all: [API] change op.Offset to take integer coordinates

op.Offset is a convenience function most often used by layouts. Layouts
usually operate in integer coordinates, and the float32 version of op.Offset
needlessly force conversions from int to float32. This change makes op.Offset
take integer coordinates, to better match its intended use.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

op/op.go

@@ -67,6 +67,7 @@ package op
 
 import (
 	"encoding/binary"
+	"image"
 	"math"
 	"time"
 
@@ -195,9 +196,10 @@ func (r InvalidateOp) Add(o *Ops) {
 	}
 }
 
-// Offset creates a TransformOp with the offset o.
-func Offset(o f32.Point) TransformOp {
-	return TransformOp{t: f32.Affine2D{}.Offset(o)}
+// Offset converts an offset to a TransformOp.
+func Offset(off image.Point) TransformOp {
+	offf := f32.Pt(float32(off.X), float32(off.Y))
+	return Affine(f32.Affine2D{}.Offset(offf))
 }
 
 // Affine creates a TransformOp representing the transformation a.

op/op_test.go

@@ -3,9 +3,8 @@
 package op
 
 import (
+	"image"
 	"testing"
-
-	"gioui.org/f32"
 )
 
 func TestTransformChecks(t *testing.T) {
@@ -15,7 +14,7 @@ func TestTransformChecks(t *testing.T) {
 		}
 	}()
 	var ops Ops
-	trans := Offset(f32.Point{}).Push(&ops)
+	trans := Offset(image.Point{}).Push(&ops)
 	Record(&ops)
 	trans.Pop()
 }