Add LayoutAllocator

core/shared/src/main/scala/eu/joaocosta/interim/TextLayout.scala

@@ -90,3 +90,37 @@ object TextLayout:
             else
               layout(nextLine, dy + lineHeight, alignH(ops, textOp.textArea.w, textOp.horizontalAlignment) ++ textAcc)
     layout(textOp.text, 0, Nil).filter(char => (char.area & textOp.area) == char.area)
+
+  private[interim] def computeArea(
+      boundingArea: Rect,
+      text: String,
+      font: Font,
+      lineHeight: Int
+  ): Rect =
+    @tailrec
+    def layout(
+        remaining: String,
+        dy: Int,
+        areaAcc: Rect
+    ): Rect =
+      remaining match
+        case "" => areaAcc
+        case str =>
+          if (dy + font.fontSize > boundingArea.h) layout("", dy, areaAcc) // Can't fit this line, end here
+          else
+            val (thisLine, nextLine) = getNextLine(str, boundingArea.w, font.charWidth)
+            val charAreas = cumulativeSum(thisLine)(font.charWidth).map { case (char, dx) =>
+              val width = font.charWidth(char)
+              val charArea = Rect(
+                x = boundingArea.x + dx - width,
+                y = boundingArea.y + dy,
+                w = width,
+                h = font.fontSize
+              )
+              charArea
+            }.toList
+            if (charAreas.isEmpty && nextLine == remaining)
+              layout("", dy, areaAcc) // Can't fit a single character, end here
+            else
+              layout(nextLine, dy + lineHeight, charAreas.fold(areaAcc)(_ ++ _))
+    layout(text, 0, boundingArea.copy(w = 0, h = 0)) & boundingArea

core/shared/src/main/scala/eu/joaocosta/interim/api/LayoutAllocator.scala

@@ -0,0 +1,70 @@
+package eu.joaocosta.interim.api
+
+import eu.joaocosta.interim.{Font, Rect, TextLayout}
+
+/** A layout allocator is a side-effectful function that, given a size (width or height) tries to allocate
+  * a new area.
+  *
+  * Note that calls to this function are side effectful, as each call reserves an area.
+  */
+trait LayoutAllocator extends (Int => Rect):
+  def allocate(size: Int): Rect
+  def apply(size: Int): Rect = allocate(size)
+  def allocate(text: String, font: Font): Rect
+
+object LayoutAllocator:
+  final class RowAllocator(area: Rect, padding: Int) extends LayoutAllocator:
+    private var currentY = area.y
+    private var currentH = area.h
+
+    def allocate(height: Int) =
+      val absHeight = math.abs(height).toInt
+      if (absHeight == 0 || currentH <= 0) // Empty
+        area.copy(y = currentY, h = 0)
+      else if (absHeight >= currentH) // Fill remaining area
+        val areaY = currentY
+        val areaH = currentH
+        currentY = area.h
+        currentH = 0
+        area.copy(y = areaY, h = areaH)
+      else if (height >= 0) // Fill from the top
+        val areaY = currentY
+        currentY += absHeight + padding
+        currentH -= absHeight + padding
+        area.copy(y = areaY, h = absHeight)
+      else // Fill from the bottom
+        val areaY = currentY + currentH - absHeight
+        currentH -= absHeight + padding
+        area.copy(y = areaY, h = absHeight)
+
+    def allocate(text: String, font: Font): Rect =
+      val textArea = TextLayout.computeArea(area, text, font, (font.fontSize * 1.3).toInt)
+      allocate(textArea.h)
+
+  final class ColumnAllocator(area: Rect, padding: Int) extends LayoutAllocator:
+    private var currentX = area.x
+    private var currentW = area.w
+
+    def allocate(width: Int): Rect =
+      val absWidth = math.abs(width).toInt
+      if (absWidth == 0 || currentW <= 0) // Empty
+        area.copy(x = currentX, w = 0)
+      else if (absWidth >= currentW) // Fill remaining area
+        val areaX = currentX
+        val areaW = currentW
+        currentX = area.w
+        currentW = 0
+        area.copy(x = areaX, w = areaW)
+      else if (width >= 0) // Fill from the left
+        val areaX = currentX
+        currentX += absWidth + padding
+        currentW -= absWidth + padding
+        area.copy(x = areaX, w = absWidth)
+      else // Fill from the right
+        val areaX = currentX + currentW - absWidth
+        currentW -= absWidth + padding
+        area.copy(x = areaX, w = absWidth)
+
+    def allocate(text: String, font: Font): Rect =
+      val textArea = TextLayout.computeArea(area, text, font, (font.fontSize * 1.3).toInt)
+      allocate(textArea.w)

core/shared/src/main/scala/eu/joaocosta/interim/api/Layouts.scala

@@ -69,58 +69,18 @@ trait Layouts:
     * The body receives a `nextRow: Int => Rect`, where `nextRow(height)` is the rect of the next row, with the
     * specified height (if possible). If the size is negative, the row will start from the bottom.
     */
-  final def dynamicRows[T](area: Rect, padding: Int)(body: (Int => Rect) => T): T =
-    var currentY = area.y
-    var currentH = area.h
-    def generateRect(height: Int): Rect =
-      val absHeight = math.abs(height).toInt
-      if (absHeight == 0 || currentH <= 0) // Empty
-        area.copy(y = currentY, h = 0)
-      else if (absHeight >= currentH) // Fill remaining area
-        val areaY = currentY
-        val areaH = currentH
-        currentY = area.h
-        currentH = 0
-        area.copy(y = areaY, h = areaH)
-      else if (height >= 0) // Fill from the top
-        val areaY = currentY
-        currentY += absHeight + padding
-        currentH -= absHeight + padding
-        area.copy(y = areaY, h = absHeight)
-      else // Fill from the bottom
-        val areaY = currentY + currentH - absHeight
-        currentH -= absHeight + padding
-        area.copy(y = areaY, h = absHeight)
-    body(generateRect)
+  final def dynamicRows[T](area: Rect, padding: Int)(body: LayoutAllocator => T): T =
+    val allocator = new LayoutAllocator.RowAllocator(area, padding)
+    body(allocator)
 
