From 6adac570879a44372abb3b239d555dcf1b492e92 Mon Sep 17 00:00:00 2001
From: Star Brilliant <m13253@hotmail.com>
Date: Thu, 5 Jun 2014 21:50:00 +0800
Subject: [PATCH] New experimental rotation handling

---
 danmaku2ass.py | 49 ++++++++++---------------------------------------
 1 file changed, 10 insertions(+), 39 deletions(-)

diff --git a/danmaku2ass.py b/danmaku2ass.py
index 20fa996..935e2d5 100755
--- a/danmaku2ass.py
+++ b/danmaku2ass.py
@@ -502,46 +502,15 @@ def GetZoomFactor(SourceSize, TargetSize):
 
 # Calculation is based on https://github.com/jabbany/CommentCoreLibrary/issues/5#issuecomment-40087282
 #                     and https://github.com/m13253/danmaku2ass/issues/7#issuecomment-41489422
-# Input: X relative horizonal coordinate: 0 for left edge, 1 for right edge.
-#        Y relative vertical coordinate: 0 for top edge, 1 for bottom edge.
 # FOV = 1.0/math.tan(100*math.pi/360.0)
-# Result: (rotX, rotY, rotZ, shearX, shearY)
-def ConvertFlashRotation(rotY, rotZ, X, Y, FOV=math.tan(2*math.pi/9.0)):
+# Result: (transX, transY, rotX, rotY, rotZ, scaleX, scaleY)
+def ConvertFlashRotation(rotY, rotZ, X, Y, width, height):
     def WrapAngle(deg):
         return 180-((180-deg)%360)
-    def CalcPerspectiveCorrection(alpha, X, FOV=FOV):
-        alpha = WrapAngle(alpha)
-        if FOV is None:
-            return alpha
-        if 0 <= alpha <= 180:
-            costheta = (FOV*math.cos(alpha*math.pi/180.0)-X*math.sin(alpha*math.pi/180.0))/(FOV+max(2, abs(X)+1)*math.sin(alpha*math.pi/180.0))
-            try:
-                if costheta > 1:
-                    costheta = 1
-                    raise ValueError
-                elif costheta < -1:
-                    costheta = -1
-                    raise ValueError
-            except ValueError:
-                logging.error('Clipped rotation angle: (alpha=%s, X=%s), it is a bug!' % (alpha, X))
-            theta = math.acos(costheta)*180/math.pi
-        else:
-            costheta = (FOV*math.cos(alpha*math.pi/180.0)-X*math.sin(alpha*math.pi/180.0))/(FOV-max(2, abs(X)+1)*math.sin(alpha*math.pi/180.0))
-            try:
-                if costheta > 1:
-                    costheta = 1
-                    raise ValueError
-                elif costheta < -1:
-                    costheta = -1
-                    raise ValueError
-            except ValueError:
-                logging.error('Clipped rotation angle: (alpha=%s, X=%s), it is a bug!' % (alpha, X))
-            theta = -math.acos(costheta)*180/math.pi
-        return WrapAngle(theta)
-    X = 2*X-1
-    Y = 2*Y-1
     rotY = WrapAngle(rotY)
     rotZ = WrapAngle(rotZ)
+    if rotY in (90, -90):
+        rotY -= 1
     if rotY == 0 or rotZ == 0:
         outX = 0
         outY = -rotY  # Positive value means clockwise in Flash
@@ -552,10 +521,12 @@ def ConvertFlashRotation(rotY, rotZ, X, Y, FOV=math.tan(2*math.pi/9.0)):
         outY = math.atan2(-math.sin(rotY)*math.cos(rotZ), math.cos(rotY))*180/math.pi
         outZ = math.atan2(-math.cos(rotY)*math.sin(rotZ), math.cos(rotZ))*180/math.pi
         outX = math.asin(math.sin(rotY)*math.sin(rotZ))*180/math.pi
-    if FOV is not None:
-        #outX = CalcPerspectiveCorrection(outX, -Y, FOV*0.75)
-        outY = CalcPerspectiveCorrection(outY, X, FOV)
-    return (WrapAngle(round(outX)), WrapAngle(round(outY)), WrapAngle(round(outZ)), 0, round(-0.75*Y*math.sin(outY*math.pi/180.0), 3))
+    rotX *= pi/180.0
+    rotY *= pi/180.0
+    rotZ *= pi/180.0
+    trX = (X*math.cos(rotZ)+Y*math.sin(rotZ))/math.cos(rotY)+math.tan(rotY*math.pi/180.0)+(1-math.cos(rotZ)/math.cos(rotY))*width/2-math.sin(rotZ)/math.cos(rotY)*height/2
+    trY = Y*math.cos(rotZ)-X*math.sin(rotZ)+math.sin(rotZ)*width/2+(1-cos(rotZ))*height/2
+    return (round(trX), round(trY), WrapAngle(round(outX)), WrapAngle(round(outY)), WrapAngle(round(outZ)), 100, 100)
 
 
 def ProcessComments(comments, f, width, height, bottomReserved, fontface, fontsize, alpha, lifetime, reduced, progress_callback):