fix: Animation fixes to reads

README.md

@@ -25,7 +25,7 @@ SparseIO is a Rust library for sparse, out-of-order materialization of large byt
 Instead of eagerly copying an entire object from source to destination, SparseIO allows you to fetch only the chunks you ask for. It tracks what is already present for efficient caching, and deduplicates concurrent reads for the same chunk.
 
 <p align="center">
-<img width="600px" src="./docs/static/general-read.gif">
+<img width="600px" src="./docs/static/general-read.gif" alt="SparseIO animation showing a cache miss, prefetch, and cache hit as sparse chunks materialize.">
 </p>
 
 ## Core Premise

scripts/animations/README.md

@@ -12,7 +12,7 @@ This directory holds short `manim` scenes used to generate README-friendly anima
 python3 -m venv .venv
 source .venv/bin/activate
 python3 -m pip install --upgrade pip
-python3 -m pip install manim==0.19.0
+python3 -m pip install -r requirements.txt
 ```
 
 `ffmpeg` is also required for GIF output.

scripts/animations/common.sh

@@ -8,13 +8,23 @@ VENV_DIR="$ANIMATIONS_DIR/.venv"
 PYTHON_BIN="$VENV_DIR/bin/python3"
 REQUIREMENTS_FILE="$ANIMATIONS_DIR/requirements.txt"
 
+ensure_ffmpeg() {
+  if ! command -v ffmpeg >/dev/null 2>&1; then
+    echo "ffmpeg is required to render GIF output" >&2
+    echo "install ffmpeg and rerun the render script" >&2
+    exit 1
+  fi
+}
+
 ensure_animation_venv() {
   if [[ ! -x "$PYTHON_BIN" ]]; then
     echo "creating animation virtualenv at $VENV_DIR" >&2
     python3 -m venv "$VENV_DIR"
     "$PYTHON_BIN" -m pip install --upgrade pip
-    "$PYTHON_BIN" -m pip install -r "$REQUIREMENTS_FILE"
   fi
+
+  "$PYTHON_BIN" -m pip install -r "$REQUIREMENTS_FILE"
 }
 
+ensure_ffmpeg
 ensure_animation_venv

scripts/animations/general-read/scene.py

@@ -9,7 +9,6 @@
     UP,
     Arrow,
     Create,
-    DashedVMobject,
     FadeIn,
     FadeOut,
     FadeTransform,
@@ -32,9 +31,6 @@
 FONT_FAMILY = "Verdana"
 
 FILE_CHUNKS = 6
-CHUNK_SIZE_LABEL = "1 chunk"
-FILE_SIZE_LABEL = "6 chunks"
-PREFETCH_AHEAD_CHUNKS = 2
 
 FRAME_STROKE = "#7F8EA3"
 MUTED_TEXT = "#AAB8C8"
@@ -45,10 +41,8 @@
 CACHE_COLOR = "#90BE6D"
 SUBREAD_COLOR = "#FFD166"
 SUBREAD_SLOT_COLOR = "#B9852A"
-STREAM_COLOR = "#B5179E"
 MISS_COLOR = "#F94144"
 HIT_COLOR = "#6E9B4B"
-PREFETCH_COLOR = "#577590"
 
 Text.set_default(font=FONT_FAMILY)
 
@@ -438,23 +432,3 @@ def make_slice(self, chunk_rect: Rectangle, center_ratio: float, height_ratio: f
         center_y = top[1] + (bottom[1] - top[1]) * center_ratio
         slice_rect.move_to([chunk_rect.get_center()[0], center_y, 0])
         return slice_rect
-
-    def make_prefetch_window(self, cache: FileColumn, start_chunk: int, chunk_span: int) -> DashedVMobject:
-        start = max(0, min(FILE_CHUNKS - 1, start_chunk))
-        end = max(start, min(FILE_CHUNKS - 1, start + chunk_span - 1))
-        top = cache.chunk_rect(start).get_top()
-        bottom = cache.chunk_rect(end).get_bottom()
-        window = Rectangle(
-            width=cache.body.width + 0.18,
-            height=top[1] - bottom[1],
-            stroke_color=PREFETCH_COLOR,
-            stroke_width=2,
-        )
-        window.move_to([cache.body.get_center()[0], (top[1] + bottom[1]) / 2, 0])
-        return DashedVMobject(window, num_dashes=18)
-
-    def make_stream_slices(self, cache: FileColumn, start_chunk: int) -> VGroup:
-        first = self.make_slice(cache.chunk_rect(start_chunk), 0.58, 0.26, STREAM_COLOR)
-        second = self.make_slice(cache.chunk_rect(start_chunk + 1), 0.42, 0.72, STREAM_COLOR)
-        third = self.make_slice(cache.chunk_rect(start_chunk + 2), 0.24, 0.24, STREAM_COLOR)
-        return VGroup(first, second, third)