support ratio layouts

ui/ui.go

@@ -12,10 +12,11 @@ type Drawable interface {
 }
 
 type Offsets struct {
-	Top    int
-	Bottom int
-	Left   int
-	Right  int
+	Top     int
+	Bottom  int
+	Left    int
+	Right   int
+	Percent int
 }
 
 type Contents []struct {
@@ -27,6 +28,8 @@ const (
 	LayoutUnmanaged = iota
 	LayoutHorizontalEven
 	LayoutVerticalEven
+	LayoutHorizontalPercent
+	LayoutVerticalPercent
 )
 
 // A Container has no visible UI of its own, but arranges sub-components on the screen.
@@ -87,6 +90,58 @@ func (c *Container) SetSize(x, y, h, w int) {
 			}
 			c.contents[r].Container.SetSize(x, y, h, w)
 		}
+	} else if c.layoutMethod == LayoutHorizontalPercent {
+		// first, work out overall distribution
+		total := 0
+		for r := range c.contents {
+			// `0` or negatives are set as minimum
+			if c.contents[r].Offsets.Percent < 1 {
+				total += 1
+			} else {
+				total += c.contents[r].Offsets.Percent
+			}
+		}
+		carry := 0
+		// push around containers
+		for r := range c.contents {
+			ratio := (float64(c.contents[r].Offsets.Percent) / float64(total))
+			w := int(float64(c.w) * ratio)
+			h := c.h
+			x := c.x + carry
+			y := c.y
+			carry += w
+			// and add any remaining space to the last container
+			if r == len(c.contents)-1 {
+				w += (c.w - carry)
+			}
+			c.contents[r].Container.SetSize(x, y, h, w)
+		}
+	} else if c.layoutMethod == LayoutVerticalPercent {
+		// first, work out overall distribution
+		total := 0
+		for r := range c.contents {
+			// `0` or negatives are set as minimum
+			if c.contents[r].Offsets.Percent < 1 {
+				total += 1
+			} else {
+				total += c.contents[r].Offsets.Percent
+			}
+		}
+		carry := 0
+		// push around containers
+		for r := range c.contents {
+			ratio := (float64(c.contents[r].Offsets.Percent) / float64(total))
+			w := c.w
+			h := int(float64(c.h) * ratio)
+			x := c.x
+			y := c.y + carry
+			carry += h
+			// and add any remaining space to the last container
+			if r == len(c.contents)-1 {
+				h += (c.h - carry)
+			}
+			c.contents[r].Container.SetSize(x, y, h, w)
+		}
 	} else {
 		for r := range c.contents {
 			x := c.x + c.contents[r].Offsets.Left