Add 'dotscape/' from commit 'f306501a68a51b634e895c5fdac70788ae899d75'

git-subtree-dir: dotscape
git-subtree-mainline: 6b91d64fc3
git-subtree-split: f306501a68

dotscape/fcore/grid.sml

@@ -0,0 +1,45 @@
+structure Grid =
+struct
+  type pixel = {r: int, g: int, b: int, a: int}
+
+  type t = pixel vector vector
+
+  val emptyPixel = {r = 0, g = 0, b = 0, a = 0}
+
+  fun isBlank ({a, ...}: pixel) = a = 0
+
+  fun changeGridSize maxSide grid =
+    Vector.tabulate (maxSide, fn i =>
+      if i < Vector.length grid then
+        let
+          val yAxis = Vector.sub (grid, i)
+        in
+          Vector.tabulate (maxSide, fn ii =>
+            if ii < Vector.length yAxis then Vector.sub (yAxis, ii)
+            else emptyPixel)
+        end
+      else
+        Vector.tabulate (maxSide, fn _ => emptyPixel))
+
+  fun updateGrid (grid, newX, newY, pixel) =
+    let
+      val yAxis = Vector.sub (grid, newX)
+      val yAxis = Vector.update (yAxis, newY, pixel)
+    in
+      Vector.update (grid, newX, yAxis)
+    end
+
+  fun makeEmpty maxSide =
+    Vector.tabulate (maxSide, fn _ =>
+      Vector.tabulate (maxSide, fn _ => emptyPixel))
+
+  fun flipHorizontally (xAxis: t) =
+    Vector.mapi
+      (fn (xIdx, yAxis) =>
+         let
+           val flippedXIdx = Vector.length xAxis - 1 - xIdx
+           val flippedYAxis = Vector.sub (xAxis, flippedXIdx)
+         in
+           Vector.mapi (fn (yIdx, _) => Vector.sub (flippedYAxis, yIdx)) yAxis
+         end) xAxis
+end