store background_rgb as 0-1 float, not 0-255 int

src/c3nav/mapdata/render/engines/base.py

@@ -43,7 +43,7 @@ class RenderEngine(ABC):
         self.buffered_width = self.width + 2 * self.buffer
         self.buffered_height = self.height + 2 * self.buffer
 
-        self.background_rgb = tuple(int(background[i:i + 2], 16) for i in range(1, 6, 2))
+        self.background_rgb = tuple(int(background[i:i + 2], 16)/255 for i in range(1, 6, 2))
 
         # keep track which area of the image has which altitude currently
         self.altitudes = {}

src/c3nav/mapdata/render/engines/opengl.py

@@ -104,7 +104,7 @@ class OpenGLWorker(threading.Thread):
             task = self._queue.get()
 
             ctx = self._get_ctx(task.width*task.samples, task.height*task.samples)
-            ctx.ctx.clear(*(i / 255 for i in task.background_rgb))
+            ctx.ctx.clear(*task.background_rgb)
 
             if task.vertices:
                 vbo = ctx.ctx.buffer(task.vertices)

src/c3nav/mapdata/render/engines/svg.py

@@ -81,7 +81,7 @@ class SVGEngine(RenderEngine):
 
         if self.width == 256 and self.height == 256 and not self.g:
             # create empty tile png with minimal size, indexed color palette with only one entry
-            plte = b'PLTE' + bytearray(self.background_rgb)
+            plte = b'PLTE' + bytearray(tuple(int(i*255) for i in self.background_rgb))
             return (b'\x89PNG\r\n\x1a\n' +
                     b'\x00\x00\x00\rIHDR\x00\x00\x01\x00\x00\x00\x01\x00\x01\x03\x00\x00\x00f\xbc:%\x00\x00\x00\x03' +
                     plte + zlib.crc32(plte).to_bytes(4, byteorder='big') +
@@ -103,7 +103,7 @@ class SVGEngine(RenderEngine):
             context = cairocffi.Context(surface)
 
             # set background color
-            context.set_source(cairocffi.SolidPattern(*(i/255 for i in self.background_rgb)))
+            context.set_source(cairocffi.SolidPattern(*self.background_rgb))
             context.paint()
 
             # paste buffered immage with offset