create lay/strain package

The lay/strain package uses the Cassowary algorithm to solve systems of
layout constraints.

1 files changed, 3 insertions, 1 deletions

diff --git a/env.go b/env.go
index 005ef80..68b02d1 100644
--- a/env.go
+++ b/env.go
@@ -3,6 +3,8 @@ package gui
 import (
 	"image"
 	"image/draw"
+
+	"github.com/faiface/gui/lay/strain"
 )
 
 // Env is the most important thing in this package. It is an interactive graphical
@@ -35,7 +37,7 @@ type Env interface {
 	// enough space.
 	//
 	// The Impose() channel may be synchronous.
-	Impose() chan<- Constraint
+	Impose() chan<- strain.Constraint
 
 	// Close destroys the Env. The Env will subsequently close the Events(), Draw(),
 	// and Impose() channels.