New trunk

bzr revid: pinky-3f10ee12cea3c4c75cef44ab04ad33ef47432907

1 files changed, 315 insertions, 0 deletions

diff --git a/bin/reportlab/graphics/renderbase.py b/bin/reportlab/graphics/renderbase.py
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+#Copyright ReportLab Europe Ltd. 2000-2004
+#see license.txt for license details
+#history http://www.reportlab.co.uk/cgi-bin/viewcvs.cgi/public/reportlab/trunk/reportlab/graphics/renderbase.py
+"""
+Superclass for renderers to factor out common functionality and default implementations.
+"""
+
+
+__version__=''' $Id $ '''
+
+from reportlab.graphics.shapes import *
+from reportlab import rl_config
+
+def inverse(A):
+    "For A affine 2D represented as 6vec return 6vec version of A**(-1)"
+    # I checked this RGB
+    det = float(A[0]*A[3] - A[2]*A[1])
+    R = [A[3]/det, -A[1]/det, -A[2]/det, A[0]/det]
+    return tuple(R+[-R[0]*A[4]-R[2]*A[5],-R[1]*A[4]-R[3]*A[5]])
+
+def mmult(A, B):
+    "A postmultiplied by B"
+    # I checked this RGB
+    # [a0 a2 a4]    [b0 b2 b4]
+    # [a1 a3 a5] *  [b1 b3 b5]
+    # [      1 ]    [      1 ]
+    #
+    return (A[0]*B[0] + A[2]*B[1],
+            A[1]*B[0] + A[3]*B[1],
+            A[0]*B[2] + A[2]*B[3],
+            A[1]*B[2] + A[3]*B[3],
+            A[0]*B[4] + A[2]*B[5] + A[4],
+            A[1]*B[4] + A[3]*B[5] + A[5])
+
+
+def getStateDelta(shape):
+    """Used to compute when we need to change the graphics state.
+    For example, if we have two adjacent red shapes we don't need
+    to set the pen color to red in between. Returns the effect
+    the given shape would have on the graphics state"""
+    delta = {}
+    for (prop, value) in shape.getProperties().items():
+        if STATE_DEFAULTS.has_key(prop):
+            delta[prop] = value
+    return delta
+
+
+class StateTracker:
+    """Keeps a stack of transforms and state
+    properties.  It can contain any properties you
+    want, but the keys 'transform' and 'ctm' have
+    special meanings.  The getCTM()
+    method returns the current transformation
+    matrix at any point, without needing to
+    invert matrixes when you pop."""
+    def __init__(self, defaults=None):
+        # one stack to keep track of what changes...
+        self.__deltas = []
+
+        # and another to keep track of cumulative effects.  Last one in
+        # list is the current graphics state.  We put one in to simplify
+        # loops below.
+        self.__combined = []
+        if defaults is None:
+            defaults = STATE_DEFAULTS.copy()
+        #ensure  that if we have a transform, we have a CTM
+        if defaults.has_key('transform'):
+            defaults['ctm'] = defaults['transform']
+        self.__combined.append(defaults)
+
+    def push(self,delta):
+        """Take a new state dictionary of changes and push it onto
+        the stack.  After doing this, the combined state is accessible
+        through getState()"""
+
+        newstate = self.__combined[-1].copy()
+        for (key, value) in delta.items():
+            if key == 'transform':  #do cumulative matrix
+                newstate['transform'] = delta['transform']
+                newstate['ctm'] = mmult(self.__combined[-1]['ctm'], delta['transform'])
+                #print 'statetracker transform = (%0.2f, %0.2f, %0.2f, %0.2f, %0.2f, %0.2f)' % tuple(newstate['transform'])
+                #print 'statetracker ctm = (%0.2f, %0.2f, %0.2f, %0.2f, %0.2f, %0.2f)' % tuple(newstate['ctm'])
+
+            else:  #just overwrite it
+                newstate[key] = value
+
+        self.__combined.append(newstate)
+        self.__deltas.append(delta)
+
+    def pop(self):
+        """steps back one, and returns a state dictionary with the
+        deltas to reverse out of wherever you are.  Depending
+        on your back end, you may not need the return value,
+        since you can get the complete state afterwards with getState()"""
+        del self.__combined[-1]
+        newState = self.__combined[-1]
+        lastDelta = self.__deltas[-1]
+        del  self.__deltas[-1]
+        #need to diff this against the last one in the state
+        reverseDelta = {}
+        #print 'pop()...'
