fix: Behaviour change in the Snowflake animation

fix: Guard against zero framesCount to avoid modulo by zero in SnowFlakeAnimation

fix: blicking illusion back

fix: added input validation

fix: fixed the interchanges animations

Author: samruddhi-Rahegaonkar

lib/badge_animation/ani_animation.dart

@@ -2,64 +2,76 @@ import 'package:badgemagic/badge_animation/animation_abstract.dart';
 
 class AniAnimation extends BadgeAnimation {
   @override
-  void processAnimation(int badgeHeight, int badgeWidth, int animationIndex,
-      List<List<bool>> processGrid, List<List<bool>> canvas) {
-    int newWidth = processGrid[0].length;
-    int newHeight = processGrid.length;
-    int verticalOffset = (badgeHeight - newHeight) ~/ 2;
-    int displayWidth = newWidth > badgeWidth ? badgeWidth : newWidth;
-    int horizontalOffset = (badgeWidth - displayWidth) ~/ 2;
-    var totalAnimationLength = badgeWidth;
-    int frame = animationIndex % totalAnimationLength;
-    var firstHalf = frame < badgeWidth ~/ 2;
-    var secondHalf = frame >= badgeWidth ~/ 2;
-
-    for (int i = 0; i < badgeHeight; i++) {
-      for (int j = 0; j < badgeWidth; j++) {
-        bool lineShow = false;
-        bool bitmapShowcenter = false;
-        bool bitmapShowOut = false;
-
-        int sourceRow = i - verticalOffset;
-        int sourceCol = j - horizontalOffset;
+  void processAnimation(
+    int badgeHeight,
+    int badgeWidth,
+    int animationIndex,
+    List<List<bool>> processGrid,
+    List<List<bool>> canvas,
+  ) {
+    if (processGrid.isEmpty ||
+        processGrid.any((row) => row.length != processGrid[0].length)) {
+      throw ArgumentError(
+        'processGrid must be a non-empty rectangular 2D list',
+      );
+    }
+    int newGridHeight = processGrid.length;
+    int newGridWidth = processGrid[0].length;
 
-        bool isWithinNewGrid = sourceRow >= 0 &&
-            sourceRow < newHeight &&
-            sourceCol >= 0 &&
-            sourceCol < displayWidth;
+    if (canvas.length < badgeHeight ||
+        canvas.any((row) => row.length < badgeWidth)) {
+      throw ArgumentError(
+        'canvas must have at least $badgeHeight rows and $badgeWidth columns',
+      );
+    }
+    int framesCount = (newGridWidth / badgeWidth).ceil();
+    framesCount = framesCount == 0 ? 1 : framesCount;
 
-        int leftCenterCol = badgeWidth ~/ 2 - 1;
-        int rightCenterCol = badgeWidth ~/ 2;
+    int currentFrame = (animationIndex ~/ badgeWidth) % framesCount;
 
-        int maxDistance = leftCenterCol;
+    int startCol = currentFrame * badgeWidth;
+    if (startCol + badgeWidth > newGridWidth) {
+      startCol = newGridWidth - badgeWidth;
+      if (startCol < 0) startCol = 0;
+    }
 
-        int currentAnimationIndex = animationIndex % (maxDistance + 1);
+    List<List<bool>> tempFrame = List.generate(
+      badgeHeight,
+      (_) => List.filled(badgeWidth, false),
+    );
 
-        int leftColPos = leftCenterCol - currentAnimationIndex;
-        int rightColPos = rightCenterCol + currentAnimationIndex;
+    for (int i = 0; i < badgeHeight; i++) {
+      for (int j = 0; j < badgeWidth; j++) {
+        int gridCol = startCol + j;
+        bool isValid = i < newGridHeight && gridCol < newGridWidth;
+        tempFrame[i][j] = isValid ? processGrid[i][gridCol] : false;
+      }
+    }
 
-        if (leftColPos < 0) leftColPos += badgeWidth;
-        if (rightColPos >= badgeWidth) rightColPos -= badgeWidth;
+    int shiftLeftBy =
+        _countLeadingEmptyCols(tempFrame, badgeHeight, badgeWidth);
 
-        if (j == leftColPos || j == rightColPos) {
-          lineShow = true;
-        } else {
-          lineShow = false;
-        }
+    for (int i = 0; i < badgeHeight; i++) {
+      for (int j = 0; j < badgeWidth; j++) {
+        int sourceCol = j + shiftLeftBy;
+        canvas[i][j] = sourceCol < badgeWidth ? tempFrame[i][sourceCol] : false;
+      }
+    }
+  }
 
-        if (firstHalf) {
-          if (isWithinNewGrid && j > leftColPos && j < rightColPos) {
-            bitmapShowcenter = processGrid[sourceRow][sourceCol];
-          }
-        }
-        if (secondHalf) {
-          if (isWithinNewGrid && (j < leftColPos || j > rightColPos)) {
-            bitmapShowOut = processGrid[sourceRow][sourceCol];
-          }
+  int _countLeadingEmptyCols(List<List<bool>> frame, int height, int width) {
+    for (int col = 0; col < width; col++) {
+      bool isColEmpty = true;
+      for (int row = 0; row < height; row++) {
+        if (frame[row][col]) {
+          isColEmpty = false;
+          break;
         }
-
-        canvas[i][j] = (lineShow || bitmapShowOut || bitmapShowcenter);
+      }
+      if (!isColEmpty) {
+        return col;
       }
     }
+    return 0;
   }
 }

