
+    Convert an array of values into an ARGB array suitable for building QImages, OpenGL textures, etc.
     
     Returns the ARGB array (values 0-255) and a boolean indicating whether there is alpha channel data.
+    This is a two stage process:
     
+        1) Rescale the data based on the values in the *levels* argument (min, max).
+        2) Determine the final output by passing the rescaled values through a lookup table.
+   
+    Both stages are optional.
+    
+    ============ ==================================================================================
     Arguments:
-        data  - 2D or 3D numpy array of int/float types
-        
-                For 2D arrays (x, y):
-                  * The color will be determined using a lookup table (see argument 'lut').
-                  * If levels are given, the data is rescaled and converted to int
-                    before using the lookup table.
+    data         numpy array of int/float types. If 
+    levels       List [min, max]; optionally rescale data before converting through the
+                 lookup table. The data is rescaled such that min->0 and max->*scale*::
                  
-                For 3D arrays (x, y, rgba):
-                  * The third axis must have length 3 or 4 and will be interpreted as RGBA.
-                  * The 'lut' argument is not allowed.
+                    rescaled = (clip(data, min, max) - min) * (*scale* / (max - min))
                  
-        lut   - Lookup table for 2D data. May be 1D or 2D (N,rgba) and must have dtype=ubyte.
-                Values in data will be converted to color by indexing directly from lut.
-                Lookup tables can be built using GradientWidget.
-        levels - List [min, max]; optionally rescale data before converting through the
-                lookup table.   rescaled = (data-min) * len(lut) / (max-min)
-        useRGBA - If True, the data is returned in RGBA order (useful for building OpenGL textures). The default is 
-                  False, which returns in BGRA order for use with QImage.
-                
+                 It is also possible to use a 2D (N,2) array of values for levels. In this case,
+                 it is assumed that each pair of min,max values in the levels array should be 
+                 applied to a different subset of the input data (for example, the input data may 
+                 already have RGB values and the levels are used to independently scale each 
+                 channel). The use of this feature requires that levels.shape[0] == data.shape[-1].
+    scale        The maximum value to which data will be rescaled before being passed through the 
+                 lookup table (or returned if there is no lookup table). By default this will
+                 be set to the length of the lookup table, or 256 is no lookup table is provided.
+                 For OpenGL color specifications (as in GLColor4f) use scale=1.0
+    lut          Optional lookup table (array with dtype=ubyte).
+                 Values in data will be converted to color by indexing directly from lut.
+                 The output data shape will be input.shape + lut.shape[1:].
+                 
+                 Note: the output of makeARGB will have the same dtype as the lookup table, so
+                 for conversion to QImage, the dtype must be ubyte.
+                 
+                 Lookup tables can be built using GradientWidget.
+    useRGBA      If True, the data is returned in RGBA order (useful for building OpenGL textures). 
+                 The default is False, which returns in ARGB order for use with QImage 
+                 (Note that 'ARGB' is a term used by the Qt documentation; the _actual_ order 
+                 is BGRA).
+    ============ ==================================================================================
     """
     prof = debug.Profiler('functions.makeARGB', disabled=True)
     
+    if lut is not None and not isinstance(lut, np.ndarray):
+        lut = np.array(lut)
+    if levels is not None and not isinstance(levels, np.ndarray):
+        levels = np.array(levels)
+    
     ## sanity checks
-    if data.ndim == 3:
-        if data.shape[2] not in (3,4):
-            raise Exception("data.shape[2] must be 3 or 4")
-        #if lut is not None:
-            #raise Exception("can not use lookup table with 3D data")
-    elif data.ndim != 2:
-        raise Exception("data must be 2D or 3D")
+    #if data.ndim == 3:
+        #if data.shape[2] not in (3,4):
+            #raise Exception("data.shape[2] must be 3 or 4")
+        ##if lut is not None:
+            ##raise Exception("can not use lookup table with 3D data")
+    #elif data.ndim != 2:
+        #raise Exception("data must be 2D or 3D")
         
