#!/usr/bin/env python # # A Diagram abstraction based on Cairo # # Copyright (C) 2018 Antonio Ospite # # This program is free software: you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation, either version 3 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program. If not, see . from math import cos, sin, pi import cairo try: from .diagram import Diagram except ValueError: from diagram import Diagram class CairoDiagram(Diagram): def __init__(self, width, height, **kwargs): super(CairoDiagram, self).__init__(width, height, **kwargs) self.surface = cairo.RecordingSurface(0, (0, 0, width, height)) self.cr = cr = cairo.Context(self.surface) cr.select_font_face("Georgia", cairo.FONT_SLANT_NORMAL, cairo.FONT_WEIGHT_NORMAL) cr.set_font_size(self.font_size) cr.set_line_width(self.stroke_width) cr.set_line_join(cairo.LINE_JOIN_ROUND) def clear(self): cr = self.cr r, g, b, a = self.color_to_rgba(self.background) cr.set_source_rgba(r, g, b, a) cr.paint() def save_svg(self, filename): surface = cairo.SVGSurface(filename + '.svg', self.width, self.height) # TODO: call surface.set_document_unit() to set units to pixels cr = cairo.Context(surface) cr.set_source_surface(self.surface, 0, 0) cr.paint() def save_png(self, filename): surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, self.width, self.height) cr = cairo.Context(surface) cr.set_source_surface(self.surface, 0, 0) cr.paint() surface.write_to_png(filename + '.png') def show(self): from PIL import Image from io import BytesIO f = BytesIO() surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, self.width, self.height) cr = cairo.Context(surface) cr.set_source_surface(self.surface, 0, 0) cr.paint() surface.write_to_png(f) f.seek(0) im = Image.open(f) im.show() def _draw_polygon(self, verts): cr = self.cr v = verts[0] cr.move_to(v[0], v[1]) for v in verts[1:]: cr.line_to(v[0], v[1]) cr.close_path() def _fill(self, fill_color, preserve=False): if fill_color: cr = self.cr r, g, b, a = self.color_to_rgba(fill_color) cr.set_source_rgba(r, g, b, a) if preserve: cr.fill_preserve() else: cr.fill() def _stroke(self, stroke_color, preserve=False): if stroke_color: cr = self.cr r, g, b, a = self.color_to_rgba(stroke_color) cr.set_source_rgba(r, g, b, a) if preserve: cr.stroke_preserve() else: cr.stroke() def draw_polygon_by_verts(self, verts, stroke_color=(0, 0, 0), fill_color=None): cr = self.cr cr.save() self._draw_polygon(verts) self._fill(fill_color, preserve=True) self._stroke(stroke_color) cr.restore() def draw_star_by_verts(self, cx, cy, verts, stroke_color=(0, 0, 0)): cr = self.cr for v in verts: cr.move_to(cx, cy) cr.line_to(v[0], v[1]) self._stroke(stroke_color) def draw_circle(self, cx, cy, radius=10.0, stroke_color=None, fill_color=(0, 0, 0, 0.5)): cr = self.cr cr.save() cr.arc(cx, cy, radius, 0, 2 * pi) self._fill(fill_color, preserve=True) self._stroke(stroke_color) cr.restore() def draw_line(self, x1, y1, x2, y2, stroke_color=(0, 0, 0, 1)): cr = self.cr cr.move_to(x1, y1) cr.line_to(x2, y2) self._stroke(stroke_color) def draw_rect_from_center(self, cx, cy, width, height, theta=0.0, stroke_color=None, fill_color=(1, 1, 1, 0.8)): # the position of the center of a rectangle at (0,0) mx = width / 2.0 my = height / 2.0 # calculate the position of the bottom-left corner after rotating the # rectangle around the center rx = cx - (mx * cos(theta) - my * sin(theta)) ry = cy - (mx * sin(theta) + my * cos(theta)) self.draw_rect(rx, ry, width, height, theta, stroke_color, fill_color) def draw_rect(self, x, y, width, height, theta=0, stroke_color=None, fill_color=(1, 1, 1, 0.8)): cr = self.cr