initial commits

scalepoint.go

@@ -0,0 +1,14 @@
+package imgrow
+
+import (
+	"image"
+)
+
+func scalePoint(scalar int, point image.Point) image.Point {
+	x2, y2 := scaleXY(scalar, point.X, point.Y)
+
+	return image.Point {
+		X: x2,
+		Y: y2,
+	}
+}

scalepoint_test.go

@@ -0,0 +1,114 @@
+package imgrow
+
+import (
+	"testing"
+
+	"image"
+)
+
+func TestScalePoint(t *testing.T) {
+
+	tests := []struct{
+		Scalar int
+		Point image.Point
+		Expected image.Point
+	}{
+		{
+			Scalar: -2,
+			Point: image.Point{
+				X: 5,
+				Y: 7,
+			},
+			Expected: image.Point{
+				X: -10,
+				Y: -14,
+			},
+		},
+		{
+			Scalar: -1,
+			Point: image.Point{
+				X: 5,
+				Y: 7,
+			},
+			Expected: image.Point{
+				X: -5,
+				Y: -7,
+			},
+		},
+		{
+			Scalar: 0,
+			Point: image.Point{
+				X: 5,
+				Y: 7,
+			},
+			Expected: image.Point{
+				X: 0,
+				Y: 0,
+			},
+		},
+		{
+			Scalar: 1,
+			Point: image.Point{
+				X: 5,
+				Y: 7,
+			},
+			Expected: image.Point{
+				X: 5,
+				Y: 7,
+			},
+		},
+		{
+			Scalar: 2,
+			Point: image.Point{
+				X: 5,
+				Y: 7,
+			},
+			Expected: image.Point{
+				X: 10,
+				Y: 14,
+			},
+		},
+		{
+			Scalar: 3,
+			Point: image.Point{
+				X: 5,
+				Y: 7,
+			},
+			Expected: image.Point{
+				X: 15,
+				Y: 21,
+			},
+		},
+
+
+
+
+		{
+			Scalar: 100,
+			Point: image.Point{
+				X: -11,
+				Y: 13,
+			},
+			Expected: image.Point{
+				X: -1100,
+				Y: 1300,
+			},
+		},
+	}
+
+	for testNumber, test := range tests {
+
+		actual := scalePoint(test.Scalar, test.Point)
+		expected := test.Expected
+
+		if expected != actual {
+			t.Errorf("For test #%d, the actual value is not what was expected.", testNumber)
+			t.Logf("EXPECTED: %v", expected)
+			t.Logf("ACTUAL:   %v", actual)
+			t.Logf("SCALAR = %d", test.Scalar)
+			t.Logf("POINT:    %v", test.Point)
+			continue
+		}
+
+	}
+}

scalerectangle.go

@@ -0,0 +1,12 @@
+package imgrow
+
+import (
+	"image"
+)
+
+func scaleRectangle(scalar int, rectangle image.Rectangle) image.Rectangle {
+	return image.Rectangle{
+		Min: scalePoint(scalar, rectangle.Min),
+		Max: scalePoint(scalar, rectangle.Max),
+	}
+}

scalerectangle_test.go

@@ -0,0 +1,190 @@
+package imgrow
+
+import (
+	"testing"
+
+	"image"
+)
+
+func TestScaleRectangle(t *testing.T) {
+
+	tests := []struct{
+		Scalar int
+		Rectangle image.Rectangle
+		Expected image.Rectangle
+	}{
+		{
+			Scalar: -2,
+			Rectangle: image.Rectangle{
+				Min: image.Point{
+					X: 2,
+					Y: 3,
+				},
+				Max: image.Point{
+					X: 5,
+					Y: 7,
+				},
+			},
+			Expected: image.Rectangle{
+				Min: image.Point{
+					X: -4,
+					Y: -6,
+				},
+				Max: image.Point{
+					X: -10,
+					Y: -14,
+				},
+			},
+		},
+		{
+			Scalar: -1,
+			Rectangle: image.Rectangle{
+				Min: image.Point{
+					X: 0,
+					Y: 0,
+				},
+				Max: image.Point{
+					X: 5,
+					Y: 7,
+				},
+			},
+			Expected: image.Rectangle{
+				Min: image.Point{
+					X: 0,
+					Y: 0,
+				},
+				Max: image.Point{
+					X: -5,
+					Y: -7,
+				},
+			},
+		},
+		{
+			Scalar: 0,
+			Rectangle: image.Rectangle{
+				Max: image.Point{
+					X: 5,
+					Y: 7,
+				},
+			},
+			Expected: image.Rectangle{
+				Max: image.Point{
+					X: 0,
+					Y: 0,
+				},
+			},
+		},
+		{
+			Scalar: 1,
+			Rectangle: image.Rectangle{
+				Min: image.Point{
+					X: 0,
+					Y: 0,
+				},
+				Max: image.Point{
+					X: 5,
+					Y: 7,
+				},
+			},
+			Expected: image.Rectangle{
+				Min: image.Point{
+					X: 0,
+					Y: 0,
+				},
+				Max: image.Point{
+					X: 5,
+					Y: 7,
+				},
+			},
+		},
+		{
+			Scalar: 2,
+			Rectangle: image.Rectangle{
+				Min: image.Point{
+					X: 2,
+					Y: 3,
+				},
+				Max: image.Point{
+					X: 5,
+					Y: 7,
+				},
+			},
+			Expected: image.Rectangle{
+				Min: image.Point{
+					X: 4,
+					Y: 6,
+				},
+				Max: image.Point{
+					X: 10,
+					Y: 14,
+				},
+			},
+		},
+		{
+			Scalar: 3,
+			Rectangle: image.Rectangle{
+				Min: image.Point{
+					X: 1,
+					Y: 2,
+				},
+				Max: image.Point{
+					X: 5,
+					Y: 7,
+				},
+			},
+			Expected: image.Rectangle{
+				Min: image.Point{
+					X: 3,
+					Y: 6,
+				},
+				Max: image.Point{
+					X: 15,
+					Y: 21,
+				},
+			},
+		},
+
+
+
+
+		{
+			Scalar: 100,
+			Rectangle: image.Rectangle{
+				Min: image.Point{
+					X: -3,
+					Y: 0,
+				},
+				Max: image.Point{
+					X: -11,
+					Y: 13,
+				},
+			},
+			Expected: image.Rectangle{
+				Min: image.Point{
+					X: -300,
+					Y: 0,
+				},
+				Max: image.Point{
+					X: -1100,
+					Y: 1300,
+				},
+			},
+		},
+	}
+
+	for testNumber, test := range tests {
+
+		actual := scaleRectangle(test.Scalar, test.Rectangle)
+		expected := test.Expected
+
+		if expected != actual {
+			t.Errorf("For test #%d, the actual value is not what was expected.", testNumber)
+			t.Logf("EXPECTED: %v", expected)
+			t.Logf("ACTUAL:   %v", actual)
+			t.Logf("SCALAR = %d", test.Scalar)
+			t.Logf("POINT:    %v", test.Rectangle)
+			continue
+		}
+
+	}
+}