[gimp-gap] move path update for acceleration charactersitics implementation #607927

[Wolfgang Hofer <wolfgangh src gnome org>]

commit 31769e61390b0af588c3041c7c32ddf536c37e25
Author: Wolfgang Hofer <wolfgangh svn gnome org>
Date:   Tue Feb 16 19:28:46 2010 +0100

    move path update for acceleration charactersitics implementation #607927

 ChangeLog                                    |   17 ++++
 docs/reference/txt/plug-in-gap-move-path.txt |   26 +++++-
 gap/gap_mov_exec.c                           |  107 ++++++++++++++++++++------
 3 files changed, 121 insertions(+), 29 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index a789b42..2bd4b39 100755
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,20 @@
+2010-02-16 Wolfgang Hofer <hof gimp org>
+
+- acceleration characteristic behavior was changed for MovePath.
+  In case movement uses acceleration characteristic other than 0
+  and other transitions (rotate, zoom, perspective, opacity)
+  do not use their own (e.g have acceleration characteristic value == 0)
+  the frametiming of those other transitions is now syncronized
+  to the frametiming of the movement.
+
+  This new behavior allows rotation following the path in case
+  the object move shall use acceleration, deceleration or constant speed
+  via acceleration characteristic setting.
+  (see also discussion at #607927)
+
+  * gap/gap_mov_exec.c
+  * docs/reference/txt/plug-in-gap-move-path.txt
+
 2010-02-15 Wolfgang Hofer <hof gimp org>
 
 - acceleration graph widget changed. Now the widget knows the connected adjustment
diff --git a/docs/reference/txt/plug-in-gap-move-path.txt b/docs/reference/txt/plug-in-gap-move-path.txt
index 6481f6f..6e8ef39 100755
--- a/docs/reference/txt/plug-in-gap-move-path.txt
+++ b/docs/reference/txt/plug-in-gap-move-path.txt
@@ -330,8 +330,7 @@ Move Path (make things move)
 	      Each line between 2 contolpoints gets an equal time slot (e.g number of frames)
 	      The speed between 2 controlpoints is constant, but depends on the length of the line,
 	      where short lines result in low speed and long lines result in high speed.
-
-
+              
         For all other Acceleration characteristic values than 0
         the line length between controlpoints does not affect
         the speed of the moving object.
@@ -386,19 +385,36 @@ Move Path (make things move)
          
         Example:
            have a path with 10 controlpoints, none of them marked as keyframe
-           specifiy rotation 0 for first controlpoint, rotation 180 for the last
+           specifiy rotation 0 for first controlpoint, rotation 360 for the last
            controlpoint and select both Acceleration characteristic for Movement
            and Rotation value 1 (for constant speed)
            
            This settings move the object along the path of 10 points and rotate it
-           with constant speed from 0 to 180 degree, regardless what rotation settings
+           with constant speed from 0 to 360 degree, regardless what rotation settings
            are define in controlpoints 2,3,4,5,6,7,8,9.
 
         
         Speed of the moving object can be controled for each segment of the path,
         where a segment is the distance to the next KEYFRAME. In case there are no
         explicite Keyframes the path has only one segment with full length
-        from the firtst to the last controlpoint.
+        from the first to the last controlpoint.
+
+
+        When acceleration characteristic other than 0 is used for movement, 
+        but not for other transitions (rotation, opacity ...), then the move path
+        tool automatically syncronizes frame timing for those other transitions
+        with the frametiming of the movement. 
+        
+        Example:
+          Have a path with 5 controlpoints and no explicite keyframe set.
+          At the first controlpoint secify acceleration caracteristic 12
+          for movement to start slow and increase speed of the moving
+          object while moving along the path.
+          Further let rotation of the object follow the path
+          (generate the rotation settings by pressing the "Rotate Follow" button)
+          
+          In this example the rotation follows the current postion of the
+          moving object with the same acceleration as the movement.
 
