added performance setting for image cache size

canvas.go

@@ -123,7 +123,10 @@ const (
 var Performance = struct {
 	IgnoreSelfIntersections bool
 	AssumeConvex            bool
-}{}
+	ImageCacheSize          int
+}{
+	ImageCacheSize: 16_000_000,
+}
 
 // New creates a new canvas with the given viewport coordinates.
 // While all functions on the canvas use the top left point as

images.go

@@ -62,7 +62,7 @@ func (cv *Canvas) LoadImage(src interface{}) (*Image, error) {
 			return img, nil
 		}
 	}
-	cv.reduceCache(16_000_000)
+	cv.reduceCache(Performance.ImageCacheSize)
 	var srcImg image.Image
 	switch v := src.(type) {
 	case image.Image:
@@ -105,7 +105,7 @@ func (cv *Canvas) getImage(src interface{}) *Image {
 	} else if img, ok := cv.images[src]; ok {
 		return img
 	}
-	cv.reduceCache(16_000_000)
+	cv.reduceCache(Performance.ImageCacheSize)
 	switch v := src.(type) {
 	case *Image:
 		return v