"attempt to divide by zero" in handwriting/models.rs

[agileadam]

I was getting this error on the latest release while trying imessage-exporter --format=html --copy-method=efficient:

thread 'main' panicked at imessage-database/src/message_types/handwriting/models.rs:215:5:
attempt to divide by zero
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

I was able to get past the error by making this change and recompiling.
DISCLAIMER: I have never programmed in rust. This change is straight from ChatGPT.
I assume the developer(s) will address the bug accordingly.

diff --git a/imessage-database/src/message_types/handwriting/models.rs b/imessage-database/src/message_types/handwriting/models.rs
index 67e4a00..321d4fd 100644
--- a/imessage-database/src/message_types/handwriting/models.rs
+++ b/imessage-database/src/message_types/handwriting/models.rs
@@ -212,7 +212,12 @@ fn fit_strokes(

 /// Resize converts `v` from a coordinate where `max_v` is the current height/width and `box_size` is the wanted height/width.
 fn resize(v: u16, box_size: u16, max_v: u16) -> u16 {
-    (v as i64 * box_size as i64 / max_v as i64) as u16
+    if max_v == 0 {
+        // Return 0, or handle this case differently if another behavior is desired
+        0
+    } else {
+        (v as i64 * box_size as i64 / max_v as i64) as u16
+    }
 }

[ReagentX]

If possible, can you send the handwritten message blob? Would be nice to have a unit test for this. max_x and max_y (which are passed as max_v in this function) are the width and height of the SVG:

imessage-exporter/imessage-database/src/message_types/handwriting/models.rs

Lines 202 to 206 in fa67b1d

	Point {
	x: resize(point.x, width, max_x),
	y: resize(point.y, height, max_y),
	width: resize(point.width, 9, max_width)+1,
	}

This error indicates that the handwritten message had 0 for height, width, or both; or possibly that there were simply zero points in the handwritten message altogether:

imessage-exporter/imessage-database/src/message_types/handwriting/models.rs

Lines 218 to 226 in fa67b1d

	/// Iterates through each point in each stroke and extracts the maximum `x`, `y`, and `width` values.
	fn get_max_dimension(strokes: &[Vec<Point>]) -> (u16, u16, u16) {
	strokes
	.iter()
	.flat_map(|stroke| stroke.iter())
	.fold((0, 0, 0), |(max_x, max_y, max_width), point| {
	(max_x.max(point.x), max_y.max(point.y), max_width.max(point.width-1))
	})
	}