-    if lut is not None:
-        if lut.ndim == 2:
-            if lut.shape[1] not in (3,4):
-                raise Exception("lut.shape[1] must be 3 or 4")
-        elif lut.ndim != 1:
-            raise Exception("lut must be 1D or 2D")
-        if lut.dtype != np.ubyte:
-            raise Exception('lookup table must have dtype=ubyte (got %s instead)' % str(lut.dtype))
+    #if lut is not None:
+        ##if lut.ndim == 2:
+            ##if lut.shape[1] :
+                ##raise Exception("lut.shape[1] must be 3 or 4")
+        ##elif lut.ndim != 1:
+            ##raise Exception("lut must be 1D or 2D")
+        #if lut.dtype != np.ubyte:
+            #raise Exception('lookup table must have dtype=ubyte (got %s instead)' % str(lut.dtype))
+            
 
     if levels is not None:
-        levels = np.array(levels)
-        if levels.shape == (2,):
-            pass
-        elif levels.shape in [(3,2), (4,2)]:
-            if data.ndim == 3:
-                raise Exception("Can not use 2D levels with 3D data.")
-            if lut is not None:
-                raise Exception('Can not use 2D levels and lookup table together.')
+        if levels.ndim == 1:
+            if len(levels) != 2:
+                raise Exception('levels argument must have length 2')
+        elif levels.ndim == 2:
+            if lut is not None and lut.ndim > 1:
+                raise Exception('Cannot make ARGB data when bot levels and lut have ndim > 2')
+            if levels.shape != (data.shape[-1], 2):
+                raise Exception('levels must have shape (data.shape[-1], 2)')
         else:
-            raise Exception("Levels must have shape (2,) or (3,2) or (4,2)")
+            print levels
+            raise Exception("levels argument must be 1D or 2D.")
+        #levels = np.array(levels)
+        #if levels.shape == (2,):
+            #pass
+        #elif levels.shape in [(3,2), (4,2)]:
+            #if data.ndim == 3:
+                #raise Exception("Can not use 2D levels with 3D data.")
+            #if lut is not None:
+                #raise Exception('Can not use 2D levels and lookup table together.')
+        #else:
+            #raise Exception("Levels must have shape (2,) or (3,2) or (4,2)")
         
     prof.mark('1')
 
-    if lut is not None:
-        lutLength = lut.shape[0]
-    else:
-        lutLength = 256
-
-    ## weave requires contiguous arrays
-    global USE_WEAVE
-    if (levels is not None or lut is not None) and USE_WEAVE:
-        data = np.ascontiguousarray(data)
+    if scale is None:
+        if lut is not None:
+            scale = lut.shape[0]
+        else:
+            scale = 255.
 
     ## Apply levels if given
     if levels is not None:
         
-        try:  ## use weave to speed up scaling
-            if not USE_WEAVE:
-                raise Exception('Weave is disabled; falling back to slower version.')
-            if levels.ndim == 1:
-                scale = float(lutLength) / (levels[1]-levels[0])
-                offset = float(levels[0])
-                data = rescaleData(data, scale, offset)
-            else:
-                if data.ndim == 2:
-                    newData = np.empty(data.shape+(levels.shape[0],), dtype=np.uint32)
-                    for i in range(levels.shape[0]):
-                        scale = float(lutLength / (levels[i,1]-levels[i,0]))
-                        offset = float(levels[i,0])
-                        newData[...,i] = rescaleData(data, scale, offset)
-                elif data.ndim == 3:
-                    newData = np.empty(data.shape, dtype=np.uint32)
-                    for i in range(data.shape[2]):
-                        scale = float(lutLength / (levels[i,1]-levels[i,0]))
-                        offset = float(levels[i,0])
-                        #print scale, offset, data.shape, newData.shape, levels.shape
-                        newData[...,i] = rescaleData(data[...,i], scale, offset)
-                data = newData
-        except:
-            if USE_WEAVE:
-                debug.printExc("Error; disabling weave.")
-                USE_WEAVE = False
-            
-            if levels.ndim == 1:
-                if data.ndim == 2:
-                    levels = levels[np.newaxis, np.newaxis, :]
-                else:
-                    levels = levels[np.newaxis, np.newaxis, np.newaxis, :]
-            else:
-                levels = levels[np.newaxis, np.newaxis, ...]
-                if data.ndim == 2:
-                    data = data[..., np.newaxis]
-            data = ((data-levels[...,0]) * lutLength) / (levels[...,1]-levels[...,0])
+        if isinstance(levels, np.ndarray) and levels.ndim == 2:
+            ## we are going to rescale each channel independently
+            if levels.shape[0] != data.shape[-1]:
+                raise Exception("When rescaling multi-channel data, there must be the same number of levels as channels (data.shape[-1] == levels.shape[0])")
+            newData = np.empty(data.shape, dtype=int)
+            for i in range(data.shape[-1]):
+                minVal, maxVal = levels[i]
+                if minVal == maxVal:
+                    maxVal += 1e-16
+                newData[...,i] = rescaleData(data[...,i], scale/(maxVal-minVal), minVal, dtype=int)
+            data = newData
+        else:
+            minVal, maxVal = levels
+            if minVal == maxVal:
+                maxVal += 1e-16
+            data = rescaleData(data, scale/(maxVal-minVal), minVal, dtype=int)
         