            
     - Keyframes
diff --git a/gap/gap_mov_exec.c b/gap/gap_mov_exec.c
index e86d5fb..add6c30 100755
--- a/gap/gap_mov_exec.c
+++ b/gap/gap_mov_exec.c
@@ -946,10 +946,13 @@ p_calculate_settings_for_current_FrameTween(
                                     * tweens can have non integer frame number like 1.5 or 1.3333 or 1.25 etc....
                                     */
   gdouble pathSegmentLength;
-  
   gdouble  posFactor;
+  gdouble  posFactorMovement;
+  gint     segmPtidx;              /* calculated controlpoint index of relevant line begin with current segment */
 
   posFactor = 0.0;
+  posFactorMovement = 0.0;
+  segmPtidx = -1;                  /* inital value -1 indicates that movement does NOT use acceleration characteristic */
 
   tweenMultiplicator = 1.0;
   if(val_ptr->tween_steps > 1.0)
@@ -983,17 +986,16 @@ p_calculate_settings_for_current_FrameTween(
   && (pathSegmentLength > 0))
   {
     /* acceleration characteristic processing */
-    gint     segmPtidx;  /* calculated controlpoint index of relevant line begin with current segment */
 
     segmPtidx = p_pick_controlpoint_at_curr_length(val_ptr
          , startOfSegmentIndex, endOfSegmentIndex, pathSegmentLength
          , val_ptr->point[startOfSegmentIndex].accPosition
          , lengthFactorLinear
-         , &posFactor
+         , &posFactorMovement
          );
 
-    cur_ptr->currX  =       GAP_BASE_MIX_VALUE(posFactor, (gdouble)val_ptr->point[segmPtidx].p_x,      (gdouble)val_ptr->point[segmPtidx +1].p_x);
-    cur_ptr->currY  =       GAP_BASE_MIX_VALUE(posFactor, (gdouble)val_ptr->point[segmPtidx].p_y,      (gdouble)val_ptr->point[segmPtidx +1].p_y);
+    cur_ptr->currX  =       GAP_BASE_MIX_VALUE(posFactorMovement, (gdouble)val_ptr->point[segmPtidx].p_x,      (gdouble)val_ptr->point[segmPtidx +1].p_x);
+    cur_ptr->currY  =       GAP_BASE_MIX_VALUE(posFactorMovement, (gdouble)val_ptr->point[segmPtidx].p_y,      (gdouble)val_ptr->point[segmPtidx +1].p_y);
 
 
     if(gap_debug)
@@ -1008,8 +1010,8 @@ p_calculate_settings_for_current_FrameTween(
        printf("p_mov_execute: Position, frameNrAtEndOfSegment=%d\n", (int)frameNrAtEndOfSegment);
        printf("p_mov_execute: Position, lengthFactorLinear=%f\n", (float)lengthFactorLinear);
        printf("p_mov_execute: Position, pathSegmentLength=%f\n", (float)pathSegmentLength);
-       printf("p_mov_execute: Position, posFactor=%f  segmPtidx=%d\n"
-             , (float)posFactor
+       printf("p_mov_execute: Position, posFactorMovement=%f  segmPtidx=%d\n"
+             , (float)posFactorMovement
              , (int)segmPtidx
              );
     }
@@ -1044,8 +1046,18 @@ p_calculate_settings_for_current_FrameTween(
   }
   else
   {
-    /* No acceleration characteristic specified for opacity (compatible to GAP 2.6.x release behavior) */
-    cur_ptr->currOpacity  = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].opacity,  (gdouble)val_ptr->point[currPtidx].opacity);
+    if(segmPtidx >= 0)
+    {
+      /* No acceleration characteristic specified for opacity, but movement uses accelertion characteristic
+       * (in this case force frametiming synchronized to movement)
+       */
+      cur_ptr->currOpacity  = GAP_BASE_MIX_VALUE(posFactorMovement, (gdouble)val_ptr->point[segmPtidx].opacity,  (gdouble)val_ptr->point[segmPtidx +1].opacity);
+    }
+    else
+    {
+      /* No acceleration characteristic specified for opacity (compatible to GAP 2.6.x release behavior) */
+      cur_ptr->currOpacity  = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].opacity,  (gdouble)val_ptr->point[currPtidx].opacity);
+    }
   }
 
