tl.geodrawing.controller

Functions

tl.geodrawing.controller.inverse_mercator(y)

Inverse Mercator projection. inverse_mercator(1) is roughly 85.

>>> abs(inverse_mercator(0)) < 1e-6
True
>>> inverse_mercator(1)
85.05112...
>>> inverse_mercator(-1)
-85.05112...

tl.geodrawing.controller.mercator(latitude)

Mercator projection. mercator(85) is roughly 1.

>>> abs(mercator(0)) < 1e-6
True
>>> mercator(85.05113)
1.00000...
>>> mercator(-85.05113)
-1.00000...

Classes

class tl.geodrawing.controller.GeoCoordinateCM(controller, ctx)

Bases: object

Context manager that transforms a cairo context to geo-coordinates.

A GeoSurfaceController applies a geo-coordinate transformation to a cairo context when the context manager is entered. Upon exit, the context’s transformation matrix is reset to what it was before.

class tl.geodrawing.controller.GeoSurfaceController(update_callback=<function <lambda> at 0x9ccbae4>, tile_source=None)

Bases: object

State and background controller for a geodrawing cairo surface.

abs2geo(x, y)

center

center_xy

create_surface()

draw_frame(ctx)

expose(ctx)

geo2abs(longitude, latitude)

geo2px(longitude, latitude)

Calculate the pixel that contains a geo-coordinate pair.

height

max_zoom

move_rel(x, y)

px2geo(x, y)

Calculate geo coordinates at the center of a pixel.

tiles()

transform_for_geo(ctx)

Transform a cairo context to geo-coordinates.

After this, the associated surface’s pixels are addressed by an appropriate interval of Mercator-transformed geo-coordinates.

transformed_for_geo(ctx)

Return a GeoCoordinateCM applied to a cairo context.

update_surface()

view(x0, y0, x1, y1, padding=0)

width

zoom

zoom_rel(x, y, dz)

class tl.geodrawing.controller.TransformSurfaceProperty(func)

Bases: object