Make marker sizes correspond to radius.

This change means that the size geometry in Marker objects is roughly the
radius of the marker.  The primary advantage of this is that the sizes no
longer step every 2 increase in size due to integer division by 2.

Fixes #70.

examples/line_plot_example.py

@@ -10,7 +10,6 @@
 from tempe import colors
 from tempe.data_view import Repeat
 from tempe.geometry import ColumnGeometry, PointsToLines
-from tempe.markers import Marker
 from tempe.surface import Surface
 from tempe.text import CENTER, TOP, RIGHT
 

examples/polar_example.py

@@ -136,7 +136,7 @@
                     ]
                 ),
             ),
-            ColumnGeometry([Repeat(24)]),
+            ColumnGeometry([Repeat(12)]),
         ]
     ),
     Repeat(grey_3),

examples/polar_plot_example.py

@@ -10,9 +10,8 @@
 
 from tempe import colors
 from tempe.colormaps.viridis import viridis
-from tempe.data_view import Range, Repeat
-from tempe.geometry import ColumnGeometry, RowGeometry, PointsToLines
-from tempe.markers import Marker
+from tempe.data_view import Repeat
+from tempe.geometry import ColumnGeometry, PointsToLines
 from tempe.polar_geometry import polar_points, polar_r_lines
 from tempe.surface import Surface
 from tempe.text import LEFT, CENTER, RIGHT, TOP, BOTTOM

examples/scatter_plot_example.py

@@ -93,7 +93,7 @@ def scale_values(self, data):
         low_screen = self.low_screen
         scale = self.scale
         for i, value in enumerate(data):
-            screen[i] = int(sqrt(low_screen + scale * (value - low_data)))
+            screen[i] = int(sqrt(low_screen + scale * (value - low_data)) // 2)
         return screen
 
 

examples/shapes_examples.py

@@ -186,7 +186,7 @@
         [
             Range(160, 320, 16),
             Repeat(30),
-            Range(5, 16, 1),
+            Range(1, 13, 1),
         ]
     ),
     Interpolated(viridis, 10),

src/tempe/markers.py

@@ -40,22 +40,22 @@ def draw_raster(self, raster):
             size = geometry[2]
             if px + size < 0 or px - size > w or py + size < 0 or py - size > h:
                 continue
-            if size < 2 or marker == Marker.PIXEL:
+            if size < 1 or marker == Marker.PIXEL:
                 buffer.pixel(px, py, color)
             elif marker == Marker.CIRCLE:
-                buffer.ellipse(px, py, size // 2, size // 2, color, True)
+                buffer.ellipse(px, py, size, size, color, True)
             elif marker == Marker.SQUARE:
-                buffer.rect(px - size // 2, py - size // 2, size, size, color, True)
+                buffer.rect(px - size, py - size, 2*size+1, 2*size+1, color, True)
             elif marker == Marker.HLINE:
-                buffer.hline(px - size // 2, py, size, color)
+                buffer.hline(px - size, py, 2*size+1, color)
             elif marker == Marker.VLINE:
-                buffer.vline(px, py - size // 2, size, color)
+                buffer.vline(px, py - size, 2*size+1, color)
             elif marker == Marker.PLUS:
-                size = 2 * (size // 2) + 1  # odd numper of pixels
-                buffer.hline(px - size // 2, py, size, color)
-                buffer.vline(px, py - size // 2, size, color)
+                d = 2 * size + 1  # odd numper of pixels
+                buffer.hline(px - size, py, d, color)
+                buffer.vline(px, py - size, d, color)
             elif marker == Marker.CROSS:
-                d = (size * 17 // 48) + 1  # very rough approximation of 1/(2*sqrt(2))
+                d = (size * 17 // 24) + 1  # very rough approximation of r/(sqrt(2)) + 1
                 buffer.line(px - d, py - d, px + d, py + d, color)
                 buffer.line(px - d, py + d, px + d, py - d, color)
             elif isinstance(marker, str):

src/tempe/markers.pyi

@@ -27,6 +27,8 @@ class Marker:
 class Markers(ColoredGeometry[point_length]):
     """Display sized, colored markers at points.
 
+    Markers expect a geometry of the form (x, y, radius).
+
     Parameters
     ----------
     geometry : Iterable[geom] | None
@@ -73,6 +75,8 @@ class Markers(ColoredGeometry[point_length]):
 class Points(ColoredGeometry[point]):
     """Display colored markers at points.
 
+    Points expect a geometry of the form (x, y)
+
     Parameters
     ----------
     geometry : Iterable[geom] | None

src/tempe/surface.pyi

@@ -342,12 +342,14 @@ class Surface:
     ) -> Markers:
         """Create a new Markers object and add it to the layer.
 
+        Markers expect a geometry of the form (x, y, radius).
+
         Parameters
         ----------
         layer : Any
             The layer that the Markers object is added to.
         geometry : Geometry[tuple[int, int, int]] | tuple[int, int, int]
-            The geometry to use, or if a tuple of 3 ints, a single point and size.
+            The geometry to use, or if a tuple of 3 ints, a single point and radius.
         colors : Iterable[int] | int
             The colors of each marker, or a color to use for all markers.
         markers : Iterable[Any] | int | str | framebuf.FrameBuffer