Added grayscale image support in put_image_data and exposed image_smoothing_enabled attribute (#353)

* Added grayscale image support in put_image_data and exposed image_smoothing_enabled attribute

* Linter

---------

Co-authored-by: AnyaPorter <[email protected]>

Author: martinRenou

ipycanvas/canvas.py

@@ -575,6 +575,9 @@ class Canvas(_CanvasBase):
     #: This property has no effect on Safari, see https://bugs.webkit.org/show_bug.cgi?id=198416
     filter = Unicode("none")
 
+    #: (bool) Indicates if scaled images are smoothed. Default to True
+    image_smoothing_enabled = Bool(True)
+
     _line_dash = List()
 
     #: (float) Specifies where to start a dash array on a line. Default is ``0.``.
@@ -614,6 +617,7 @@ class Canvas(_CanvasBase):
         "shadow_blur": 15,
         "shadow_color": 16,
         "filter": 17,
+        "image_smoothing_enabled": 18,
     }
 
     def __init__(self, *args, **kwargs):

ipycanvas/utils.py

@@ -27,7 +27,9 @@ def image_bytes_to_array(im_bytes):
 
 def binary_image(ar, quality=75):
     f = BytesIO()
-    if ar.shape[2] == 3:
+    if len(ar.shape) == 2:
+        filetype = "PNG"
+    elif ar.shape[2] == 3:
         filetype = "JPEG"
     else:
         filetype = "PNG"

src/widget.ts

@@ -609,7 +609,8 @@ export class CanvasModel extends DOMWidgetModel {
     'shadowOffsetY',
     'shadowBlur',
     'shadowColor',
-    'filter'
+    'filter',
+    'imageSmoothingEnabled'
   ];
 
   initialize(attributes: any, options: any) {