[SVG] Fixed issues with the synchronisation of animation timers.

src/svg/animation.cpp

@@ -3,7 +3,50 @@
 // https://www.w3.org/TR/2001/REC-smil-animation-20010904
 
 //********************************************************************************************************************
-// Set common animation properties
+
+void anim_base::activate(extSVG *SVG)
+{ 
+   // Reset all the variables that control time management and the animation will start from scratch.
+   begin_offset = (double(PreciseTime()) / 1000000.0) - SVG->AnimEpoch;
+   repeat_index = 0;
+   start_time   = SVG->AnimEpoch + begin_offset;
+   end_time     = 0;
+
+   // Test: w3-animate-elem-21-t.svg
+
+   for (auto &other : start_on_begin) {
+      other->activate(SVG);
+      other->start_time = start_time; // Ensure that times match exactly
+   }
+}
+
+//********************************************************************************************************************
+
+void anim_base::stop(extSVG *SVG, double Time)
+{
+   if (!begin_series.empty()) {
+      // Check if there's a serialised begin offset following the one that's completed.
+      LONG i;
+      for (i=0; i < std::ssize(begin_series)-1; i++) {
+         if (begin_offset IS begin_series[i]) {
+            begin_offset = begin_series[i+1];
+            start_time = 0;
+            return;
+         }
+      }
+   }
+
+   end_time = Time;
+   seek = 1.0; // Necessary in case the seek range calculation has overflowed
+
+   // Start animations that are to be triggered from our ending.
+   for (auto &other : start_on_end) {
+      other->activate(SVG);
+      other->start_time = Time;
+   }
+}
+
+//********************************************************************************************************************
 
 static ERR parse_spline(APTR Path, LONG Index, LONG Command, double X, double Y, anim_base::SPLINE_POINTS &Meta)
 {
@@ -17,6 +60,9 @@ static ERR parse_spline(APTR Path, LONG Index, LONG Command, double X, double Y,
    return ERR::Okay;
 }
 
+//********************************************************************************************************************
+// Set common animation properties
+
 static ERR set_anim_property(extSVG *Self, anim_base &Anim, XMLTag &Tag, ULONG Hash, const std::string_view Value)
 {
    switch (Hash) {

src/svg/animation.h

@@ -120,7 +120,6 @@ class anim_base {
    double min_duration = 0;    // The minimum value of the active duration.  If zero, the active duration is not constrained.
    double max_duration = 0;    // The maximum value of the active duration.
    double duration   = 0;      // Measured in seconds, anything < 0 means infinite.
-   double first_time = 0;      // Time-stamp of the first iteration
    double start_time = 0;      // This is time-stamped once the animation has started (the first begin event is hit)
    double end_time   = 0;      // This is time-stamped once the animation has finished all of its cycles (including repetitions)
    double end  = 0;
@@ -145,40 +144,11 @@ class anim_base {
    double get_numeric_value(objVector &, FIELD);
    std::string get_string();
    FRGB get_colour_value(objVector &, FIELD);
-   bool started(double);
+   bool started(extSVG *, double);
    bool next_frame(double);
    void set_orig_value();
-
-   void activate(void) { 
-      // Reset all the variables that control time management and the animation will start from scratch.
-      begin_offset = 0;
-      repeat_index = 0;
-      start_time   = 0;
-      end_time     = 0;
-   }
-
-   void stop(double Time) {
-      if (!begin_series.empty()) {
-         // Check if there's a serialised begin offset following the one that's completed.
-         LONG i;
-         for (i=0; i < std::ssize(begin_series)-1; i++) {
-            if (begin_offset IS begin_series[i]) {
-               begin_offset = begin_series[i+1];
-               start_time = 0;
-               return;
-            }
-         }
-      }
-
-      end_time = Time;
-      seek = 1.0; // Necessary in case the seek range calculation has overflowed
-
-      // Start animations that are to be triggered from our ending.
-      for (auto &other : start_on_end) {
-         other->activate();
-         other->start_time = Time;
-      }
-   }
+   void activate(extSVG *);
+   void stop(extSVG *, double);
 
    virtual void perform(class extSVG &) = 0;
 

src/svg/animation_timing.cpp

@@ -1,27 +1,26 @@
 
 //********************************************************************************************************************
-// Return true if the animation has started
+// Return true if the animation has started.  For absolute consistency, animations start 'at the time they should have 
+// started', which we can strictly calculate from begin and duration timing values.
 
