tex mobjects implemented

tex_utils.py

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+import os
+import itertools as it
+from PIL import Image
+from constants import *
+
+def tex_to_image(expression, size = "\HUGE"):
+    """
+    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"):
+        if not os.path.exists(filestem + ".tex"):
+            print " ".join([
+                "Writing ",
+                "".join(arg),
+                "at size %s to "%(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")
+    return result if return_list else result[0]
+
+
+
+def dvi_to_png(filename, regen_if_exists = False):
+    """
+    Converts a dvi, which potentially has multiple slides, into a 
+    directory full of enumerated pngs corresponding with these slides.
+    Returns a list of PIL Image objects for these images sorted as they
+    where in the dvi
+    """
+    possible_paths = [
+        filename,
+        os.path.join(TEX_DIR, filename),
+        os.path.join(TEX_DIR, filename + ".dvi"),
+    ]
+    for path in possible_paths:
+        if os.path.exists(path):
+            directory, filename = os.path.split(path)
+            name = filename.split(".")[0]
+            images_dir = os.path.join(TEX_IMAGE_DIR, name)
+            if not os.path.exists(images_dir):
+                os.mkdir(images_dir)
+            if os.listdir(images_dir) == [] or regen_if_exists:
+                commands = [
+                    "convert",
+                    "-density",
+                    str(PDF_DENSITY),
+                    path,
+                    "-size",
+                    str(DEFAULT_WIDTH) + "x" + str(DEFAULT_HEIGHT),
+                    os.path.join(images_dir, name + ".png")
+                ]
+                os.system(" ".join(commands))
+            image_paths = [
+                os.path.join(images_dir, name)
+                for name in os.listdir(images_dir)
+                if name.endswith(".png")
+            ]
+            image_paths.sort(cmp_enumerated_files)
+            return [Image.open(path).convert('RGB') for path in image_paths]
+    raise IOError("File not Found")
+
+def cmp_enumerated_files(name1, name2):
+    num1, num2 = [
+        int(name.split(".")[0].split("-")[-1]) 
+        for name in (name1, name2)
+    ]
+    return num1 - num2
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