cssanimation: Compute progress correctly

We were computing the wrong progress, in particular when the iteration
count was non-integer.

Test included.

gtk/gtkcssanimation.c

@@ -68,37 +68,35 @@ static double
 gtk_css_animation_get_progress_from_iteration (GtkCssAnimation *animation,
                                                double           iteration)
 {
-  double d;
+  gboolean reverse;
+  double completed;
 
-  iteration = CLAMP (iteration, 0, animation->iteration_count);
+  iteration = CLAMP (iteration, 0.0, animation->iteration_count);
+  completed = floor (iteration);
 
   switch (animation->direction)
     {
     case GTK_CSS_DIRECTION_NORMAL:
-      if (iteration == animation->iteration_count)
-        return 1;
-      else
-        return iteration - floor (iteration);
+      reverse =   completed == iteration && iteration > 0;
+      break;
     case GTK_CSS_DIRECTION_REVERSE:
-      if (iteration == animation->iteration_count)
-        return 1;
-      else
-        return ceil (iteration) - iteration;
+      reverse = !(completed == iteration && iteration > 0);
+      break;
     case GTK_CSS_DIRECTION_ALTERNATE:
-      d = floor (iteration);
-      if (fmod (d, 2))
-        return 1 + d - iteration;
-      else
-        return iteration - d;
+      reverse =   fmod (iteration, 2) >= 1.0;
+      break;
     case GTK_CSS_DIRECTION_ALTERNATE_REVERSE:
-      d = floor (iteration);
-      if (fmod (d, 2))
-        return iteration - d;
-      else
-        return 1 + d - iteration;
+      reverse = !(fmod (iteration, 2) >= 1.0);
+      break;
     default:
-      g_return_val_if_reached (0);
+      g_return_val_if_reached (0.0);
     }
+
+  iteration -= completed;
+  if (reverse)
+    iteration = 1.0 - iteration;
+
+  return iteration;
 }
 
 static void

testsuite/reftests/Makefile.am

@@ -83,6 +83,9 @@ testdata = \
 	animation-direction.css \
 	animation-direction.ref.ui \
 	animation-direction.ui \
+	animation-fill-mode-iteration-count.css \
+	animation-fill-mode-iteration-count.ref.ui \
+	animation-fill-mode-iteration-count.ui \
 	background-area.css \
 	background-area.ref.ui \
 	background-area.ui \

testsuite/reftests/animation-fill-mode-iteration-count.css

@@ -0,0 +1,83 @@
+@keyframes cssrocks {
+  from { background-color: yellow; }
+  to   { background-color: red; }
+}
+
+box {
+  background-color: blue;
+  animation-fill-mode: both;
+  animation-duration: 100s;
+  padding: 1px;
+  background-clip: content-box;
+  animation-timing-function: linear;
+}
+
+.after {
+  animation-name: cssrocks;
+  animation-delay: -10000s;
+}
+
+.before {
+  animation-name: cssrocks;
+  animation-delay: 10000s;
+}
+
+.normal {
+  animation-direction: normal;
+}
+
+.reverse {
+  animation-direction: reverse;
+}
+
+.alternate {
+  animation-direction: alternate;
+}
+
+.alternate-reverse {
+  animation-direction: alternate-reverse;
+}
+
+.x0 {
+  animation-iteration-count: 0;
+}
+
+.x02 {
+  animation-iteration-count: 0.2;
+}
+
+.x1 {
+  animation-iteration-count: 1;
+}
+
+.x12 {
+  animation-iteration-count: 1.2;
+}
+
+.x2 {
+  animation-iteration-count: 2;
+}
+
+.x22 {
+  animation-iteration-count: 2.2;
+}
+
+.yellow {
+  animation: none;
+  background-color: yellow;
+}
+
+.red {
+  animation: none;
+  background-color: red;
+}
+
+.darkorange {
+  animation: none;
+  background-color: rgb(255,51,0);
+}
+
+.lightorange {
+  animation: none;
+  background-color: rgb(255,204,0);
+}