left and right insets for SFSymbol format are ignored after a certain value.

[jonmindtrip]

to reproduce, export a series of sfsymbol images based on the key.svg image in the test bundle. These all use identical 30px insets for the top and bottom, but use different values for the left and right:

$ INSETS="30,30,30,30" && swiftdraw SwiftDraw/Tests/Test.bundle/key.svg --format sfsymbol --insets $INSETS --ultralightInsets $INSETS --blackInsets $INSETS --output key.symbol.30.svg

$ INSETS="30,45,30,45" && swiftdraw SwiftDraw/Tests/Test.bundle/key.svg --format sfsymbol --insets $INSETS --ultralightInsets $INSETS --blackInsets $INSETS --output key.symbol.45.svg

$ INSETS="30,60,30,60" && swiftdraw SwiftDraw/Tests/Test.bundle/key.svg --format sfsymbol --insets $INSETS --ultralightInsets $INSETS --blackInsets $INSETS --output key.symbol.60.svg

Comparing the 30 and 40 variants gets a diff that you'd expect:

$ diff key.symbol.30.svg key.symbol.45.svg
24,29c24,29
<         <path id="left-margin-Ultralight-S" d="M220,56 l0,110" />
<         <path id="right-margin-Ultralight-S" d="M310,56 l0,110" />
<         <path id="left-margin-Regular-S" d="M420,56 l0,110" />
<         <path id="right-margin-Regular-S" d="M510,56 l0,110" />
<         <path id="left-margin-Black-S" d="M620,56 l0,110" />
<         <path id="right-margin-Black-S" d="M710,56 l0,110" />
---
>         <path id="left-margin-Ultralight-S" d="M221,56 l0,110" />
>         <path id="right-margin-Ultralight-S" d="M309,56 l0,110" />
>         <path id="left-margin-Regular-S" d="M421,56 l0,110" />
>         <path id="right-margin-Regular-S" d="M509,56 l0,110" />
>         <path id="left-margin-Black-S" d="M621,56 l0,110" />
>         <path id="right-margin-Black-S" d="M709,56 l0,110" />

However, there is no difference between the 30 and 45 variants, even though those margins should have moved again.

I believe the fix is to stop using min() in this section of code here:

% git diff SwiftDraw/Sources/Renderer/Renderer.SFSymbol.swift
diff --git a/SwiftDraw/Sources/Renderer/Renderer.SFSymbol.swift b/SwiftDraw/Sources/Renderer/Renderer.SFSymbol.swift
index 25539df..26f93be 100644
--- a/SwiftDraw/Sources/Renderer/Renderer.SFSymbol.swift
+++ b/SwiftDraw/Sources/Renderer/Renderer.SFSymbol.swift
@@ -523,9 +523,9 @@ private extension SFSymbolTemplate.Variant {
             }

         let midX = bounds.midX
-        let newWidth = ((source.width * matrix.a) / 2) + 10
-        left.x = min(left.x, midX - newWidth)
-        right.x = max(right.x, midX + newWidth)
+        let newWidth = ((source.width * matrix.a) / 2)
+        left.x = midX - newWidth
+        right.x = midX + newWidth
     }
 }

SwiftDraw/SwiftDraw/Sources/Renderer/Renderer.SFSymbol.swift

Line 527 in 335e287

left.x = min(left.x, midX - newWidth)

[swhitty]

Thanks @jonmindtrip you for raising this 🙏🏻.

Starting with this image with inbuilt guides:

Using --insets 30,60,30,60 the output is this:

The issue occurs because SwiftDraw will always preserve the aspect ratio of the image and places the image within the SFSymbol template prioritising the vertical alignment with the guides.

Maybe we also need to be moving the left and right guides for each variation to align like so:

[jonmindtrip]

Moving the left / right guides further in is exactly what I expected the behavior to be when increasing the left/right insets. And in fact, the current code does do that, up to a certain point. To see this, compare your key image with built in guides using --insets 30,10,30,10:

vs --insets 30,30,30,30:

---

FWIW, If I make the following change to the sfsymbol renderer, I get exactly the behavior I'm looking for:

% git diff SwiftDraw/Sources/Renderer/Renderer.SFSymbol.swift
diff --git a/SwiftDraw/Sources/Renderer/Renderer.SFSymbol.swift b/SwiftDraw/Sources/Renderer/Renderer.SFSymbol.swift
index 25539df..26f93be 100644
--- a/SwiftDraw/Sources/Renderer/Renderer.SFSymbol.swift
+++ b/SwiftDraw/Sources/Renderer/Renderer.SFSymbol.swift
@@ -523,9 +523,9 @@ private extension SFSymbolTemplate.Variant {
             }

         let midX = bounds.midX
-        let newWidth = ((source.width * matrix.a) / 2) + 10
-        left.x = min(left.x, midX - newWidth)
-        right.x = max(right.x, midX + newWidth)
+        let newWidth = ((source.width * matrix.a) / 2)
+        left.x = midX - newWidth
+        right.x = midX + newWidth
     }
 }