Add an example with cistom 'text labels'. Closes #10.

Author: flopp

Makefile

@@ -32,6 +32,7 @@ format:
 
 .PHONY: run-examples
 run-examples:
+	(cd examples && PYTHONPATH=.. ../.env/bin/python custom_objects.py)
 	(cd examples && PYTHONPATH=.. ../.env/bin/python draw_gpx.py running.gpx)
 	(cd examples && PYTHONPATH=.. ../.env/bin/python frankfurt_newyork.py)
 	(cd examples && PYTHONPATH=.. ../.env/bin/python freiburg_area.py)

examples/custom_objects.py

@@ -0,0 +1,134 @@
+#!/usr/bin/env python
+
+# py-staticmaps
+# Copyright (c) 2021 Florian Pigorsch; see /LICENSE for licensing information
+
+import cairo  # type: ignore
+import s2sphere  # type: ignore
+import staticmaps
+
+
+class TextLabel(staticmaps.Object):
+    def __init__(self, latlng: s2sphere.LatLng, text: str) -> None:
+        staticmaps.Object.__init__(self)
+        self._latlng = latlng
+        self._text = text
+        self._margin = 4
+        self._arrow = 16
+        self._font_size = 12
+
+    def latlng(self) -> s2sphere.LatLng:
+        return self._latlng
+
+    def bounds(self) -> s2sphere.LatLngRect:
+        return s2sphere.LatLngRect.from_point(self._latlng)
+
+    def extra_pixel_bounds(self) -> staticmaps.PixelBoundsT:
+        # Guess text extents.
+        tw = len(self._text) * self._font_size * 0.5
+        th = self._font_size * 1.2
+        w = max(self._arrow, tw + 2.0 * self._margin)
+        return (int(w / 2.0), int(th + 2.0 * self._margin + self._arrow), int(w / 2), 0)
+
+    def render_svg(self, renderer: staticmaps.SvgRenderer) -> None:
+        x, y = renderer.transformer().ll2pixel(self.latlng())
+
+        # guess text extents
+        tw = len(self._text) * self._font_size * 0.5
+        th = self._font_size * 1.2
+
+        w = max(self._arrow, tw + 2 * self._margin)
+        h = th + 2 * self._margin
+
+        path = renderer.drawing().path(
+            fill="#ffffff",
+            stroke="#ff0000",
+            stroke_width=1,
+            opacity=1.0,
+        )
+        path.push(f"M {x} {y}")
+        path.push(f" l {self._arrow / 2} {-self._arrow}")
+        path.push(f" l {w / 2 - self._arrow / 2} 0")
+        path.push(f" l 0 {-h}")
+        path.push(f" l {-w} 0")
+        path.push(f" l 0 {h}")
+        path.push(f" l {w / 2 - self._arrow / 2} 0")
+        path.push("Z")
+        renderer.group().add(path)
+
+        renderer.group().add(
+            renderer.drawing().text(
+                self._text,
+                text_anchor="middle",
+                dominant_baseline="central",
+                insert=(x, y - self._arrow - h / 2),
+                font_family="sans-serif",
+                font_size=f"{self._font_size}px",
+                fill="#000000",
+            )
+        )
+
+    def render_cairo(self, renderer: staticmaps.CairoRenderer) -> None:
+        x, y = renderer.transformer().ll2pixel(self.latlng())
+
+        ctx = renderer.context()
+        ctx.select_font_face("Sans", cairo.FONT_SLANT_NORMAL, cairo.FONT_WEIGHT_NORMAL)
+
+        ctx.set_font_size(self._font_size)
+        x_bearing, y_bearing, tw, th, _, _ = ctx.text_extents(self._text)
+
+        w = max(self._arrow, tw + 2 * self._margin)
+        h = th + 2 * self._margin
+
+        path = [
+            (x, y),
+            (x + self._arrow / 2, y - self._arrow),
+            (x + w / 2, y - self._arrow),
+            (x + w / 2, y - self._arrow - h),
+            (x - w / 2, y - self._arrow - h),
+            (x - w / 2, y - self._arrow),
+            (x - self._arrow / 2, y - self._arrow),
+        ]
+
+        ctx.set_source_rgb(1, 1, 1)
+        ctx.new_path()
+        for p in path:
+            ctx.line_to(*p)
+        ctx.close_path()
+        ctx.fill()
+
+        ctx.set_source_rgb(1, 0, 0)
+        ctx.set_line_width(1)
+        ctx.new_path()
+        for p in path:
+            ctx.line_to(*p)
+        ctx.close_path()
+        ctx.stroke()
+
+        ctx.set_source_rgb(0, 0, 0)
+        ctx.set_line_width(1)
+        ctx.move_to(x - tw / 2 - x_bearing, y - self._arrow - h / 2 - y_bearing - th / 2)
+        ctx.show_text(self._text)
+        ctx.stroke()
+
+
+context = staticmaps.Context()
+
+p1 = staticmaps.create_latlng(48.005774, 7.834042)
+p2 = staticmaps.create_latlng(47.988716, 7.868804)
+p3 = staticmaps.create_latlng(47.985958, 7.824601)
+
+context.add_object(TextLabel(p1, "X"))
+context.add_object(TextLabel(p2, "Label"))
+context.add_object(TextLabel(p3, "This is a very long text label"))
+
+context.set_tile_provider(staticmaps.tile_provider_CartoDarkNoLabels)
+
+# render png
+image = context.render_cairo(800, 500)
+image.write_to_png("custom_objects.png")
+
+# render svg
+svg_image = context.render_svg(800, 500)
+with open("custom_objects.svg", "w", encoding="utf-8") as f:
+    svg_image.write(f, pretty=True)

staticmaps/__init__.py

@@ -3,6 +3,7 @@
 
 # flake8: noqa
 from .area import Area
+from .cairo_renderer import CairoRenderer
 from .circle import Circle
 from .color import (
     parse_color,
@@ -26,13 +27,18 @@
 from .marker import Marker
 from .meta import GITHUB_URL, LIB_NAME, VERSION
 from .object import Object, PixelBoundsT
+from .svg_renderer import SvgRenderer
 from .tile_downloader import TileDownloader
 from .tile_provider import (
     TileProvider,
     default_tile_providers,
     tile_provider_OSM,
     tile_provider_StamenTerrain,
     tile_provider_StamenToner,
+    tile_provider_StamenTonerLite,
     tile_provider_ArcGISWorldImagery,
+    tile_provider_CartoNoLabels,
+    tile_provider_CartoDarkNoLabels,
+    tile_provider_None,
 )
 from .transformer import Transformer

staticmaps/cairo_renderer.py

@@ -84,7 +84,7 @@ def render_attribution(self, attribution: typing.Optional[str]) -> None:
             return
         width, height = self._trans.image_size()
         self._context.select_font_face("Sans", cairo.FONT_SLANT_NORMAL, cairo.FONT_WEIGHT_NORMAL)
-        font_size = 12.0
+        font_size = 9.0
         while True:
             self._context.set_font_size(font_size)
             _, f_descent, f_height, _, _ = self._context.font_extents()