From 85de4ffd88d214c2129678581cc974c0e4416714 Mon Sep 17 00:00:00 2001
From: turtlebasket <turtlebasket@gmail.com>
Date: Thu, 24 Nov 2022 21:09:13 +0900
Subject: [PATCH] some backend stuff (untested)

---
 backend/main.py                 | 76 ++++++++++++++++++++++++++++++---
 backend/tools/math_transform.py | 29 +++++++++----
 2 files changed, 92 insertions(+), 13 deletions(-)

diff --git a/backend/main.py b/backend/main.py
index a3c2e90..93536cd 100644
--- a/backend/main.py
+++ b/backend/main.py
@@ -1,24 +1,90 @@
-from fastapi import FastAPI
+from fastapi import FastAPI, Request
 from os import getenv
 import cv2 as cv
 from tools import math_transform
+import base64
+import numpy as np
 
 app = FastAPI(
     openapi_url="/resources/openapi.json",
     docs_url="/resources/docs"
 ) if getenv("ENV") == 'dev' else FastAPI()
 
+# Image endpoints
+
 @app.post("/image/math-transform")
-def math_image_transform_grayscale(image_b64: str, latex: str):
+async def math_image_transform_grayscale(
+    req: Request
+):
+
+    image_b64: str = req.body['image_b64']
+    latex: str = req.body['latex']
+    autominmax: bool = req.body['autominmax']
+    heatmap_out: bool = req.body['heatmap_out']
+
     img = cv.imdecode(image_b64)
 
     transformed = img.copy()
-    func = math_transform.generate_func(latex)
+
+    func = math_transform.transform_func_from_latex(
+        latex,
+        ["R", "G", "B", "A"]
+    )
+
+    alpha_on = len(img[0][0]) == 4
 
     for i in range(len(img)):
         for j in range(len(img[i])):
-            transformed[i][j] = func(inputs)
+            pix = img[i][j]
+            transformed[i][j] = func(
+                pix[2],
+                pix[1],
+                pix[0],
+                255 if alpha_on else pix[3]
+            )
+
+    transformed_b64 = base64.b64encode(
+        cv.imencode('.png', transformed)[1]
+    ).decode(encoding='utf-8')
 
     return {
-        "transformed_b64": transformed
+        "img_b64": transformed_b64,
+        "legend": None
     }
+
+@app.post("/image/smooth-conv")
+async def convolutional_smooth(
+    image_b64: str,
+    smoothing_radius: int
+):
+    img = cv.imdecode(image_b64)
+
+    # build & apply smoothing conv kernel
+    k = []
+    for i in range(smoothing_radius):
+        k.append([1/(smoothing_radius**2) for i in range(smoothing_radius)])
+    kernel = np.array(k)
+
+    transformed = cv.filter2D(img, -1, kernel)
+
+    transformed_b64 = base64.b64encode(
+        cv.imencode('.png', transformed)[1]
+    ).decode(encoding='utf-8')
+
+    return transformed_b64
+
+
+@app.post("/image/heatmap")
+async def intensity_heatmap(
+    image_b64: str,
+    smoothing_radius: int
+):
+    img = cv.imdecode(image_b64)
+
+    transformed = cv.applyColorMap(img, cv.COLORMAP_JET)
+
+    transformed_b64 = base64.b64encode(
+        cv.imencode('.png', transformed)[1]
+    ).decode(encoding='utf-8')
+
+    return transformed_b64
diff --git a/backend/tools/math_transform.py b/backend/tools/math_transform.py
index 121c36d..190eed7 100644
--- a/backend/tools/math_transform.py
+++ b/backend/tools/math_transform.py
@@ -1,14 +1,27 @@
+from typing import List
 from latex2sympy2 import latex2sympy
 
-def generate_func(latex_input: str) -> function:
+def transform_func_from_latex(
+    latex_input: str,
+    arg_names: List[str]
+):
     latex_clean = latex_input.replace('\ ', '')
-    res: str
     try:
-        res = latex2sympy(latex_clean)
+        expr = latex2sympy(latex_clean)
+        arg_list_string = ""
+        subst_dict_string = "{"
+        for i in range(len(arg_names)):
+            name = arg_names[i]
+            arg_list_string += f"{name}"
+            subst_dict_string += f'"{name}":{name}'
+            if i < len(arg_names) - 1:
+                arg_list_string += ","
+                subst_dict_string += ","
+        subst_dict_string += "}"
+        f: function = eval(f"""
+lambda {arg_list_string}: expr.subs({subst_dict_string}).evalf()
+""", {"expr": expr})
+        return f
+
     except Exception as e:
         print(e)
-
-    def func(input: dict):
-        return eval(res)
-
-