   /** Lays out the components in a sequence of columns of different sizes, separated by a padding.
     *
     * The body receives a `nextColumn: Int => Rect`, where `nextColumn(width)` is the rect of the next column, with the
     * specified width (if possible). . If the size is negative, the row will start from the right.
     */
-  final def dynamicColumns[T](area: Rect, padding: Int)(body: (Int => Rect) => T): T =
-    var currentX = area.x
-    var currentW = area.w
-    def generateRect(width: Int): Rect =
-      val absWidth = math.abs(width).toInt
-      if (absWidth == 0 || currentW <= 0) // Empty
-        area.copy(x = currentX, w = 0)
-      else if (absWidth >= currentW) // Fill remaining area
-        val areaX = currentX
-        val areaW = currentW
-        currentX = area.w
-        currentW = 0
-        area.copy(x = areaX, w = areaW)
-      else if (width >= 0) // Fill from the left
-        val areaX = currentX
-        currentX += absWidth + padding
-        currentW -= absWidth + padding
-        area.copy(x = areaX, w = absWidth)
-      else // Fill from the right
-        val areaX = currentX + currentW - absWidth
-        currentW -= absWidth + padding
-        area.copy(x = areaX, w = absWidth)
-    body(generateRect)
+  final def dynamicColumns[T](area: Rect, padding: Int)(body: LayoutAllocator => T): T =
+    val allocator = new LayoutAllocator.ColumnAllocator(area, padding)
+    body(allocator)
 
   /** Handle mouse events inside a specified area.
     *

core/shared/src/main/scala/eu/joaocosta/interim/api/Panels.scala

@@ -1,7 +1,7 @@
 package eu.joaocosta.interim.api
 
-import eu.joaocosta.interim.*
-import eu.joaocosta.interim.skins.*
+import eu.joaocosta.interim._
+import eu.joaocosta.interim.skins._
 
 /** Objects containing all default panels.
   *

core/shared/src/main/scala/eu/joaocosta/interim/skins/ButtonSkin.scala

@@ -1,8 +1,8 @@
 package eu.joaocosta.interim.skins
 
-import eu.joaocosta.interim.TextLayout.*
-import eu.joaocosta.interim.*
-import eu.joaocosta.interim.api.Primitives.*
+import eu.joaocosta.interim.TextLayout._
+import eu.joaocosta.interim._
+import eu.joaocosta.interim.api.Primitives._
 
 trait ButtonSkin:
   def buttonArea(area: Rect): Rect

core/shared/src/main/scala/eu/joaocosta/interim/skins/CheckboxSkin.scala

@@ -1,7 +1,7 @@
 package eu.joaocosta.interim.skins
 
-import eu.joaocosta.interim.*
-import eu.joaocosta.interim.api.Primitives.*
+import eu.joaocosta.interim._
+import eu.joaocosta.interim.api.Primitives._
 
 trait CheckboxSkin:
   def checkboxArea(area: Rect): Rect

core/shared/src/main/scala/eu/joaocosta/interim/skins/HandleSkin.scala

@@ -1,7 +1,7 @@
 package eu.joaocosta.interim.skins
 
-import eu.joaocosta.interim.*
-import eu.joaocosta.interim.api.Primitives.*
+import eu.joaocosta.interim._
+import eu.joaocosta.interim.api.Primitives._
 
 trait HandleSkin:
   def moveHandleArea(area: Rect): Rect

core/shared/src/main/scala/eu/joaocosta/interim/skins/SliderSkin.scala

@@ -1,7 +1,7 @@
 package eu.joaocosta.interim.skins
 
-import eu.joaocosta.interim.*
-import eu.joaocosta.interim.api.Primitives.*
+import eu.joaocosta.interim._
+import eu.joaocosta.interim.api.Primitives._
 
 trait SliderSkin:
   def sliderArea(area: Rect): Rect

core/shared/src/main/scala/eu/joaocosta/interim/skins/TextInputSkin.scala

@@ -1,7 +1,7 @@
 package eu.joaocosta.interim.skins
 
-import eu.joaocosta.interim.*
-import eu.joaocosta.interim.api.Primitives.*
+import eu.joaocosta.interim._
+import eu.joaocosta.interim.api.Primitives._
 
 trait TextInputSkin:
   def textInputArea(area: Rect): Rect

core/shared/src/main/scala/eu/joaocosta/interim/skins/WindowSkin.scala

@@ -1,9 +1,9 @@
 package eu.joaocosta.interim.skins
 
-import eu.joaocosta.interim.TextLayout.*
-import eu.joaocosta.interim.*
-import eu.joaocosta.interim.api.Components.*
-import eu.joaocosta.interim.api.Primitives.*
+import eu.joaocosta.interim.TextLayout._
+import eu.joaocosta.interim._
+import eu.joaocosta.interim.api.Components._
+import eu.joaocosta.interim.api.Primitives._
 
 trait WindowSkin:
   def titleArea(area: Rect): Rect