/usr/lib/python2.7/dist-packages/ginga/cairow/CanvasRenderCairo.py is in python-ginga 2.6.1-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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# CanvasRenderCairo.py -- for rendering into a ImageViewCairo widget
#
# This is open-source software licensed under a BSD license.
# Please see the file LICENSE.txt for details.
import math
import cairo
from ginga import colors
# force registration of all canvas types
import ginga.canvas.types.all
class RenderContext(object):
def __init__(self, viewer):
self.viewer = viewer
self.cr = viewer.get_offscreen_context()
self.fill = False
self.fill_color = None
self.fill_alpha = 1.0
def __get_color(self, color, alpha):
if isinstance(color, str) or isinstance(color, type(u"")):
r, g, b = colors.lookup_color(color)
elif isinstance(color, tuple):
# color is assumed to be a 3-tuple of RGB values as floats
# between 0 and 1
r, g, b = color
else:
r, g, b = 1.0, 1.0, 1.0
return (r, g, b, alpha)
def _set_color(self, color, alpha=1.0):
r, g, b, a = self.__get_color(color, alpha)
self.cr.set_source_rgba(r, g, b, a)
def _reset_path(self):
self.cr.new_path()
def _draw_fill(self):
if self.fill:
self._set_color(self.fill_color, alpha=self.fill_alpha)
self.cr.fill()
def set_line_from_shape(self, shape):
alpha = getattr(shape, 'alpha', 1.0)
self._set_color(shape.color, alpha=alpha)
linewidth = getattr(shape, 'linewidth', 1)
self.cr.set_line_width(linewidth)
if hasattr(shape, 'linestyle'):
if shape.linestyle == 'dash':
self.cr.set_dash([ 3.0, 4.0, 6.0, 4.0], 5.0)
def set_fill_from_shape(self, shape):
self.fill = getattr(shape, 'fill', False)
if self.fill:
color = getattr(shape, 'fillcolor', None)
if color is None:
color = shape.color
self.fill_color = color
alpha = getattr(shape, 'alpha', 1.0)
self.fill_alpha = getattr(shape, 'fillalpha', alpha)
def set_font_from_shape(self, shape):
if hasattr(shape, 'font'):
if hasattr(shape, 'fontsize') and shape.fontsize is not None:
fontsize = shape.fontsize
else:
fontsize = shape.scale_font(self.viewer)
self.cr.select_font_face(shape.font)
self.cr.set_font_size(fontsize)
def initialize_from_shape(self, shape, line=True, fill=True, font=True):
if line:
self.set_line_from_shape(shape)
if fill:
self.set_fill_from_shape(shape)
if font:
self.set_font_from_shape(shape)
def set_line(self, color, alpha=1.0, linewidth=1, style='solid'):
self._set_color(color, alpha=alpha)
self.cr.set_line_width(linewidth)
if style == 'dash':
self.cr.set_dash([ 3.0, 4.0, 6.0, 4.0], 5.0)
def set_fill(self, color, alpha=1.0):
if color is None:
self.fill = False
else:
self.fill = True
self.fill_color = color
self.fill_alpha = alpha
def set_font(self, fontname, fontsize, color='black', alpha=1.0):
self.cr.select_font_face(fontname)
self.cr.set_font_size(fontsize)
self._set_color(color, alpha=alpha)
def text_extents(self, text):
a, b, wd, ht, i, j = self.cr.text_extents(text)
return wd, ht
##### DRAWING OPERATIONS #####
def draw_text(self, cx, cy, text, rot_deg=0.0):
self.cr.save()
self.cr.translate(cx, cy)
self.cr.move_to(0, 0)
self.cr.rotate(-math.radians(rot_deg))
self.cr.show_text(text)
self.cr.restore()
self.cr.new_path()
def draw_polygon(self, cpoints):
(cx0, cy0) = cpoints[-1]
self.cr.move_to(cx0, cy0)
for cx, cy in cpoints:
self.cr.line_to(cx, cy)
#cr.move_to(cx, cy)
self.cr.close_path()
self.cr.stroke_preserve()
self._draw_fill()
self.cr.new_path()
def draw_circle(self, cx, cy, cradius):
self.cr.arc(cx, cy, cradius, 0, 2*math.pi)
self.cr.stroke_preserve()
self._draw_fill()
self.cr.new_path()
def draw_bezier_curve(self, cp):
self.cr.move_to(cp[0][0], cp[0][1])
self.cr.curve_to(cp[1][0], cp[1][1], cp[2][0], cp[2][1], cp[3][0], cp[3][1])
self.cr.stroke()
self.cr.new_path()
def draw_ellipse_bezier(self, cp):
# draw 4 bezier curves to make the ellipse
self.cr.move_to(cp[0][0], cp[0][1])
self.cr.curve_to(cp[1][0], cp[1][1], cp[2][0], cp[2][1], cp[3][0], cp[3][1])
self.cr.curve_to(cp[4][0], cp[4][1], cp[5][0], cp[5][1], cp[6][0], cp[6][1])
self.cr.curve_to(cp[7][0], cp[7][1], cp[8][0], cp[8][1], cp[9][0], cp[9][1])
self.cr.curve_to(cp[10][0], cp[10][1], cp[11][0], cp[11][1], cp[12][0], cp[12][1])
self.cr.stroke_preserve()
self._draw_fill()
self.cr.new_path()
def draw_line(self, cx1, cy1, cx2, cy2):
self.cr.set_line_cap(cairo.LINE_CAP_ROUND)
self.cr.move_to(cx1, cy1)
self.cr.line_to(cx2, cy2)
self.cr.stroke()
self.cr.new_path()
def draw_path(self, cpoints):
(cx0, cy0) = cpoints[0]
self.cr.move_to(cx0, cy0)
for cx, cy in cpoints[1:]:
self.cr.line_to(cx, cy)
self.cr.stroke()
self.cr.new_path()
class CanvasRenderer(object):
def __init__(self, viewer):
self.viewer = viewer
def setup_cr(self, shape):
cr = RenderContext(self.viewer)
cr.initialize_from_shape(shape, font=False)
return cr
def get_dimensions(self, shape):
cr = self.setup_cr(shape)
cr.set_font_from_shape(shape)
return cr.text_extents(shape.text)
#END
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