140 lines
5.6 KiB
Python
140 lines
5.6 KiB
Python
#Copyright ReportLab Europe Ltd. 2000-2017
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#see license.txt for license details
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#history https://hg.reportlab.com/hg-public/reportlab/log/tip/src/reportlab/pdfgen/pathobject.py
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__version__='3.3.0'
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__doc__="""
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PDFPathObject is an efficient way to draw paths on a Canvas. Do not
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instantiate directly, obtain one from the Canvas instead.
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Progress Reports:
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8.83, 2000-01-13, gmcm: created from pdfgen.py
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"""
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from reportlab.pdfgen import pdfgeom
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from reportlab.lib.rl_accel import fp_str
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class PDFPathObject:
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"""Represents a graphic path. There are certain 'modes' to PDF
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drawing, and making a separate object to expose Path operations
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ensures they are completed with no run-time overhead. Ask
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the Canvas for a PDFPath with getNewPathObject(); moveto/lineto/
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curveto wherever you want; add whole shapes; and then add it back
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into the canvas with one of the relevant operators.
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Path objects are probably not long, so we pack onto one line
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the code argument allows a canvas to get the operations appended directly so
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avoiding the final getCode
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"""
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def __init__(self,code=None):
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self._code = (code,[])[code is None]
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self._code_append = self._init_code_append
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def _init_code_append(self,c):
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assert c.endswith(' m') or c.endswith(' re'), 'path must start with a moveto or rect'
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code_append = self._code.append
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code_append('n')
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code_append(c)
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self._code_append = code_append
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def getCode(self):
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"pack onto one line; used internally"
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return ' '.join(self._code)
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def moveTo(self, x, y):
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self._code_append('%s m' % fp_str(x,y))
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def lineTo(self, x, y):
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self._code_append('%s l' % fp_str(x,y))
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def curveTo(self, x1, y1, x2, y2, x3, y3):
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self._code_append('%s c' % fp_str(x1, y1, x2, y2, x3, y3))
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def arc(self, x1,y1, x2,y2, startAng=0, extent=90):
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"""Contributed to piddlePDF by Robert Kern, 28/7/99.
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Draw a partial ellipse inscribed within the rectangle x1,y1,x2,y2,
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starting at startAng degrees and covering extent degrees. Angles
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start with 0 to the right (+x) and increase counter-clockwise.
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These should have x1<x2 and y1<y2.
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The algorithm is an elliptical generalization of the formulae in
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Jim Fitzsimmon's TeX tutorial <URL: http://www.tinaja.com/bezarc1.pdf>."""
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self._curves(pdfgeom.bezierArc(x1,y1, x2,y2, startAng, extent))
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def arcTo(self, x1,y1, x2,y2, startAng=0, extent=90):
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"""Like arc, but draws a line from the current point to
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the start if the start is not the current point."""
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self._curves(pdfgeom.bezierArc(x1,y1, x2,y2, startAng, extent),'lineTo')
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def rect(self, x, y, width, height):
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"""Adds a rectangle to the path"""
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self._code_append('%s re' % fp_str((x, y, width, height)))
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def ellipse(self, x, y, width, height):
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"""adds an ellipse to the path"""
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self._curves(pdfgeom.bezierArc(x, y, x + width,y + height, 0, 360))
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def _curves(self,curves,initial='moveTo'):
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getattr(self,initial)(*curves[0][:2])
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for curve in curves:
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self.curveTo(*curve[2:])
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def circle(self, x_cen, y_cen, r):
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"""adds a circle to the path"""
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x1 = x_cen - r
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y1 = y_cen - r
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width = height = 2*r
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self.ellipse(x1, y1, width, height)
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def roundRect(self, x, y, width, height, radius):
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"""Draws a rectangle with rounded corners. The corners are
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approximately quadrants of a circle, with the given radius."""
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#use a precomputed set of factors for the bezier approximation
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#to a circle. There are six relevant points on the x axis and y axis.
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#sketch them and it should all make sense!
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m = 0.4472 #radius multiplier
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xhi = x,x+width
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xlo, xhi = min(xhi), max(xhi)
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yhi = y,y+height
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ylo, yhi = min(yhi), max(yhi)
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if isinstance(radius,(list,tuple)):
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r = [max(0,r) for r in radius]
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if len(r)<4: r += (4-len(r))*[0]
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self.moveTo(xlo + r[2], ylo) #start at bottom left
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self.lineTo(xhi - r[3], ylo) #bottom row
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if r[3]>0:
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t = m*r[3]
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self.curveTo(xhi - t, ylo, xhi, ylo + t, xhi, ylo + r[3]) #bottom right
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self.lineTo(xhi, yhi - r[1]) #right edge
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if r[1]>0:
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t = m*r[1]
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self.curveTo(xhi, yhi - t, xhi - t, yhi, xhi - r[1], yhi) #top right
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self.lineTo(xlo + r[0], yhi) #top row
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if r[0]>0:
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t = m*r[0]
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self.curveTo(xlo + t, yhi, xlo, yhi - t, xlo, yhi - r[0]) #top left
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self.lineTo(xlo, ylo + r[2]) #left edge
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if r[2]>0:
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t = m*r[2]
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self.curveTo(xlo, ylo + t, xlo + t, ylo, xlo + r[2], ylo) #bottom left
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# 4 radii top left top right bittom left bottom right
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else:
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t = m * radius
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self.moveTo(xlo + radius, ylo)
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self.lineTo(xhi - radius, ylo) #bottom row
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self.curveTo(xhi - t, ylo, xhi, ylo + t, xhi, ylo + radius) #bottom right
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self.lineTo(xhi, yhi - radius) #right edge
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self.curveTo(xhi, yhi - t, xhi - t, yhi, xhi - radius, yhi) #top right
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self.lineTo(xlo + radius, yhi) #top row
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self.curveTo(xlo + t, yhi, xlo, yhi - t, xlo, yhi - radius) #top left
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self.lineTo(xlo, ylo + radius) #left edge
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self.curveTo(xlo, ylo + t, xlo + t, ylo, xlo + radius, ylo) #bottom left
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self.close()
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def close(self):
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"draws a line back to where it started"
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self._code_append('h')
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