Fix missing size for applied ShaderBrush to span (#1389)

Correctly initialize `brushSize` even without calling explicit text
style setter.

Fixes JetBrains/compose-multiplatform#4897

## Testing

Use reproduction from the issue

## Release Notes

### Fixes - Multiple Platforms

- Fix applying `ShaderBrush` to part of `AnnotatedString`

compose/ui/ui-text/src/skikoMain/kotlin/androidx/compose/ui/text/SkiaParagraph.skiko.kt

@@ -70,6 +70,12 @@ internal class SkiaParagraph(
         }
 
     init {
+        // Size is not known until layout is complete but to apply it, we need to re-create
+        // skia's paragraph :'(
+        // layouter might use cached instance if no [ShaderBrush] was applied.
+        layouter.setBrushSize(Size(width, height))
+        paragraph = layouter.layoutParagraph(width)
+
         paragraph.layout(width)
     }
 

compose/ui/ui-text/src/skikoMain/kotlin/androidx/compose/ui/text/platform/ParagraphLayouter.skiko.kt

@@ -18,20 +18,23 @@ package androidx.compose.ui.text.platform
 
 import androidx.compose.ui.geometry.Size
 import androidx.compose.ui.geometry.isUnspecified
-import androidx.compose.ui.graphics.*
+import androidx.compose.ui.graphics.BlendMode
+import androidx.compose.ui.graphics.Brush
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.ShaderBrush
+import androidx.compose.ui.graphics.Shadow
 import androidx.compose.ui.graphics.drawscope.DrawStyle
+import androidx.compose.ui.graphics.takeOrElse
 import androidx.compose.ui.text.AnnotatedString
 import androidx.compose.ui.text.ExperimentalTextApi
 import androidx.compose.ui.text.Placeholder
 import androidx.compose.ui.text.SpanStyle
 import androidx.compose.ui.text.TextStyle
 import androidx.compose.ui.text.font.FontFamily
-import androidx.compose.ui.text.style.LineHeightStyle
 import androidx.compose.ui.text.style.ResolvedTextDirection
 import androidx.compose.ui.text.style.TextDecoration
 import androidx.compose.ui.unit.Density
 import kotlin.math.abs
-import org.jetbrains.skia.Paint
 import org.jetbrains.skia.paragraph.LineMetrics
 import org.jetbrains.skia.paragraph.Paragraph
 
@@ -94,6 +97,22 @@ internal class ParagraphLayouter(
         }
     }
 
+    fun setBrushSize(
+        brushSize: Size,
+    ) {
+        if (builder.brushSize != brushSize) {
+            builder.brushSize = brushSize
+
+            // [brushSize] requires only for shader recreation and does not require re-layout,
+            // but we have to invalidate it because it's backed into skia's paragraph.
+            // Since it affects only [ShaderBrush] we can keep the cache if it's not used.
+            if (builder.textStyle.brush is ShaderBrush ||
+                builder.spanStyles.any { it.item.brush is ShaderBrush }) {
+                paragraphCache = null
+            }
+        }
+    }
+
     fun setTextStyle(
         color: Color,
         shadow: Shadow?,