+        for key, curValue in lastDelta.items():
+            #print '   key=%s, value=%s' % (key, curValue)
+            prevValue = newState[key]
+            if prevValue <> curValue:
+                #print '    state popping "%s"="%s"' % (key, curValue)
+                if key == 'transform':
+                    reverseDelta[key] = inverse(lastDelta['transform'])
+                else:  #just return to previous state
+                    reverseDelta[key] = prevValue
+        return reverseDelta
+
+    def getState(self):
+        "returns the complete graphics state at this point"
+        return self.__combined[-1]
+
+    def getCTM(self):
+        "returns the current transformation matrix at this point"""
+        return self.__combined[-1]['ctm']
+
+    def __getitem__(self,key):
+        "returns the complete graphics state value of key at this point"
+        return self.__combined[-1][key]
+
+    def __setitem__(self,key,value):
+        "sets the complete graphics state value of key to value"
+        self.__combined[-1][key] = value
+
+def testStateTracker():
+    print 'Testing state tracker'
+    defaults = {'fillColor':None, 'strokeColor':None,'fontName':None, 'transform':[1,0,0,1,0,0]}
+    deltas = [
+        {'fillColor':'red'},
+        {'fillColor':'green', 'strokeColor':'blue','fontName':'Times-Roman'},
+        {'transform':[0.5,0,0,0.5,0,0]},
+        {'transform':[0.5,0,0,0.5,2,3]},
+        {'strokeColor':'red'}
+        ]
+
+    st = StateTracker(defaults)
+    print 'initial:', st.getState()
+    print
+    for delta in deltas:
+        print 'pushing:', delta
+        st.push(delta)
+        print 'state:  ',st.getState(),'\n'
+
+    for delta in deltas:
+        print 'popping:',st.pop()
+        print 'state:  ',st.getState(),'\n'
+
+
+def _expandUserNode(node,canvas):
+    if isinstance(node, UserNode):
+        try:
+            if hasattr(node,'_canvas'):
+                ocanvas = 1
+            else:
+                node._canvas = canvas
+                ocanvas = None
+            onode = node
+            node = node.provideNode()
+        finally:
+            if not ocanvas: del onode._canvas
+    return node
+
+class Renderer:
+    """Virtual superclass for graphics renderers."""
+
+    def __init__(self):
+        self._tracker = StateTracker()
+
+    def undefined(self, operation):
+        raise ValueError, "%s operation not defined at superclass class=%s" %(operation, self.__class__)
+
+    def draw(self, drawing, canvas, x=0, y=0, showBoundary=rl_config._unset_):
+        """This is the top level function, which draws the drawing at the given
+        location. The recursive part is handled by drawNode."""
