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// 13 february 2014
package ui
import (
"fmt"
"sync"
)
// Orientation defines the orientation of controls in a Stack.
type Orientation int
const (
Horizontal Orientation = iota
Vertical
)
// A Stack stacks controls horizontally or vertically within the Stack's parent.
// A horizontal Stack gives all controls the same height and their preferred widths.
// A vertical Stack gives all controls the same width and their preferred heights.
// Some controls may be marked as "stretchy": when the Window they are in changes size, stretchy controls resize to take up the remaining space after non-stretchy controls are laid out. If multiple controls are marked stretchy, they are alloted equal distribution of the remaining space.
type Stack struct {
lock sync.Mutex
created bool
orientation Orientation
controls []Control
stretchy []bool
xpos, ypos []int // caches to avoid reallocating these each time
width, height []int
}
// NewStack creates a new Stack with the specified orientation.
func NewStack(o Orientation, controls ...Control) *Stack {
if o != Horizontal && o != Vertical {
panic(fmt.Sprintf("invalid orientation %d given to NewStack()", o))
}
return &Stack{
orientation: o,
controls: controls,
stretchy: make([]bool, len(controls)),
xpos: make([]int, len(controls)),
ypos: make([]int, len(controls)),
width: make([]int, len(controls)),
height: make([]int, len(controls)),
}
}
// SetStretchy marks a control in a Stack as stretchy.
func (s *Stack) SetStretchy(index int) {
s.lock.Lock()
defer s.lock.Unlock()
s[index] = true // TODO explicitly check for index out of bounds?
}
func (s *Stack) make(window *sysData) error {
for i, c := range s.controls {
err := c.make(window)
if err != nil {
return fmt.Errorf("error adding control %d to Stack: %v", i, err)
}
}
s.created = true
return nil
}
func (s *Stack) setRect(x int, y int, width int, height int) error {
var dx, dy int
if len(s.controls) == 0 { // do nothing if there's nothing to do
return nil
}
switch s.orientation {
case Horizontal:
dx = width / len(s.controls)
width = dx
case Vertical:
dy = height / len(s.controls)
height = dy
default:
panic(fmt.Sprintf("invalid orientation %d given to Stack.setRect()", s.orientation))
}
for i, c := range s.controls {
err := c.setRect(x, y, width, height)
if err != nil {
return fmt.Errorf("error setting size of control %d: %v", i, err)
}
x += dx
y += dy
}
return nil
}
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