diff --git a/geometry.go b/geometry.go index 99514cc..52dfa73 100644 --- a/geometry.go +++ b/geometry.go @@ -236,8 +236,8 @@ func (r Rect) Resized(anchor, size Vec) Rect { } fraction := Vec{size.X / r.W(), size.Y / r.H()} return Rect{ - Min: anchor.Add(r.Min.Sub(anchor)).ScaledXY(fraction), - Max: anchor.Add(r.Max.Sub(anchor)).ScaledXY(fraction), + Min: anchor.Add(r.Min.Sub(anchor).ScaledXY(fraction)), + Max: anchor.Add(r.Max.Sub(anchor).ScaledXY(fraction)), } } diff --git a/geometry_test.go b/geometry_test.go new file mode 100644 index 0000000..85a21ce --- /dev/null +++ b/geometry_test.go @@ -0,0 +1,94 @@ +package pixel_test + +import ( + "testing" + + "github.com/faiface/pixel" +) + +func TestResizeRect(t *testing.T) { + testCases := []pixel.Rect{ + pixel.R(-10, -10, 10, 10), + pixel.R(10, 10, 30, 30), + } + + resizeAroundCenterAnswers := []pixel.Rect{ + pixel.R(-5, -5, 5, 5), + pixel.R(15, 15, 25, 25), + } + + for i, rect := range testCases { + answer := resizeAroundCenterAnswers[i] + + // resize rectangle by 50% anchored at it's current center point + resizedRect := rect.Resized(rect.Center(), rect.Size().Scaled(0.5)) + + if resizedRect != answer { + t.Errorf("Rectangle resize was incorrect, got %v, want: %v.", resizedRect, answer) + } + } + + resizeAroundMinAnswers := []pixel.Rect{ + pixel.R(-10, -10, 0, 0), + pixel.R(10, 10, 20, 20), + } + + for i, rect := range testCases { + answer := resizeAroundMinAnswers[i] + + // resize rectangle by 50% anchored at it's Min coordinate + resizedRect := rect.Resized(rect.Min, rect.Size().Scaled(0.5)) + + if resizedRect != answer { + t.Errorf("Rectangle resize was incorrect, got %v, want: %v.", resizedRect, answer) + } + } + + resizeAroundMaxAnswers := []pixel.Rect{ + pixel.R(0, 0, 10, 10), + pixel.R(20, 20, 30, 30), + } + + for i, rect := range testCases { + answer := resizeAroundMaxAnswers[i] + + // resize rectangle by 50% anchored at it's Max coordinate + resizedRect := rect.Resized(rect.Max, rect.Size().Scaled(0.5)) + + if resizedRect != answer { + t.Errorf("Rectangle resize was incorrect, got %v, want: %v.", resizedRect, answer) + } + } + + resizeAroundMiddleOfLeftSideAnswers := []pixel.Rect{ + pixel.R(-10, -5, 0, 5), + pixel.R(10, 15, 20, 25), + } + + for i, rect := range testCases { + answer := resizeAroundMiddleOfLeftSideAnswers[i] + + // resize rectangle by 50% anchored at the middle of it's left side + resizedRect := rect.Resized(pixel.V(rect.Min.X, rect.Center().Y), rect.Size().Scaled(0.5)) + + if resizedRect != answer { + t.Errorf("Rectangle resize was incorrect, got %v, want: %v.", resizedRect, answer) + } + } + + resizeAroundOriginAnswers := []pixel.Rect{ + pixel.R(-5, -5, 5, 5), + pixel.R(5, 5, 15, 15), + } + + for i, rect := range testCases { + answer := resizeAroundOriginAnswers[i] + + // resize rectangle by 50% anchored at the origin + resizedRect := rect.Resized(pixel.ZV, rect.Size().Scaled(0.5)) + + if resizedRect != answer { + t.Errorf("Rectangle resize was incorrect, got %v, want: %v.", resizedRect, answer) + } + } +}