Changes between Version 4 and Version 5 of tilegen

Timestamp:

Jun 28, 2011, 3:30:37 PM (13 years ago)

Author:

dennisw

Comment:

--

tilegen

@@ -2 +2 @@
 Let's assume that non-existed tiles will be generated realtime:
 == Website ==
-It all starts at the website. A user opens the heatmap, and the browser starts requesting tiles. Let's say tile 1,1 at zoomlevel (x)1 is requested, using the classic colorscheme. The browser will request {{{classic/1/1,1.png}}}. 
+It all starts at the website. A user opens the heatmap, and the browser starts requesting tiles. Let's say tile 1,1 at zoomlevel (x)1 is requested. The browser will request {{{tile/1/1,1.png}}}. 
 
-Note that these values are variables. In fact, in the gheat/urls.py, the following urlpattern is given: {{{r'^(?P<color_scheme>\w+)/(?P<zoom>\d+)/(?P<x>\d+),(?P<y>\d+).png$'}}}. So when the browser requests an image, the urlpattern is recognized and the url is sent to the {{{serve_tile}}} function in {{{gheat.views}}}, as declared in gheat/urls.py.
+Note that these values are variables. In fact, in the website/urls.py, the following urlpattern is given: {{{r'^tile/(?P<zoom>\d+)/(?P<x>\d+),(?P<y>\d+).png$'}}}. So when the browser requests an image, the urlpattern is recognized and the url is sent to the {{{serve_tile}}} function in {{{website/tile.py}}}, as declared in website/urls.py.
+
+== website/tile.py ==
+=== serve_tile ===
+This function starts with a check for cached files. A key is made with the variables from the url and the database is checked for a tile linked to that key. If no cached tile is found, a new one will be created. The {{{make_tile}}} function is called for this using the same parameters from url as before.
+
+=== make_tile ===
+This function requests data from the database using the parameters, and for every coordinate it get's in return, it places a dot on the tile. Dot size and transparancy are scaled by the signal strength the accespoint was received with.
+
+Some calculations are made before and after the data request, and then tile is returned and will be shown on the map.
 
 == gheat/views.py ==
 === serve_tile ===
 The serve_tile function is responsible for serving the tile images.
-
-The function starts with a variable validation. Is the colorscheme existing? And are the zoomlevels, x, and y really digits? Is the zoomrange supported? If any error should occur, the tile will not be generated.
-
-Since our variables passed the validation, and the tile doesn't exist yet, the data will be sent to the {{{generate_tile}}} function.
+The url parameters validated, and a request with these parameters will be sent to the {{{generate_tile}}} function.
 
 === generate_tile ===
-This function sends the variables to the backend class Tile: {{{tile = backend.Tile(color_scheme, dots, zoom, x, y, fspath)}}}. The backend, declared in gheat/gheatsettings.py is the gheat/pygame_.py file. --This calculates the lat/lng bounds for the tile. After this, depending on existence, a tile will be rebuild and served or served from cache, or an empty will be served.--
+This function sends the parameters to the backend class Tile: {{{tile = backend.Tile(color_scheme, dots, zoom, x, y, fspath)}}}. The backend, declared in gheat/gheatsettings.py is the gheat/pygame_.py file. --This calculates the lat/lng bounds for the tile. After this, depending on existence, a tile will be rebuild and served or served from cache, or an empty will be served.--
 
 == gheat/pygame_.py & gheat/base.py ==
 These two files will be explained in one section, since the Tile class in base.py is the base class for the Tile class in pygame.py.
 
-It starts with translating the tile coords to pixel coords. It adds the image height and with to the pixel coords, and translates it to lat & lon. These values represent the boundaries of the tile.
+Combined, these files get the parameters, request data from the database, and for every coordinate they place a dot on the map. These dots are shown in a color depending on the selected color scheme. Instead of the actual dots being generated by the scripts (like in tile.py), the source of these dots are images located in {{{gheat/etc/dots/}}}. The same goes for the color schemes, {{{gheat/etc/color-schemes/}}}
 
-still WIP
+A tile is returned back to {{{views.generate_tile}}}, which returns it to {{{views.serve_tile}}}, which returns it to the user and is shown on the map.