models: Move model into their own directory

This allows there to be a file that is a list of models that is
not mixed into the runner code.

model/models/qwen2vl/imageproc.go

@@ -0,0 +1,74 @@
+package qwen2vl
+
+import (
+	"fmt"
+	"image"
+	_ "image/jpeg"
+	_ "image/png"
+	"io"
+	"math"
+
+	"github.com/ollama/ollama/model/imageproc"
+)
+
+const (
+	DefaultFactor    = 28
+	DefaultMinPixels = 56 * 56
+	DefaultMaxPixels = 14 * 14 * 4 * 1280
+)
+
+// smartResize calculates the size of the image to resize to based on the
+// factor, minPixels, and maxPixels.
+func smartResize(size image.Point, factor, minPixels, maxPixels int) image.Point {
+	// 1. Both dimensions of size are divisible by factor
+	// 2. The area of the image is between minPixels and maxPixels
+	// 3. The aspect ratio of the image is as close to 1:1 as possible
+
+	if size.Y < factor || size.X < factor {
+		panic("image is too small to resize")
+	} else if max(size.X, size.Y)/min(size.X, size.Y) > 200 {
+		panic("aspect ratio must be less than 200:1")
+	}
+
+	f := float64(factor)
+	width := float64(size.X)
+	height := float64(size.Y)
+
+	xBar := math.Round(width/f) * f
+	yBar := math.Round(height/f) * f
+
+	if xBar*yBar > float64(maxPixels) {
+		beta := math.Sqrt(height * width / float64(maxPixels))
+		xBar = math.Floor(width/beta/f) * f
+		yBar = math.Floor(height/beta/f) * f
+	} else if xBar*yBar < float64(minPixels) {
+		beta := math.Sqrt(float64(minPixels) / (height * width))
+		xBar = math.Ceil(width*beta/f) * f
+		yBar = math.Ceil(height*beta/f) * f
+	}
+
+	return image.Point{int(xBar), int(yBar)}
+}
+
+func resizeImage(img image.Image, format string, size image.Point) image.Image {
+	if format == "png" {
+		img = imageproc.Composite(img)
+	}
+
+	return imageproc.Resize(img, size, imageproc.ResizeBilinear)
+}
+
+func Preprocess(imageData io.Reader) ([]float32, map[string]any, error) {
+	img, format, err := image.Decode(imageData)
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to decode image: %w", err)
+	}
+
+	size := smartResize(img.Bounds().Max, DefaultFactor, DefaultMinPixels, DefaultMaxPixels)
+	img = resizeImage(img, format, size)
+
+	data := imageproc.Normalize(img, imageproc.ClipDefaultMean, imageproc.ClipDefaultSTD, true, true)
+
+	opts := map[string]any{}
+	return data, opts, nil
+}