Improve the long press to zoom feature.

Close #287

lib/pages/reader/images.dart

@@ -455,6 +455,7 @@ class _ContinuousModeState extends State<_ContinuousMode>
   bool jumpToPrevChapter = false;
 
   bool isZoomedIn = false;
+  bool isLongPressing = false;
 
   @override
   void initState() {
@@ -668,8 +669,23 @@ class _ContinuousModeState extends State<_ContinuousMode>
         if (photoViewController.scale == 1 || fingers != 1) {
           return;
         }
+        Offset offset;
+        var sp = scrollController.position;
+        if (sp.pixels < sp.minScrollExtent
+            || sp.pixels > sp.maxScrollExtent) {
+          offset = Offset(value.dx, value.dy);
+        } else {
+          if (reader.mode == ReaderMode.continuousTopToBottom) {
+            offset = Offset(value.dx, 0);
+          } else {
+            offset = Offset(0, value.dy);
+          }
+        }
+        if (isLongPressing) {
+          offset += value;
+        }
         photoViewController.updateMultiple(
-          position: photoViewController.position + Offset(value.dx, value.dy),
+          position: photoViewController.position + offset,
         );
       },
       onPointerSignal: onPointerSignal,
@@ -807,12 +823,12 @@ class _ContinuousModeState extends State<_ContinuousMode>
       return;
     }
     double target = photoViewController.getInitialScale!.call()! * 1.75;
-    var size = MediaQuery.of(context).size;
     photoViewController.animateScale?.call(
       target,
-      Offset(size.width / 2 - location.dx, size.height / 2 - location.dy),
+      Offset(0, 0),
     );
     onScaleUpdate(target);
+    isLongPressing = true;
   }
 
   @override
@@ -822,6 +838,8 @@ class _ContinuousModeState extends State<_ContinuousMode>
     }
     double target = photoViewController.getInitialScale!.call()!;
     photoViewController.animateScale?.call(target);
+    onScaleUpdate(target);
+    isLongPressing = false;
   }
 
   @override

pubspec.lock

@@ -725,8 +725,8 @@ packages:
     dependency: "direct main"
     description:
       path: "."
-      ref: d71faf3c75e059d013b0ce9ddaf5ecc1680e2eb6
-      resolved-ref: d71faf3c75e059d013b0ce9ddaf5ecc1680e2eb6
+      ref: a1255d1b5945aad4b7323303ec2ecdf0c90ffc4c
+      resolved-ref: a1255d1b5945aad4b7323303ec2ecdf0c90ffc4c
       url: "https://github.com/wgh136/photo_view"
     source: git
     version: "0.14.0"

pubspec.yaml

@@ -29,7 +29,7 @@ dependencies:
   photo_view:
     git:
       url: https://github.com/wgh136/photo_view
-      ref: d71faf3c75e059d013b0ce9ddaf5ecc1680e2eb6
+      ref: a1255d1b5945aad4b7323303ec2ecdf0c90ffc4c
   mime: ^2.0.0
   share_plus: ^10.1.4
   scrollable_positioned_list: