ollama source for Momentry Core verification

x/imagegen/image_processor.go

@@ -0,0 +1,56 @@
+package imagegen
+
+import (
+	"fmt"
+	"image"
+	_ "image/jpeg"
+	_ "image/png"
+	"os"
+
+	"github.com/ollama/ollama/x/imagegen/mlx"
+	"golang.org/x/image/draw"
+)
+
+// ProcessImage loads and preprocesses an image for multimodal vision towers.
+// Returns [1, H, W, C] tensor in NHWC format normalized for SigLIP.
+func ProcessImage(path string, imageSize int32) (*mlx.Array, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, fmt.Errorf("open image: %w", err)
+	}
+	defer f.Close()
+
+	img, _, err := image.Decode(f)
+	if err != nil {
+		return nil, fmt.Errorf("decode image: %w", err)
+	}
+
+	return ProcessImageData(img, imageSize)
+}
+
+// ProcessImageData preprocesses an image.Image for multimodal vision towers.
+func ProcessImageData(img image.Image, imageSize int32) (*mlx.Array, error) {
+	// Resize to target size using bilinear interpolation.
+	resized := image.NewRGBA(image.Rect(0, 0, int(imageSize), int(imageSize)))
+	draw.BiLinear.Scale(resized, resized.Bounds(), img, img.Bounds(), draw.Over, nil)
+
+	// Convert to float32 array [H, W, C] and normalize.
+	// SigLIP normalization: (pixel / 255.0 - 0.5) / 0.5 = pixel / 127.5 - 1.0.
+	data := make([]float32, imageSize*imageSize*3)
+	idx := 0
+	for y := int32(0); y < imageSize; y++ {
+		for x := int32(0); x < imageSize; x++ {
+			r, g, b, _ := resized.At(int(x), int(y)).RGBA()
+			// RGBA returns 16-bit values, convert to 8-bit.
+			data[idx] = float32(r>>8)/127.5 - 1.0
+			data[idx+1] = float32(g>>8)/127.5 - 1.0
+			data[idx+2] = float32(b>>8)/127.5 - 1.0
+			idx += 3
+		}
+	}
+
+	// Create MLX array [1, H, W, C] for NHWC layout.
+	arr := mlx.NewArrayFloat32(data, []int32{1, imageSize, imageSize, 3})
+	mlx.Eval(arr) // Materialize to prevent use-after-free.
+	return arr, nil
+}