An initial implementation of a Line (untested)

lib/SVG/Line.py

@@ -0,0 +1,419 @@
+#!python
+
+# $Id$
+
+from operator import itemgetter, add
+from itools import flatten
+
+import SVG
+from Plot import float_range
+
+class Line(SVG.Graph):
+	"""     === Create presentation quality SVG line graphs easily
+     
+     = Synopsis
+     
+       require 'SVG/Graph/Line'
+     
+       fields = %w(Jan Feb Mar);
+       data_sales_02 = [12, 45, 21]
+       data_sales_03 = [15, 30, 40]
+       
+       graph = SVG::Graph::Line.new({
+       	:height => 500,
+        	:width => 300,
+     	  :fields => fields,
+       })
+       
+       graph.add_data({
+       	:data => data_sales_02,
+     	  :title => 'Sales 2002',
+       })
+     
+       graph.add_data({
+       	:data => data_sales_03,
+     	  :title => 'Sales 2003',
+       })
+       
+       print "Content-type: image/svg+xml\r\n\r\n";
+       print graph.burn();
+     
+     = Description
+     
+     This object aims to allow you to easily create high quality
+     SVG line graphs. You can either use the default style sheet
+     or supply your own. Either way there are many options which can
+     be configured to give you control over how the graph is
+     generated - with or without a key, data elements at each point,
+     title, subtitle etc.
+     
+     = Examples
+     
+     http://www.germane-software/repositories/public/SVG/test/single.rb
+     
+     = Notes
+     
+     The default stylesheet handles upto 10 data sets, if you
+     use more you must create your own stylesheet and add the
+     additional settings for the extra data sets. You will know
+     if you go over 10 data sets as they will have no style and
+     be in black.
+     
+     = See also
+     
+     * SVG::Graph::Graph
+     * SVG::Graph::BarHorizontal
+     * SVG::Graph::Bar
+     * SVG::Graph::Pie
+     * SVG::Graph::Plot
+     * SVG::Graph::TimeSeries
+
+     == Author
+
+     Sean E. Russell <serATgermaneHYPHENsoftwareDOTcom>
+
+     Copyright 2004 Sean E. Russell
+     This software is available under the Ruby license[LICENSE.txt]
+
+"""
+
+	"""Show a small circle on the graph where the line goes from one point to
+	the next"""
+	show_data_points = True
+	show_data_values = True
+	"""Accumulates each data set. (i.e. Each point increased by sum of all
+	previous series at same point)."""
+	stacked = False
+	"Fill in the area under the plot"
+	area_fill = False
+
+	#override some defaults
+	top_align = top_font = right_align = right_font = True
+
+	def max_value(self):
+		data = map(itemgetter('data'), self.data)
+		if self.stacked:
+			data = self.get_cumulative_data()
+		return max(flatten(data))
+
+	def min_value(self):
+		if self.min_scale_value:
+			return self.min_scale_value
+		data = map(itemgetter('data'), self.data)
+		if self.stacked:
+			data = self.get_cumulative_data()
+		return min(flatten(data))
+
+	def get_cumulative_data():
+		"""Get the data as it will be charted.  The first set will be
+		the actual first data set.  The second will be the sum of the
+		first and the second, etc."""
+		sets = map(itemgetter('data'), self.data)
+		if not sets: return
+		sum = sets.pop(0)
+		yield sum
+		while sets:
+			sum = map(add, sets.pop(0))
+			yield sum
+
+	def get_x_labels(self):
+		return self.fields
+
+	def calculate_left_margin(self):
+		super(self.__class__, self).calculate_left_margin()
+		label_left = self.fields[0].length / 2 * self.font_size * 0.6
+		self.border_left = max(label_left, self.border_left)
+
+	def get_y_labels(self):
+		max_value = self.max_value()
+		min_value = self.min_value()
+		range = max_value - min_value
+		top_pad = (range / 20.0) or 10
+		scale_range = (max_value + top_pad) - min_value
+		
+		scale_division = self.scale_divisions or (scale_range / 10.0)
+		
+		if self.scale_integers:
+		  scale_division = min(1, round(scale_division))
+		
+		#maxvalue = maxvalue%scale_division == 0 ? 