+        #stash references for ease of  communication
+        if showBoundary is rl_config._unset_: showBoundary=rl_config.showBoundary
+        self._canvas = canvas
+        canvas.__dict__['_drawing'] = self._drawing = drawing
+        drawing._parent = None
+        try:
+            #bounding box
+            if showBoundary: canvas.rect(x, y, drawing.width, drawing.height)
+            canvas.saveState()
+            self.initState(x,y)
+            self.drawNode(drawing)
+            self.pop()
+            canvas.restoreState()
+        finally:
+            #remove any circular references
+            del self._canvas, self._drawing, canvas._drawing, drawing._parent
+
+    def initState(self,x,y):
+        deltas = STATE_DEFAULTS.copy()
+        deltas['transform'] = [1,0,0,1,x,y]
+        self._tracker.push(deltas)
+        self.applyStateChanges(deltas, {})
+
+    def pop(self):
+        self._tracker.pop()
+
+    def drawNode(self, node):
+        """This is the recursive method called for each node
+        in the tree"""
+        # Undefined here, but with closer analysis probably can be handled in superclass
+        self.undefined("drawNode")
+
+    def drawNodeDispatcher(self, node):
+        """dispatch on the node's (super) class: shared code"""
+
+        canvas = getattr(self,'_canvas',None)
+        # replace UserNode with its contents
+
+        try:
+            node = _expandUserNode(node,canvas)
+            if hasattr(node,'_canvas'):
+                ocanvas = 1
+            else:
+                node._canvas = canvas
+                ocanvas = None
+
+            #draw the object, or recurse
+            if isinstance(node, Line):
+                self.drawLine(node)
+            elif isinstance(node, Image):
+                self.drawImage(node)
+            elif isinstance(node, Rect):
+                self.drawRect(node)
+            elif isinstance(node, Circle):
+                self.drawCircle(node)
+            elif isinstance(node, Ellipse):
+                self.drawEllipse(node)
+            elif isinstance(node, PolyLine):
+                self.drawPolyLine(node)
+            elif isinstance(node, Polygon):
+                self.drawPolygon(node)
+            elif isinstance(node, Path):
+                self.drawPath(node)
+            elif isinstance(node, String):
+                self.drawString(node)
+            elif isinstance(node, Group):
+                self.drawGroup(node)
+            elif isinstance(node, Wedge):
+                self.drawWedge(node)
+            else:
+                print 'DrawingError','Unexpected element %s in drawing!' % str(node)
+        finally:
+            if not ocanvas: del node._canvas
+
+    _restores = {'stroke':'_stroke','stroke_width': '_lineWidth','stroke_linecap':'_lineCap',
+                'stroke_linejoin':'_lineJoin','fill':'_fill','font_family':'_font',
+                'font_size':'_fontSize'}
+
+    def drawGroup(self, group):
+        # just do the contents.  Some renderers might need to override this
+        # if they need a flipped transform
+        canvas = getattr(self,'_canvas',None)
+        for node in group.getContents():
+            node = _expandUserNode(node,canvas)
+            try:
+                if hasattr(node,'_canvas'):
+                    ocanvas = 1
+                else:
+                    node._canvas = canvas
+                    ocanvas = None
+                node._parent = group
+                self.drawNode(node)
+            finally:
+                del node._parent
+                if not ocanvas: del node._canvas
+
+    def drawWedge(self, wedge):
+        # by default ask the wedge to make a polygon of itself and draw that!
+        #print "drawWedge"
+        polygon = wedge.asPolygon()
+        self.drawPolygon(polygon)
+
+    def drawPath(self, path):
+        polygons = path.asPolygons()
+        for polygon in polygons:
+                self.drawPolygon(polygon)
+
+    def drawRect(self, rect):
+        # could be implemented in terms of polygon
+        self.undefined("drawRect")
+
+    def drawLine(self, line):
+        self.undefined("drawLine")
+
+    def drawCircle(self, circle):
+        self.undefined("drawCircle")
+
+    def drawPolyLine(self, p):
+        self.undefined("drawPolyLine")
+
+    def drawEllipse(self, ellipse):
+        self.undefined("drawEllipse")
+
+    def drawPolygon(self, p):
+        self.undefined("drawPolygon")
+
+    def drawString(self, stringObj):
+        self.undefined("drawString")
+
+    def applyStateChanges(self, delta, newState):
+        """This takes a set of states, and outputs the operators
+        needed to set those properties"""
+        self.undefined("applyStateChanges")
+
+if __name__=='__main__':
+    print "this file has no script interpretation"
+    print __doc__