Remove matplotlib dependency

app/api/common.py

@@ -40,4 +40,25 @@ def path_traversal_check(unsafe_path, known_safe_path):
         raise SuspiciousFileOperation("{} is not safe".format(unsafe_path))
 
     # Passes the check
-    return unsafe_path
+    return unsafe_path
+
+def hex2rgb(hex_color, with_alpha=False):
+    """
+    Adapted from https://stackoverflow.com/questions/29643352/converting-hex-to-rgb-value-in-python/29643643
+    """
+    hex_color = hex_color.lstrip('#')
+    if len(hex_color) != 6:
+        if with_alpha:
+            return tuple((255, 255, 255, 255))
+        else:
+            return tuple((255, 255, 255))
+    try:
+        v = tuple(int(hex_color[i:i+2], 16) for i in (0, 2, 4))
+        if with_alpha:
+            v += (255, )
+        return v
+    except ValueError:
+        if with_alpha:
+            return tuple((255, 255, 255, 255))
+        else:
+            return tuple((255, 255, 255))

app/api/custom_colormaps_helper.py

@@ -1,19 +1,14 @@
-import matplotlib
-import numpy
-def generate_discrete_color_map_from_list_of_hex(list_of_hex_colors):
-    colormap = matplotlib.colors.ListedColormap(list_of_hex_colors)
-    color_map_dict = extract_colormap_dict_from_arr(colormap)
-    return color_map_dict
-def generate_linerar_segmented_color_map_from_list_of_hex(list_of_hex_colors, name_of_colormap="default_name", N=256):
-    colormap = matplotlib.colors.LinearSegmentedColormap.from_list(name_of_colormap, list_of_hex_colors, N)
-    color_map_dict = extract_colormap_dict_from_arr(colormap)
-    return color_map_dict
-def extract_colormap_dict_from_arr(colormap):
-    x = numpy.linspace(0, 1, 256)
-    cmap_vals = colormap(x)[:, :]
-    cmap_uint8 = (cmap_vals * 255).astype('uint8')
-    ndvi_dict = {idx: value.tolist() for idx, value in enumerate(cmap_uint8)}
-    return ndvi_dict
+import math
+from .common import hex2rgb
+
+def discrete_cmap_from_hex(hex_colors):
+    rgb_colors = [hex2rgb(h, with_alpha=True) for h in hex_colors]
+    res = {}
+    for x in range(0, 255):
+        idx = math.floor(x / 256.0 * len(rgb_colors))
+        res[x] = rgb_colors[idx]
+    return res
+
 
 ndvi_arr = [
     '#AD0028',
@@ -46,7 +41,7 @@ contrast_ndvi_arr = [
 ]
 
 custom_colormaps = [
-    {"discrete_ndvi": generate_discrete_color_map_from_list_of_hex(contrast_ndvi_arr)},
-    {"better_discrete_ndvi": generate_discrete_color_map_from_list_of_hex(ndvi_arr)},
+    {"discrete_ndvi": discrete_cmap_from_hex(contrast_ndvi_arr)},
+    {"better_discrete_ndvi": discrete_cmap_from_hex(ndvi_arr)},
     #add custom maps here
 ]

app/api/imageuploads.py

@@ -9,6 +9,7 @@ from app.models.task import assets_directory_path
 from PIL import Image, ImageDraw, ImageOps
 from django.http import HttpResponse
 from .tasks import download_file_response
+from .common import hex2rgb
 import numpy as np
 
 def normalize(img):
@@ -26,18 +27,6 @@ def normalize(img):
 
     return Image.fromarray(arr)
 
-def hex2rgb(hex_color):
-    """
-    Adapted from https://stackoverflow.com/questions/29643352/converting-hex-to-rgb-value-in-python/29643643
-    """
-    hex_color = hex_color.lstrip('#')
-    if len(hex_color) != 6:
-        return tuple((255, 255, 255))
-    try:
-        return tuple(int(hex_color[i:i+2], 16) for i in (0, 2, 4))
-    except ValueError:
-        return tuple((255, 255, 255))
-
 class Thumbnail(TaskNestedView):
     def get(self, request, pk=None, project_pk=None, image_filename=""):
         """

requirements.txt

@@ -63,5 +63,4 @@ Shapely==1.7.0 ; sys_platform == "win32"
 eventlet==0.25.1 ; sys_platform == "win32"
 pyopenssl==19.1.0 ; sys_platform == "win32"
 numpy==1.21.1
-urllib3~=1.24.1
-matplotlib==3.4.3
+urllib3~=1.24.1