Implemented resizer

image/image.go

@@ -0,0 +1,52 @@
+package image
+
+import (
+	"bytes"
+	"github.com/anthonynsimon/bild/transform"
+	"image"
+	"image/jpeg"
+	"io"
+)
+
+func ResizeImage(imageBytes []byte, minWidth, minHeight int) ([]byte, error) {
+	img, _, err := image.Decode(bytes.NewReader(imageBytes))
+	if err != nil {
+		return nil, err
+	}
+	var buffer bytes.Buffer
+	writer := io.Writer(&buffer)
+
+	rX, rY := Resize(minWidth, minHeight, img.Bounds().Dx(), img.Bounds().Dy())
+
+	img = transform.Resize(img, rX, rY, transform.Gaussian)
+
+	if err = jpeg.Encode(writer, img, nil); err != nil {
+		return nil, err
+	}
+	return buffer.Bytes(), nil
+}
+
+func Resize(minX, minY, x, y int) (int, int) {
+	return resize(float32(minX), float32(minY), float32(x), float32(y))
+}
+
+func resize(minX, minY, x, y float32) (int, int) {
+	if x <= minX && y <= minY {
+		return int(x), int(y)
+	}
+
+	// try by width
+	rX := minX
+	rY := y * (rX / x)
+	if rX >= minX && rY >= minY && rX <= x && rY <= y {
+		return int(rX), int(rY)
+	}
+	// try by height
+	rY = minY
+	rX = x * (rY / y)
+	if rX >= minX && rY >= minY && rX <= x && rY <= y {
+		return int(rX), int(rY)
+	}
+
+	return int(x), int(y)
+}

image/image_test.go

@@ -0,0 +1,31 @@
+package image_test
+
+import (
+	"git.bbr-dev.info/brajkovic/resource_manager/image"
+	"testing"
+)
+
+func TestResize(t *testing.T) {
+
+	cases := [][]int{
+		// minX, minY, x, y, newX, newY
+		{400, 300, 400, 800, 400, 800},
+		{400, 300, 800, 400, 600, 300},
+		{1024, 1280, 800, 400, 800, 400},
+		{400, 300, 800, 100, 800, 100},
+		{1200, 900, 1600, 1400, 1200, 1050},
+	}
+
+	for _, testCase := range cases {
+		minX, minY, x, y, newX, newY := destructure(testCase)
+
+		rX, rY := image.Resize(minX, minY, x, y)
+		if rX != newX || rY != newY {
+			t.Errorf("for (%d, %d, %d, %d)expected (%d, %d) received (%d, %d)", minX, minY, x, y, newX, newY, rX, rY)
+		}
+	}
+}
+
+func destructure(testCase []int) (minX, minY, x, y, newX, newY int) {
+	return testCase[0], testCase[1], testCase[2], testCase[3], testCase[4], testCase[5]
+}