redimentary ability to preview scenes

tex_utils.py

@@ -3,51 +3,55 @@ import itertools as it
 from PIL import Image
 from constants import *
 
+#TODO, Cleanup and refactor this file.
+
 def tex_to_image(expression, 
                  size = "\HUGE",
                  template_tex_file = TEMPLATE_TEX_FILE):
     """
     Returns list of images for correpsonding with a list of expressions
     """
-    return_list = False
-    arg = expression
-    if not isinstance(expression, str):
-        #TODO, verify that expression is iterable of strings
-        expression = "\n".join([
-            "\onslide<%d>{"%count + exp + "}"
-            for count, exp in zip(it.count(1), expression)
-        ])
-        return_list = True
-    filestem = os.path.join(
-        TEX_DIR, str(hash(expression + size))
-    )
-    if not os.path.exists(filestem + ".dvi"):
+    return_list = isinstance(expression, list)
+    simple_tex = "".join(expression)
+    if return_list:
+        expression = tex_expression_list_as_string(expression)
+    exp_hash  = str(hash(expression + size))
+    image_dir = os.path.join(TEX_IMAGE_DIR, exp_hash)
+    if os.path.exists(image_dir):
+        result = [
+            Image.open(os.path.join(image_dir, png_file)).convert('RGB')
+            for png_file in os.listdir(image_dir)
+        ]
+    else:
+        filestem = os.path.join(TEX_DIR, exp_hash)
         if not os.path.exists(filestem + ".tex"):
-            print " ".join([
-                "Writing ",
-                "".join(arg),
-                "at size %s to "%(size),
-                filestem,
-            ])
+            print "Writing %s at size %s to %s.tex"%(
+                simple_tex, size, filestem
+            )
             with open(template_tex_file, "r") as infile:
                 body = infile.read()
                 body = body.replace(SIZE_TO_REPLACE, size)
                 body = body.replace(TEX_TEXT_TO_REPLACE, expression)
             with open(filestem + ".tex", "w") as outfile:
                 outfile.write(body)
-        commands = [
-            "latex", 
-            "-interaction=batchmode", 
-            "-output-directory=" + TEX_DIR,
-            filestem + ".tex"
-        ]
-        #TODO, Error check
-        os.system(" ".join(commands))
-    assert os.path.exists(filestem + ".dvi")
-    result = dvi_to_png(filestem + ".dvi")
+        if not os.path.exists(filestem + ".dvi"):
+            commands = [
+                "latex", 
+                "-interaction=batchmode", 
+                "-output-directory=" + TEX_DIR,
+                filestem + ".tex",
+                "> /dev/null"
+            ]
+            #TODO, Error check
+            os.system(" ".join(commands))
+        result = dvi_to_png(filestem + ".dvi")
     return result if return_list else result[0]
 
-
+def tex_expression_list_as_string(expression):
+    return "\n".join([
+        "\onslide<%d>{"%count + exp + "}"
+        for count, exp in zip(it.count(1), expression)
+    ])
 
 def dvi_to_png(filename, regen_if_exists = False):
     """