def _write(self, shapes, svg_file, args):
stroke_width = args.stroke_width if args.stroke_width else "0.1%"
write_preamble(args, svg_file)
shift = Vector2D(args.width / 2.0, args.height / 2.0)
for points, polygon in shapes:
rgb = self.parts.colours.get(polygon.colour, "#ffffff")
stroke_colour = args.stroke_colour if args.stroke_colour else rgb
context = dict(rgb=rgb,
stroke_width=stroke_width,
stroke_colour=stroke_colour,
opacity=self._opacity_from_colour(polygon.colour))
if len(points) == 2:
context['point1'] = Vector2D(points[0].x, -points[0].y) + shift
context['point2'] = Vector2D(points[1].x, -points[1].y) + shift
svg_file.write(SVG_LINE.format(**context))
else:
svg_file.write(SVG_POLYGON_PREAMBLE.format(**context))
for point in points:
dpoint = Vector2D(point.x, -point.y) + shift
svg_file.write('{point.x:.6f},{point.y:.6f} '.format(point=dpoint))
svg_file.write('" />\n')
svg_file.write("</svg>\n")
svg_file.close()
def _project_polygons(width, height, polygons):
# vx' = width + az
# vy' = height + bz
pixel_x = 0.5
pixel_y = 0.5
half_width = width / 2.0
half_height = height / 2.0
new_polygons = []
for polygon in polygons:
new_points = []
for point in polygon.points:
point_x = half_width * (point.x / (half_width + pixel_x * -point.z))
point_y = half_height * (point.y / (half_height + pixel_y * -point.z))
new_point = Vector2D(point_x, point_y)
new_points.append(new_point)
new_polygons.append((new_points, polygon))
return new_polygons
def project_polygons(width, height, polygons):
# vx' = width + az
# vy' = height + bz
print(len(polygons))
pixel_x = 0.5
pixel_y = 0.5
half_width = width / 2.0
half_height = height / 2.0
new_polygons = []
for polygon in polygons:
new_points = []
for point in polygon:
point_x = half_width * (point["x"] / (half_width + pixel_x * -point["z"]))
point_y = half_height * (point["y"] / (half_height + pixel_y * -point["z"]))
new_point = Vector2D(point_x, point_y)
new_points.append(new_point)
new_polygons.append((new_points, polygon))
return new_polygons
def render(self, image, depth, viewport_scale, stroke_colour):
"""
Sort the edges of the polygon by their minimum projected y
coordinates, discarding horizontal edges.
"""
edges = self.get_edges(image, viewport_scale)
if not edges:
return
width, height = image.size
end_py = edges[-1].point2.y
if end_py < 0:
return
edge1 = edges.pop(0)
if edge1.point1.y >= height:
return
edge2 = edges.pop(0)
int_edge1_y1 = int(edge1.point1.y)
if int_edge1_y1 < edge1.point1.y or int_edge1_y1 < edge2.point1.y:
int_edge1_y1 += 1
while int_edge1_y1 <= end_py and int_edge1_y1 < height:
# Retrieve new edges as required.
if int_edge1_y1 >= edge1.point2.y:
if not edges:
break
edge1 = edges.pop(0)
if int_edge1_y1 >= edge2.point2.y:
if not edges:
break
edge2 = edges.pop(0)
if int_edge1_y1 < 0:
int_edge1_y1 += 1
continue
# Calculate the starting and finishing coordinates of the span
# at the current y coordinate.
gradient_1 = Vector2D(edge1.dx_dy, edge1.dz_dy)
start_point_1 = Vector2D(edge1.point1.x, edge1.point1.z)
start_1 = start_point_1 + (int_edge1_y1 -
edge1.point1.y) * gradient_1
gradient_2 = Vector2D(edge2.dx_dy, edge2.dz_dy)
start_point_2 = Vector2D(edge2.point1.x, edge2.point1.z)
start_2 = start_point_2 + (int_edge1_y1 -
edge2.point1.y) * gradient_2
# Do not render the span if it lies outside the image or has
# values that cannot be stored in the depth buffer.
# Truncate the span if it lies partially within the image.
if start_1.x > start_2.x:
start_2, start_1 = start_1, start_2
# Only calculate a depth gradient for the span if it is more than
# one pixel wide.
if start_1.y <= 0 and start_2.y <= 0:
int_edge1_y1 += 1
continue
elif start_1.y >= Z_MAX and start_2.y >= Z_MAX:
int_edge1_y1 += 1
continue
start_x, end_sx = int(start_1.x), int(start_2.x)
if start_x < start_1.x:
start_x += 1
if start_x >= width:
int_edge1_y1 += 1
continue
elif end_sx < 0:
int_edge1_y1 += 1
continue
int_edge1_y1 = self.draw_span(depth, end_sx, image, int_edge1_y1,
start_1, start_2, start_x,
stroke_colour, width)