From f4eb2724c5f7621f85935929fd6135d429539a24 Mon Sep 17 00:00:00 2001
From: TonyCrane <tonycrane@foxmail.com>
Date: Tue, 25 Jan 2022 14:04:35 +0800
Subject: [PATCH] refactor SVGMobject.handle_transforms

---
 manimlib/mobject/svg/svg_mobject.py | 107 +++++++++++++++-------------
 1 file changed, 58 insertions(+), 49 deletions(-)

diff --git a/manimlib/mobject/svg/svg_mobject.py b/manimlib/mobject/svg/svg_mobject.py
index 650252ac..dd94a634 100644
--- a/manimlib/mobject/svg/svg_mobject.py
+++ b/manimlib/mobject/svg/svg_mobject.py
@@ -236,7 +236,6 @@ class SVGMobject(VMobject):
         return mob
 
     def handle_transforms(self, element, mobject):
-        # TODO, this could use some cleaning...
         x, y = 0, 0
         try:
             x = self.attribute_to_float(element.getAttribute('x'))
@@ -246,56 +245,66 @@ class SVGMobject(VMobject):
         except Exception:
             pass
 
-        transform = element.getAttribute('transform')
+        transform_names = [
+            "matrix", 
+            "translate", "translateX", "translateY", 
+            "scale", "scaleX", "scaleY", 
+            "rotate", 
+            "skew", "skewX", "skewY"
+        ]
+        transform_pattern = re.compile("|".join([x + r"[^)]*\)" for x in transform_names]))
+        number_pattern = re.compile(r"[-+]?(?:\d+(?:\.\d*)?|\.\d+)(?:[eE][-+]?\d+)?")
+        transforms = transform_pattern.findall(element.getAttribute('transform'))[::-1]
 
-        try:  # transform matrix
-            prefix = "matrix("
-            suffix = ")"
-            if not transform.startswith(prefix) or not transform.endswith(suffix):
-                raise Exception()
-            transform = transform[len(prefix):-len(suffix)]
-            transform = string_to_numbers(transform)
-            transform = np.array(transform).reshape([3, 2])
-            x = transform[2][0]
-            y = -transform[2][1]
-            matrix = np.identity(self.dim)
-            matrix[:2, :2] = transform[:2, :]
-            matrix[1] *= -1
-            matrix[:, 1] *= -1
+        for transform in transforms:
+            op_name, op_args = transform.split("(")
+            op_name = op_name.strip()
+            op_args = [float(x) for x in number_pattern.findall(op_args)]
+            
+            if op_name == "matrix":
+                self._handle_matrix_transform(mobject, op_name, op_args)
+            elif op_name.startswith("translate"):
+                self._handle_translate_transform(mobject, op_name, op_args)
+            elif op_name.startswith("scale"):
+                self._handle_scale_transform(mobject, op_name, op_args)
+    
+    def _handle_matrix_transform(self, mobject, op_name, op_args):
+        transform = np.array(op_args).reshape([3, 2])
+        x = transform[2][0]
+        y = -transform[2][1]
+        matrix = np.identity(self.dim)
+        matrix[:2, :2] = transform[:2, :]
+        matrix[1] *= -1
+        matrix[:, 1] *= -1
+        for mob in mobject.family_members_with_points():
+            mob.apply_matrix(matrix.T)
+        mobject.shift(x * RIGHT + y * UP)
 
-            for mob in mobject.family_members_with_points():
-                mob.apply_matrix(matrix.T)
-            mobject.shift(x * RIGHT + y * UP)
-        except:
-            pass
-
-        try:  # transform scale
-            prefix = "scale("
-            suffix = ")"
-            if not transform.startswith(prefix) or not transform.endswith(suffix):
-                raise Exception()
-            transform = transform[len(prefix):-len(suffix)]
-            scale_values = string_to_numbers(transform)
-            if len(scale_values) == 2:
-                scale_x, scale_y = scale_values
-                mobject.scale(np.array([scale_x, scale_y, 1]), about_point=ORIGIN)
-            elif len(scale_values) == 1:
-                scale = scale_values[0]
-                mobject.scale(np.array([scale, scale, 1]), about_point=ORIGIN)
-        except:
-            pass
-
-        try:  # transform translate
-            prefix = "translate("
-            suffix = ")"
-            if not transform.startswith(prefix) or not transform.endswith(suffix):
-                raise Exception()
-            transform = transform[len(prefix):-len(suffix)]
-            x, y = string_to_numbers(transform)
-            mobject.shift(x * RIGHT + y * DOWN)
-        except:
-            pass
-        # TODO, ...
+    def _handle_translate_transform(self, mobject, op_name, op_args):
+        if op_name.endswith("X"):
+            x, y = op_args[0], 0
+        elif op_name.endswith("Y"):
+            x, y = 0, op_args[0]
+        else:
+            x, y = op_args
+        mobject.shift(x * RIGHT + y * DOWN)
+    
+    def _handle_scale_transform(self, mobject, op_name, op_args):
+        if op_name.endswith("X"):
+            sx, sy = op_args[0], 1
+        elif op_name.endswith("Y"):
+            sx, sy = 1, op_args[0]
+        elif len(op_args) == 2:
+            sx, sy = op_args 
+        else:
+            sx = sy = op_args[0]
+        if sx < 0:
+            mobject.flip(UP)
+            sx = -sx 
+        if sy < 0:
+            mobject.flip(RIGHT)
+            sy = -sy
+        mobject.scale(np.array([sx, sy, 1]), about_point=ORIGIN)
 
     def flatten(self, input_list):
         output_list = []