 
@@ -1063,8 +1075,19 @@ p_calculate_settings_for_current_FrameTween(
   }
   else
   {
-    cur_ptr->currWidth    = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].w_resize, (gdouble)val_ptr->point[currPtidx].w_resize);
-    cur_ptr->currHeight   = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].h_resize, (gdouble)val_ptr->point[currPtidx].h_resize);
+    if(segmPtidx >= 0)
+    {
+      /* No acceleration characteristic specified for zoom, but movement uses accelertion characteristic
+       * (in this case force frametiming synchronized to movement)
+       */
+      cur_ptr->currWidth    = GAP_BASE_MIX_VALUE(posFactorMovement, (gdouble)val_ptr->point[segmPtidx].w_resize, (gdouble)val_ptr->point[segmPtidx +1].w_resize);
+      cur_ptr->currHeight   = GAP_BASE_MIX_VALUE(posFactorMovement, (gdouble)val_ptr->point[segmPtidx].h_resize, (gdouble)val_ptr->point[segmPtidx +1].h_resize);
+    }
+    else
+    {
+      cur_ptr->currWidth    = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].w_resize, (gdouble)val_ptr->point[currPtidx].w_resize);
+      cur_ptr->currHeight   = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].h_resize, (gdouble)val_ptr->point[currPtidx].h_resize);
+    }
   }
 
 
@@ -1081,18 +1104,37 @@ p_calculate_settings_for_current_FrameTween(
   }
   else
   {
-    cur_ptr->currRotation = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].rotation, (gdouble)val_ptr->point[currPtidx].rotation);
- 
-    if(gap_debug)
+    if(segmPtidx >= 0)
     {
-      printf("p_mov_execute: framesPerLine=%f, flt_posfactor=%f\n"
+      /* No acceleration characteristic specified for rotation, but movement uses accelertion characteristic
+       * (in this case force frametiming synchronized to movement)
+       */
+      cur_ptr->currRotation = GAP_BASE_MIX_VALUE(posFactorMovement, (gdouble)val_ptr->point[segmPtidx].rotation, (gdouble)val_ptr->point[segmPtidx +1].rotation);
+      if(gap_debug)
+      {
+        printf("ROTATE [%02d] %f    [%02d] %f       MixFctor: %f  MixValue: %f\n"
+          , (int)segmPtidx,      (float)val_ptr->point[currPtidx -1].rotation
+          , (int)segmPtidx+1,    (float)val_ptr->point[currPtidx].rotation
+          , (float)posFactorMovement
+          , (float)cur_ptr->currRotation
+          );
+      }
+    }
+    else
+    {
+      cur_ptr->currRotation = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].rotation, (gdouble)val_ptr->point[currPtidx].rotation);
+ 
+      if(gap_debug)
+      {
+        printf("p_mov_execute: framesPerLine=%f, flt_posfactor=%f\n"
            , (float)framesPerLine
            , (float)flt_posfactor
            );
-      printf("ROTATE [%02d] %f    [%02d] %f       MIX: %f\n"
+        printf("ROTATE [%02d] %f    [%02d] %f       MIX: %f\n"
           , (int)currPtidx-1,  (float)val_ptr->point[currPtidx -1].rotation
           , (int)currPtidx,    (float)val_ptr->point[currPtidx].rotation
           , (float)cur_ptr->currRotation);
+      }
     }
 
