imageproc mllama refactor (#7537)

Refactor mllama image processing code, and add pixtral and qwen2vl

model/qwen2vl/imageproc_test.go

@@ -0,0 +1,78 @@
+package qwen2vl
+
+import (
+	"bytes"
+	"image"
+	"image/png"
+	"testing"
+)
+
+func TestSmartResize(t *testing.T) {
+	type smartResizeCase struct {
+		TestImage image.Image
+		Expected  image.Point
+	}
+
+	cases := []smartResizeCase{
+		{
+			TestImage: image.NewRGBA(image.Rect(0, 0, 1024, 1024)),
+			Expected:  image.Point{980, 980},
+		},
+		{
+			TestImage: image.NewRGBA(image.Rect(0, 0, 1024, 768)),
+			Expected:  image.Point{1036, 756},
+		},
+		{
+			TestImage: image.NewRGBA(image.Rect(0, 0, 2000, 2000)),
+			Expected:  image.Point{980, 980},
+		},
+	}
+
+	for _, c := range cases {
+		b := c.TestImage.Bounds().Max
+		actual := smartResize(b, DefaultFactor, DefaultMinPixels, DefaultMaxPixels)
+		if actual != c.Expected {
+			t.Errorf("expected: %v, actual: %v", c.Expected, actual)
+		}
+	}
+}
+
+func TestPreprocess(t *testing.T) {
+	type preprocessCase struct {
+		TestImage   image.Image
+		ExpectedLen int
+	}
+
+	cases := []preprocessCase{
+		{
+			TestImage:   image.NewRGBA(image.Rect(0, 0, 256, 256)),
+			ExpectedLen: 252 * 252 * 3 * 1,
+		},
+		{
+			TestImage:   image.NewRGBA(image.Rect(0, 0, 2000, 2000)),
+			ExpectedLen: 980 * 980 * 3 * 1,
+		},
+	}
+
+	for _, c := range cases {
+		var buf bytes.Buffer
+		err := png.Encode(&buf, c.TestImage)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		imgData, _, err := Preprocess(&buf)
+		if err != nil {
+			t.Fatalf("error processing: %q", err)
+		}
+
+		switch len(imgData) {
+		case 0:
+			t.Errorf("no image data returned")
+		case c.ExpectedLen:
+			// ok
+		default:
+			t.Errorf("unexpected image data length: %d, expected: %d", len(imgData), c.ExpectedLen)
+		}
+	}
+}