     prof.mark('2')
 
 
     ## apply LUT if given
-    if lut is not None and data.ndim == 2:
-        
-        if data.dtype.kind not in ('i', 'u'):
-            data = data.astype(int)
-            
-        data = np.clip(data, 0, lutLength-1)
-        try:
-            if not USE_WEAVE:
-                raise Exception('Weave is disabled; falling back to slower version.')
-            
-            newData = np.empty((data.size,) + lut.shape[1:], dtype=np.uint8)
-            flat = data.reshape(data.size)
-            size = data.size
-            ncol = lut.shape[1]
-            newStride = newData.strides[0]
-            newColStride = newData.strides[1]
-            lutStride = lut.strides[0]
-            lutColStride = lut.strides[1]
-            flatStride = flat.strides[0] / flat.dtype.itemsize
-            
-            #print "newData:", newData.shape, newData.dtype
-            #print "flat:", flat.shape, flat.dtype, flat.min(), flat.max()
-            #print "lut:", lut.shape, lut.dtype
-            #print "size:", size, "ncols:", ncol
-            #print "strides:", newStride, newColStride, lutStride, lutColStride, flatStride
-            
-            code = """
-            
-            for( int i=0; i<size; i++ ) {
-                for( int j=0; j<ncol; j++ ) {
-                    newData[i*newStride + j*newColStride] = lut[flat[i*flatStride]*lutStride + j*lutColStride];
-                }
-            }
-            """
-            scipy.weave.inline(code, ['flat', 'lut', 'newData', 'size', 'ncol', 'newStride', 'lutStride', 'flatStride', 'newColStride', 'lutColStride'])
-            data = newData.reshape(data.shape + lut.shape[1:])
-        except:
-            if USE_WEAVE:
-                debug.printExc("Error; disabling weave.")
-                USE_WEAVE = False
-            data = lut[data]
+    if lut is not None:
+        data = applyLookupTable(data, lut)
     else:
         if data.dtype is not np.ubyte:
             data = np.clip(data, 0, 255).astype(np.ubyte)
@@ -895,25 +973,6 @@ def imageToArray(img, copy=False, transpose=True):
         return arr
     
     
-    
-
-def rescaleData(data, scale, offset):
-    newData = np.empty((data.size,), dtype=np.int)
-    flat = data.reshape(data.size)
-    size = data.size
-    
-    code = """
-    double sc = (double)scale;
-    double off = (double)offset;
-    for( int i=0; i<size; i++ ) {
-        newData[i] = (int)(((double)flat[i] - off) * sc);
-    }
-    """
-    scipy.weave.inline(code, ['flat', 'newData', 'size', 'offset', 'scale'], compiler='gcc')
-    data = newData.reshape(data.shape)
-    return data
-    
-
 #def isosurface(data, level):
     #"""
     #Generate isosurface from volumetric data using marching tetrahedra algorithm.
@@ -1090,7 +1149,7 @@ def isosurface(data, level):
     *data*   3D numpy array of scalar values
     *level*  The level at which to generate an isosurface
     
-    Returns a list of faces; each face is a list of three vertexes and each vertex is a tuple of three floats.
+    Returns an array of vertex coordinates (N, 3, 3);
     
     This function is SLOW; plenty of room for optimization here.
     """
@@ -1457,7 +1516,7 @@ def isosurface(data, level):
                         pts.append(p)
                     facets.append(pts)
 
-    return facets
+    return np.array(facets)
 
