Added printing requirements

reportlab/pdfgen/pathobject.py

@@ -0,0 +1,127 @@
+#Copyright ReportLab Europe Ltd. 2000-2012
+#see license.txt for license details
+#history http://www.reportlab.co.uk/cgi-bin/viewcvs.cgi/public/reportlab/trunk/reportlab/pdfgen/pathobject.py
+__version__=''' $Id$ '''
+__doc__="""
+PDFPathObject is an efficient way to draw paths on a Canvas. Do not
+instantiate directly, obtain one from the Canvas instead.
+
+Progress Reports:
+8.83, 2000-01-13, gmcm: created from pdfgen.py
+
+"""
+
+from reportlab.pdfgen import pdfgeom
+from reportlab.lib.rl_accel import fp_str
+
+
+class PDFPathObject:
+    """Represents a graphic path.  There are certain 'modes' to PDF
+    drawing, and making a separate object to expose Path operations
+    ensures they are completed with no run-time overhead.  Ask
+    the Canvas for a PDFPath with getNewPathObject(); moveto/lineto/
+    curveto wherever you want; add whole shapes; and then add it back
+    into the canvas with one of the relevant operators.
+
+    Path objects are probably not long, so we pack onto one line
+
+    the code argument allows a canvas to get the operatiosn appended directly so
+    avoiding the final getCode
+    """
+    def __init__(self,code=None):
+        self._code = (code,[])[code is None]
+        self._code_append = self._init_code_append
+
+    def _init_code_append(self,c):
+        assert c.endswith(' m') or c.endswith(' re'), 'path must start with a moveto or rect'
+        code_append = self._code.append
+        code_append('n')
+        code_append(c)
+        self._code_append = code_append
+
+    def getCode(self):
+        "pack onto one line; used internally"
+        return ' '.join(self._code)
+
+    def moveTo(self, x, y):
+        self._code_append('%s m' % fp_str(x,y))
+
+    def lineTo(self, x, y):
+        self._code_append('%s l' % fp_str(x,y))
+
+    def curveTo(self, x1, y1, x2, y2, x3, y3):
+        self._code_append('%s c' % fp_str(x1, y1, x2, y2, x3, y3))
+
+    def arc(self, x1,y1, x2,y2, startAng=0, extent=90):
+        """Contributed to piddlePDF by Robert Kern, 28/7/99.
+        Draw a partial ellipse inscribed within the rectangle x1,y1,x2,y2,
+        starting at startAng degrees and covering extent degrees.   Angles
+        start with 0 to the right (+x) and increase counter-clockwise.
+        These should have x1<x2 and y1<y2.
+
+        The algorithm is an elliptical generalization of the formulae in
+        Jim Fitzsimmon's TeX tutorial <URL: http://www.tinaja.com/bezarc1.pdf>."""
+
+        self._curves(pdfgeom.bezierArc(x1,y1, x2,y2, startAng, extent))
+
+    def arcTo(self, x1,y1, x2,y2, startAng=0, extent=90):
+        """Like arc, but draws a line from the current point to
+        the start if the start is not the current point."""
+        self._curves(pdfgeom.bezierArc(x1,y1, x2,y2, startAng, extent),'lineTo')
+
+    def rect(self, x, y, width, height):
+        """Adds a rectangle to the path"""
+        self._code_append('%s re' % fp_str((x, y, width, height)))
+
+    def ellipse(self, x, y, width, height):
+        """adds an ellipse to the path"""
+        self._curves(pdfgeom.bezierArc(x, y, x + width,y + height, 0, 360))
+
+    def _curves(self,curves,initial='moveTo'):
+        getattr(self,initial)(*curves[0][:2])
+        for curve in curves:
+            self.curveTo(*curve[2:])
+
+    def circle(self, x_cen, y_cen, r):
+        """adds a circle to the path"""
+        x1 = x_cen - r
+        y1 = y_cen - r
+        width = height = 2*r
+        self.ellipse(x1, y1, width, height)
+
+    def roundRect(self, x, y, width, height, radius):
+        """Draws a rectangle with rounded corners. The corners are
+        approximately quadrants of a circle, with the given radius."""
+        #use a precomputed set of factors for the bezier approximation
+        #to a circle. There are six relevant points on the x axis and y axis.
+        #sketch them and it should all make sense!
+        t = 0.4472 * radius
+
+        x0 = x
+        x1 = x0 + t
+        x2 = x0 + radius
+        x3 = x0 + width - radius
+        x4 = x0 + width - t
+        x5 = x0 + width
+
+        y0 = y
+        y1 = y0 + t
+        y2 = y0 + radius
+        y3 = y0 + height - radius
+        y4 = y0 + height - t
+        y5 = y0 + height
+
+        self.moveTo(x2, y0)
+        self.lineTo(x3, y0) #bottom row
+        self.curveTo(x4, y0, x5, y1, x5, y2) #bottom right
+        self.lineTo(x5, y3) #right edge
+        self.curveTo(x5, y4, x4, y5, x3, y5) #top right
+        self.lineTo(x2, y5) #top row
+        self.curveTo(x1, y5, x0, y4, x0, y3) #top left
+        self.lineTo(x0, y2) #left edge
+        self.curveTo(x0, y1, x1, y0, x2, y0) #bottom left
+        self.close()
+
+    def close(self):
+        "draws a line back to where it started"
+        self._code_append('h')