+		#  maxvalue : maxvalue + scale_division
+		labels = tuple(float_range(min_value, max_value, scale_division))
+		return labels
+
+	def calc_coords(self, field, value, width = None, height = None):
+		if width is None: width = self.field_width
+		if height is None: height = self.field_height
+		coords = dict(
+			x = width * field,
+			y = self.graph_height - value * height,
+			)
+		return coords
+
+	def draw_data(self):
+		min_value = self.min_value()
+		field_height = self.graph_height - self.font_size*2*self.top_font
+		y_label_span = max(self.get_y_labels()) - min(self.get_y_labels())
+		field_height /= float(y_label_span)
+		
+		field_width = self.field_width
+		#line = len(self.data)
+		
+		prev_sum = [0]*len(self.fields)
+		cum_sum = [-min_value]*len(self.fields)
+
+		coord_format = lambda c: '%(x)s %(y)s' % c
+		
+		for line_n, data in list(enumerate(self.data)).reversed():
+			apath = ''
+			
+			if not self.stacked: cum_sum = [-min_value]*len(self.fields)
+		
+			cum_sum = map(add, cum_sum, data['data'])
+			get_coords = lambda (i, val): self.calc_coords(i,
+														 val,
+														 field_width,
+														 field_height)
+			coords = map(get_coords, enumerate(cum_sum))
+			paths = map(coord_format, coords)
+			line_path = ' '.join(paths)
+
+			if self.area_fill:
+				# to draw the area, we'll use the line above, followed by
+				#  tracing the bottom from right to left
+				if self.stacked:
+					prev_sum_rev = list(enumerate(prev_sum)).reversed()
+					coords = map(get_coords, prev_sum_rev)
+					paths = map(coord_format, coords)
+					area_path = ' '.join(paths)
+					origin = paths[-1]
+				else:
+					area_path = "V#@graph_height"
+					origin = coord_format(get_coords(0,0))
+
+				p = self._create_element('path')
+				d = ' '.join((
+					'M',
+					origin,
+					'L',
+					line_path,
+					area_path,
+					'Z'
+				)
+				p.setAttribute('d', d)
+				p.setAttribute('class', 'fill%(line_n)s' % vars())
+				self.graph.appendChild(p)
+
+			# now draw the line itself
+			p = self._create_element('path')
+			p.setAttribute('d', 'M0 '+self.graph_height+' L'+line_path)
+			p.setAttribute('class', 'line%(line_n)s' % vars())
+			self.graph.appendChild(p)
+			
+			if self.show_data_points or self.show_data_values:
+				for i, value in enumerate(cum_sum):
+					if self.show_data_points:
+						circle = self._create_element(
+							'circle',
+							dict(
+								cx = str(field_width*i),
+								cy = str(self.graph_height - value*field_height),
+								r = '2.5',
+								)
+						circle.setAttribute('class', 'dataPoint%(line_n)s' % vars())
+						self.graph.appendChild(circle)
+					self.make_datapoint_text(
+						field_width*i,
+						self.graph_height - value*field_height - 6,
