WIP to make svg of database usage

This will be folded into the codebase proper once
proved

makesvg.py

@@ -0,0 +1,136 @@
+from __future__ import annotations
+import dis
+
+import apsw, pprint, sys, apsw.ext, math, apsw.shell
+
+
+con = apsw.Connection(sys.argv[1])
+
+
+root, group, each = (apsw.ext.analyze_pages(con, n) for n in range(3))
+
+if False:
+    pprint.pprint(root)
+    pprint.pprint(group)
+
+# angles are 0.0 through 1.0
+# distance (radius) is 0 through 1.0
+
+# use this as radius for output coordinates as int
+RADIUS = 1000
+
+
+def colour_for_angle(angle: float) -> str:
+    # these are zero to one and cover how dark to light the colours
+    # become.  base is added to each rgb, while span is how much
+    # the values range above that.
+    base = 0
+    span = 1
+    assert base + span <= 1
+
+    radians = angle * math.pi
+    third = 1 / 3 * math.pi
+
+    red = int(255 * (base + span * abs(math.cos(radians))))
+    green = int(255 * (base + span * abs(math.cos(third + radians))))
+    blue = int(255 * (base + span * abs(math.cos(third + third + radians))))
+
+    return f"#{red:02x}{green:02x}{blue:02x}"
+
+
+def pos_for_angle(angle: float, distance: float) -> tuple[float, float]:
+    "give x,y for distance from centre"
+
+    # the minus bit is because trig has east as 0 but we want north as
+    # zero
+    radians = angle * 2 * math.pi - (1 / 4 * 2 * math.pi)
+
+    return distance * math.cos(radians), distance * math.sin(radians)
+
+
+def c(v: float | list[float]) -> str:
+    # outputs a coordinate scaling by RADIUS
+    if isinstance(v, float):
+        return str(round(v * RADIUS))
+    return " ".join(str(round(x * RADIUS)) for x in v)
+
+
+def p(angle, distance):
+    return c(pos_for_angle(angle, distance))
+
+
+def slice(id: str, start_angle: float, end_angle: float, start_distance: float, end_distance: float):
+    assert 0 <= start_angle <= 1.0
+    assert 0 <= end_angle <= 1.0
+    assert end_angle > start_angle
+    assert 0 <= start_distance <= 1.0
+    assert 0 <= end_distance <= 1.0
+    assert end_distance > start_distance
+
+    l = 1 if (end_angle - start_angle) > 1 / 2 else 0
+
+    d = []
+    d.append(f"M {p(start_angle, start_distance)}")
+    d.append(f"L {p(start_angle, end_distance)}")
+    d.append(f"A {c(end_distance)} {c(end_distance)} 0 {l} 1 {p(end_angle, end_distance)}")
+    d.append(f"L {p(end_angle, start_distance)}")
+    d.append(f"A {c(start_distance)} {c(start_distance)} 0 {l} 0 {p(start_angle, start_distance)}")
+
+    ds = " ".join(d)
+
+    fill = colour_for_angle((start_angle + end_angle) / 2)
+    return f"""<path id="{id}" d="{ds}" stroke="black" fill="{fill}" stroke-width="1"/>"""
+
+def text(id: str, usage)->str:
+    return f"""<text id="{id}">{usage}</text>"""
+
+
+# controls how much whitespace is around the edges
+OVERSCAN = 1.2
+header = f"""<svg xmlns="http://www.w3.org/2000/svg" viewBox="-{round(RADIUS*OVERSCAN)} {-round(RADIUS*OVERSCAN)} {round(RADIUS*OVERSCAN*2)} {round(RADIUS*OVERSCAN*2)}">"""
+footer = "</svg>"
+
+# maps which element hovering over causes a response on
+hover_response :dict[str,str]= {}
+
+id_counter = 0
+def next_id():
+    global id_counter
+    id_counter+=1
+    return f"id{id_counter}"
+
+out = [header]
+
+# inner summary circle
+id = next_id()
+out.append(f"""<circle id="{id}" r="{c(.3)}" fill="#777"/>""")
+
+resp=next_id()
+out.append(text(resp, root))
+hover_response[id]=resp
+
+
+
+ring1_start = 0
+for name, usage in group.items():
+    ring1_proportion = usage.pages_used / root.pages_total
+    id=next_id()
+    out.append(slice(id, ring1_start, ring1_start + ring1_proportion, 1 / 3, 0.6))
+    ring2_start = ring1_start
+    ring1_start += ring1_proportion
+
+    for child in sorted(usage.tables + usage.indices):
+        usage2 = each[child]
+        ring2_proportion = usage2.pages_used / root.pages_total
+        id=next_id()
+        out.append(slice(id, ring2_start, ring2_start + ring2_proportion, 2 / 3, 1.0))
+        ring2_start += ring2_proportion
+
+out.append("<style>")
+for source, target in hover_response.items():
+    out.append(f"""#{target} {{ display: none;}}""")
+    out.append(f"""#{source}:hover ~ #{target}, #{target}:hover {{display:block;}}""")
+out.append("</style>")
+
+with open(sys.argv[2], "wt") as f:
+    f.write("\n".join(out))