 
     
diff --git a/graphicsItems/GraphicsItem.py b/graphicsItems/GraphicsItem.py
index 7eee89f3..4f4753b1 100644
--- a/graphicsItems/GraphicsItem.py
+++ b/graphicsItems/GraphicsItem.py
@@ -166,13 +166,15 @@ class GraphicsItem(object):
         ## attempt to re-scale direction vector to fit within the precision of the coordinate system
         if direction.x() == 0:
             r = abs(dt.m32())/(abs(dt.m12()) + abs(dt.m22()))
+            #r = 1.0/(abs(dt.m12()) + abs(dt.m22()))
         elif direction.y() == 0:
             r = abs(dt.m31())/(abs(dt.m11()) + abs(dt.m21()))
+            #r = 1.0/(abs(dt.m11()) + abs(dt.m21()))
         else:
             r = ((abs(dt.m32())/(abs(dt.m12()) + abs(dt.m22()))) * (abs(dt.m31())/(abs(dt.m11()) + abs(dt.m21()))))**0.5
-        direction = direction * r
+        directionr = direction * r
         
-        viewDir = Point(dt.map(direction) - dt.map(Point(0,0)))
+        viewDir = Point(dt.map(directionr) - dt.map(Point(0,0)))
         if viewDir.manhattanLength() == 0:
             return None, None   ##  pixel size cannot be represented on this scale
             
@@ -182,7 +184,7 @@ class GraphicsItem(object):
             normView = viewDir.norm()  ## direction of one pixel orthogonal to line
             normOrtho = orthoDir.norm()
         except:
-            raise Exception("Invalid direction %s" %direction)
+            raise Exception("Invalid direction %s" %directionr)
             
         
         dti = fn.invertQTransform(dt)
diff --git a/graphicsItems/ViewBox/ViewBox.py b/graphicsItems/ViewBox/ViewBox.py
index 89fa1487..0e344e16 100644
--- a/graphicsItems/ViewBox/ViewBox.py
+++ b/graphicsItems/ViewBox/ViewBox.py
@@ -166,7 +166,7 @@ class ViewBox(GraphicsWidget):
             ViewBox.NamedViews[name] = self
             ViewBox.updateAllViewLists()
             sid = id(self)
-            self.destroyed.connect(lambda: ViewBox.forgetView(sid, name) if ViewBox is not None else None)
+            self.destroyed.connect(lambda: ViewBox.forgetView(sid, name) if (ViewBox is not None and 'sid' in locals() and 'name' in locals()) else None)
             #self.destroyed.connect(self.unregister)
 
     def unregister(self):
@@ -1154,7 +1154,7 @@ class ViewBox(GraphicsWidget):
         if any(changed):
             self.sigRangeChanged.emit(self, self.state['viewRange'])
             
-        self.sigTransformChanged.emit(self)
+        self.sigTransformChanged.emit(self)  ## segfaults here: 1
 
     def paint(self, p, opt, widget):
         if self.border is not None:
diff --git a/parametertree/Parameter.py b/parametertree/Parameter.py
index e32f0b4a..e84bcebe 100644
--- a/parametertree/Parameter.py
+++ b/parametertree/Parameter.py
@@ -460,7 +460,10 @@ class Parameter(QtCore.QObject):
         self.childs.pop(self.childs.index(child))
         child.parentChanged(None)
         self.sigChildRemoved.emit(self, child)
-        child.sigTreeStateChanged.disconnect(self.treeStateChanged)
+        try:
+            child.sigTreeStateChanged.disconnect(self.treeStateChanged)
+        except TypeError:  ## already disconnected
+            pass
 
     def clearChildren(self):
         """Remove all child parameters."""
@@ -550,6 +553,8 @@ class Parameter(QtCore.QObject):
     def __getattr__(self, attr):
         ## Leaving this undocumented because I might like to remove it in the future..
         #print type(self), attr
+        if 'names' not in self.__dict__:
+            raise AttributeError(attr)
         if attr in self.names:
             return self.param(attr)
         else:
diff --git a/widgets/LayoutWidget.py b/widgets/LayoutWidget.py
index bcf88199..f567ad74 100644
--- a/widgets/LayoutWidget.py
+++ b/widgets/LayoutWidget.py
@@ -56,8 +56,13 @@ class LayoutWidget(QtGui.QWidget):
         """
         Add a widget to the layout and place it in the next available cell (or in the cell specified).
         """
-        if row is None:
+        if row == 'next':
+            self.nextRow()
             row = self.currentRow
+        elif row is None:
+            row = self.currentRow
+            
+        
         if col is None:
             col = self.nextCol(colspan)