   }
@@ -1117,14 +1159,31 @@ p_calculate_settings_for_current_FrameTween(
   }
   else
   {
-    cur_ptr->currTTLX     = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].ttlx,     (gdouble)val_ptr->point[currPtidx].ttlx);
-    cur_ptr->currTTLY     = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].ttly,     (gdouble)val_ptr->point[currPtidx].ttly);
-    cur_ptr->currTTRX     = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].ttrx,     (gdouble)val_ptr->point[currPtidx].ttrx);
-    cur_ptr->currTTRY     = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].ttry,     (gdouble)val_ptr->point[currPtidx].ttry);
-    cur_ptr->currTBLX     = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].tblx,     (gdouble)val_ptr->point[currPtidx].tblx);
-    cur_ptr->currTBLY     = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].tbly,     (gdouble)val_ptr->point[currPtidx].tbly);
-    cur_ptr->currTBRX     = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].tbrx,     (gdouble)val_ptr->point[currPtidx].tbrx);
-    cur_ptr->currTBRY     = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].tbry,     (gdouble)val_ptr->point[currPtidx].tbry);
+    if(segmPtidx >= 0)
+    {
+      /* No acceleration characteristic specified for rotation, but movement uses accelertion characteristic
+       * (in this case force frametiming synchronized to movement)
+       */
+      cur_ptr->currTTLX     = GAP_BASE_MIX_VALUE(posFactorMovement, (gdouble)val_ptr->point[segmPtidx].ttlx,     (gdouble)val_ptr->point[segmPtidx +1].ttlx);
+      cur_ptr->currTTLY     = GAP_BASE_MIX_VALUE(posFactorMovement, (gdouble)val_ptr->point[segmPtidx].ttly,     (gdouble)val_ptr->point[segmPtidx +1].ttly);
+      cur_ptr->currTTRX     = GAP_BASE_MIX_VALUE(posFactorMovement, (gdouble)val_ptr->point[segmPtidx].ttrx,     (gdouble)val_ptr->point[segmPtidx +1].ttrx);
+      cur_ptr->currTTRY     = GAP_BASE_MIX_VALUE(posFactorMovement, (gdouble)val_ptr->point[segmPtidx].ttry,     (gdouble)val_ptr->point[segmPtidx +1].ttry);
+      cur_ptr->currTBLX     = GAP_BASE_MIX_VALUE(posFactorMovement, (gdouble)val_ptr->point[segmPtidx].tblx,     (gdouble)val_ptr->point[segmPtidx +1].tblx);
+      cur_ptr->currTBLY     = GAP_BASE_MIX_VALUE(posFactorMovement, (gdouble)val_ptr->point[segmPtidx].tbly,     (gdouble)val_ptr->point[segmPtidx +1].tbly);
+      cur_ptr->currTBRX     = GAP_BASE_MIX_VALUE(posFactorMovement, (gdouble)val_ptr->point[segmPtidx].tbrx,     (gdouble)val_ptr->point[segmPtidx +1].tbrx);
+      cur_ptr->currTBRY     = GAP_BASE_MIX_VALUE(posFactorMovement, (gdouble)val_ptr->point[segmPtidx].tbry,     (gdouble)val_ptr->point[segmPtidx +1].tbry);
+    }
+    else
+    {
+      cur_ptr->currTTLX     = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].ttlx,     (gdouble)val_ptr->point[currPtidx].ttlx);
+      cur_ptr->currTTLY     = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].ttly,     (gdouble)val_ptr->point[currPtidx].ttly);
+      cur_ptr->currTTRX     = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].ttrx,     (gdouble)val_ptr->point[currPtidx].ttrx);
+      cur_ptr->currTTRY     = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].ttry,     (gdouble)val_ptr->point[currPtidx].ttry);
+      cur_ptr->currTBLX     = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].tblx,     (gdouble)val_ptr->point[currPtidx].tblx);
+      cur_ptr->currTBLY     = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].tbly,     (gdouble)val_ptr->point[currPtidx].tbly);
+      cur_ptr->currTBRX     = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].tbrx,     (gdouble)val_ptr->point[currPtidx].tbrx);
+      cur_ptr->currTBRY     = GAP_BASE_MIX_VALUE(flt_posfactor, (gdouble)val_ptr->point[currPtidx -1].tbry,     (gdouble)val_ptr->point[currPtidx].tbry);
+    }
   }
 
   /* calculate Selection Feather Radius settings for the currently processed Frame (or tween) */