lib/badge_animation/ani_snowflake.dart

@@ -4,26 +4,61 @@ class SnowFlakeAnimation extends BadgeAnimation {
   @override
   void processAnimation(int badgeHeight, int badgeWidth, int animationIndex,
       List<List<bool>> processGrid, List<List<bool>> canvas) {
-    int newGridHeight = processGrid.length;
-    int newGridWidth = processGrid[0].length;
+    int newWidth = processGrid[0].length;
+    int newHeight = processGrid.length;
+    int verticalOffset = (badgeHeight - newHeight) ~/ 2;
+    int displayWidth = newWidth > badgeWidth ? badgeWidth : newWidth;
+    int horizontalOffset = (badgeWidth - displayWidth) ~/ 2;
+    var totalAnimationLength = badgeWidth;
+    int frame = animationIndex % totalAnimationLength;
+    var firstHalf = frame < badgeWidth ~/ 2;
+    var secondHalf = frame >= badgeWidth ~/ 2;
+
     for (int i = 0; i < badgeHeight; i++) {
       for (int j = 0; j < badgeWidth; j++) {
-        // Calculate the total number of frames that fit the badge width
-        int framesCount = (newGridWidth / badgeWidth).ceil();
+        bool lineShow = false;
+        bool bitmapShowcenter = false;
+        bool bitmapShowOut = false;
+
+        int sourceRow = i - verticalOffset;
+        int sourceCol = j - horizontalOffset;
+
+        bool isWithinNewGrid = sourceRow >= 0 &&
+            sourceRow < newHeight &&
+            sourceCol >= 0 &&
+            sourceCol < displayWidth;
+
+        int leftCenterCol = badgeWidth ~/ 2 - 1;
+        int rightCenterCol = badgeWidth ~/ 2;
+
+        int maxDistance = leftCenterCol;
+
+        int currentAnimationIndex = animationIndex % (maxDistance + 1);
 
-        // Determine the current frame based on the animation value
-        int currentcountFrame = animationIndex ~/ badgeWidth % framesCount;
+        int leftColPos = leftCenterCol - currentAnimationIndex;
+        int rightColPos = rightCenterCol + currentAnimationIndex;
 
-        // Calculate the starting column for the current frame in newGrid
-        int startCol = currentcountFrame * badgeWidth;
+        if (leftColPos < 0) leftColPos += badgeWidth;
+        if (rightColPos >= badgeWidth) rightColPos -= badgeWidth;
 
-        bool isNewGridCell = i < newGridHeight && (startCol + j) < newGridWidth;
+        if (j == leftColPos || j == rightColPos) {
+          lineShow = true;
+        } else {
+          lineShow = false;
+        }
 
-        // Update the grid based on the current frame's data
-        bool snowflakeCondition =
-            (isNewGridCell && processGrid[i][startCol + j]);
+        if (firstHalf) {
+          if (isWithinNewGrid && j > leftColPos && j < rightColPos) {
+            bitmapShowcenter = processGrid[sourceRow][sourceCol];
+          }
+        }
+        if (secondHalf) {
+          if (isWithinNewGrid && (j < leftColPos || j > rightColPos)) {
+            bitmapShowOut = processGrid[sourceRow][sourceCol];
+          }
+        }
 
-        canvas[i][j] = snowflakeCondition;
+        canvas[i][j] = (lineShow || bitmapShowOut || bitmapShowcenter);
       }
     }
   }

lib/constants.dart

@@ -30,9 +30,10 @@ const String aniLeft = 'assets/animations/ic_anim_left.gif';
 const String aniDown = 'assets/animations/ic_anim_down.gif';
 const String aniFixed = 'assets/animations/ic_anim_fixed.gif';
 const String aniLaser = 'assets/animations/ic_anim_laser.gif';
-const String aniPicture = 'assets/animations/ic_anim_picture.gif';
+const String aniPicture = 'assets/animations/ic_anim_animation.gif';
 const String aniUp = 'assets/animations/ic_anim_up.gif';
 const String aniRight = 'assets/animations/ic_anim_right.gif';
+const String aniSnowflake = 'assets/animations/ic_anim_picture.gif';
 
 //path to all the effects assets used
 const String effFlash = 'assets/effects/ic_effect_flash.gif';

lib/providers/animation_badge_provider.dart

@@ -24,8 +24,8 @@ Map<int, BadgeAnimation?> animationMap = {
   2: UpAnimation(),
   3: DownAnimation(),
   4: FixedAnimation(),
-  5: SnowFlakeAnimation(),
-  6: PictureAnimation(),
+  5: PictureAnimation(),
+  6: SnowFlakeAnimation(),
   7: AniAnimation(),
   8: LaserAnimation(),
 };

lib/view/widgets/homescreentabs.dart

@@ -46,9 +46,7 @@ class _EffectsTabState extends State<EffectTab> {
 
 //Animation tab to show animation choices for the user
 class AnimationTab extends StatefulWidget {
-  const AnimationTab({
-    super.key,
-  });
+  const AnimationTab({super.key});
 
   @override
   State<AnimationTab> createState() => _AnimationTabState();
@@ -91,7 +89,7 @@ class _AnimationTabState extends State<AnimationTab> {
               index: 4,
             ),
             AniContainer(
-              animation: aniFixed,
+              animation: aniSnowflake,
               animationName: 'Snowflake',
               index: 5,
             ),