Added tests for crop_to_point

wagtail/wagtailimages/tests.py

@@ -17,6 +17,8 @@ from wagtail.wagtailimages.formats import (
 
 from wagtail.wagtailimages.backends import get_image_backend
 from wagtail.wagtailimages.backends.pillow import PillowBackend
+from wagtail.wagtailimages.utils.crop import crop_to_point, CropBox
+from wagtail.wagtailimages.utils.focal_point import FocalPoint
 
 
 def get_test_image_file():
@@ -471,3 +473,60 @@ class TestFormat(TestCase):
         register_image_format(self.format)
         result = get_image_format('test name')
         self.assertEqual(result, self.format)
+
+
+class TestCropToPoint(TestCase):
+    def test_basic(self):
+        "Test basic cropping in the centre of the image"
+        self.assertEqual(
+            crop_to_point((640, 480), (100, 100), FocalPoint(x=320, y=240)),
+            CropBox(270, 190, 370, 290),
+        )
+        
+    def test_doesnt_exit_top_left(self):
+        "Test that the cropbox doesn't exit the image at the top left"
+        self.assertEqual(
+            crop_to_point((640, 480), (100, 100), FocalPoint(x=0, y=0)),
+            CropBox(0, 0, 100, 100),
+        )
+
+    def test_doesnt_exit_bottom_right(self):
+        "Test that the cropbox doesn't exit the image at the bottom right"
+        self.assertEqual(
+            crop_to_point((640, 480), (100, 100), FocalPoint(x=640, y=480)),
+            CropBox(540, 380, 640, 480),
+        )
+
+    def test_doesnt_get_smaller_than_focal_point(self):
+        "Test that the cropbox doesn't get any smaller than the focal point"
+        self.assertEqual(
+            crop_to_point((640, 480), (10, 10), FocalPoint(x=320, y=240, width=100, height=100)),
+            CropBox(270, 190, 370, 290),
+        )
+
+    def test_keeps_composition(self):
+        "Test that the cropbox tries to keep the composition of the original image as much as it can"
+        self.assertEqual(
+            crop_to_point((300, 300), (150, 150), FocalPoint(x=100, y=200)),
+            CropBox(50, 100, 200, 250), # Focal point is 1/3 across and 2/3 down in the crop box
+        )
+
+    def test_keeps_focal_point_in_view_bottom_left(self):
+        """
+        Even though it tries to keep the composition of the image,
+        it shouldn't let that get in the way of keeping the entire subject in view
+        """
+        self.assertEqual(
+            crop_to_point((300, 300), (150, 150), FocalPoint(x=100, y=200, width=150, height=150)),
+            CropBox(25, 125, 175, 275),
+        )
+
+    def test_keeps_focal_point_in_view_top_right(self):
+        """
+        Even though it tries to keep the composition of the image,
+        it shouldn't let that get in the way of keeping the entire subject in view
+        """
+        self.assertEqual(
+            crop_to_point((300, 300), (150, 150), FocalPoint(x=200, y=100, width=150, height=150)),
+            CropBox(125, 25, 275, 175),
+        )