chore: introduced FlexRect

Makes it easier to deal with rectangles that should be based on the size of enclosing rectangles

Author: quintesse

src/main/java/org/codejive/context/terminal/FlexRect.java

@@ -0,0 +1,19 @@
+package org.codejive.context.terminal;
+
+public class FlexRect {
+    private final int left, top, width, height;
+
+    public FlexRect(int left, int top, int width, int height) {
+        this.left = left;
+        this.top = top;
+        this.width = width;
+        this.height = height;
+    }
+
+    public Rect actualRect(Size availableSize) {
+        Rect availableRect = new Rect(0, 0, availableSize.width(), availableSize.height());
+        int w = width >= 0 ? width : availableSize.width() - left + width + 1;
+        int h = height >= 0 ? height : availableSize.height() - top + height + 1;
+        return new Rect(left, top, w, h).limited(availableRect);
+    }
+}

src/main/java/org/codejive/context/terminal/Rect.java

@@ -51,6 +51,14 @@ public Rect grow(int leftAmount, int topAmount, int rightAmount, int bottomAmoun
                 Math.max(height() + topAmount + bottomAmount, 0));
     }
 
+    public Rect limited(Rect availableRect) {
+        int l = Math.max(left, availableRect.left());
+        int t = Math.max(top, availableRect.top());
+        int r = Math.min(right(), availableRect.right());
+        int b = Math.min(bottom(), availableRect.bottom());
+        return new Rect(l, t, r - l + 1, b - t + 1);
+    }
+
     @Override
     public String toString() {
         return "Rect{"