cr.save() cr.translate(x, y) cr.rotate(theta) cr.rectangle(0, 0, width, height) self._fill(fill_color, preserve=True) self._stroke(stroke_color) cr.restore() def draw_centered_text(self, cx, cy, text, theta=0.0, color=(0, 0, 0), align_baseline=False, bb_stroke_color=None, bb_fill_color=None): cr = self.cr x_bearing, y_bearing, width, height, x_advance = cr.text_extents(text)[:5] ascent, descent = cr.font_extents()[:2] # The offset of the lower-left corner of the text. tx = width / 2.0 + x_bearing if align_baseline: # When aligning to the baseline it is convenient the make the # bounding box depend on the font vertical extent and not from the # text content. ty = 0 bb = [0, descent, width, -ascent] else: ty = height / 2.0 + y_bearing bb = [0, y_bearing, width, height] # The coordinate of the lower-left corner of the rotated rectangle rx = cx - tx * cos(theta) + ty * sin(theta) ry = cy - tx * sin(theta) - ty * cos(theta) cr.save() cr.translate(rx, ry) cr.rotate(theta) if bb_stroke_color or bb_fill_color: self.draw_rect(bb[0], bb[1], bb[2], bb[3], 0, bb_stroke_color, bb_fill_color) r, g, b, a = self.color_to_rgba(color) cr.set_source_rgba(r, g, b, a) cr.move_to(0, 0) cr.show_text(text) cr.restore() return x_advance def test(): diagram = CairoDiagram(400, 400) diagram.clear() x = 40 y = 200 x_offset = x theta = 0 diagram.draw_line(0, y, 400, y, (1, 0, 0, 1)) advance = diagram.draw_centered_text(x_offset, y, "Ciao", theta, align_baseline=True, bb_stroke_color=(0, 0, 0, 0.5), bb_fill_color=(1, 1, 1, 0.8)) x_offset += advance advance = diagram.draw_centered_text(x_offset, y, "____", theta + pi / 4, align_baseline=True, bb_stroke_color=(0, 0, 0, 0.5), bb_fill_color=(1, 1, 1, 0.8)) x_offset += advance advance = diagram.draw_centered_text(x_offset, y, "jxpqdlf", theta + pi / 2, align_baseline=True, bb_stroke_color=(0, 0, 0, 0.5), bb_fill_color=(1, 1, 1, 0.8)) x_offset += advance advance = diagram.draw_centered_text(x_offset, y, "pppp", theta + 3 * pi / 4, align_baseline=True, bb_stroke_color=(0, 0, 0, 0.5), bb_fill_color=(1, 1, 1, 0.8)) x_offset += advance advance = diagram.draw_centered_text(x_offset, y, "dddd", theta + pi, align_baseline=True, bb_stroke_color=(0, 0, 0, 0.5), bb_fill_color=(1, 1, 1, 0.8)) x_offset += advance advance = diagram.draw_centered_text(x_offset, y, "Jjjj", theta + 5 * pi / 4, align_baseline=True, bb_stroke_color=(0, 0, 0, 0.5), bb_fill_color=(1, 1, 1, 0.8)) x_offset += advance advance = diagram.draw_centered_text(x_offset, y, "1369", theta + 3 * pi / 2, color=(0, 1, 0), align_baseline=True, bb_stroke_color=(0, 0, 0, 0.5), bb_fill_color=(1, 1, 1, 0.8)) x_offset += advance advance = diagram.draw_centered_text(x_offset, y, "qqqq", theta + 7 * pi / 4, align_baseline=True, bb_stroke_color=(0, 0, 0, 0.5), bb_fill_color=(1, 1, 1, 0.8)) x_offset += advance diagram.draw_rect(40, 40, 300, 100, stroke_color=(0, 0, 0, 0.8)) diagram.draw_rect(40, 40, 300, 100, pi / 30, stroke_color=(0, 0, 0, 0.8)) verts = diagram.draw_regular_polygon(190, 90, 3, 20) diagram.draw_rect(40, 250, 300, 100, stroke_color=(0, 0, 0, 0.8)) diagram.draw_rect_from_center(40 + 150, 250 + 50, 300, 100, theta=(pi / 40), stroke_color=(1, 0, 0), fill_color=None) verts = diagram.draw_regular_polygon(190, 300, 6, 20, pi / 3., (0, 0, 1, 0.5), (0, 1, 0.5)) diagram.draw_apothem_star(190, 300, 6, 20, 0, (1, 0, 1)) diagram.draw_star_by_verts(190, 300, verts, (1, 0, 0, 0.5)) diagram.draw_star(190, 300, 6, 25, 0, (1, 0, 1, 0.2)) diagram.draw_circle(190, 300, 30, (0, 1, 0, 0.5), None) diagram.draw_circle(100, 300, 30, (1, 0, 0, 0.5), (0, 1, 1, 0.5)) diagram.show() if __name__ == "__main__": test()