From 784a9d36bda7db14e1faced16d8f848d9b1d5158 Mon Sep 17 00:00:00 2001
From: Rob Parrett <robparrett@gmail.com>
Date: Wed, 22 Jan 2025 18:43:59 -0800
Subject: [PATCH] Add warning for font sizes `<= 0.0` (#17501)

# Objective

Alternative to #9660, which is outdated since "required components"
landed.

Fixes #9655

## Solution

This is a different approach than the linked PR, slotting the warning
into an existing check for zero or negative font sizes in the text
pipeline.

## Testing

Replaced a font size with `0.0` in `examples/ui/text.rs`.

```
2025-01-22T23:26:08.239688Z  INFO bevy_winit::system: Creating new window App (0v1)
2025-01-22T23:26:08.617505Z  WARN bevy_text::pipeline: Text span 10v1 has a font size <= 0.0. Nothing will be displayed.
```
---
 crates/bevy_text/Cargo.toml      | 1 +
 crates/bevy_text/src/pipeline.rs | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/crates/bevy_text/Cargo.toml b/crates/bevy_text/Cargo.toml
index dd4ed912a6..3ad3ef9557 100644
--- a/crates/bevy_text/Cargo.toml
+++ b/crates/bevy_text/Cargo.toml
@@ -19,6 +19,7 @@ bevy_color = { path = "../bevy_color", version = "0.16.0-dev" }
 bevy_derive = { path = "../bevy_derive", version = "0.16.0-dev" }
 bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev" }
 bevy_image = { path = "../bevy_image", version = "0.16.0-dev" }
+bevy_log = { path = "../bevy_log", version = "0.16.0-dev" }
 bevy_math = { path = "../bevy_math", version = "0.16.0-dev" }
 bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev", features = [
   "bevy",
diff --git a/crates/bevy_text/src/pipeline.rs b/crates/bevy_text/src/pipeline.rs
index 9ab627b562..ef1f0e42ba 100644
--- a/crates/bevy_text/src/pipeline.rs
+++ b/crates/bevy_text/src/pipeline.rs
@@ -8,6 +8,7 @@ use bevy_ecs::{
     system::ResMut,
 };
 use bevy_image::prelude::*;
+use bevy_log::{once, warn};
 use bevy_math::{UVec2, Vec2};
 use bevy_reflect::{std_traits::ReflectDefault, Reflect};
 use bevy_utils::HashMap;
@@ -139,6 +140,10 @@ impl TextPipeline {
 
             // Save spans that aren't zero-sized.
             if scale_factor <= 0.0 || text_font.font_size <= 0.0 {
+                once!(warn!(
+                    "Text span {entity} has a font size <= 0.0. Nothing will be displayed.",
+                ));
+
                 continue;
             }
             spans.push((span_index, span, text_font, face_info, color));