Miscellaneous

Simple Pygame Features

Displaying Text

# 1. define font:
font = pygame.font.SysFont('Arial', 20)
# 2. use font to write to canvas:
canvas.blit(font.render(str(mouse_pos), True, (255,255,255)), (200,700))

Polygons

Draw polygons on specific surface

# general:
# points = [[x1, y1], [x1, y2], [x2, y1], [x2, y2]]
#          [[bottom-left], [top-left], [bottom-right], [top-right]]
# points_transformed = reference_surface.transform(points)
# pygame.draw.polygon(reference_surface, color, points_transformed)

# example:
points = [[20, 70], [20, 20], [80, 20], [80, 70]]  # percentage relative to surface
points_transformend = session.grid_1.surface.transform(points)

#                   surface,   color,      coords_transformed
pygame.draw.polygon(viewport, (255, 0, 0), viewport.transform(rect_points))

Draw Polygon Layer (simple)

gis.py - simply draw polygons on a specific surface with a specific stroke and color. Note: when stroke is 0, the polygon will be filled.

def draw_polygon_layer(self, surface, df, stroke, fill):
  '''draw polygon layer, do not lerp'''
  try:
      for polygon in df.to_dict('records'):
          if fill:
              fill_color = pygame.Color(*fill)

          points = self.surface.transform(polygon['geometry'].exterior.coords)
          pygame.draw.polygon(self.surface, fill_color, points, stroke)

  except Exception as e:
      session.log += "\n%s" % e
      print("cannot draw polygon layer: ", e)

Draw polygon layer and lerp color using bool

gis.py - draw polygons on a specific surface with certain stroke; lerp color according to bool

def draw_polygon_layer_bool(self, surface, df, stroke, fill_false, fill_true=None, fill_attr=None):
  '''draw polygon layer, lerp using bool value'''
  try:
      for polygon in df.to_dict('records'):
          if fill_false:
              fill_color = pygame.Color(*fill_false)

              if fill_true:
                  fill_color = pygame.Color(fill_true) if polygon[fill_attr] else fill_color

          points = self.surface.transform(polygon['geometry'].exterior.coords)
          pygame.draw.polygon(self.surface, fill_color, points, stroke)

  except Exception as e:
      session.log += "\n%s" % e
      print("cannot draw polygon layer: ", e)

draw polygon layer and lerp colors according to float:

gis.py - draw polygons on a specific surface with certain stroke; lerp color according to float values

  def draw_polygon_layer_float(self, surface, df, stroke, fill, lerp_target=None, lerp_attr=None):
    '''draw polygon layer and lerp using float'''
    try:
        for polygon in df.to_dict('records'):
            if fill:
                fill_color = pygame.Color(*fill)

                if lerp_target:
                    target_color = pygame.Color(lerp_target)
                    fill_color = fill_color.lerp(target_color, polygon[lerp_attr] / df[lerp_attr].max())

            points = self.surface.transform(polygon['geometry'].exterior.coords)
            pygame.draw.polygon(self.surface, fill_color, points, stroke)

    except Exception as e:
        session.log += "\n%s" % e
        print("cannot draw polygon layer: ", e)

Images

Pygame is able to load images onto Surface objects from PNG, JPG, GIF, and BMP image files.

image = pygame.image.load("images/scenario_progressive.bmp")
canvas.blit(image, (0,0))

See more about the usage of pygame images under graphictools.

Creating your own project

In order to transfer the project’s focus to another neighborhood, you’d need to conduct the following steps:

input basemap raster file
- in our example project, we have a basemap file stored in .jpg-format. This file is provided by the config.py and should be set there.
input shapefile for polygons and raster data:
- further geodata can be loaded via Shapefiles using geopandas. In our example project, we have implemented a custom function in gis.py called read_shapefile() (evoked in buildings.py/load_data()) that handles the readout of the shapefile’s metadata, transfers the data into a pandas DataFrame and adds more custom data categories.
define corner coordinates / ROI (using GIS) and rotation of map. The basemap is essentially initialized in session.py with the corner coordinates of the image:

session.py:120

############################## INITIALIZATION #########################
#--------------------------------- gis --------------------------------
# Initialize geographic viewport and basemap
_gis = gis.GIS(
    config['CANVAS_SIZE'],
    # northeast          northwest           southwest           southeast
    [[1013631, 7207409], [1012961, 7207198], [1013359, 7205932], [1014029, 7206143]],
    viewport)

basemap = gis.Basemap(
    config['CANVAS_SIZE'], config['BASEMAP_FILE'],
    # northwest          southwest           southeast           northeast
    [[1012695, 7207571], [1012695, 7205976], [1014205, 7205976], [1014205, 7207571]],
    _gis)
basemap.warp()

Take care to crop the basemap image properly in the frontend section:

frontend.py:216 crop_width and crop_height define how much the basemap has to be cropped.

# basemap
if session.show_basemap:
    crop_width = 4644
    crop_height = 800
    self.canvas.blit(session.basemap.image, (0, 0),
                      (0, 0, crop_width, crop_height))