+						value + min_value
+						)
+
+			prev_sum = list(cum_sum)		
+
+
+	def get_css(self):
+		return """
+/* default line styles */
+.line1{
+	fill: none;
+	stroke: #ff0000;
+	stroke-width: 1px;	
+}
+.line2{
+	fill: none;
+	stroke: #0000ff;
+	stroke-width: 1px;	
+}
+.line3{
+	fill: none;
+	stroke: #00ff00;
+	stroke-width: 1px;	
+}
+.line4{
+	fill: none;
+	stroke: #ffcc00;
+	stroke-width: 1px;	
+}
+.line5{
+	fill: none;
+	stroke: #00ccff;
+	stroke-width: 1px;	
+}
+.line6{
+	fill: none;
+	stroke: #ff00ff;
+	stroke-width: 1px;	
+}
+.line7{
+	fill: none;
+	stroke: #00ffff;
+	stroke-width: 1px;	
+}
+.line8{
+	fill: none;
+	stroke: #ffff00;
+	stroke-width: 1px;	
+}
+.line9{
+	fill: none;
+	stroke: #ccc6666;
+	stroke-width: 1px;	
+}
+.line10{
+	fill: none;
+	stroke: #663399;
+	stroke-width: 1px;	
+}
+.line11{
+	fill: none;
+	stroke: #339900;
+	stroke-width: 1px;	
+}
+.line12{
+	fill: none;
+	stroke: #9966FF;
+	stroke-width: 1px;	
+}
+/* default fill styles */
+.fill1{
+	fill: #cc0000;
+	fill-opacity: 0.2;
+	stroke: none;
+}
+.fill2{
+	fill: #0000cc;
+	fill-opacity: 0.2;
+	stroke: none;
+}
+.fill3{
+	fill: #00cc00;
+	fill-opacity: 0.2;
+	stroke: none;
+}
+.fill4{
+	fill: #ffcc00;
+	fill-opacity: 0.2;
+	stroke: none;
+}
+.fill5{
+	fill: #00ccff;
+	fill-opacity: 0.2;
+	stroke: none;
+}
+.fill6{
+	fill: #ff00ff;
+	fill-opacity: 0.2;
+	stroke: none;
+}
+.fill7{
+	fill: #00ffff;
+	fill-opacity: 0.2;
+	stroke: none;
+}
+.fill8{
+	fill: #ffff00;
+	fill-opacity: 0.2;
+	stroke: none;
+}
+.fill9{
+	fill: #cc6666;
+	fill-opacity: 0.2;
+	stroke: none;
+}
+.fill10{
+	fill: #663399;
+	fill-opacity: 0.2;
+	stroke: none;
+}
+.fill11{
+	fill: #339900;
+	fill-opacity: 0.2;
+	stroke: none;
+}
+.fill12{
+	fill: #9966FF;
+	fill-opacity: 0.2;
+	stroke: none;
+}
+/* default line styles */
+.key1,.dataPoint1{
+	fill: #ff0000;
+	stroke: none;
+	stroke-width: 1px;	
+}
+.key2,.dataPoint2{
+	fill: #0000ff;
+	stroke: none;
+	stroke-width: 1px;	
+}
+.key3,.dataPoint3{
+	fill: #00ff00;
+	stroke: none;
+	stroke-width: 1px;	
+}
+.key4,.dataPoint4{
+	fill: #ffcc00;
+	stroke: none;
+	stroke-width: 1px;	
+}
+.key5,.dataPoint5{
+	fill: #00ccff;
+	stroke: none;
+	stroke-width: 1px;	
+}
+.key6,.dataPoint6{
+	fill: #ff00ff;
+	stroke: none;
+	stroke-width: 1px;	
+}
+.key7,.dataPoint7{
+	fill: #00ffff;
+	stroke: none;
+	stroke-width: 1px;	
+}
+.key8,.dataPoint8{
+	fill: #ffff00;
+	stroke: none;
+	stroke-width: 1px;	
+}
+.key9,.dataPoint9{
+	fill: #cc6666;
+	stroke: none;
+	stroke-width: 1px;	
+}
+.key10,.dataPoint10{
+	fill: #663399;
+	stroke: none;
+	stroke-width: 1px;	
+}
+.key11,.dataPoint11{
+	fill: #339900;
+	stroke: none;
+	stroke-width: 1px;	
+}
+.key12,.dataPoint12{
+	fill: #9966FF;
+	stroke: none;
+	stroke-width: 1px;	
+}
+"""