-bool anim_base::started(double CurrentTime)
+bool anim_base::started(extSVG *SVG, double CurrentTime)
 {
-   if (not first_time) first_time = CurrentTime;
-
+   if (end_time) return false;
    if (start_time) return true;
    if (repeat_index > 0) return true;
 
-   if (begin_offset) {
-      // Check if one of the animation's begin triggers has been tripped.
-      const double elapsed = CurrentTime - start_time;
-      if (elapsed < begin_offset) return false;
-   }
+   // Check if the begin trigger has been tripped.  If begin_offset is 0 then we start immediately.
+
+   if (CurrentTime < SVG->AnimEpoch + begin_offset) return false;
+   start_time = SVG->AnimEpoch + begin_offset;
+
+   // Start/Reset linked animations that are to start when we do
 
-   // Start/Reset linked animations
    for (auto &other : start_on_begin) {
-      other->activate();
-      other->start_time = CurrentTime;
+      other->activate(SVG);
+      other->start_time = start_time; // Ensure that times match exactly
    }
 
-   start_time = CurrentTime;
    return true;
 }
 
@@ -71,17 +70,19 @@ static ERR animation_timer(extSVG *SVG, LARGE TimeElapsed, LARGE CurrentTime)
       matrix.second.transforms.clear();
    }
 
-   for (auto &record : SVG->Animations) {
-      std::visit([SVG](auto &&anim) {
-         double current_time = double(PreciseTime()) / 1000000.0;
+   if (!SVG->AnimEpoch) {
+      SVG->AnimEpoch = double(CurrentTime) / 1000000.0;
+   }
 
-         if (not anim.started(current_time)) return;
+   double current_time = double(CurrentTime) / 1000000.0;
 
-         if (anim.next_frame(current_time)) {
-            anim.perform(*SVG);
-            anim.stop(current_time);
-         }
-         else anim.perform(*SVG);
+   for (auto &record : SVG->Animations) {
+      std::visit([ SVG, current_time ](auto &&anim) {
+         if (not anim.started(SVG, current_time)) return;
+
+         bool stop = anim.next_frame(current_time);
+         anim.perform(*SVG);
+         if (stop) anim.stop(SVG, current_time);
       }, record);
    }
 

src/svg/parser.cpp

@@ -2371,8 +2371,8 @@ static ERR link_event(objVector *Vector, const InputEvent *Events, svgLink *Link
             // The link activates a document node, like an animation.
             if (find_href_tag(Self, Link->ref)) {
                for (auto &record : Self->Animations) {
-                  std::visit([ Link ](auto &&anim) {
-                     if (anim.id IS Link->ref.substr(1)) anim.activate();
+                  std::visit([ Link, Self ](auto &&anim) {
+                     if (anim.id IS Link->ref.substr(1)) anim.activate(Self);
                   }, record);
                }
             }

src/svg/svg.cpp

@@ -29,7 +29,6 @@ Relevant SVG reference manuals:
 #include <parasol/modules/display.h>
 #include <parasol/strings.hpp>
 #include "svg_def.c"
-#include "animation.h"
 #include <katana.h>
 #include <math.h>
 
@@ -71,6 +70,10 @@ struct svgAnimState {
 
 #include <parasol/modules/svg.h>
 
+class extSVG;
+
+#include "animation.h"
+
 //********************************************************************************************************************
 
 class extSVG : public objSVG {
@@ -79,6 +82,7 @@ class extSVG : public objSVG {
    std::unordered_map<std::string, XMLTag> IDs;
    std::unordered_map<std::string, objFilterEffect *> Effects; // All effects, registered by their SVG identifier.
    DOUBLE SVGVersion;
+   DOUBLE AnimEpoch;  // Epoch time for the animations.
    objXML *XML;
    objVectorScene *Scene;
    STRING Folder;