add more test transforms, now includes: center, origin, min, max and middle of side

geometry_test.go

@@ -12,13 +12,13 @@ func TestResizeRect(t *testing.T) {
 		pixel.R(10, 10, 30, 30),
 	}
 
-	answers := []pixel.Rect{
+	resizeAroundCenterAnswers := []pixel.Rect{
 		pixel.R(-5, -5, 5, 5),
 		pixel.R(15, 15, 25, 25),
 	}
 
 	for i, rect := range testCases {
-		answer := answers[i]
+		answer := resizeAroundCenterAnswers[i]
 
 		// resize rectangle by 50% anchored at it's current center point
 		resizedRect := rect.Resized(rect.Center(), rect.Size().Scaled(0.5))
@@ -28,4 +28,67 @@ func TestResizeRect(t *testing.T) {
 		}
 	}
 
+	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)
+		}
+	}
 }